# Digitalis Therapy Is Associated With an Increased Risk of ICD Shock Delivery and Device Revision

## TL;DR

Digitalis therapy in heart failure patients with ICD devices is linked to more device revisions and shocks, but not higher mortality or major complications.

## Contribution

Identifies increased device-related risks with digitalis therapy in ICD/CRT-ICD patients, despite similar mortality and major event rates.

## Key findings

- Digitalis-treated patients had higher ICD shock delivery rates (19.7% vs. 15.0%)
- Digitalis therapy was associated with increased device revision rates (11.4% vs. 7.5%)
- No significant differences in mortality or major cardiovascular events were observed

## Abstract

Digitalis glycosides are employed for rate control of atrial fibrillation and treatment of heart failure. Previous studies suggested potential harmful effects of digitalis therapy. The aim of the present study was to assess the prevalence and potential impact of digitalis therapy on outcomes in patients with systolic failure who were implanted with an ICD‐ or CRT‐ICD system.

The German Device Registry is a nationwide, prospective registry with a 1‐year follow‐up investigating 4384 patients receiving either ICD or CRT systems in 52 German centers. The present analysis focused on the presence of digitalis therapy in 3826 patients undergoing device implantation. Patients receiving digitalis therapy (n = 800) presented a more severely impaired left ventricular function, higher NYHA class, and an increased incidence of left bundle branch block. Consequently, the implantation of CRT systems was more common in this group. One‐year mortality did not significantly differ between both groups (9.1% vs. 7.4%, p = 0.14). Similar results were obtained for the combined endpoint, including death, myocardial infarction, and stroke. ICD shock delivery (19.7% vs. 15.0%, p = 0.006) and device revision (11.4% vs. 7.5%, p < 0.004) were more common in digitalis‐treated patients.

In this study in patients undergoing ICD or CRT implantation, an association of digitalis therapy with an increased risk of device revision was observed. Of note, mortality or severe cardiovascular events did not differ between both groups. Furthermore, an increased risk of ICD shock delivery was observed in digitalis‐treated patients.

In the presence of more nonischemic cardiomyopathy and more comorbidities in the digoxin group, digitalis glycosides were associated with an increased risk for rehospitalization or device revision, while no significant differences in mortality or major complications, including stroke or myocardial infarction, were observed.