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.


Dr Tom Keeble Hospital Hero

A couple of weeks ago I wrote about the Southend NHS Hospital heroes awards and asked for help with nominations for someone who has been extremely supportive to SCA UK for the past couple of years – Dr Tom Keeble.

We now need your help to get him as many votes as possible in the public vote – VOTE HERE – a couple of clicks is all that’s needed!

With his CARE (Care After REsucitation) study at the Essex Cardiothoracic Centre he has valuable experience and insights into what life is really like after a cardiac arrest.  Cardiac arrest patients at the CTC now get some of the best care in the country  and with help from SADS UK this is being progressed even further.   Receiving an award like this can help raise his profile and the work he is doing to help patient like us – so a vote for him is a vote for cardiac arrest survivors.

He has supported us for the past couple of years, giving his time freely to do webinars to the group, answering questions for members, raising funds for the group and most notably being a driving force behind the recent Guinness World Record Attempt which was announced just as beiung successful.

Dr Keeble received 29 nominations from members of the public, over half of the total nominations received in total this year, praising him for his outstanding care.

Below are some comments from the nominators:

“Doctor Keeble demonstrates an understanding of how we feel, the overwhelming trials that we survivors face psychologically and emotionally as well as physically. I trust him, and feel safe in his care, and for me that’s top of my list of wants about a Doctor.”

“A true NHS superstar, one of a kind that has a heart of gold, thank you Doctor Tom.”

“The hospital could benefit from hundreds of Doctor Keeble(s), FANTASTIC Man.”

Of his nomination, Doctor Keeble said: “”It is an incredible honour to be nominated for the Hospital Heroes award from patients that I have treated, and I am grateful to all of them. I try to give each and every patient time to understand and explore their diagnosis, investigation and treatment options, being sensitive to the patient’s opinions and getting the right tests and treatments for the right patient, and reassuring when I can.”

Please help and


a couple of clicks is all that’s needed!


It’s Official, we’re Guinness World Record Holders!!

After a nervous wait of some weeks, we’ve heard back from Guinness World Records that our attempt has been approved and that we can officially call ourselves “Guinness World Record Holders!”

It’s been on ice, but we’ve officially done it!

Massive thanks must be given to those involved in organising and supporting the day especially Dr Tom Keeble and all yellow shirted volunteers (Essex Cardiothoracic Centre (Basildon Hospital)SADS UK, et al) for giving their time freely and making it such a wonderful day.

In fact you can repay your thanks in some way by voting for Dr Keeble in the NHS Hospital Heroes Awards that he has been nominated for.  Just click this voting link and select Dr Tom Keeble, then click OK – that’s it!

It is fantastic to get the record and a real testament to the many people involved in the “Chain of Survival” of each of the 127 survivors, so the record is as much for them as it is us.

Survivors came from all over the country with many making a weekend of it and seeing Essex in a new light I think!  Much appreciation must go to those who made the effort to travel long distances and to those where travelling is not easy.  A special thanks must go to those who made significant sacrifices to be there especially the person who broke off from their holiday and flew in from Gran Canaria and then back the next day!

Those taking part in the record attempt were shown the following video which was essentially about them and the emotional 3 years of Sudden Cardiac Arrest UK.

The day was not just about making a record but about bringing together as many as possible to hopefully help them realise they are not alone and that there is indeed Life After Cardiac Arrest!

With a great selection of talks, an exhibition and tours of the cath lab the 300+ attendees had not only plenty to keep them occupied but also a rare chance to chat with others who’d had a similar experience.

We received a good number of feedback forms completed and the response was overwhelmingly positive (92% gave the day a 5/5 and the rest a 4/5!) and again nearly everyone (98%) said that it had been helpful to them.  There were lot’s of positive comments about most of the aspects of the day but many were about the fact that this was an opportunity to meet other survivors.

Some quotes:

“The whole event was one big party, but the attempt with us all in the room, just survivors was the most emotional and happy thing that I have been subject to in years”

“Meeting other survivors and their families, it was like therapy as everyone just gets it.”

“Being part of something amazing and feeling like a majority rather than a minority! Wonderful people with whom I have made friends and something I will treasure forever.”

“So many people with similar tales to tell who had overcome cardiac arrest (with significant help from the NHS and friends and family) and seeing similarities between your own experience and theirs”

“Best experience since my SCA by far.”

“Helpers were amazing”

“Hard to complain about anything really. VERY well organised”

There were a couple of grumbles which related to the timings and we can only apologise as we had a few hiccups along the way which did throw out a little and some on the fly decisions had to be made, so some lessons learnt there.

After the excitement of the day we had a “Celebration of Life” party in the evening which seemed to go down a treat with lots of people letting their hair down and getting in the spirit of things.  Dr Keeble’s dancing and the sight of Gareth simulating resuscitation on him with an alien on his head will be a lasting memory for many! Possibly one of the most emotional moments of the day was the helicopter fly past by the Essex Air Ambulance.

“The evening event was so relaxed with people just getting to know each other – think we all feel we have made friends for life.”

“Amazing day, great organisers and the volunteers were very helpful throughout the day”

“You rock!!!!!! Simply one of the best weekends of my life!!!”

Unfortunately we will only get one copy of an official GWR certificate, but they do sell additional ones for the princely sum of £20!  More information on this will be forthcoming soon.

The whole day was largely funded by donations sourced by Dr Keeble aided by SADS UK and we thank them, the organisations involved and the raffle prize donators hugely.

Obviously as the whole event has been such a success it would be sad not to follow it up with something else, there have been some suggestions already floated in the Facebook group and so we’ll just have to see.  However, these things cost money and although SCA UK isn’t a charity you can help us make events like this happen by supporting us via SADS UK.  We have a JustGiving page which they can take donations on our behalf. If you can spare anything we’d much appreciate it.

Of course the day wouldn’t of happened without the multitude of helpers and volunteers from various organisations (see below) and we thank you all, especially Dr Matt O’Meara of Essex Air Ambulance, Tom Gudde, Kevin Maloney of Headway Essex, Dr Bill Toff and colleagues from Heartwize, Dr Marco Mion, Neil Magee, James Whitfield, Liz Sharpe of Live Your Life Therapies, James Fenwick, Stuart Wright, James Young, St Johns Ambulance, London Ambulance Service, Henry Savage (photography), Alan Larn (video), Rory Keeble (video) and Mark Penn of Penn Sports for the t-shirts.

HeadwayHeadway Essex (NB: until 3pm)

Wel Medical – Resuscitation equipment

Heartwize – Project to bring CPR/AED skills to schools

EHAAT – Air Ambulance service for Essex & Herts

Medtronic – Implant and other cardiac devices

Boston Scientific – Implant and other cardiac devices

Cardiac Science Corporation – AED’s and other cardiac devices

Abiomed – Cardiac products

Cardionovum – Cardiac products such as coronary balloons and stents

Laerdal – Cardiac products

Livanova/Micrport – Cardiac products

Zoll – Defibrillators

Abbot Vascular (formerly St Judes) – Cardiac implants