Verapamil in cardiac arrhythmias: an overview.

1. Verapamil remains the most widely used calcium antagonist for the treatment of cardiac arrhythmias. It is the most potent and effective drug for the acute treatment of paroxysmal supraventricular tachycardia particularly, circus movement tachycardia with or without pre-excitation. 2. As it is a powerful depressant of atrioventricular nodal conduction it reduces the ventricular rate in atrial flutter and fibrillation with reversion to sinus rhythm in a proportion of patients with these arrhythmias. Because verapamil does not increase airways resistance it can be used in patients with obstructive airways disease. The drug is also effective in supraventricular tachyarrhythmias following open-heart surgery and myocardial infarction. 3. It is not an effective drug against ventricular arrhythmias unless due to coronary artery spasm. The use of verapamil should be avoided in the presence of sick sinus node syndrome, clinical cardiac failure and treatment with other negative inotropic drugs.