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

https://doi.org/10.1016/j.amjcard.2009.12.057Get rights and content

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.

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Methods

We investigated, in an observational, single-center study, the risk factors for appropriate ICD shocks, inappropriate ICD shocks, and interval to all-cause mortality in 434 men and 115 women (mean age 74 years) with heart failure and ICDs. Of the 549 patients, 322 (59%) had ischemic cardiomyopathy and 227 (41%) had nonischemic cardiomyopathy.

The left ventricular ejection fraction was measured from 2-dimensional echocardiograms, as previously described.7 At follow-up every 3 months, the ICD was

Results

Of 549 patients, 163 (30%) had appropriate ICD shocks, 71 (13%) had inappropriate ICD shocks, and 63 (12%) died. Table 1 lists the baseline characteristics of patients with and without inappropriate shocks and the levels of statistical significance. The mean follow-up was 1,243 ± 655 days.

Appropriate ICD shocks occurred in 33 (46%) of 71 patients who had inappropriate ICD shocks and in 130 (27%) of 478 patients who had no inappropriate ICD shocks (p <0.0001). Of the 71 patients with

Discussion

In the present study of 549 patients with heart failure and ICDs, smoking significantly increased the incidence of appropriate ICD shocks 3.7 times, and the use of statins significantly reduced appropriate ICD shocks by 46%. In the MADIT II trial, smoking significantly increased the incidence of appropriate ICD shocks 2.1 times and inappropriate ICD shocks 2.9 times.1 In 209 patients with heart failure and combined cardiac resynchronization-ICD therapy, smoking significantly increased the

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