Prevalence and outcomes of patients receiving implantable cardioverter-defibrillators for primary prevention not based on guidelines.

Implantable cardioverter-defibrillator (ICD) implantation outside practice guidelines remains contentious, particularly during the mandated waiting periods in patients with recent cardiac events. We assessed the prevalence and outcomes of non-guideline-based (NGB) ICD implantations in a tertiary academic medical center, with a specific focus on adjudication of arrhythmia events. All patients who underwent initial primary prevention ICD implantation at our institution from 2004 to 2012 were categorized as having received guideline-based (GB) or NGB implants and were retrospectively assessed for first episode of appropriate ICD therapy and total mortality. Of 807 patients, 137 (17.0%) received NGB implants. During a median follow-up of 2.9 years, patients with NGB implants had similar times to first appropriate ICD therapy (median time to event 1.94 vs 2.17 years in patients with GB implants, p = 0.20). After multivariable analysis, patients with NGB implants remained at higher risk for death (hazard ratio 1.54, 95% confidence interval 1.1 to 2.2, p = 0.03) but not appropriate ICD therapy (hazard ratio 0.83, 95% confidence interval 0.5 to 1.3, p = 0.51). Furthermore, only 1 of 125 patients who underwent implant within the 40-day waiting period after myocardial infarction or 3-month waiting period after revascularization or cardiomyopathy diagnosis received an appropriate therapy within this period. In conclusion, few patients received NGB ICD implants in our academic medical center. Although these patients have similar long-term risk of receiving appropriate ICD therapy compared with patients with GB implants, this risk is very low during the waiting periods mandated by clinical practice guidelines. These results suggest that there is little need to rush into implanting ICDs during these waiting periods.