ANALYSIS OF DEATHS IN PATIENTS WITH AN IMPLANTABLE CARDIOVERTER DEFIBRILLATOR

The cause of death and clinical characteristics of 26 patients that died after implantable cardioverter defibrilator placement were reviewed and compared to the 145 patients still living after a mean follow-up of 17 months. Operative mortality was 4% (7/171) and resulted from postoperative ventricular arrhythmias (four patients), heart failure (two patients), and respiratory failure (one patient). Operative mortality was significantly higher (1.7% vs 9.6%, P < 0.05) following concomitant surgical procedures. Total late mortality was 11% (18/171). Thirteen deaths (75%) occurred in-hospital from progressive deterioration of left ventricular function (nine patients), arrhythmia (two patients), and noncardiac causes (two patients). Outpatient mortality was 3.5% (6/171) and resulted from presumed sudden cardiac death in five of six patients; two of the five had devices that were inactive, one had high defibrillation thresholds, and two had suspected bradyarrhythmic deaths. One postoperative death and one late in-hospital death were also considered sudden cardiac deaths for a total of seven patients with defibrillation system failures. By multivariant analysis, preoperative clinical characteristics associated with a worse prognosis following defibrillator implantation were identified: presentation as ventricular tachycardia (P < 0.02), induction of sustained monomorphic ventricular tachycardia (P < 0.05), poor left ventricular performance (P < 0.01), poor functional status (P < 0.001), and the use of diuretics (P < 0.01). Frequent device discharges (P < 0.001) and concomitant antitachycardia pacing systems (P < 0.001) were markers for greater arrhythmia recurrence and were potent predictors of a worse prognosis and particularly sudden death.