All about implantable cardiac defibrillators (ICDs)

Updated 17 June 2015

Medical validation: 10 December 2015

Heart rhythm disturbances (fibrillation atrial, ventricular, tachycardia, etc.) and the diseases associated with them cause 20 000 deaths per year. One of the therapeutic approaches for these arrhythmias is based on the implantation of pacemakers or automatic implantable defibrillators (ICDs).

50 sudden deaths occur every year in France. An essential cause of these deaths is extreme runaway heart contractions (the ventricular tachycardia ) which can become totally anarchic and ineffective: it is the ventricular fibrillation . This accident can lead to reversible cardiac arrest ( syncope ) or not ( sudden death ).

What is an Automatic Implantable Defibrillator (AID)? The implantable cardiac defibrillator also called automatic implantable defibrillator (AID) is a small device (box) implanted under the skin that detects and corrects abnormalities in the electrical activity of the heart. It can detect:

Ventricular tachycardia (heartbeat too fast ). In this case, it sends a series of fast pulses (tachycardia stimulation) or an electric shock to the heart in order to quickly restore an adequate heart rate; A bradycardia (when the heart beats too slowly). So, it acts as a pacemaker to restore a normal heart rate. Cardiomyopathy associated with a high risk of sudden cardiac death. A drug treatment is sometimes associated to reduce the occurrence of arrhythmias.

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Why install an automatic implantable defibrillator? Every year, 80 000 people in France are victims of such cardiac arrhythmias responsible for 02 annual deaths . Faced with such a cardiac arrest, the immediate rescue actions are too often absent or ineffective because the entourage is too rarely trained. According to Prof. Jean-Paul Fauchier, President of the French Society of Cardiology, “the poor regulation, in most of our cities, of emergency transport to the appropriate Medical Center means that the chances of survival do not exceed 4%” . 2

However, in addition to a Adequate resuscitation and an electric shock thanks to an external defibrillator, a solution exists: implant a defibrillator on patients at risk.

Numerous studies have attested to its tolerance and its benefits in the prevention of sudden death in coronary patients:

Reduction of a third of patient mortality who escaped cardiac arrest compared to drug treatment alone; Halving the risk of death from high-risk heart failure patients compared to patients receiving only drug treatment. The defibrillator is placed in the operating room under local anesthesia. He is sometimes associated with intravenous sedation . A 4 to 5 cm incision is necessary to place the case on or under the pectoral muscle (at the level of the shoulder, under the collarbone). It is connected to electrodes which are introduced by a vein to the heart.

The duration of the operation is of approximately one hour for a device with one or two probes . Technological progress has made it possible to reduce the size of defibrillators so much so that today cases measure between 9 and 11 mm thick, weigh between 43 and 80 g.

Note : the healthcare team will give you a Defibrillator card (European card), always keep it with your identity papers.

What is the lifespan of an ICD? Developed twenty years ago by Dr Mirowsky, the implantable defibrillator has lost in volume but gained in strength and reliability .

Its lifespan is between 5 and 10 years. The longevity of the defibrillator will be shorter if the box is used often.

Its price oscillates Between 15 000 and 20 000 euros.

Who are the people who can benefit from an ICD? Two situations require the implantation of a defibrillator:

In a person who has already had a severe ventricular rhythm disorder with or without cardiac arrest (secondary prevention to avoid recurrence); In one person who has never presented an arrhythmia but has a heart disease likely to predispose to it, for example a large myocardial infarction, an insufficiency heart with dilated heart, genetic diseases affecting the electrical properties of the heart … (secondary prevention before the first event). To see also

These patients, once identified, must be referred to a specialized center who will confirm the indication and perform the procedure during which the defibrillator will be placed. The aim of these recommendations is to increase the number of establishments, but also to allow a better identification of candidates for such an operation and to erase certain regional disparities.

Living with an automatic implantable defibrillator Once the defibrillator is installed, it is possible to live quite normally. It may take 4 weeks for the ICD electrodes to attach to the heart. During this period, there are important guidelines to follow, such as avoiding carrying heavy weights and avoiding sports. Normally after this period it is quite possible to resume all the usual activities.

However, there are certain precautions to adopt in daily life to avoid any problem or malfunction:

During a medical consultation or before going a medical examination, report that you have a defibrillator ; Avoid electrical appliances in poor condition Steps ; If you hear ring your defibrillator , if you become unwell or lose consciousness, contact a doctor or the French Federation of Cardiology; At the gantries airport security, do not pass and show the staff your coach you of a defibrillator; Do not put your cell phone in a pocket next to the ICD. Preferably call from the opposite ear ; If you are in shock, sit or lie down for a few minutes , calm down if necessary, and resume calm activity. An isolated shock is not an emergency. What to do in the event of an electric shock? As recommended, receiving a sudden and unexpected discharge does not require surrender in the emergency room if you feel well afterwards.

On the other hand, it is good to consult quickly if:

After receiving an electric shock you do not feel better . Symptoms are getting worse If you receive several electric shocks 69263714 The implantable automatic defibrillator without a lead Without making the probe disappear, an American start-up, Cameron Health, designed ICDs implanted directly under the skin and no longer inside of the heart, baptized S-ICD®. Presented at the Cardiostim World Congress, it received the “innovation price” in the management of rhythmic pathologies. The case which detects an arrhythmia is placed under the skin in the armpit, while the probe runs along the rib and then rises vertically towards the heart without being introduced into the veins. The results of studies carried out on this innovative device show “good discrimination of rhythm disorders, between potentially fatal disorders and those which do not require immediate treatment” , as well as good efficiency of the shocks delivered, underlines Professor Ritter. 1 And above all, adds the cardiologist, they show the disappearance of potentially vascular complications

For Jean-Luc Hamelin, president of the Association of Cardiac Defibrillator Powers (APODEC), ICDs without a probe are “a good start … but there is always a probe! And the size of the case continues to grow problematic”. If he welcomes the technical progress, he emphasizes that the implantation under the armpit where there is little flesh is far from be the panacea. “The shape and size of the housing needs to be improved” , he confides to Doctissimo, on the sidelines of the Cardiostim congress.

By elsewhere, the analysis of cardiac parameters would be less good than with an endocavitary probe, according to him. “We lose in finesse of analysis. In addition, the shock must be stronger to be able to defibrillate” , causing severe pain to patients. Its intensity, of To 65 Joules, is in fact up to twice that of conventional DAIs , with intracardiac probe. Progress is therefore expected on these different aspects, but these new devices already bear witness to the efforts made to improve the lives of implanted patients.


1-Constitution of the World Health Organization
2- NHS UK conditions