Clinical research
Incidence of appropriate cardioverter-defibrillator shocks and mortality in patients with implantable cardioverter-defibrillators with ischemic cardiomyopathy versus nonischemic cardiomyopathy at 33-month follow-up

Introduction: The aim of the study was to investigate at long-term follow-up the incidence of appropriate implantable cardioverter-defibrillator (ICD) shocks and of all-cause mortality in patients with ICDs with ischemic cardiomyopathy versus nonischemic cardiomyopathy.

Material and methods: ICDs were implanted in 485 patients with ischemic cardiomyopathy and in 299 patients with nonischemic cardiomyopathy, all of whom had coronary angiography. Baseline characteristics were not significantly different between the 2 groups. Follow-up was 965 days in patients with ischemic cardiomyopathy versus 1039 days in patients with nonischemic cardiomyopathy (p not significant). The ICDs were interrogated every 3 months to see if shocks occurred.

Results: Appropriate ICD shocks occurred in 179 of 485 patients (37%) with ischemic cardiomyopathy and in 93 of 299 patients (31%) with nonischemic cardiomyopathy (p not significant). All-cause mortality occurred in 162 of 485 patients (33%) with ischemic cardiomyopathy and in 70 of 299 patients (23%) with nonischemic cardiomyopathy (p = 0.002).

Conclusions: The incidence of appropriate ICD shocks was not significantly different at 33-month follow-up in patients with ischemic cardiomyopathy versus nonischemic cardiomyopathy. However, patients with ischemic cardiomyopathy had a significantly higher incidence of all-cause mortality than patients with nonischemic cardiomyopathy (p = 0.002).