To determine whether implantable cardioverter-defibrillator (ICD) therapy is influenced by new technological advances, we studied the follow-up of 480 patients who underwent ICD implantation between January 1984 and March 1996. In these patients surgical risk, complications, and mean survival was evaluated in relation to the time of ICD implant: 124 patients (26%) underwent ICD implantation during 1984–1989 (group 1) and 356 patients (74%) during 1990–1996 (group 2). Epicardial lead systems were implanted in 209 patients (44%), whereas transvenous lead systems were implanted in 271 patients (56%). Perioperatively, 13 patients (3%) died, significantly more frequently after epicardial (12 of 209 patients, 5%) than after transvenous (1 of 271 patients, <1%) ICD implantation (p < 0.05). During a mean follow-up of 28 ± 26 months (range < 1 to 129 months), 97 patients (20%) died. Of these, 9 patients (2%) died from sudden arrhythmic death; 7 patients (1%) died suddenly, probably as a result of nonarrhythmic causes; 60 (13%) died from other cardiac causes (congestive heart failure, myocardial infarction); and 21 (4%) died from noncardiac causes. The 3-, 5-, and 6-year survival for arrhythmic mortality was 90% and 89% in patients who underwent ICD implantation during 1984–1989 as compared with a 3-, 5-, and 6-year survival rate of 97% in patients with ICD implant since 1990 (p <0.05). In addition, the 3-, 5-, and 6-year total mortality was significantly better in group 2 (81%, 67%, 67%) than in group 1 (70%, 61%, 54%) (p <0.05). A total of 362 (75%) received ICD discharges (mean incidence 21 ± 43 shocks per patient), with a similar incidence among both patient groups (group 1: 78%; group 2: 74%; p = nonsignificant). The mean interval between ICD implant and the first ICD therapy was similar between both groups with a mean interval of 11 ± 13 months (group 1: 11 ± 13 months, group 2: 9 ± 6 months; p = nonsignificant). Our data demonstrate that patients who underwent ICD implantation since 1990 clearly benefit from technical advances (nonthoracotomy ICDs, biphasic shocks, antitachycardia pacing). (Am J Cardiol 1996;78(suppl 5A):3–8)