Digoxin provides symptomatic relief in patients with
systolic heart failure, yet it has potential proarrhythmic mechanisms and has not been formally studied in patients with
cardiac resynchronization therapy-
defibrillators (CRT-Ds). We evaluated the association between
digoxin use and appropriate
tachyarrhythmia therapy in patients with CRT-D with advanced
heart failure, analyzing the incidence of appropriate device
therapies and overall survival in 350 consecutive primary prevention recipients with CRT-D with baseline left ventricular ejection fraction (LVEF) ≤35%, non-
right bundle-branch block native QRS complex ≥120 ms, New York Heart Association III to IV
heart failure, and significant
coronary artery disease.
Digoxin was prescribed in 162 patients (46%) at discharge from CRT-D implant. Over 48 ± 32 months of follow-up, 59 patients (17%) received ≥1 appropriate
shock.
Digoxin therapy was associated with shorter time to first
shock in intention-to-treat (corrected hazard ratio 2.18, 95% confidence interval 1.23 to 3.87, p = 0.007) and on-treatment analysis (corrected hazard ratio 2.27, 95% confidence interval 1.27 to 4.07, p = 0.006). Patients prescribed
digoxin had a lower baseline LVEF, and
digoxin therapy was associated with increased risk of shocks only in patients with LVEF <22% (median); there was no increased risk in patients with LVEF ≥22%. Overall survival and incidence of antitachycardia pacing were similar regardless of
digoxin therapy. In conclusion,
digoxin therapy is associated with increased likelihood of appropriate CRT-D shocks for rapid ventricular arrhythmias in primary prevention patients with
coronary artery disease, and this risk appears to be most evident in patients with more severe baseline
LV dysfunction.
Digoxin use should be reexamined prospectively in patients with CRT-D.