Aspects of defibrillator therapy in congestive heart failure

The beneficial effects of implantable cardioverter defibrillator (ICD) ther apy in patients (pts) with life-threatening ventricular tachyarrhythmias an d impaired left ventricular (LV) function is still unclear. We studied the follow-up of 410 pts (368 males, 42 females, mean age 57 +/- 11 years) afte r ICD implant. The LV function was assessed by the New York Heart Associati on functional class of heart failure (NYHA). Fifty pts (12 %) were in NYHA I-II, 151 pts (37 %) in NYHA II, 117 pts (29 %) in NYHA II-III and 92 pts ( 22 %) in NYHA III. Epicardial ICD implantation was performed in 209 pts (51 %) and 201 pts (49 %) received nonthoracotomy ICDs. Perioperatively (withi n 30 days after implant), 12 pts (3 %) died, significantly more frequent af ter epicardial (11 of 209 pts, 5 %) than after transvenous ICD implant (1 o f 201 pts, < 1 %) (p < 0.05). During a mean follow-up of 28 +/- 24 months ( range < 1 to 114 months), 90 pts (23 %) died: 9 pts (2 %) died from sudden arrhythmic death and 5 pts (1 %) suddenly, but probably not from arrhythmic causes; 55 pts (14 %) died from cardiac causes (congestive heart failure, myocardial reinfarction) and 21 pts (5 %) from noncardiac causes. The 3-yea r, 5-year and 7-year survival was 92 % to 96 % for arrhythmic mortality in NYHA class I, II and III compared to the S-year survival of 94 %, and a 5-y ear and 7-year survival of 84 % in patients with NYHA class II-III. 338 pts (82 %) received ICD shocks (mean incidence 21 +/- 43 shocks per pt); pts i n NYHA class II (83 %), class II-III (84 %), class III (90 %) received ICD discharges significantly more frequently than in class I-II (64 %) (p < 0.0 5). Our data show that pts with LV dysfunction benefit from ICD therapy and that these pts survive for a considerable time after the first shock. Howe ver, survival is clearly influenced by the degree of left ventricular dysfu nction and, in addition to ICD therapy, aggressive treatment of heart failu re is necessary.