INTRAVENOUS DILTIAZEM IN SUPRAVENTRICULAR TACHYARRHYTHMIAS

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, uncontr olled trial, 34 patients with supraventricular tachyarrhythmias (15 wi th paroxysmal supraventricular tachycardia [PSVT], 17 with atrial fibr illation, and 2 with atrial flutter) were treated with diltiazem 150 m u g/kg intravenous bolus once or repeated at the same dose within 20 a nd 40 minutes if the arrhythmia had not disappeared. Conversion to sin us 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 patient s with atrial flutter. Improvement or partial treatment success tie, p ersistence of arrhythmia but with a ventricular rate lower than 100 be ats/min) was observed in 8 patients with atrial fibrillation and 1 wit h 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 diastoli c blood pressure increases averaged 10 mm Hg and were associated with hemodynamic improvement. Only four patients complained of transient he adache and facial erythema after the first dose of diltiazem.