Effects of digitalis on mortality in a large cohort of implantable cardioverter defibrillator recipients: results of a long-term follow-up study in 1020 patients

Aims The effects of digitalis on mortality in patients with structural heart disease are controversially discussed. We aimed to assess the effects of digitalis administration in implantable cardioverter defibrillator (ICD) recipients. Methods and results This retrospective analysis comprises 1020 consecutive patients who received an ICD at our institution and who were followed for up to 10 years (median 37 months). A total of 438 patients were receiving digitalis at the time of ICD implantation and 582 did not. Patients on digitalis were more often in atrial fibrillation and had more often a prolonged QRS duration of = 120 ms, a severely impaired left ventricular ejection fraction, and higher New York Heart Association (NYHA) classification heart failure. Crude Kaplan-Meier analysis demonstrated significantly higher mortality in patients on digitalis (HR = 2.47; 95% CI 1.87-3.25; P = 0.001). After adjustment for patient characteristics found statistically significant in adjusted Cox regression analysis (age, gender, NYHAclassification, and QRS duration of = 120 ms), a HR of 1.65 remained (95% CI 1.14-2.39; P = 0.01). Patients on digitalis died more often from cardiac arrhythmic and cardiac non-arrhythmic causes than patients not on digitalis (P = 0.04). There was no difference in mortality between patients receiving digitoxin and those receiving digoxin (HR = 1.55; 95% CI 0.74-3.25; P = 0.25). Conclusion In this large ICD patient population, digitalis use at baseline was independently associated with increased mortality even after careful adjustment for possible confounders. Digitalis should be used with great caution in this population.