Efficacy and Safety of Intravenous Diltiazem vs. Verapamil in the Acute Treatment of Atrial Fibrillation

This study evaluates the effectiveness and safety of intravenous diltiazem and veraparnil for the acute treatment of atrial fibrillation (AF). A double - blind, parallel, randomized and comparative study protocol was used. The study involved 24 patients with AF, a ventricular rate > 120 beats/min and systolic blood pressure >90 mmHg. Patients were randomized to receive either intravenous diltiazem (n= ı2 ) 0.35 mg/kg (maximum 25 mg) or intravenous veraparnil (n= 1 2) O.ı5 mg/kg (maximum ı O mg). Therapeutic response was defined as a 20 % decrease in ventricular rate from basel ine, a heart rate bel o w ı 00/min. and conversion to sinus rhythm. Eleven of 12 patients (% 92) in diltiazem group and 12 of 12 (100 %) in veraparnil group responded (p>0.05). The mean time to achieve response was 2.7±1 minutes for diltiazem and 3.9±5 minutes for veraparnil (p>0.05). The mean reduction in heart rate from baseline was % 35 with veraparnil and % 24 with diltiazem. Veraparnil reduced systolic blood pressure from baseline by 24 % and diastolic blood pressure by 20 %, diltiazem by ll % and ı3 %, respectively. Symptomatic hypotension was observed in 4 patients in veraparnil group and none in diltiazem group (p<0.05). It is concluded that intravenous diltiazem and veraparnil are equally effective in reducing the heart rate and diltiazem seems to be a safer drug to be used for the acute treatment of AF, for symptomatic hypotension is seen more frequently with veraparniL