[Implantable ventricular defibrillator. Systematic induction of ventricular arrhythmia is not useful except for...

Checking the efficacy of a defibrillator after its implantation is current practice. This control usually entails induction of ventricular fibrillation (VF). The aim of this study was to assess the utility of this practice in patients with an endovascular system of electrodes. Implantation was acquired when a margin of security of 10 days or more had been obtained. During the postoperative test, the choice of energy was that which reduced VF at implantation. Of the 84 patients included in this study, 59 were implanted with an endovascular electrode system alone and the other 25 patients had endovascular electrodes associated with a subcutaneous patch electrode. The average time from implantation to the postoperative test was 31 +/- 12 days. Arrhythmia sensing was normal and reduction by the defibrillator was observed in all patients. The average energy of the electric shocks was not significantly different to that observed at implantation (18.6 +/- 3.6 J and 19.3 +/- 4.7 J). Fifty patients had antiarrhythmic drugs (amiodarone = 43) at implantation, and 32 at the time of the postoperative test (amiodarone = 17). This study showed that the postoperative test with induction of VF was normal in all patients. Therefore, the authors propose that follow-up should consist of consultation including interrogation of the defibrillator and a chest X-ray to check the position of the electrodes. If one of these tests is abnormal or if the perioperative threshold of defibrillation does not provide an adequate margin of safety, induction of a ventricular arrhythmia is necessary to check the function of the system.