THE EFFECT OF MAGNESIUM VERSUS VERAPAMIL ON SUPRAVENTRICULAR ARRHYTHMIAS

Magnesium has previously been used in the treatment of various arrhyth mias, but few randomized and prospective studies are available. In a s ingle-blind study, the efficacy and safety of intravenous magnesium su lfate (bolus doses of 5 + 5 mmol followed by infusion of 0.04 mmol/min ) versus verapamil (5 + 5 mg followed by 0.1 mg/min) was evaluated in 57 patients with supraventricular arrhythmias (supraventricular tachyc ardia, atrial fibrillation, and atrial flutter) of recent onset (less than 1 week). Fifteen (58%) of the patients receiving magnesium (n = 2 6) converted to sinus rhythm within 4 h, and 16 (62%) within 24 h. Ver apamil caused a lower ventricular rate, but only six (19%) of the pati ents (n = 31) converted to sinus rhythm within 4 h (p < 0.01) and 16 ( 52%) within 24 h (NS). No side effects were observed during magnesium infusion, whereas six patients receiving verapamil had to be withdrawn from further study medication due to symptomatic side effects (hypote nsion in three, cardiac failure in three). Magnesium appears to be an effective and safe drug for the treatment of supraventricular arrhythm ias. The overall efficacy for conversion to sinus rhythm is at least a s effective as with verapamil, and its action is more rapid.