Outcomes in heart failure patients referred for consideration of implantable cardioverter defibrillator for primary prophylaxis of sudden cardiac death: what are the risks of waiting?

Background: Clinical trials have confirmed that implantable cardioverter defibrillators (ICDs) reduce mortality in patients with a left ventricular ejection fraction below 30%. The 'real-world' prognosis before ICD implantation in such patients is not known. The estimated risk of death is 0.8% per month, and this forms the basis for wait-time recommendations.

Objectives: To determine the consequences of waiting for ICD implantation among heart failure patients eligible for primary prophylactic ICD.

Methods: The present retrospective study evaluated consecutive patients who were deemed eligible for primary prophylactic ICD implantation. Survival outcomes were tracked for patients who declined an ICD, those who accepted and received an ICD, and patients who accepted an ICD but died while waiting.

Results: Of 470 patients referred for evaluation, 218 were deemed eligible for an ICD. A total of 174 of 218 patients (79.8%) accepted an ICD; 39 (17.9%) declined, and five (2.3%) were deemed to be at too great a risk for the procedure. The mortality rate at two years among patients who accepted an ICD was 18.8% before ICD implantation and 12.2% after ICD implantation. Among patients who declined ICD implantation, the two year mortality rate was 5.3%. Among patients waiting for an ICD, five of 19 deaths were out-of- hospital sudden deaths. Of 12 patients who died after ICD implantation, there were no documented out-of-hospital sudden deaths.

Conclusion: Consistent with current estimates, the mortality rate at two years among patients who accepted and were waiting for an ICD implant was 18.8%. After receiving an ICD, the mortality rate was 12.2% at two years.