October is Sudden Cardiac Arrest Awareness Month

A cardiac arrest or when it happens unexpectedly, a Sudden Cardiac Arrest is one of the UK biggest killers with a extremely low survival rate – on average just 8.6%.  This is in contrast to the condition it is often confused with – myocardial infarction, more commonly known as a heart attack, which has a survival rate up to 80%.  This is a “plumbing” issue where the blood supply is blocked or restricted to the heart, but importantly the heart is still pumping and the patient still conscious and alive.  This is in contrast to a sudden cardiac arrest which is an “electrical” issue which stops the heart from pumping resulting in the person collapsing unconscious and being essentially “dead” – if no immediate action is taken to rectify the situation they will sadly stay that way. More information on the difference can be found here.

According to the Resuscitation Council approximately 30,000 resuscitations are attempted in England each year, with an estimated similar number to far gone to warrant intervention.  This extrapolates to roughly 100,000 a year in the UK, or to put to another way – 250 per day!

A major heart attack can lead to a sudden cardiac arrest and is a significant cause of them, but they have a multitude of other known causes and also unknown causes.

They can occur at any time, any where and to any one – age or fitness is no indicator.  Indeed the Sudden Cardiac Arrest UK peer support group has many people who thought they were fit and healthy prior to their event and it is estimated that 12-15 young people die each week of an SCA.

When a person has Sudden Cardiac Arrest, unless they get immediate attention they are often without oxygen for some time and this can often lead to serious repercussions including brain injury.

If you would like to know more about life after a cardiac arrest you might be interested in reading more on this website or blog or even our Kindle ebook…

If you are on Social Media eg Facebook and you want to help spread awareness please Like, Share and comment on the post for this article and also Like our page.  In addition you can also use the following image for your profile pic…

Sudden Cardiac Arrest UK aims to provide support to those affected by this event and is run totally voluntary and if you would like to help support the group to build on the work it is doing, such as the recent successful Guinness World Record attempt, then please feel free to donate on our Just Giving page

To recap, a cardiac arrest and a heart attack are not the same, and although both are medical emergencies and require 999, the former is considerably more lethal.

You can help by spreading awareness of this simple piece of information and you can also help yourself by ensuring that you and your loved ones know CPR and where you nearest defibrillators are (and if there aren’t any near maybe you can do something about that?)

Dr Tom Keeble – Southend Hospital – NHS Hero!

We’re pleased to announce, that Dr Tom Keeble, consultant cardiologist and supporter of Sudden Cardiac Arrest UK has won the patients prize for NHS Hero at Southend Hospital.  A fantastic accolade and well deserved, especially for all his help with the group especially the successful Guinness World Record Attempt in June.  Well done Tom!

Dr Keeble said he was most honoured to receive the prize and gave thanks to all in the group.  A special mention should go to Charlie Dickens who instigated his nomination and helped ensure Dr Keeble was in the running.

The invention of the ICD

The following post is largely taken from “The Development of Implantable Medical Devices at The Applied Physics Laboratory” By Robert E. Fischell.  It documents the history of a number important and common devices seen today including the ICD, which I’m sure many SCA survivors are familiar with but may not know the history of it’s development.

Dr. Mirowski’ s Invention

Shortly after the rechargeable pacemaker development work began at John Hopkins University Applied Physics Lab, Dr. Michel Mirowski, a cardiologist at the Johns Hopkins School of Medicine and the Sinai Hospital of Baltimore, conceived the Automatic Implantable Cardiac Defibrillator (AICD).

The AICD was to be implanted just under the skin in the upper abdominal area of patients at risk for ventricular fibrillation, which is a rapid, uncoordinated contraction of heart fibres brought on by a severe disturbance of cardiac electrical actIvIty.

The Human Tissue Stimulator implanted under the skin in the chest with electrodes stimulating the brachial plexus nerves
Dr. Donlin M. Long (right) adjusting the electrical stimulation parameters for the first Human Tissue Stimulator patient

The shape of the AICD is similar to that of commonly used heart pacemakers, but its function is markedly different. About the size of a cigarette package, the implanted defibrillator is programmed to monitor the heart continuously, recognise life-threatening arrhythmias, and automatically deliver electric shocks through electrodes directly in contact with the heart to restore the normal rhythm.

The highly miniaturised version of the bulky conventional defibrillator does essentially what doctors do in emergency rooms when they apply a powerful external shock to a patient suffering from this form of episode. Because it is implanted, the defibrillator uses only a fraction of the voltage needed externally to accomplish the same thing.

Most importantly, the implanted defibrillator automatically makes the diagnosis and implements the appropriate therapeutic decision. Thus, its unique advantage is its permanent availability to the patient without requiring the presence of special personnel or bulky equipment.

The above shows the AICD device with the long, slender lead that goes into the patient’s superior vena cava and a cup electrode

The above shows the cup electrode just under the heart, the long, slender lead in the superior vena cava, and the AICD pulse generator under the skin in the patient’s chest

The role of APL in the AICD Project

Having heard of APL’S high-technology capabilities, Dr. Mirowski sought out the Laboratory ‘s assistance in 1974. Among the first improvements in the AICD instigated by APL was the introduction of the same satellite reliability and quality control techniques that had been applied to component selection, fabrication, and test procedures for APL spacecraft. These were the same techniques that had made a success of the rechargeable pacemaker. Furthermore, a system was created by the APL engineers for alerting the patient with a subcutaneous buzzer when an episode of ventricular fibrillation had occurred. Further, APL developed a system for holding in digital form the patients electrocardiogram (ECG) for 10 s before and 15 s after a fibrillation event. Both features were designed to provide the physician with an improved understanding of how to apply the AICD therapeutically. To verify how well such an alarm and recording system would work without interfering with progress toward completing an implantable version of the AICD, funding was obtained from NASA to develop an external system capable of recording the ECG both before and after the fibrillation event.

The recorder as it was worn by an AICD patient
The entire recording system, including the recorder, straps for holding the chest electrodes and the recorder, and the console for playing back the recorded data

The First Implant

The first implant was performed by Johns Hopkins surgeon Dr. Levi Watkins, Jr., on 4 February 1980. The first patient was a 47-year-old woman from San Mateo, California, who had experienced two episodes of ventricular fibrillation but had miraculously survived.  The glass-enclosed gallery above the operating room included many engineers and scientists who had been working on the AICD development for many years. The attendees were surprised to see that the surgery was much more extensive than that for a pacemaker implant.

For these first AICD patients, the entire rib cage was opened until the heart lay clearly visible for the surgeon to attach the cup electrode at the bottom (apex) of the heart. The vena cava electrical lead was then carefully inserted into the large vein above the patient’s heart. Everything was now ready for placing the AICD device subcutaneously just under the abdominal skin. The surgeon turned away from the operating table and asked the nurse to hand him the AICD, which was contained in a sterilised pouch.

Ten people in the operating room and twice that number in the gallery gasped when the nurse opened the pouch and then dropped the AICD on the floor! One thing learned from spacecraft operations was to have spare parts available. In this instance, a second AICD unit had already been placed on the sterile table, and it was taken out of its pouch with great care. Dr. Watkins proceeded calmly to implant it in the patient, connect the leads, and close the incision.

The First Test

Because the AICD had never been tested in a human subject, it was decided to evaluate the device’s performance in the first patient under very controlled conditions. These “controlled” conditions really became an extraordinary experiment in the catheterisation laboratory. The only way to tell if the AICD functioned properly was to stop the patient’s heart from beating by sending a strong electric current through the heart muscle so that the heart would go into ventricular fibrillation.

The AICD would then (hopefully) automatically restart the heart. As a backup for the AICD, an external defibrillator was close at hand and ready to go to work. The first test of APL’s ECG recording system was to record the entire event. With the catheterisation laboratory filled with a dozen people, Dr. Philip Reid directed the critical first test on 22 February 1980. It took quite a while to drive her heart into the typically fatal rhythm of ventricular fibrillation, during which time the tension rose in the crowded room.

Finally, the CRT display showed the classical EGG signal that indicated fibrillation. After ten years of effort, the real moment of truth for the AICD system was at hand. In about 15 seconds, the AICD was to sense the lethal rhythm and fire a 600-Volt pulse into the heart.

But that did not happen! At 30 seconds, with no response from the AICD, Dr. Reid started charging the external defibrillator. He placed the paddles on the woman’s chest and yelled “stand back” when, at last, the AICD “automatically” fired. After an 8-second post-shock recorder recovery time, the patient once again displayed a normal ECG signal.

ECG record made with the APL recording equipment

Only a short portion of the 40 seconds of time that the patient was in ventricular fibrillation is shown. It was probably the longest 40 seconds that the attendees had ever endured, but the AICD fired and promptly restored the patient’s heartbeat to a normal rhythm.