The effect of verapamil hydrochloride on cardiac rhythm and frequency of arrhythmias in domestic donkey

Abstract

Verapamil is a calcium channel blocker (CCB) that blocks long-lasting calcium channels, resulting in depression of cardiac and vascular function that depends on calcium influx. Verapamil inhibits calcium influx across the cell membrane of the SA and AV nodes. This study was conducted on 10 non-pregnant domestic female donkeys a base-apex lead was used for recording ECG for diagnosing arrhythmias. Sinus arrest (2cases), bradycardia (1case) and wandering pacemaker (1case) were diagnosed before the experiment. Verapamil was injected at the dosage of 0.3 mg/kgBW as an intravenous bolus over 2 minutes. ECG was taken during and at 0, 20, 30, 40, 50, and 60 minutes after injection. Sinus tachycardia was observed in 8 cases during drug injection and limited to one case at 20 and 30 minutes after injection. Wandering pacemaker was seen in one case, 20 minutes after Verapamil injection and disappeared 50 minutes after injection. Bradycardia disappeared during drug injection and reappeared at the minute 10 and remained until the end of experiment. First degree AV block was observed in two cases at the time of drug injection and was observed in only one case 10 minutes after injection. Second degree AV block was recorded in one case at the time of Verapamil injection and was remained stable to the final stage.