Risk Factors for Appropriate Cardioverter-Defibrillator Shocks, Inappropriate Cardioverter-Defibrillator Shocks, and Time to Mortality in 549 Patients With Heart Failure

We investigated the risk factors for appropriate and inappropriate implantable cardioverter-defibrillator (ICD) shocks and mortality in 549 patients (mean age 74 years) with heart failure and ICDs. During a mean follow-up of 1,243 ± 655 days, of the 549 patients, 163 (30%) had appropriate ICD shocks, 71 (13%) had inappropriate ICD shocks, and 63 (12%) died. Stepwise logistic regression analysis showed that significant independent prognostic factors for appropriate ICD shocks were smoking (odds ratio 3.7) and statins (odds ratio 0.54). The significant independent prognostic factors for inappropriate ICD shocks were atrial fibrillation (odds ratio 6.2) and statins (odds ratio 0.52). Finally, those for the interval to mortality were age (hazard ratio 1.08/1-year increase), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (hazard ratio 0.25), atrial fibrillation (hazard ratio 4.1), right ventricular pacing (hazard ratio 3.6), digoxin (hazard ratio 2.9), hypertension (hazard ratio 5.3), and statins (hazard ratio 0.32). In conclusion, in patients with heart failure and ICDs, smoking increased and statins reduced appropriate ICD shocks, atrial fibrillation increased and statins reduced inappropriate ICD shocks, and the interval to mortality was increased by age, atrial fibrillation, right ventricular pacing, hypertension, and digoxin and reduced by angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and statins.