QTc interval as a guide to select those patients with congestive heart failure and reduced left ventricular systolic function who will benefit from antiarrhythmic treatment with dofetilide

Abstract

Background—A prolonged QTc interval is considered a contraindication for class III antiarrhythmic drugs, but the influence of a normal or a slightly increased baseline QTc interval on the risk or benefit of treatment with a class III antiarrhythmic drug is not sufficiently clarified. Methods and Results—This prospectively defined substudy included 703 patients enrolled in the Danish Investigations of Arrhythmia and Mortality on Dofetilide-Congestive Heart Failure (DIAMOND-CHF) study. Patients included had moderate to severe CHF and reduced left ventricular systolic function. Baseline QTc interval was measured before randomization to either dofetilide, a new class III antiarrhythmic drug, or placebo. During a median follow-up of 18 months (minimum 1 year), 285 patients (41%) died. Baseline QTc interval had no prognostic value on survival in placebo-treated patients. In dofetilide-treated patients, a baseline QTc interval <429 ms was associated with a significant risk reduction (risk ratio 0.4, 95% CI 0.3 t...