The implantable cardioverter-defibrillator (ICD) is highly effective in terminating ventricular tachyarrhythmias, including ventricular tachycardia (VT) and ventricular fibrillation (VF), thereby aborting sudden cardiac death (SCD). ICD use has been associated with improved survival due to fewer arrhythmic deaths, when compared to antiarrhythmic drugs in survivors of sudden cardiac death (SCD). There is also evidence of benefit when used for primary prevention in selected groups of patients. (See "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy" and "Role of implantable cardioverter-defibrillators for the primary prevention of sudden cardiac death after myocardial infarction".)
There are a variety of potential complications associated with ICD use . However, the rate of complications related to the ICD has fallen markedly with the evolution from a large device that required an abdominal pocket and insertion of an epicardial lead system via thoracotomy to the current use of much smaller transvenous pectoral devices [2,3]. In one report, the incidence of complications with nonthoracotomy ICDs was significantly lower with a pectoral compared to an abdominal generator site (6 versus 13 percent) .
Complications associated with an ICD will be reviewed here. The general principles of the ICD, and recommendations for ICD use, are discussed separately. (See "General principles of the implantable cardioverter-defibrillator" and "Role of implantable cardioverter-defibrillators for the primary prevention of sudden cardiac death after myocardial infarction", section on 'Summary and recommendations' and "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy", section on 'Our approach'.)
The exact incidence of ICD malfunction is difficult to determine due to inconsistent definitions and the lack of mandatory reporting. Information comes from small observational studies, as well as from annual reports filed with the United States Food and Drug Administration by companies that make devices and from voluntary registries [4-6]. The latter sources generally include device malfunctions severe enough to require explantation.
The incidence of a broad list of major and minor complications was illustrated in a prospective study of 778 patients receiving a transvenous ICD. The rate of freedom from any adverse event at 1, 3, and 12 months was 79, 68, and 51 percent, respectively . Among the complications that occurred, 60 percent were due to the ICD system, 29 percent were related to the implantation procedure, and 11 percent were not device related. The most common events were inappropriate detection and subsequent delivery of a shock (16 percent), which usually resolved with device reprogramming or drug readjustment, wound/pocket problems (4 percent) and lead/ICD can dislodgement or migration (3 percent).