Effect of Digitalis on ICD or CRT-D Recipients: A Systematic Review and Meta-Analysis

Background: Digitalis has been widely utilized for heart failure therapy and several studies have demonstrated an association of digitalis and adverse outcome events in patients receiving implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds). Hence, we conducted this meta-analysis to assess the effect of digitalis on ICD or CRT-D recipients. Methods: We systematically retrieved relevant studies using the Cochrane Library, PubMed, and Embase database. A random effect model was used to pool the effect estimates (hazard ratios (HRs) and 95% confidence intervals (CIs)) when the studies were of high heterogeneity, otherwise a fixed effect model was used. Results: Twenty-one articles containing 44,761 ICD or CRT-D recipients were included. Digitalis was associated with an increased rate of appropriate shocks (HR = 1.65, 95% CI: 1.46-1.86, p < 0.001) and a shortened time to first appropriate shock (HR = 1.76, 95% CI: 1.17-2.65, p = 0.007) in ICD or CRT-D recipients. Furthermore, the all-cause mortality increased in ICD recipients with digitalis therapy (HR = 1.70, 95% CI: 1.34-2.16, p < 0.01), but the all-cause mortality was unchanged in CRT-D recipients (HR = 1.55, 95% CI: 0.92-2.60, p = 0.10) or patients who received ICD or CRT-D therapy (HR = 1.09, 95% CI: 0.80-1.48, p = 0.20). The sensitivity analyses confirmed the robustness of the results. Conclusion: ICD recipients with digitalis therapy may tend to have higher mortality rates, but digitalis may not be associated with the mortality rate of CRT-D recipients. Further studies are required to confirm the effects of digitalis on ICD or CRT-D recipients.

Automated summary

A meta-analysis was conducted to assess the effect of digitalis on recipients of implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy defibrillators (CRT-D). The results showed that digitalis was associated with an increased rate of appropriate shocks and a shortened time to first appropriate shock in ICD or CRT-D recipients. Furthermore, digitalis therapy was found to increase all-cause mortality in ICD recipients, but had no effect on the mortality rate of CRT-D recipients or patients who received ICD or CRT-D therapy.