Initial experience with nifekalant hydrochloride (MS-551), a novel class III antiarrhythmic agent, in patients with acute extensive infarction and severe ventricular dysfunction.

Nifekalant hydrocholoride, a novel class III antiarrhythmic agent, was used as the treatment in 4 patients with extensive anterior infarction and severe ventricular dysfunction. The malignant ventricular tachyarrhythmia was effectively suppressed at a relatively low dose, without compromising the hemodynamics, indicating that this potent K+ channel blocker has therapeutic potential for acute myocardial infarction.