Implantation of the automatic cardioverter-defibrillator.

The automatic implantable cardioverter-defibrillator (AICD) is an electronic device that can be implanted in patients identified as being at high risk for sudden cardiac death (SCD) due to ventricular tachycardia or fibrillation (VT/VF). This device continuously monitors heart rhythm, senses malignant arrhythmias, and aborts them by means of an electronic shock. A previous assessment of the AICD concluded that the device is safe and clinically effective in patients selected on the basis of the demonstration of inducibile Vt/VF during baseline electrophysiological study (EPS). Recent clinical experience and data have indicated that the risk of recurrent VT/VF or SCD in survivors of prior episodes is significant and unpredictable, and that inducibility at baseline EPS cannot reliably discriminate all patients who might be at either high or low risk, or responders to any therapy. Although optimal treatment for noninducible patients remains controversial, the AICD is no longer regarded as a treatment of last resort and is frequently applied as the treatment of choice in patients who are resuscitated from SCD, unassociated with a concurrent myocardial infarction, and in whom a sustained monomorphic ventricular tachycardia cannot be induced in the electrophysiological laboratory.