Intravenous diltiazem in supraventricular tachyarrhythmias

Abstract

Diltiazem is a benzothiazepine calcium channel blocker with depressive activity on sinus and atrioventricular node fibers that is useful in the control of several types of arrhythmias. In an open-label uncontrolled trial, 34 patients with supraventricular tachyarrhythmias (15 with paroxysmal supraventricular tachycardia [PSVT], 17 with atrial fibrillation, and 2 with atrial flutter) were treated with diltiazem 150 μg/kg intravenous bolus once or repeated at the same dose within 20 and 40 minutes if the arrhythmia had not disappeared. Conversion to sinus rhythm was observed in 13 (86.7%) of 15 patients with PSVT, 4 (23.5%) of 17 patients with atrial fibrillation, and 1 (50.0%) of 2 patients with atrial flutter. Improvement or partial treatment success (ie, persistence of arrhythmia but with a ventricular rate lower than 100 beats/min) was observed in 8 patients with atrial fibrillation and 1 with atrial flutter. Five patients with atrial fibrillation and two with PSVT were considered to be treatment failures and received intravenous lanatoside C. No patient developed hypotension. Systolic and diastolic blood pressure increases averaged 10 mm Hg and were associated with hemodynamic improvement. Only four patients complained of transient headache and facial erythema after the first dose of diltiazem.