Verapamil or adenosine for the immediate treatment of supraventricular tachycardia.

A comparison of verapamil with adenosine for the immediate treatment of supraventricular tachycardia was made from a retrospective review of 164 spontaneous episodes of paroxysmal tachycardia in 43 patients. Verapamil administered to 33 patients restored sinus rhythm in 91 of 112 episodes (81 per cent). Hypotension occurred in 9 per cent of episodes. Adenosine terminated 94 per cent of episodes of supraventricular tachycardia in 25 patients. The arrhythmia recurred shortly after adenosine restored sinus rhythm in 20 episodes. Transient side effects were common. Fifteen patients were treated with both agents. Adenosine was successful in all, but verapamil failed to restore sinus rhythm at least once in seven of the 15 patients. Early recurrence of tachycardia occurred in five of these after adenosine, but in only one after verapamil. Verapamil and adenosine are both effective in the treatment of supraventricular tachycardia; adenosine has the higher success rate and is safer, but transient symptoms are common and arrhythmias may recur.