The aim of an implantable cardioverter-defibrillator is to stop severe cardiac arrhythmias (accelerations).
These are essentially severe ventricular arrhythmias (tachycardia or ventricular fibrillation) that can progress to permanent cardiac arrest if not stopped quickly.
In many studies, the implantation of these prostheses has shown a very significant reduction in overall and rhythm-related mortality in selected patients.
This completely autonomous prosthesis is placed under the skin near the collarbone and is connected to the heart by one or more leads. This device continuously monitors the patient’s heart rhythm and is able to recognise potentially serious arrhythmias, which it will then try to stop.
The defibrillator then has two options for stopping these episodes of tachycardia:
- it can either deliver a rapid ventricular stimulation, which has the advantage of being almost painless for the patient but with the risk of being ineffective;
- or (in case the first method fails) the defibrillator can deliver an electric shock, which may be unpleasant for the patient but has the advantage of almost always stopping the initial arrhythmia.
Note that in most defibrillators, a pacemaker is incorporated, which aims to avoid any risk of the heart slowing down.