Post arrest cooling with Professor Tobias Cronberg

In episode #44, Paul talks with Professor Tobias Cronberg from Lund University in Sweden who is a consultant in Neurology and has a deep interest in brain injury after a cardiac arrest.

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Professor Cronberg has been working with cooling technologies for over 20 years and is a senior member of the team behind the world wide Targeted Temperature Management 2 (TTM2) trial. The trial is a continuation of the original TTM trial and with almost 2000 patients enrolled, it will supercede it as the largest trial on temperature management as a post-cardiac arrest intervention.

Professor Cronberg talks about the history of cooling and what the study hopes to achieve and where it currently is. A fascinating overview of this intervention that many cardiac arrest patients will have received as part of their treatment.

Available to listen on the link below or Spotify, Apple , Google, YouTube and your favourite podcast player.

#044 Post arrest cooling with Professor Tobias Cronberg

Paul Swindell: [00:00:00] Hello, and welcome to another episode of the life after cardiac arrest podcast with me, your host, Paul Swindell.

Today I'm joined by professor and consultant in neurology at Lund University, Tobias Cronberg, who has a special interest in cardiac induced brain injuries.

Welcome to the show, Tobias, and it's great to talk to you.

Professor Tobias Cronberg: [00:00:32] Thank you, Paul. Very nice to be here.

Paul Swindell: [00:00:35] And just to say that you're in Sweden at the moment, aren't you? How's life there?

Professor Tobias Cronberg: [00:00:41] Well, the sun is blue, and the sky is up, but of course we are suffering from the pandemic as everybody else. So, it's an extraordinary situation,but it hasn't hit the Southern part of Sweden very much. Yeah. So, we are still very, and much business as usual.

Paul Swindell: [00:01:01] Yeah. So, you're just saying before we started recording your life seems not quite normal, but it's not as drastically hit as it is in the UK.

Professor Tobias Cronberg: [00:01:11] That's right.

Paul Swindell: [00:01:11] And I just wonder if you could briefly introduce yourself and tell me a little bit about your interest in neurology and in particular, cardiac arrest induced brain injury. How did you come into that?

Professor Tobias Cronberg: [00:01:24] Well, I tried to make a long story short, it started actually during my, my early years in Lund from, the middle of the 1990s when I was working in a laboratory doing my PhD in experimental brain research. And we worked a lot with stroke models and with a models of cardiac arrest, and the basic mechanisms of cell injury after cardiac arrest and stroke, which is rather similar diseases in the sense that the blood it gets a loss of blood flow for a period, and then we have a reperfusion of the brain and then we have a damage, and the mechanisms are quite similar, actually.

So, it started then and when I, I had done my dissertation, I was working full time clinics and I got interested in the cardiac arrest population.

I started a collaboration with Hans Freberg, who was intensive care physician at that time, and he was a professor there and now, we started, with hypothermia treatment early in 2003 when, when the two important studies were published, showing that cooling patients after cardiac arrest had a protective effect.

And we were strong believers of hypothermia and we wanted to, to study outcome in those patients long-term outcome, and also to look at different methods to try to diagnose brain injury and to try to decide the prognosis for the patients, in the ICU, when the patients were still unconscious, and we started working with different methods, mainly biomarkers in the blood, clinical neurological examination and, electrophysiology, where we could work would continous EEG, for example, as a method to look at the brain activity after cardiac arrest, we started publishing our results about this and, gradually, we got more and more international collaboration. Nicholas Nielson, who is intensive care physician in Helsingborg became part of the team and he was very important for us building up a big network of international sites in the hyperthermia register, which was the foundation for the first TTM trial. After that, which we did in 2010 until 2013, studying the effects of, temperature management in patients.

Paul Swindell: [00:04:04] When was it sort of first realized that hypothermia could be sort of therapeutic and be a useful tool in the medical toolkit as it were. I mean, I guess people have known for quite a long time. I mean, when I used to play sports as a youngster and I, if I got a strain on my leg, you get an ice pack put on your, on your knee or the muscle or whatever, and that would help alleviate any inflammation there.

And you get back to playing the sport quicker, but when was it sort of the light bulb moment, if you like that, Hey, we can use this in a bigger way for something like the brain?

Professor Tobias Cronberg: [00:04:43] Well, that has been known for the, for the brain. It has been known for many years, that it's possible to cool a patient, for example, to, be able to do thoracic surgery in the main aortic vessel, to be able to stop the blood flow to the brain you have to cool the patient very much all the way down to two 19 degrees.

At that level it's, it's almost like putting the brain into the refrigerator and all biological processes slow down, very much. Very similar to what happens in your knee, actually. You slow down all the biological processes, all the damaging, degrading processes are being slowed down and, for a patient operated and, thoracic surgery, you could, you could do, keep operating for approximately one hour at the temperature of 19 degrees.

And during that period, you have basically no activity in the brain. If you, if you look at the cortical activity with an EEG, it's completely silent and then you could rewarm the patient and they will be functioning, more or less normally after that, maybe some, some minor problems, but most patients could return to normal life.

And, comparing that with a cardiac arrest, it would be completely impossible to have a human who, who is without any circulation and normal body temperature for one hour. After that time, you're certainly dead. There's no chance to, revive that person, if the body temperature is normal. So, it has been very obvious and it has been known, for a long, long time.

But, there were, early research, on this, I'm not sure about the exact years, but there were pioneering research done in, in the U S in Pittsburgh at the Safar Institute, and then it was more or less abandoned until the 1970s, when this, when there was some major new focus on hypothermia in experimental settings and a lot of experimental done.

In, in animals, with mild hypothermia, not down to 19 degrees, but only two 33 to 32 33, or maybe 34 degrees, and it was shown that this was effective in different models, experimental models of cardiac arrest and stroke. So, when I got to the lab laboratory and started my research in 1995, it was very well known.

I mean, that laboratory here in Lund, a lot of the pioneering work had also been done on hypothermia in experimental animals. And for me it was very clear. Also, I worked with the whole animal models, and I also worked with cell cultures and when we did this scheme in the cell cultures, and we just lowered the temperature.

The cells didn't get damaged. So it was, it was sort of a concept that was, very much for all the researchers. Very, very clear concept that hypothermia works. And then we had these two trials in 2013 showing in a clinical setting that it worked also in patients. And that led to a major implementation over the whole world, of hypothermia treatment.

But unfortunately, those two trials were not, very good trials, they were small trials. One Australia trial from, from, Bernard and his collaborators, which we'd only less than 100 patient, I think it was 77 patients. And then as European trial, which was stopped early because they didn't have enough funding and they had, I think, 200 and, and 73 patients, which is not very much in these suction circumstances. So, so for us later, it became evident that we need more information in patients, to know whether it is effective or not. We need to do large clinical trials to study, temperature management, hypothermia treatment in patients.

Paul Swindell: [00:09:09] Could I just take you back to one of the things you were saying when you were doing your study and your PhD, you were saying you were looking at animals.

Do animals though, that they have, a lot of them have a natural ability to hibernate anyway, don't they? So how does that come into the picture and do humans have anything like that?

Professor Tobias Cronberg: [00:09:26] No, humans don't have that ability to hibernate, and, and the animals used, in the experiments for hypothermia, don't have that ability. So a rat, which is the most common laboratory experimental animal, it can�t hibernate, and pigs has also been used, but not very much.

But the animals, rats and mice, they don't, they don't hibernate.

Paul Swindell: [00:09:51] And, and also, as I mentioned to you just before we came on, on the air,

There was a, famous case at the end of the nineties, which featured a, a Swedish doctor Ana Bagenholm, who I believe, experienced a case of hypothermia for a couple of hours, I believe it was, cause she was skiing in Norway and, fell into a river.

Do you know much about that?

Professor Tobias Cronberg: [00:10:14] Yes, I remember. I know I've seen a program on television about her.

Professor Tobias Cronberg: [00:10:19] This, this is a very, very interesting case and it's sort of a proof of principle case. With Ana Bagenholm because what happened was that she was skiing, and down a slope and she went out on the ice at the end of the slope and was sliding out on quite thin ice, actually, and got trapped with her head into the water, and was, and drowned, on the ice with her head being put into the water, and then she had a cardiac arrest, if I've understood it correctly. So, so this is not an unusual situation with cardiac arrest, in the circumstance of drowning, of course.

But what was very special with Anna Bagenholm and ideal for her was that her body, and particularly her head was cooled before she had the cardiac arrest.

And we also know that from experimental settings that the most protective effect of cooling is if you could the brain of the animal or of the human in this case before the heart stops. Because then all the damaging processes will be much slower.And for her, they couldn't rescue her because of the thin ice.

So, her friends couldn't, couldn't rescue her, and they eventually got a helicopter and somehow they rescued her and she was transported and put on, on, artificial circulation in the helicopter. And slowly rewarmed and very, very slowly, her heart started beating again.

And it was so remarkable because she had at least, I'm not sure how long, but at least one hour of circulatory arrest. And that's very similar to these thoracic surgery patients. And, and that explains why her brain didn't get damaged or more damaged, by the cardiac arrest.

Paul Swindell: [00:12:19] I understand that she was like, over two hours in arrest and her body temperature went down to 13.7 degrees, which apparently was the lowest ever recorded. And it's pretty amazing. But I don't know if you saw the news last year, towards the end of last year, there was a report of a British lady who had a similar case who suffered hypothermia in the mountains of Spain.

And she arrested for, six hours, I think it was. But they managed to bring her back, and they always say, "they made a full recovery", but of course, we're never really know whether she has made a full recovery.

Professor Tobias Cronberg: [00:12:59] No, but it's, I think it's a very, very strong and important message here. And that is if you are cooled before you have the arrest, then you have a very favorable situation.

And that's also very well known to doctors that you cannot decide that the person is dead.

Before the person has been rewarmed, because there's always the chance that the cooling or the chill has had a protective effect and not the patient will survive.

Paul Swindell: [00:13:31] There's a saying isn't there?

You're not dead until you're warm and dead.

Professor Tobias Cronberg: [00:13:35] Exactly, exactly. And it's also interesting, we did a meta-analysis of the experimental data on hypothermia after cardiac arrest, all the animal research we put together. And looked at the evidence in favour of hypothermia. And it showed that the strongest evidence is for, prearrest cooling or intra arrest cooling of the small animals.

And we have actually. All too few data on large animals with post cardiac arrest cooling, which is what we do with the humans. When, when we are cooling after arrival to hospital.

Paul Swindell: [00:14:17] Obviously we don't know for My cohort, for people like myself, we don't know. The majority of them are going to go into an arrest. So, we can't really put us into a cooling situation firsthand unless you, you're there by chance. But do you think it would, I don't know if the technologies are there, but, in first aid situations with paramedics and things like that, would they have cooling apparatus with them?

Would that be a practical scenario for them to adopt in the future if they know that, you know, as well as getting a defib and doing CPR that we get a cooling pack, whatever that looks like? I don't know. But is that something that you could see perhaps coming in the future?

Professor Tobias Cronberg: [00:15:02] Well, we can certainly, we can't exclude it, but there have been studies trying that approach because it's so obvious for, from, from experimental studies that it would be a great advantage. So there has been a big study looking at the prehospital cooling with intravenous cold fluids, but that did not show any benefit, some signal towards harm, because cold fluids will give you a load on the heart.

So, there's a risk of, cardiogenic shock. The patients will go to shock because of the fluids. So that was not a good approach. And then there was a, study, which was, centered from Stockholm in Sweden, with, with nasal cooling, where they try to call through the, nose. Most of the patients with a special technique, uh, with preparation and, that didn't show any effect. however, a small signal to boards possible effect, at least the context included that it may have some effect, but it was not a significant can't affect anyway. And I, it may tell us that it's the main, main thing if a person has a cardiac arrest, is to get the heart restarted.

And if we start doing other things, maybe we won't be as successful restarting the heart.

Paul Swindell: [00:16:30] That�s true, that�s true.

Professor Tobias Cronberg: [00:16:31] So there are, there are problems with any approach. And if we compare a human to a mice or a rat, well, it's much more difficult to cool a human. You can't just put a few ice packs. It won't too much difference to lower the body temperature of such a big animal, lesser human.

It takes a lot of time and a lot of effort and a lot of cooling power.

Paul Swindell: [00:16:59] Okay.

So, can we go back to sort of the turn of the century? It sounds a funny sort of phrase. So back, back at the early two thousands, you said, you noticed that, it was obvious that cooling worked for you. So, you started doing that in your hospital then presumably.

Professor Tobias Cronberg: [00:17:14] Yeah, that's true.

Paul Swindell: [00:17:19] What did you start seeing?

Professor Tobias Cronberg: [00:17:21] Well, it was a great enthusiasm. And the big thing I, I think at that time was a shift in favour of the cardiac arrest patients. They became a very interesting patient group in the ICU because suddenly the cardiac arrest went from being a condition where we could do nothing, to become a condition where we could do a lot because we could do cooling with the cooling machines, fancy new apparatus.

I think that was very good for the cardiac arrest patients. And, and, it was shown in, in many registers that, survival, went up after the introduction of, cooling. I think that's important too, to remember as well that, probably many things improved for the cardiac arrest patients because before that time, it wasn't obvious that a cardiac arrest patient would go to the ICU.

They may go even go to a regular ward without any artificial ventilation, and now because they needed to be sedated and not officially ventilated during the cooling process, they probably got very good intensive care, in the package, so to say.

Also, we started with a more advanced methods to diagnose brain injury, to, to be able to do a more advanced prognostication to decide which patients would have a good outcome eventually in which patients had such severe brain injury that it wouldn't be beneficial to continue treatment.

And that was also probably very good for the patient. It made it the care more safe and the decisions around life sustaining therapy more safe, I think.

Paul Swindell: [00:19:10] What would these patients, in hospital cardiac arrest victims or were they out of hospital or were they both?

Professor Tobias Cronberg: [00:19:17] Both. Both. we didn't make any difference whether it was in the hospital or out of hospital. for in hospital cardiac arrest patients, they often have more significant comorbidities because they're in the hospital for a reason. And that may be a reason not to. To give full intensive care, for example, for a patient with advanced, cancer of some kind, may not be of benefit for the patient to have that care path.

But those decisions have to come later. When a patient have a cardiac arrest, it's a full action and full intensive care from the beginning. And then you can, you can sometimes have to back off.

Paul Swindell: [00:20:02] What was the scenario in Sweden at that time?

Cause there's sort of general consensus from the UK is that the Scandinavian countries are ahead of us in the curve. As it were, regarding having AEDs in the community and encouraging people to do CPR and having the equipment and the processes in the hospital once you get there.

Professor Tobias Cronberg: [00:20:23] I wouldn't say, I think, I think at this that the curve is lifting around that time around 2000, around 2000 or even, even later. So, I think you could see the real surge in, in survival rates in Sweden comes after the introduction of hypothermia. But at the same period, there is a lot of training in CPR in the community, and there is a public movement of, lay people, CPR.

it's around that time and, and we have seen very clearly in the Swedish cardiac arrest register, how survival and the use of bystander CPR are parallel curves.

Paul Swindell: [00:21:21] So you've been doing, therapeutic treatments for a while then, and then, had that been spreading around to other hospitals and to other parts of the world? And then what, what was the motivation for coming up with the TTM, trial? The initial one.

Professor Tobias Cronberg: [00:21:37] Yeah. So, so the, the introduction or the implementation of therapeutic hypothermia was a global movement. And, a lot of believers, who had been doing experimental research perhaps, or were just doing clinical research. We're implementing these treatment all over the world in a parallel process.

So, it wasn't something that spread from Lund to a other places, certainly not, but it spread from many places. And there is still a very much of a movement and a great interest in hypothermia all over the world. But the TTM. So, we were also part of the believers, because we had so much evidence from the experimental research.

As we, as we thought, at least, and then Nicholas Nielsen, he did a meta-analysis, of the clinical evidence for therapeutic hypothermia, together with the clinical trials unit in Copenhagen. Copenhagen is very close to Lund, it's just over the sound here. And we have a lot of collaborations. And Nicholas works with very good statisticians and clinical trialists in Copenhagen, and they could show that the evidence, for therapeutic hypothermia in humans were insufficient, and that, it could be a benefit or it could be no benefit, or it could even be harm.

We couldn't tell from the studies that were performed. And I think that changed something fundamentally for us, in the group. And we decided to, do a large international trial and we started to, form the group around the TTM. The first TTM trial when we were discussing the TTM trial, we first thought that we would just redo the previous trial.

Test whether coding is better than no coding, but since the guidelines at that time, they recommended cooling for these patients. We many people thought it would be unethical to randomize patients to know cooling. Since, since a lot of people all over the world thought that it was shown. That cooling was working and the guidelines stated that it was shown or there was evidence, strong evidence in favour of hypothermia.

So that therefore, the first TTM tried was a bit of a compromise where we decided to, just to compare two different targeted temperature, 33 degrees and 36 degrees. Temperature where 36 was quite similar to no treatment or as far as we could go in that direction. And then we did this very large trial with 950 patients, so it's much more than the other trials together.

And we saw absolutely no difference between 33 and 36 degrees. And I think that was very, very surprising for many people in the field because from the experimental research, we should certainly have a very big difference between 33 and 36 but we didn't, and we looked at a lot of different outcomes for the patients.

Of course, survivor level, of cause neurological function at six months after the cardiac arrest, and we looked at cognitive functioning detail, we looked at biomarkers of brain injury in the blood. And we saw no differences between the groups. So, so that led to a change in the recommendations from the international organizations that, 33 or 36 degrees is just, just as good.

Paul Swindell: [00:25:22] You still felt that cooling was better than no cooling?

Professor Tobias Cronberg: [00:25:27] Well, I felt that we needed to take it all the way. I didn't feel that, I personally, I didn't feel very strongly that cooling was better than no cooling. I felt that the may be in effect still, but I'm, I'm not sure. And I'm still not sure because we are still doing the TTM 2 trial. I think it's a, I think it's equally possible that there is no effect of cooling.

That there is, is an effect.

Paul Swindell: [00:26:01] Oh, interesting. So what, what is it the people who, say that cooling works, what is it they think is actually happening with the, with the brain and with the body when you actually call someone? What, what processes are we changing?

Professor Tobias Cronberg: [00:26:14] Well, we are certainly doing a lot of things in the brain when we see, when we cool a patient that's no doubt about it. I mean, we. We slow down all the biological processes. It's just the same as when you take your milk package of milk and put it in the refrigerator. You protect the milk from, from breakdown, and you protect the brain from, from breakdown and damage due to a lot of different processes that has been shown in the experimental animals.

And we have proof of principle. Well, w with this, physician who went into the cold water, as you, as you referred to, and, we have from patients being cooled for thoracic surgery, we know that it's very a very potent, treatment, but we don't know if. When we do it in a delayed fashion as we do with the patients today, if that is effective.

And that's my major doubt. I'm doubt that, that we do it early enough, I think we would need to be much faster, and have some kind of method to very effectively, without any side effect cool the patient, on the scene.

I doubt that it is effective to do it, as, we do it.

Paul Swindell: [00:27:35] So you think that the damage is already done as it were?

Professor Tobias Cronberg: [00:27:39] Exactly, exactly

That's what I'm afraid of. At least that we are not, we are not, protecting the brain early enough

Paul Swindell: [00:27:49] And I guess that comes back to what we briefly talked about earlier, getting the paramedics, equipment to be able to do that. But then, as you said, that adds another, another job to be done, as well as trying to restart the heart, which is obviously the most important thing to do.

So, its a tricky one isn�t it really?

Professor Tobias Cronberg: [00:28:08] Yeah.

So, this would, with hypothermia treatment or targeted temperature meat treatment is something that we will be living with for many years to come, I'm sure. And we will have to work with it and try to refine it to get as much as possible out of the treatment. But I'm not sure that what we are doing today, is effective

Paul Swindell: [00:28:31] are most hospitals these days might do most cardiac arrest patients say in, developed nations, will they experience the calling that, you�ve been talking about?

Professor Tobias Cronberg: [00:28:41] Yes, I would say so. Certainly, in the Scandinavian countries, but it varies over Europe and it varies globally as well. I think it's a lot more variations in the in the U S but there's big variations within Europe as well.

Paul Swindell: [00:28:59] you're currently undertaking a TTM 2, so how does that differ from your original trial.

Professor Tobias Cronberg: [00:29:05] Yeah.

So, in the TTM two we are taking the question one step further. We are now trying to evaluate whether hypothermia to 33 degrees as in the TTM one trial compared to no cooling unless the patient gets fever.

So, we're in the control group. We will only treat those patients who develop fever, which is about a temperature above 37.8.

So, if a patient gets 37.8, we will take them down to 37.5 and, and keep them there with the cooling device, for the first, 24 hours.

Paul Swindell: [00:29:45] Do people naturally go into a fever after they've had a cardiac arrest?

Professor Tobias Cronberg: [00:29:50] Yes, many people develop a fever of the cardiac arrest, and that's part of probably part of the global, systemic organ damage with a global, inflammatory process in the body.

So, it's common that you develop fever and the more fever you develop, the worst is your prognosis. It's related to worst prognosis to have fever.

So that's a, the reason why there is a recommendation to treat fever, and it's the same in stroke. Actually, there's a recommendation to treat fever because there is an association with the worst outcome.

However, whether we are actually doing something good by cooling, we don't know, because it may be that it's just a marker of a more severe damage.

So, so we don't, we don't even know that for sure, but we thought that in the TTM 2 trial, we will take it just one step further and decide whether cooling for patients who do not develop fever, whether that is any good or not.

Paul Swindell: [00:30:54] Yeah, that's interesting. And so how far along are you in this trial?

Professor Tobias Cronberg: [00:31:00] The TTM two trial has included 1900 patients just as planned. It's the largest cardiac arrest trial ever performed, and we are now performing the follow-up, the six months follow up and trying to complete it. It has been, a problem with the covert pandemic of course, because we can't see the patients face to face.

We have to do follow ups, with telephone instead. But we are, are pressing on with our, schedule and we believe we will be able to publish the results in the end of this year or the beginning or next year.

Paul Swindell: [00:31:39] Okay that�s great.

So, what are the outcomes you're looking for? Is, is it just, not that they survive, but they survive with particular or better neurological outcome, is it?

Professor Tobias Cronberg: [00:31:46] Yeah, certainly we are looking at different things, but the primary outcome is survival. And that's because it's a very robust thought. I'll come off the cardiac arrest. You can't really, you can't, you can never manipulate survival, either you survive or not, and if you can't get any, any kind of influence from your own perceptions into that, but the secondary outcomes is quality of life.

Of the survivors and also their neurological function in more detail. And then we have a lot of exploratory outcomes where we are looking at their cognitive function, their physical activity, and how they are, are participating in, in the community, et cetera, et cetera.

Paul Swindell: [00:32:35] Okay. So, you say you'd be publishing next year, and then do you get a feel for whether this is, been a, a benefit doing TTM two as opposed to TTM one?

Professor Tobias Cronberg: [00:32:47] Yes, I think. I mean, it will have a fundamental impact. If we can show that hypothermia is, or cooling to 33 degrees is effective, then I think a lot more centers will start using this treatment all over the world. That will be a very, very strong signal for, for working, to refine, hyperthermia treatment as well.

But if we don't show any effect, that will be to the other side. People will probably stop doing hyperthermia for patients who don't have fever, that will also have a fundamental effect. So, I think the world is sort of rather much, the or the cardiac arrest community's rather much waiting for the results of the TTM to try and.

Paul Swindell: [00:33:33] Yes. Yes. I can understand that. A lot A lot of weight on your shoulders.

Professor Tobias Cronberg: [00:33:38] Yes, yes, it is.

Paul Swindell: [00:33:41] I'd just like to finish off this, conversation about, therapeutic management is, it's sort of throw you a left field type question.

Do you think we can use this sort of technology, to put humans into a sort of pseudo hibernation so that maybe it can be used in other fields like space travel or preserving people so there life span is longer?

Professor Tobias Cronberg: [00:34:04] No, I don't think so, no.

Paul Swindell: [00:34:08] No?

Professor Tobias Cronberg: [00:34:09] I don't know, but to slow down, your metab, metabolism may be good for you. It may make you live longer. There are some, I mean, some, some data that the starving is slow grade starving will make you live somewhat longer. Cooling down the body and then re awake patient or a person, I don't know. It's signed. It's sort of a scientific future that I don't, I don't want to be part of, at least I think we are so many people on the world anyhow so we should leave space for those coming after us, but that's more ethical issue I guess.

Of course, I mean, hypothetically cooling down somebody and putting them in a spaceship and having some, some, machine to thaw them when they arrive. It's, yeah, theoretically you may be right. Maybe, maybe possible for long travel is extending over a hundred years or something like that.

Paul Swindell: [00:35:13] Or maybe, even though I don't know if for shorter periods, like getting to Mars or coming back from, there can be a couple of years, I believe, if, if you, leave at the wrong time in the orbit,

Professor Tobias Cronberg: [00:35:25] Yes, yes. I think you could, I mean, probably you could extrapolate from, from the, from your package of milk again, that putting the milk in a refrigerator will buy you some time, but not a lot of time. A few days, for, it gets sour, but putting it in the freezer would buy you a lot more time, I mean, it's still a limited time and putting a human in a freezer. I don't think we will be able to thaw them afterwards because there is so much cell damage.

Paul Swindell: [00:35:59] It�s not all good news being in the freezer.

Professor Tobias Cronberg: [00:36:02] No, I don't think so.

Paul Swindell: [00:36:08] Okay. Tobias, thank you very much, has been a really interesting conversation about this subject, which is, you know, it's, it's played a part in my recovery and I'm sure that played a part in many other people's recovery as well. And I'm, really glad that you guys are looking at this subject and that you did back in.

Back at the end of the nineties, last century. And it's going to be really interesting to see the results of the TTM 2 and where that takes us.

So, good luck with it all and I hope we speak again soon

Professor Tobias Cronberg: [00:36:38] Thank you, Paul. I just want to say a last word and that is that even if we would, show that therapeutic hypothermia is ineffective in the way we use it today, it wouldn't mean that the treatment has not been beneficial for the patients. I think it has been tremendously beneficial. Because a lot of things came with the package, had a lot more focused on the cardiac arrest patient in the ICU.

A lot more, more, artificial ventilation of focus on that, sedation regimes, EEG, surveillance, et cetera. And we will talk more about that

Paul Swindell: [00:37:15] Yes, it's very valid points and yeah, thanks for raising them.

Alright, Thanks a lot. Bye. Bye.

Professor Tobias Cronberg: [00:37:18] Bye

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Presented and edited by Paul Swindell.

Recorded April 2020. 

Tracking cardiac arrest outcomes with Professor Terry Brown

In episode #43, Paul talks with assistant Professor Terry Brown on the out of hospital outcomes registry which is a project conducted by The University of Warwick medical school.

Terry takes us through what the registry is and how it fits in internationally (CARES, EURECA, PAROS), what information they collect and some of the projects that they have been looking at.

From the data they have collated from the 11 ambulance services in England they have produced a number of outputs and have calculated the stats that are commonly quoted such as the survival rate of 8-10%.

Terry also talks about how the data from the registry is helping to shape the future by guiding them on what areas of the country need better coverage of defibrillators and CPR training and how drones may deliver AED’s to needy areas.

Available to listen on the link below or Spotify, Apple , Google, YouTube and your favourite podcast player.

#043 Tracking cardiac arrest outcomes with Professor Terry Brown

Paul Swindell: [00:00:11] Hello and welcome to another episode of the Life After Cardiac Arrest podcast with me, your host, Paul Swindell.

Today I'm speaking with Terry Brown, who is an assistant professor at the Warwick University clinical trials unit and has a deep interest in cardiac arrest survival and their outcomes and is currently working on the out of hospital cardiac arrest outcomes registry.

So welcome Terry on this beautiful sunny day.

Professor Terry Brown: [00:00:38] Good morning, Paul. It is a

Paul Swindell: [00:00:39] I hope it, I hope it's sunny where you are. It's sunny where I am.

Professor Terry Brown: [00:00:43] It is sunny now after early morning fog when I got up early. So yeah, it is bright sunshine now.

Paul Swindell: [00:00:49] And you work at Warwick university, clinical trials unit, and I see quite often a lot of, research on cardiac arrest comes from Warwick university. Why is that?

Professor Terry Brown: [00:00:59] It's mainly because Professor Gavin Perkins, who's a director of the clinical trials unit is sort of a world leader. In the area of, out of, out of hospital, cardiac arrest, resuscitation care, critical care.

He's on the national committees and the international committees. There's the International Relation Committee on Resuscitation (ILCOR).

So yeah, Gavin is, a major leader in the research on out of hospital cardiac arrest.

Paul Swindell: [00:01:26] So he pulls in projects and et cetera, and into your area.

So, I mean, you're, you're a researcher, is that right?

Professor Terry Brown: [00:01:34] I am, yeah. My, background is, epidemiology statistics. prior to Warwick, I've worked at numerous universities and for health and safety laboratory, health and safety executive. So, background in occupational, environmental, and public health epidemiology.

Paul Swindell: [00:01:52] I see that you have done quite a few, projects over your, time relating to cardiac arrest. Could you sort of briefly mention about those?

Professor Terry Brown: [00:02:01] Well, I've been with Warwick for nearly five years now, and I started with the registry to look at, changes in bystander CPR rates on how they have changed. So initial project was looking at, as I say, bystander CPR, and how it varies, has varied over time within England. It�s mainly looking at English data because of how the OHCAO registry is set up.

So, we're looking at the variation over time and also how it's varied during the daytime and what impact it has on survival. So, the research that I've carried out is looking at the characteristics of neighbourhoods of where bystander CPR occurs, and there�s a paper that had published last year.

And then more recently is looking at public access, defibrillation.

Where are the defibrillators in the community?

Are they in the right place?

And in the right place to sort of treat or be available to treat any out of hospital cardiac arrest.

So those are the main two areas, but there's other bits of areas that we look been involved in, looking at attitudes towards CPR, training, and issues like that.

We've been very busy with sorting out the registry and getting all the data cleaned up and producing our annual reports. That, we've not, sort of produced that many publications from the data, but we have planned to do that, but we are, we do encourage external researchers to get in touch with the registry to do their own research using the data from the registry.

But yeah, we have, the data. We have little projects that we'd like to get going. And, you know, there's many thoughts on what we can do with the data, that it�s just finding enough time to sort of look at them as I said.

There's small projects that I'm interested in looking at, as I mentioned earlier, a patient being administered to cardiac arrest centres in England and the UK, and it's in line with what Tom Keeble does at Essex Cardiothoracic centre, looking at those patients, and then also looking at termination of resuscitation rules.

So, there's little projects that we can get involved in. It's just a finding the matter of time and to analyze the data.

Paul Swindell: [00:04:25] Okay, so on this podcast, we're be talking about the out of hospital cardiac arrest registry (OHCAO).

Can you tell me what this registry is and what is the point of it?

Professor Terry Brown: [00:04:36] The background of the registry is to standardize the care of out of hospital cardiac arrests to see what the variation is with regards to treatment and outcomes.

The feasibility of setting up the registry was carried out in, 2013. And then the data collection really started in, 2014, and since then we collected data on an annual basis, but as of April of last year, the data comes into the registry on a monthly basis.

So, as I say, we have data from 2014 and it's looks at patient characteristics, ambulance indicators.

So, with regards to characteristics, we have information on patient's age, and gender, those sorts of things.

With regards to ambulance service information, we have Information on where the arrest occurred, all the call times, so when the call was made to nine, nine, nine. Call was connected to the ambulance dispatch centre, when they arrived on scene, and then basic information on the etiology. So, what caused the cardiac arrest, whether it was of cardiac origin?

Also have information on whether it was a result of trauma, drowning, drug overdose, and then what was the initial cardiac, rhythm. That was measured by the paramedics, whether the event was witnessed or not, who witnessed it, whether the bystander CPR was carried out.

And then information that, the ambulance staff provide with regards to administration of drugs. Whether intubation was carried out, whether they applied a defibrillator, where the shocks were given. And then as a result of that, whether there is a return of spontaneous circulation or a patient was declared deceased, and whether the patient was admitted to the hospital with or without a ROSC.

And then the ambulance staff have been collecting on whether patient has been discharged, from the hospital alive or not.

Paul Swindell: [00:06:42] So it's quite, there's quite a lot of data you're collecting there, isn't there? Perhaps we can, we can sort of delve down into that a little bit later, but to sort of put it into context, I think, you mentioned this is NHS England. Are you collecting information from the other parts of the UK and where does this fit in, say a world program?

Is this such a thing as a world program or other countries doing similar things?

Professor Terry Brown: [00:07:06] There are a number of other registries around the world, the main ones, there's North America, which is the CARES registry. There are small registries all around Europe. There is a project called EURECA, which is the EUropean REgistry of Cardiac Arrest and the papers just been published from EURECA 2. And in that study there was data submitted from 27 registries.

And then worldwide, there is the Victorian ambulance registry in Australia. And don't quote me on this, I think there is a similar registry for Western Australia.

There's the Australia New Zealand registry.

There's PAROS which is a collection of Asian registries, and that covers Singapore, Japan, and a number of other countries.

So there, other registries around the world, and we've had, two meetings now to discuss What data to collect and how we should collect the data and what research we need to need to carry out.

Within the UK, the registry only collects information from English ambulance services, we're sorting out, the Welsh data. Northern Ireland are very keen to be involved as well, but they have, personnel/logistic problems.

Scotland, have their own registry, but we can't access the raw data, because of data confidentiality.

Paul Swindell: [00:08:36] You mentioned that you�ve had two get togethers as with the people behind the registries. I guess the idea is to try and get some new unified format so that you can understand each other's results and improvements perhaps?

Professor Terry Brown: [00:08:49] Yes.

So, there are a set of guidelines that's called the UTSTEIN guidelines, and that basically tells you what information is required. So that we have a definitive set of key variables that we ask the ambulance services to provide. And then there's supplementary information and then additional information that we ask for.

Paul Swindell: [00:09:09] Can we compare results from the UK with another country?

When we say that the average is 8% survival in the UK, and, and they quote I think is about 25% for somewhere like Norway. Are we quoting apples with apples or is it slightly different?

Professor Terry Brown: [00:09:26] It does vary with regards to how you define a case. Some look at the survival overall. So overall, our survival, in England is, about 8 to 10%, and that's all cases.

If you then dig down deeper into if the case was witnessed?

Did they receive bystander CPR?

Was the initial rhythm shockable?

If you look at more specific cases, then the survival goes up.

So, survival, for all cases, ROSC at hospital handover, for all patients is about 20%.

For those that the first rhythm is shockable the ROSC hospital handover is 52%.

So, there's a big, difference.

And then if you look at survival to discharge, in a shockable rhythm, their survival to discharge is nearly 30%.

The earlier you get to a cardiac arrest and CPR is applied and treatment starts, then the more chance that that patient is in a shockable rhythm.

So, you know, it is important.

Paul Swindell: [00:10:36] It is, it is just to take a step back a bit, we're just talking about England, aren't we at the moment because that�s all you collect the data for?

Professor Terry Brown: [00:10:43] Yeah, it�s just England at the moment, yeah.

Paul Swindell: [00:10:46] And how many ambulance services are there, is it?

Professor Terry Brown: [00:10:50] It�s 11.

Paul Swindell: [00:10:51] 11 is it, okay.

Professor Terry Brown: [00:10:54] If we include the Isle of Wight

Paul Swindell: [00:10:54] Okay, so we�ve got 11, ambulance services feeding data into you, and they go out to a cardiac arrest, how many of those are we talking about roughly every year within England, the ambulance attend?

Professor Terry Brown: [00:11:08] So for 2018, we had just under 31,000 cases submitted to the registry. That does not include three months data from two registries. On that basis it's about another 500 cases.

But in addition to those, there are those that they don't attempt resuscitation. So, the ambulance services also send information on the total number of cases that are attended.

And it works out for the whole of the country about 80,000.

So, there are about 80,000 cardiac arrests in England, in 2018 of which only about 31,000, received, resuscitation attempts by ambulance staff.

Paul Swindell: [00:11:55] We've got 11 ambulance services and in England there�s 80,000 cardiac arrest of which 31,000 are attempted resuscitations.

And what's the average, success rate?

Professor Terry Brown: [00:12:10] ROSC at hospital is about 20%. And survival to discharge is just under 10%

Paul Swindell: [00:12:18] So basically that translates as, if you get to hospital alive, you�ve got a 50/50 chance of coming out alive.

Professor Terry Brown: [00:12:25] Yeah, that's about it.

Paul Swindell: [00:12:26] That�s roughly it.

Professor Terry Brown: [00:12:27] Yeah.

Paul Swindell: [00:12:28] That equates to something similar that Dr Keeble said to me before actually.

Professor Terry Brown: [00:12:33] Of course. It varies with age and gender.

Paul Swindell: [00:12:36] Okay, can you tell me a little bit about variability in different ambulance services?

Professor Terry Brown: [00:12:41] I think the original quote was about 8 to 24%. There was a significant variation, but it too, to an extent is that was because how, the ambulance services was submitting the data, who they were submitting the data on and who they were not submitting the data on.

So, the actual variation is, about 5 or 6% between the ambulance services. Again, these, down to the resources, you know, the locality of, where the events occur.

If you think about, the more rural communities, you know, people that have a cardiac arrest up in the middle of the Lake District and get into them is very difficult.

But they might say, sometimes it's more difficult to get to a cardiac arrest in, in the middle of London, than it is in rural communities. We're trying to sort of make adjustments to the information and looking at what impacts survival rates. So, they're basically, they're doing the same thing. It's just that there are things beyond their control that they can't allow for.

Paul Swindell: [00:13:42] I guess from what you're doing, you can learn from the data where perhaps the best place where public access to defibrillators are, or perhaps more training of the community and CPR skills comes into play

Professor Terry Brown: [00:13:55] We had a paper published the beginning of last year looking at the neighbourhood characteristics of where there is a high incidence of cardiac arrest and where bystander CPR rates are low.

So those communities, the more, more deprived areas of the country. Where there is sort of a more ethnic diverse population, where there's more older people, more unemployment, things like that.

So those, those areas where we've identified where incidence is high and bystander CPR rates are low. We've identified these hotspot areas and some preliminary work has been done with Andy Lockie and the University of Leeds medical school to target hotspot areas in West Yorkshire.

So, target those areas for CPR training. And some similar workers just starting for a West Midlands as well. And this is sort of in addition to the training that goes on as part of Restart a Heart Day, and other training that goes on, on an ad hoc basis throughout the country.

Paul Swindell: [00:15:02] So is there anyone actually sort of coordinating all of that training that goes on is, or is it very much ad hoc?

Professor Terry Brown: [00:15:09] The Restart a Heart Day is a very coordinated training day. It's coordinated mainly through a Yorkshire ambulance service and Resuscitation Council UK. It's Dr Andy Lockie, and Jason Carline who works for Yorkshire ambulance service.

It's all coordinated through the ambulance services to an extent. And, so it's normally 16th of October every year. People go into, mainly schools at the moment. They go into schools, secondary schools and do sort of mass CPR training. And last year, I think it was nearly 300,000 children.

So that anybody who wants training, if they get in touch with, the of ambulance service, there is somebody that coordinates training who'll be able to help.

Paul Swindell: [00:15:55] Is all this extra training in the public showing any dividends yet?

Professor Terry Brown: [00:15:59] When we did some analysis, a couple of years ago, presented a paper at the European Resuscitation Council annual conference, in about 2014, 15, the bystander CPR rates were about 50-55%, of those cases that were witnessed by a bystander. Last year, of all the cases that were witnessed the bystander CPR rate was about 74%.

So, it's a significant improvement in bystander CPR rates, if the case was witnessed.

Paul Swindell: [00:16:31] Wow. Yeah, that that really surprises me. It's that high, but I guess we got to put them into context where, whereabouts all these cardiac risks happening. When we say, 74%, is that all of 74% of people in the street who has a cardiac arrest?

Professor Terry Brown: [00:16:48] Those cardiac arrests that occur in a public place are more likely to receive bystander CPR. A bystander can mean anybody really, we don't distinguish who the bystander is.

But about 80% of out of hospital cardiac arrest occur in place of residence. And for some reason, the, CPR rates in, those are lower, because a lot of, cardiac arrests that occur in the home are not witnessed, or there is a reluctance for members of the family to perform CPR on a relative.

Paul Swindell: [00:17:22] I mean, that's really interesting, isn't it?

Professor Terry Brown: [00:17:24] A lot of arrests are unwitnessed in places of residence. Cause they you know will occur in the middle of the night and you know the relative will not know.

Paul Swindell: [00:17:34] That�s interesting in itself, what you just said there. So, they're in bed asleep and they have a cardiac arrest, even though there's someone next to them that that's counted as unwitnessed, I guess, because they're asleep.

Professor Terry Brown: [00:17:45] Yeah, basically that, you know, they have not witnessed the patient having the arrest.

Paul Swindell: [00:17:49] Do we know how many occur like that?

Professor Terry Brown: [00:17:51] I how don't know offhand.

Paul Swindell: [00:17:54] Presumably you have the, the time of day that the event occurred.

Professor Terry Brown: [00:17:57] There�s a small, paper looking at the time of day the events occurred and the bystander CPR rates, vary during the day. if I can remember rightly, the bystander CPR rates are low overnight.

Then they pick up, during the morning, and then they peak at about midafternoon, and then after midafternoon until early evening, and then they drop off again overnight.

Paul Swindell: [00:18:22] Is that reflective of when cardiac arrest happened or are cardiac arrests, sort of steady throughout the 24-hour day.

Professor Terry Brown: [00:18:30] No, there is a variation of when they arrest occur, but it�s all to do with, I think where people have their arrests.

Paul Swindell: [00:18:38] I did read a while ago that there was a, propensity for people to have a cardiac arrest on a Monday morning but I think that's less than now.

Professor Terry Brown: [00:18:46] Yes. Yeah. Yeah. I there is some variation during the week. It's Monday morning and it's quieter over the weekend. It's going back to work on a Monday morning events and there is some variation in the day of the week, and they'll show there's some variation over the year as well.

Paul Swindell: [00:19:01] Okay. Seasonal factors come into play, the cold or extreme cold and heat and extreme heat play a factor?

Professor Terry Brown: [00:19:09] And you said we weren't going to mention COVID 19, but infections and things like that place, a burden on the heart. And if there's a heavy flu outbreak over the winter, that will impact on the number of cases that will, suffer a cardiac arrest as a result of any infection

Paul Swindell: [00:19:23] So, what are the outputs of your project?

Professor Terry Brown: [00:19:28] The main output for the registry is an annual epidemiology report. So, over the past three, four years, we have looked at, foreach ambulance service that are submitting data to the registry.

So, we look at, well, you probably know the Chain of Survival.

So, we look the incidents of events in the year.

So, looking at, the incidence of adult and pediatric events, the demographics of them, sort of, age, sex distribution, the etiology, which is what caused the cardiac arrest. In most cases, it will be of cardiac origin.

And I think there's, I mentioned earlier, we do receive, information on traumatic and drug overdose events.

Where the event occurs.

So, if it's occurs in a rural community or in urban environments, and then going for the Chain of Survival, looking at the scene outcomes.

So, whether a patient was declared deceased on scene, whether they were transported to hospital and when they were transported to the hospital, whether it was, a ROSC had been achieved or ongoing CPR with was being carried out.

And then we look at, the initial rhythm. I'm looking at whether it's shockable and the outcomes from that.

How many cases were witnessed as how many received bystander CPR and then the main outcomes that we have, we have three really, although we only really present information on two, we have information on whether a ROSC.

And I assume, hopefully all your listeners know what ROSC is.

Paul Swindell: [00:21:04] You should probably just remind us, Terry.

Professor Terry Brown: [00:21:07] Its return of spontaneous circulation.

So basically, if somebody has had an arrest, they�re not conscious not responding they're not breathing, but ROSC basically the heart starts beating without any CPR or defibrillation.

So, it's, they're there, they're on their, on their own so they, they've come back to life.

Early defibrillation is the key for the majority of cases. Sometimes it can be as a result of CPR, if it's good quality, CPR, you know, somebody could come back to life if they're doing good CPR.

So, we have gone scene. So that's basically before the ambulance service leaves the scene to go to hospital.

So, then we have ROSC on scene. And then the main outcomes that we are interested in and which is part of the ambulance quality indicators for NHS England, is whether a patient has achieved ROSC at hospital handover.

So, when the ambulance gets to A&E whether the patient has, has a ROSC or not,

Paul Swindell: [00:22:05] So you're saying that they might not have been able to resuscitate them at the scene, but they may have on the journey to hospital. I guess because E-CPR type equipment? Lucas machines, and even coming into play is in some countries is ECMO, it?

Professor Terry Brown: [00:22:21] So yeah, I'm performing CPR in a moving ambulance is very difficult, but there will be decisions made. So those, that achieve ROSC on scene, not all of them will have ROSC at hospital handover, and they, might rearrest in the ambulance and vice versa.

There might be some that are, they transport start to transport that hadn't achieved ROSC, but achieve ROSC in the ambulance on the way in. So we have ROSC at hospital handover, and then we have survival to discharge.

Paul Swindell: [00:22:49] I guess some, patients are, or from speaking with many in the group have multiple arrests. They have one and they're down. The ambulance gets to them, they resuscitate them. Then perhaps in the ambulance or later on they have multiple events, I guess this is all presented as one event. I take it.

Professor Terry Brown: [00:23:09] If it�s, on the same day. Wherever the original location is, if it's at home and they've resuscitated, put in the ambulance and rearrests again, that that is all counted as the same event. If they subsequently are discharged and then rearrests at a later date, then that's counted as a separate event.

Paul Swindell: [00:23:27] So, is this data only provided for certain parties or can anyone. See this information, can the members of the public, if they've got an interest, to see where they, they sort of fit into the picture. Because my arrest was in 2014 which is the first year that you did your, stats. But can other people see about their year.

Professor Terry Brown: [00:23:47] We have a website and on the website, what we have now is the annual EPI report, and we have an infographic, that shows all the sort of the incidents, bystander witness rates, bystander CPR rates. The variation between each ambulance service.

So, all the information that's provided on the, for the ambulance quality indicators, that information is on, on our website, and it's backed up by data from the registry.

So, the information that's on the website is for annual average. And then for the current year, we update it as every month data is submitted to the registry.

So, for 2019 we have data up to the end of November.

Paul Swindell: [00:24:33] Oh excellent.

Professor Terry Brown: [00:24:34] You click on the, ambulance service. and then it shows the, the figures for that. But with regards to individual patient information.

Paul Swindell: [00:24:42] I guess people can go to that if they really want to know the individual details of their case, they can go to the hospital, can�t they? Or the ambulance service.

Professor Terry Brown: [00:24:51] If they want, to, about individual cases in you go to the ambulance service, but anybody who wants to know whether they're on the registry or not, they can put in freedom information requests through the normal channels.

Your arrest was in, what did you say, 2014?

We can't confirm that now because, as part of our information governance, after two years, we have to delete all personal identifiable information from the registry. So yeah, so for 2014, although you probably are on the registry, we wouldn�t be able to confirm that, now.

Paul Swindell: [00:25:26] Okay.

Just to go back to what you said about your website, I've just Googled and I put in O H C A O and then space Warwick, and that brought up you as the first option, and I clicked on the first link, and as you say that, brings up your website with information about the project and the information for health professionals and information for public.

So, there's more info if you're lay-person. And then, there's some publications, and at the bottom of the menu, there's a link to your interactive map. And that's, very nice. infographic, as you mentioned, you�ve got all of the various regions highlighted in lovely colours.

And if I clicked on the East of England, which is my region, it then brings up a nice page with full stats, number of ROSCs, number of ROSCs within a particular subgroup, the number of survivals and the bystander CPR and the number of public accessible defibrillators that were used, which is, it's really interesting.

One thing that only goes back to 2015 there is that when the data was published in 2015 or we would mine be in that 2015 one or is 2014 not on here for some reason?

Professor Terry Brown: [00:26:45] Its not on there because of the completeness of the information. The registry has data back to 2014, but it was just the completeness of the registry. Not every ambulance service was submitting data in that year, so we didn't want to at that, to the interactive map.

So for completeness, we just thought oh well start at 2015 where, when everybody was sending us good quality information.

Paul Swindell: [00:27:10] Okay.

Well, I think if anyone's interested in looking at that, that data, it's a really nice infographic and there's lots of information on there. It's really worth having a little bit of a, delve into that if you want to have more. And I don't think I've got any more questions for you Terry.

So, I don't know if you've got anything else that you'd like to say.

Professor Terry Brown: [00:27:29] My interest is looking at public access defibrillation at the moment. And with the current project that I'm involved, is, is looking at where are the public access defibrillators in relation to a cardiac arrest and are they in the right place?

So, I�m doing a three-year study, looking at, the location of all defibrillators.

So, we're working closely with British Heart Foundation. who are developing their, Circuit database of all defibrillators in the country.

So, are they, are they located in the right place in relation to cardiac arrests?

If not, where should we put defibrillators in the future so that they are made of, are available to everybody that has a cardiac arrest?

So, for example, we had a medical student, a couple of years ago that looked at, cardiac arrest occurred in schools, and as a byproduct of that small project, found out that if, a defibrillator was put in every school in the West Midlands and made available, nearly 40% of all cardiac arrests could be treated with a defibrillator.

They were in within 300 meters of 40% of all cardiac arrests.

Paul Swindell: [00:28:45] That�s quite a staggering statistic really, isn�t it?

Professor Terry Brown: [00:28:48] Yeah, it is a big number considering that only 5% of cases are treated with a public access defibrillator.

So, we're looking at where to put defibrillators in the community, doing some mathematical modeling.

And then there's another little project, which is everybody's keen to be part of that's been funded by Resuscitation Council, is looking at the use of drones to deliver AEDs to cardiac arrests, where it's going to be, it's difficult for ambulances to get to. So, in rural communities or, where ambulances having, long traveling times.

So, this is another small project, that we're getting involved with.

Paul Swindell: [00:29:31] Over the last couple of years, I've seen various sort of newspaper reports about drone usage, typically in, Europe, I think possibly Belgium and the Netherlands,

Professor Terry Brown: [00:29:41] Sweden is the, is the big place as well.

Yeah. Yeah .

Paul Swindell: [00:29:45] Has anyone got them in actual use yet?

Professor Terry Brown: [00:29:48] I don't think they are at a moment.

The main problem with, using drones in the UK is getting, civil aviation authority authorization. To, fly the drones, out of line of sight.

Because at the moment, as far as I understand that regulation, you're only allowed to fly drones within 500 meters. So, you only see them. You have to be able to see the drone, whereas with, AED delivery, you're going to fly them remotely.

Paul Swindell: [00:30:17] I imagine the shenanigans that happened at the Gatwick airport or some other airport in the last year or two, that only complicates the scenario and the legal aspect, doesn't it?

Professor Terry Brown: [00:30:27] They are officially no fly zones, so you have to build into whatever model you use. You have to fly them around, no fly zones, to deliver them. So, if, you know if you can't fly over military air airbases or military training grounds or things like that.

So, there are certain areas you can't fly them.

Paul Swindell: [00:30:45] But in in certain places like cities and things like that, they could be, they could be quite useful.

Professor Terry Brown: [00:30:50] Well, there is, colleagues in Canada have done some feasibility studies. We're looking at delivering, AEDs, sort of, into high rise building and whether it�s feasible to do that.

Paul Swindell: [00:31:02] Yeah, because I believe the stats on survival from a cardiac arrest when you're above full three up pretty dire really aren't

Professor Terry Brown: [00:31:09] Yeah, it can be. Yeah.

Marcus, in Singapore that looked at modeling, you know, where do you put a defibrillator in a high-rise building? Is it on the ground floor or do you actually put one in, in the lift?

So yeah.

Paul Swindell: [00:31:22] That's true.

Professor Terry Brown: [00:31:23] Yep.

Paul Swindell: [00:31:23] One on every floor, every other floor. Ideally.

Professor Terry Brown: [00:31:26] If you can afford

Paul Swindell: [00:31:29] I don't know if you listened to my podcast recently with, Gary Montague of the Heart Hero AED, which is an, an American startup and their, their aim is to deliver a high quality, low cost device. I think they're aiming currently for under $700 for a device that's got GPS tracking.

It uses batteries that you can buy in the shop, links to the, emergency services in the States anyway, but they hope to have it so they can go to most, emergency services.

So, essentially, it's a domestic AED and they aim to get it down to as low cost as possible.

So, it may be in a few years� time if they've get the volume that they can actually get it in a high proportion of people's houses,

Professor Terry Brown: [00:32:19] Yep. Yep.

Paul Swindell: [00:32:20] Which is the perfect place for them really.

Professor Terry Brown: [00:32:24] Yeah.

Paul Swindell: [00:32:24] So, thank you very much, Terry, for your time today. It's been a.

Professor Terry Brown: [00:32:29] I just want to add another thing, and I must do this.

But just say that the registry is currently funded by the British Heart Foundation and the Resuscitation Council. We have funding for another three years. We are backed by the association of ambulance chief executives and the national association of ambulance chief medical officers.

And I�d just like to thank the work of all of my colleagues at Warwick

Paul Swindell: [00:33:00] Yeah I think it's worthwhile mentioning that because without, without their funds and their support, you wouldn't be able to do this. And, and in time, I'm sure it's going to see, or reap dividends in, in feeding back into the chain of survival so that more and more people to survive.

Professor Terry Brown: [00:33:18] Yup, hopefully.

Paul Swindell: [00:33:20] So it's been a really interesting, chat and, thank you very much for your time and, take care in this, strange times we're in, and I look forward to seeing more, more stats and information from you and your website.

Professor Terry Brown: [00:33:32] If anybody wants to get in touch with me, please don't hesitate.

Paul Swindell: [00:33:36] And your contact details presumably will be on the website?

Professor Terry Brown: [00:33:39] If you contact us through the website is the OHCAO resource email address that will be picked up by one of the team and passed on.

Paul Swindell: [00:33:47] I will put all the links into the show notes on the website and the podcast.

Professor Terry Brown: [00:33:53] Yup, Okay.

Paul Swindell: [00:33:55] So thanks very much Terry, and we'll speak again soon.

This concludes this episode of the life After Cardiac Arrest podcast, and I'd love to know what you think. And you can do that via Facebook, Twitter, Instagram, or the website, SuddenCardiacArrestUK.org and you can find this by Googling Sudden Cardiac Arrest UK or the Life after cardiac arrest podcast.

If you have found value in this or other episodes, please help spread the word by leaving a review on your podcast provider such as Apple or wherever is convenient.

And don't forget, if you want to know more about life after cardiac arrest, check out our books, life after cardiac arrest on Amazon. Make sure you click subscribe.

And I'll speak to you next time.

If you enjoyed this podcast please do leave a positive review on Apple or other podcast providers as it helps us to spread the word.

Presented and edited by Paul Swindell.

Recorded March 2020. 

Visualising the heart with Dr Sanjay Gupta

In episode #42, Paul talks with consultant cardiologist Dr Sanjay Gupta on a subject that he specialises in, cardiac imaging.

Blog | Dr Sanjay Gupta Cardiologist

Dr Gupta takes us through the various tools that he uses such as echocardiograms, computerised tomography (CT) scanning and Magnetic Resonance Imaging (MRI) scanning.

Dr Gupta explains everything about these techniques that patients need to know and also talks about how future tools may help prevent the main cause of sudden cardiac deaths – heart attacks.

Available to listen on the link below or Spotify, Apple , Google, YouTube and your favourite podcast player.

#042 Visualising the heart with Dr Sanjay Gupta

Paul Swindell: [00:00:00] Hello and welcome to another episode of the life after cardiac arrest podcast with me, your host, Paul Swindell.

And today I'm joined by Dr Sanjay Gupta, who is a consultant cardiologist at York teaching hospital, in the North of England. He also is a very popular on social media and you'll have seen him possibly doing, YouTube videos and Facebook videos on all sorts of cardiac related matters and he has a specialist interest in cardiac imaging, which we will be talking about today.

. So, welcome Dr Gupta and nice to speak with you again.

Dr Sanjay Gupta: [00:00:46] Thank you so much for having me.

Paul Swindell: [00:00:48] So cardiac imaging.

So what are we talking about there?

Dr Sanjay Gupta: [00:00:52] We're talking about, modalities which allow us to visualize the heart and the arteries surrounding the heart.

So visualizing the heart, both, to make a diagnosis, to tell you about the health of the heart, and to also guide you, about prognosis.

Paul Swindell: [00:01:14] So what are the, tools that you use?

What have you got in your toolbox ?

And, why would someone need to go through those processes that you do?

Dr Sanjay Gupta: [00:01:22] So, common modalities include echocardiography, ultrasound of the heart, CT scanning of the heart. MRI scanning of the heart, and also, radio nuclear imaging of the heart, so perfusion scanning, et cetera.

Okay, so the first thing to say is that by far and away the commonest and the most easily accessible tool we have this echocardiography.

One of the unique things about the heart is it's a moving structure and therefore, to try and understand it. you have to have moving images and that is different from say, imaging the liver or imaging the brain.

Echocardiography uses ultrasound waves, which bounce off different structures of the heart and produce a moving image on a screen.

It's very easily accessible, is available in every hospital and it offers a crude, but, well validated way to assess the structure of the heart. So, on echocardiography, you can see the heart, you can see the heart valves, you can see the size of the chambers of the heart.

You can work out whether there's any leaking of the valves, whether there's any tightness of the valves and you can see whether the function of the heart is strong or weak. And what we do know is from all the studies that if you have a structurally normal heart on the echocardiogram, then in general that points to an excellent prognosis and if you have damage to the heart or if the heart is weak on the echocardiogram, then that points your worst prognosis.

Paul Swindell: [00:03:01] And the echocardiogram, am I right in thinking these are similar tools to what the you use on a pregnant lady to look at the fetus

Dr Sanjay Gupta: [00:03:09] Absolutely, exactly the same.

Paul Swindell: [00:03:12] So that's a noninvasive procedure and you just typically put some gel on someone don't you?

Dr Sanjay Gupta: [00:03:17] You, put some jelly on the, on the patient, and then, you have this transducer and the transducer will emit, sound waves and the sound waves will hit different structures and bounce back.

And that will create an image on the screen, it can also, it is also useful in terms of working out which way blood is flowing. So, for example, if you close your eyes, you can tell usually whether an ambulance is coming towards you or going away. This is the Doppler principle. And so if you can use that information and convert it into a colour signal, you can then see where the blood is coming towards you or going away.

And that then tells you whether valves are leaky or functioning normally.

Paul Swindell: [00:04:03] Oh okay. I see. That's clever.

So you said that it's quite accurate at determining whether someone's got a functionally correct heart?

Dr Sanjay Gupta: [00:04:11] Yeah, I mean, I think it's a, I think it's still a crude test, but, there's two things.

One, it's well validated.

A lot of all the major research studies have shown that actually, you know, the information it gives, does, point towards prognosis. It's the gold standard in terms of trying to make a diagnosis of something like heart failure where the heart is weak or not.

All valvular problems, the echocardiogram is a very good way of determining, the nature of the problem, the severity of problem, and may also help you work out the best treatment for the problem.

Paul Swindell: [00:04:47] And presumably before that you would have done a, I know it's not, an imaging test, but a 12 lead ECG.

Dr Sanjay Gupta: [00:04:55] Yeah, so the 12 lead ECG is telling you something different, right?

12 lead ECG is just telling you about the electricity through the heart. So it is just telling you, about the electricity and you are making assumptions based on those electrical patterns.

With an echocardiogram you're actually looking at the heart.

So with a 12 lead ECG, if you had a valve and your valve was, let's say, very narrowed, that would cause the heart to become more muscular because it would have to generate more force against that narrowed valve. The heart would become more muscular, which means the electricity would have to go through a thicker heart muscle, and you would get much bigger complexes on the ECG.

So if you saw bigger complexes on the ECG, you would say, okay, that looks like it's a more muscular heart, which means that it could be due to this or that.

It didn't really give you the diagnosis, it just told you, but the heart had changed this way, based on the, electricity through the heart muscle.

With the echo, you're actually visualizing the heart.

So, a far better way, you're actually seeing, you can actually measure the thickness of the heart and you can look at the valves, et cetera.

So, yeah, in the old days, we didn't really have very much at all to determine what was going on, but, since echocardiography has come along and, now we have more complex echocardiographies. So previously we just used to have something called M mode echocardiography, then change it two dimensional echocardiography. Now we have three dimensional echocardiography.

So that has really revolutionized how we diagnose certain conditions, and how we monitor conditions, because it is accessible.

You know, the machines are not that expensive.

There's a lot of expertise on how to, you know, experienced staff, et cetera. It doesn't require, really, it doesn't require very, very highly specialized, just because it's so much more accessible. So, echocardiography is the kind of staple investigation.

And from my perspective, if the first test I would do, if I was worried about someone would be an echocardiogram.

If they have a strong heart, I feel relieved. If they have a weak heart, I get more worried.

Paul Swindell: [00:07:02] And so what would you progress to next if, the echocardiogram hasn't told you what you needed to know or shown that there's a problem there, but you need a little bit more detail, where would you go next?

Dr Sanjay Gupta: [00:07:14] The echocardiogram is like if you thought of the heart as a car. The echocardiography is looking at the engine of the car.

It doesn't tell you what the arteries that supply the blood to the heart look like. So with an echocardiogram, you can't see the heart arteries. You can't tell whether the heart arteries are narrowed or anything.

All you can tell is that there's been no damage to the heart.

So if you wanted to visualize the heart arteries then the next step would be to do something called cardiac CT, CT scanning, which has now become the gold standard for looking at heart arteries, you know, for the majority of patients with chest discomfort, and with cardiac CT, what you're doing is you're delineating the heart arteries themselves, and that will then tell you whether the heart arteries are narrowed or whether there are any blockages, et cetera.

Paul Swindell: [00:08:07] So , CT, what does that stand for?

And again, is this an invasive procedure ?

Dr Sanjay Gupta: [00:08:13] No, it's a noninvasive procedure and CT stands for computer tomogram or a cat scan. That's, you know, how people recognize it, but basically it involves going through a scanner. The is heart slowed down because again, the heart is a moving structure, and if you want to visualize the arteries, if you don't slow the heart down, then the arteries will move with the heart and you'll get blurred images.

So what they try and do is they slow the heart down.

And therefore in that short period of time when the heart is very slow, they're trying to image these arteries. The arteries are imaged by giving the person a contrast through one of their veins, contrast agent. And that contrast agent goes through the vessels and you can then take pictures of the heart arteries.

Paul Swindell: [00:09:00] Okay, sounds like, is it a little bit more expensive piece of equipment?

Dr Sanjay Gupta: [00:09:04] Definitely, not all centers have access to cardiac CT.

Currently the guidance says that if you, for example, came and said to me, look, I'm getting chest pain. And I'm like, you know, I would say, well, I'm not quite sure.

Maybe it could be your heart.

Maybe it couldn't be.

Maybe it isn't your heart.

What tests should we do?

The current guidance is that the majority of those patients should have a cardiac CT. And a cardiac CT is an exceptionally good test in terms of if your heart arteries are normal, it's probably the best test we have out there that tells us that if your heart arteries looked normal in the cardiac CT, then the chances of something bad happening to you are really, really low.

It's not so good if you have abnormalities because you still then need to image it further. Because what tends to happen is a lot of times when you get buildup of plaque and disease in the, in the blood vessels, you get deposition of calcium and calcium reflects rays.

So what, what then happens is, you know, when you're doing the cardiac CT, you get these bright bits of calcium and you can't see beyond them because of the calcium.

So when you see a lot of kind of calcium in the heart arteries, one, it tells you that the arteries are diseased, but then you have to do a better test or a more invasive test to see exactly how bad the narrowings are beyond those lumps of calcium, which are in some way blurring the image because they're reflecting these.

It's like taking a flash photograph in front of a mirror. You get a, you know, you get that bright light hitting you back. and so, in that setting, if, if you have an abnormal cardiac CT, most people would then go on and do something called an invasive angiogram.

Which actually involves putting a needle into either the groin or the the wrist and passing a tube all the way to the heart, and then squirting some dye into that tube that dye that fills up the heart arteries and then you take x-rays.

That way you're purely looking at the heart arteries that actually lumen of the heart arteries, and that is the gold standard kind of invasive test for coronary disease.

Paul Swindell: [00:11:16] So with the CT and the angiogram, you're not actually looking at the heart, you're just looking at the

Dr Sanjay Gupta: [00:11:22] Artery

Paul Swindell: [00:11:22] Arteries around it.

Dr Sanjay Gupta: [00:11:23] Yeah, exactly, exactly.

Paul Swindell: [00:11:25] Okay.

Dr Sanjay Gupta: [00:11:26] If we wanted the heart and more details, so you know where you have the echocardiogram, is there another test which can offer you the same thing but in a lot more detail?

And the answer is yes.

That's where you go to cardiac, magnetic resonance imaging, cardiac MRI.

Cardiac MRI, allows a much better visualization of the heart, but obviously it's a much more sophisticated procedure, it involves the patients having to go in this very claustrophobic tunnel for about an hour with lots of noise and clanging, but it is a test which allows excellent visualization of the heart.

One other thing which is really useful for you to know, I guess, is that, there was a series of experiments. Done in America where they took a bunch of dogs and they occluded the heart arteries and they studied the damage that was done to the heart when they occluded the heart arteries.

When you create a heart attack, what is the pattern of the damage that occurs in the heart?

And what they found is that all damage caused by heart attacks goes from inwards, outwards, so from within the heart, outwards. The inner most layer is always affected first.

With cardiac magnetic resonance, you can give a dye called gadolinium and that can delineate scar that accumulates in scar. And so if you then take the images and you find that that scar is involving the inner most layer, then you make a good assumption that that scar was caused by a heart attack. So in that sense with an echocardiogram, all you see is a bit that's not moving and you assume that there's been damage.

But what we don't know for sure, and sometimes we cannot be sure is was that because the person that had a heart attack was that because the person had a virus? Was that because of something else?

And MRI is very good because it delineates exactly the nature of the damage and the pattern of the damage by gives you a good clue as to why that may have happened in the first place.

Paul Swindell: [00:13:27] Can you do a, an MRI or a moving MRI of the heart? Like you, like you said, the echo-cardiogram, you can see the blood moving and whether it's going in the right direction, what have you, do you get that similar sort of picture from the MRI.

Dr Sanjay Gupta: [00:13:43] Yeah again, with an MRI you get, you can get moving images and, so you can see the function of the heart, you can see the function of the heart better than with echocardiography. It's not so good for looking at the way blood moves in and out in the valves, et cetera. But people are developing a MRI and you know it's coming along, but in that sense, echocardiography is probably still better to look at the heart valves and you know, the, the actual physiology to study physiological changes within the heart I think echocardiography is still better.

But echocardiography has a problem, you know, not everyone has the best pictures. You know, you have to get a window and some people carry extra weight or who have ribs very close together. You may not necessarily get any kind of decent pictures to be able to make, any kind of assessment of their hearts.

MRI doesn't have those constraints.

So with MRI, you're not so worried, you can still visualize the heart very well.

Paul Swindell: [00:14:43] So it sounds like all of them have a part to play in your toolbox as it were. The they, they will show you something slightly different.

Dr Sanjay Gupta: [00:14:51] Absolutely. I mean, there are anatomical tests.

There are functional tests, there are tests for the heart arteries, and then there are tests with the actual heart itself, the heart muscle.

Paul Swindell: [00:15:02] So is there anything, anything else that you might do or this is something else that you'd like, that isn't invented yet?

Dr Sanjay Gupta: [00:15:10] So in the old days, what we used to think is if the heart looks okay on the heart scan, on an echocardiogram, then the person doesn't have heart failure, for example. You know the heart, if the heart looks okay on an echocardiogram, then it's not your heart. So someone comes in and says, oh, I'm getting more and more breathless, my legs are filling up with fluid. Those are typical signs of the heart being weak, but if you then did the echocardiogram and the found that the heart was strong, then most people would turn around at that point and say, no, that's not your heart.

Now they're beginning to realize that actually there are some people who have what may look like a normal heart on the scan, but may still have signs of heart failure. And actually when you follow these people up, they do badly in the long run anyway. And so we're beginning to realize that we've used a two dimensional modality to study a very complex three dimensional structure.

You know, the heart will move.

When the heart contracts, it contracts in different ways.

It contracts radially.

It contracts longetudinally it contracts, it twists and turns.

But the modalities we're using are only looking at one movement. And therefore, I think, we are beginning to realize that sometimes our tests have their own kind of limitations, but it is that recognition which will allow us to move forward and identify new modalities, which will help us determine, what's going on with the heart.

The other thing of course, to say is that most of these are a visual impression. You know, you're just looking at the heart, right?

You haven't gone inside the heart. You haven't studied in under a microscope.

So can the heart still be diseased if it looks normal?

And the answer is yes, it can still be diseased, even if it looks normal.

This is the fundamental problem when we hear about people like, athletes you know, who are playing football and then suddenly dropped down, dead on the pitch.

I mean, these guys have been investigated, they've gone through medical screening, I'm sure they've come through a whole manner of tests. And so it is always sort of something that is very worrying when someone like that suddenly drops down dead because you say, well, he had all the tests, they were all normal, why did this happen?

And the answer is because we are only basing our assessments on a visual interpretation. We haven't actually taken the heart, looked at it under a microscope. We don't know. You know, we can only look for things that are causing an outward change in appearance.

Paul Swindell: [00:17:42] I guess the heart isn't an under stress as well when you're doing these tests either.

Dr Sanjay Gupta: [00:17:47] We do something called stress echocardiography, so where you can actually look at the heart and then you put the person on a treadmill and make the heart beat really, really fast, and then you bring them off and study the heart again, and that's a good way of assessing, well, the strength of the heart.

And those aren't, those aren't, you know, those are relatively straightforward. It is that kind of patient like yourself, you know, when you mentioned that looking at out of the blue, suddenly, you know, one day you're out.

Why did that happen?

What was there anything that could have determined that that was going to happen beforehand?

And the reality is probably not.

And those are the groups of patients we need to study better and we need to develop more, advanced, modalities, which allow us to determine, you know, determine risk. I think, I think what we have is a good tools, for a population to study a population.

Are we very good at using those tools to study an individual? And that's a bit more difficult, you know, because the reality is anyone anywhere can have something bad happens to the many ones suffer cardiac arrest at any point.

What we are doing is we're saying, okay, well if you've got a strong looking heart, then you in general belong to that population is going to do well.

Paul Swindell: [00:19:00] And so you talked about these other modalities , do you know of any technologies that are coming along?

Dr Sanjay Gupta: [00:19:05] I think there'll be metabolic imaging is a very interesting field.

So one of the very interesting things that the big problem by far as heart attacks, that is the, by far the biggest killer, right? So sudden heart attacks, heart attacks, which come out of the blue, they, they're responsible for the majority of sudden deaths.

And, the, the question is why two heart attacks occur?

And, you know, the general kind of understanding certainly amongst the public is that you get narrowing. So if your heart arteries, the heart arteries get narrower and narrower and one day one blocks off and that causes the heart not to get the blood, it gets damaged.

The heart misbehaves because it's not getting any blood and the person drops down dead. The reality is. when you look at the, or, our understanding has changed because what we're starting to realize this, not all people who have significant narrowings are going die because that narrowing has blocked off.

Sometimes people don't have significant narrowings. They have a may have a very, very minor narrowing and one day, for whatever reason, that particular area, that little clot breaks off. And the body thinks you've sustained a wound and forms a blood clot to try and heal that wound and the blood clot inadvertently blocks of the vessel and stops the blood getting to the heart, which causes the heart attack.

And that can occur within a matter of two or three minutes.

Paul Swindell: [00:20:29] Oh wow. I didn't realize it was that quick.

Dr Sanjay Gupta: [00:20:31] Yeah. So those are the people. You see that there are two groups of people. There'll be those people who will say, I've been getting chest pain every time I walk, I walk. So I went to see my doctor. My doctor did a test.

He said, I have 99% blockage in, says I need an emergency bypass. Thank God I have the bypass. It saved my life. The reality is actually when you look at all the data, bypasses and stents done in that kind of non-acute setting have not been shown to prolong life. So the question is why have they not been shown to prolong life.

And the answer is because that narrowing was probably not the narrowing that was going to kill that patient. The patients, a lot of patients die because they get unstable clot, which may not be causing a narrow, and that unstable clot chooses to break off. If you think about it, you get cold clots, which are nice sort of clots, which have been there for a long time.

They're like, cement. They're not, they're not fragile, they don't break off. And then you have hot plaque, which is a lot more, a lot more fragile, a lot more inflamed, and one chooses to break off. And that's where you get that sudden, the patient who is completely fine and boom, dead. so when you image the heart at the moment, anatomical imaging is only largely geared towards trying to identify the narrowest bits.

It doesn't identify the bits that are most likely to break off.

So if in some way you can develop techniques which identify which plaques are hot and which plaques are cold, then you can start treating hot plaques. And if you treated hot plaques may be the risk of sudden death from heart attacks will go less.

Paul Swindell: [00:22:15] I see. That sounds good.

Is that feasible, do you think?

Dr Sanjay Gupta: [00:22:19] I think so. I think because, I think there's, you know, the, the hot plaque tend to be more inflamed. They tend to be newer. So the process is going on with a hot plaque are a different, I think there are centers, there's a center in Oxford that has an interest in this, so I think that would be a really interesting thing.

The problem at the moment is, you know, stents and bypasses are only done for the narrow bits. Right? Because if you, if you don't have a narrowing, then if you bypass the narrowing, there's no reason the blood will go down the bypass because there's no real narrowing. So the blood will choose to go down where it's always gone down and the bypass would fail.

Similarly, if you stent something which is not narrowed, you don't derive any benefit.

So, of course, it'd be one thing to try and identify hot plugs and then it would be another thing to try and say, well, how would you go about treating these hot plugs?

How would you make these hot plugs colder?

And I think that would be a very interesting field.

Paul Swindell: [00:23:15] Topic for another podcast, I think.

Well, I think there's a topic for a lot of researchers and probably a lot of money as well.

Dr Sanjay Gupta: [00:23:23] I think it's a very interesting field. I think that's, I think is the most important thing that's come out in my understanding of cardiology, which is, you know, the bits that we think are the most threatening tend, you know, the people die of things, which can actually look relatively innocuous, but then choose to misbehave rather than something that looks ugly.

Because it's, long standing things are unlikely just to suddenly cause a problem, whereas something that is relatively acute, something which is very hot, as much more likely to be dangerous.

Paul Swindell: [00:23:56] Okay.

Have you got anything else to add in this imaging arena?

Anything you'd like to impart, or have we said it all basically?

Dr Sanjay Gupta: [00:24:06] I think we've said it all, no, I think we've said it all.

I can't think of anything else.

Paul Swindell: [00:24:10] So in general, cardiac imaging patients should never be really worried about them cause they're either noninvasive or minimally invasive.

You might have to have an injection or something like that.

Dr Sanjay Gupta: [00:24:23] Yeah. I think this is the real advantage with noninvasive modalities because, you know, they offer a high yield, low risk and the invasive ones are generally only done when the patient really, really needs them now, not an ad hoc so to speak.

So there's a lot to be said. I mean, we've moved, you know, as cardiac CT is incredible. It's to be able to visualize the heart arteries in this way, and to have a test which has been shown that if it's normal, it portends to really good patient outcomes is really reassuring.

Paul Swindell: [00:24:55] Well. That's brilliant.

Thank you very much, Dr Gupta for that really interesting overview of all of the types of imaging that patients might expect to encounter if there are ever become a cardiac patient.

And thank you very much again for your time. It's been really enjoyable.

Thanks a lot.

Dr Sanjay Gupta: [00:25:15] Thank you so much. I've enjoyed it.

Paul Swindell: [00:25:19] This concludes this episode of the life After Cardiac Arrest podcast, and I'd love to know what you think. And you can do that via Facebook, Twitter, Instagram, or the website, SuddenCardiacArrestUK.org and you can find this by Googling Sudden Cardiac Arrest UK or the Life after cardiac arrest podcast.

If you have found value in this or other episodes, please help spread the word by leaving a review on your podcast provider such as Apple or wherever is convenient. And don't forget, if you want to know more about life after cardiac arrest, check out our books, life after cardiac arrest on Amazon. Make sure you click subscribe.

And I'll speak to you next time.

If you enjoyed this podcast please do leave a positive review on Apple or other podcast providers as it helps us to spread the word.

Presented and edited by Paul Swindell.

Recorded March 2020.