Atrioventricular node blocking agents including
beta-adrenergic blockers, non-
dihydropyridine calcium channel blockers and
digoxin are usually effective in controlling ventricular rate in
atrial fibrillation and flutter. Intravenous beta-blockers and non-
dihydropyridine calcium channel blockers are equally effective in rapidly controlling the ventricular rate. The addition of
digoxin to the regimen causes a favorable outcome but
digoxin as a single agent is generally less effective in slowing the ventricular rate in acute setting.
Clonidine,
magnesium, and
amiodarone have also been used for acute ventricular rate control in
atrial fibrillation. Limited data suggest that combination regimens provide better ventricular rate control than any agent alone. The agent of first choice is usually individualized depending upon the clinical situation. Beta-blockers are preferable in patients with
myocardial ischemia,
myocardial infarction and
hyperthyroidism and in post-operative state, but should be avoided in patients with
bronchial asthma and
chronic obstructive pulmonary disease where non-
dihydropyridine calcium channel blockers are preferred. Beta-blockers are preferred drugs used for acute ventricular rate control in
atrial fibrillation during pregnancy. In
atrial fibrillation with
Wolff-Parkinson-White syndrome, beta-
blockers, calcium channel blockers and
digoxin should be avoided, as these drugs are selective atrioventricular node blockers without slowing conduction through the accessory pathway, which can lead to increased transmission of impulses preferentially through the accessory pathway and precipitate
ventricular fibrillation. The
drug of choice for
atrial fibrillation in
pre-excitation syndrome is
procainamide but
propafenone,
flecainide and
disopyramide have also been used. When clinical condition is unstable or patient is hemodynamically compromised, immediate
electrical cardioversion is the treatment of choice, as the best measure to control ventricular rate is by conversion to sinus rhythm. Factors precipitating rapid ventricular rate should be treated as well.