Atrial fibrillation and flutter. Immediate control and conversion with intravenously administered verapamil

Abstract

The safety and efficacy of the intravenous (IV) calcium channel blocker, verapamil, in controlling the ventricular response or converting to sinus rhythm patients with atrial flutter or atrial fibrillation were assessed. Seventeen patients (nine with atrial flutter and eight with atrial fibrillation) with these arrhythmias that were difficult to control pharmacologically were chosen for the study. All patients at the time of study were receiving digoxin. Either verapamil or placebo was chosen randomly and a bolus of 0.075 mg/kg (up to 5 mg) was administered. Twelve patients had a marked reduction in their ventricular response after IV administration of verapamil (seven with atrial flutter and five with atrial fibrillation). None of these 12 patients converted (nonconverters). The average reduction in heart rate was from 120 +/- 6 beats per minute to a minimum of 83 +/- 13 beats per minute within 20 minutes after drug administration. Verapamil was found to convert five patients with atrial arrhythmias to sinus rhythm (two with atrial flutter and three with atrial fibrillation) (converters). In addition, three patients with atrial arrhythmias of less than one month who did not convert with parenteral drug therapy converted within 24 hours while receiving the oral drug. Converters had their supraventricular arrhythmias of significantly shorter duration (median, three hours v 30 days) and tended to have smaller left atrial size (3.8 +/- 0.7 cm v 4.3 +/- 1.3 cm) compared with the nonconverters. We conclude that verapamil is safe and effective when administered IV to patients with atrial flutter and fibrillation for control of ventricular response. In short duration atrial arrhythmias, conversion to sinus rhythm is likely once the ventricular response is controlled.

The peri‐operative management of atrial fibrillation

“…Verapamil. Conversion of atrial fibrillation to sinus rhythm using verapamil is generally poor (8-37%) [72,[83][84][85][86]. Amiodarone, esmolol and flecainide are all more effective than verapamil in converting recent onset atrial fibrillation to sinus rhythm [60,72,87].…”

“…Amiodarone, esmolol and flecainide are all more effective than verapamil in converting recent onset atrial fibrillation to sinus rhythm [60,72,87]. However, verapamil is effective in slowing the ventricular rate [83][84][85][86][88][89][90].…”

Acute pressure overload cardiac arrhythmias are dependent on the presence of myocardial tissue catecholamines

“…Historically, calcium antagonists did not seem to exert any eVect on AF, apart from controlling the ventricular rate. 34 By contrast, a reduced probability of spontaneous termination of AF during infusion of diltiazem or verapamil was reported. 11 18 35 After internal electrical cardioversion of chronic AF, refractory periods were shorter in patients pretreated with verapamil than in those not pretreated 22 ; moreover, verapamil pretreatment increased the duration of AF in dogs both before and after long term atrial pacing.…”

Effects of pretreatment with verapamil on early recurrences after electrical cardioversion of persistent atrial fibrillation: a randomised study

“…9 12 14 16 23 28 Despite these encouraging findings, there is controversial clinical evidence of a possible role of pretreatment with intracellular calcium lowering drugs in the prevention of electrical remodelling induced by persistent or chronic AF. Historically, calcium antagonists did not seem to exert any effect on AF, apart from controlling the ventricular rate 34. By contrast, a reduced probability of spontaneous termination of AF during infusion of diltiazem or verapamil was reported 11…”