Efficacy of dofetilide in the treatment of atrial fibrillation-flutter in patients with reduced left ventricular function - A Danish Investigations of Arrhythmia and Mortality ON Dofetilide (DIAMOND) substudy

Background - In patients with left ventricular dysfunction, atrial fibrillation and flutter (AF and AFl, respectively) are common arrhythmias associated with increased morbidity and mortality. The present study investigated the potential of dofetilide in AF-AFl patients with left ventricular dysfunction to restore and maintain sinus rhythm, which might reduce mortality and hospitalizations. Methods and Results - In the Danish Investigations of Arrhythmia and Mortality ON Dofetilide (DIAMOND) studies, 506 patients were in AF-AFl at baseline. Over the course of study, cardioversion occurred in 148 (59%) dofetilide- and 86 (34%) placebo-treated patients. In these patients, the probability of maintaining sinus rhythm for 1 year was 79% with dofetilide versus 42% with placebo (P <0.001). Dofetilide had no effect on all-cause mortality, but restoration and maintenance of sinus rhythm was associated with significant reduction in mortality (risk ratio ERR], 0.44; 95% CI, 0.30 to 0.631 P <0.0001). In addition, dofetilide therapy was associated with a significantly lower risk ratio versus placebo for either all-cause (RR, 0.70; 95% CI, 0.56 to 0.89; P less than or equal to0.005) or congestive heart failure (RR, 0.69; 95% CI, 0.51 to 0.93; P less than or equal to0.02) rehospitalization. Conclusions - Dofetilide is safe and increases the probability of obtaining and maintaining sinus rhythm in patients with structural heart disease. The present study suggests that restoration of sinus rhythm is associated with improved survival.