Response of automatic atrial tachycardia to intravenous adenosine.

The electrophysiologic responses to intravenous adenosine observed in a patient with automatic atrial tachycardia are presented. Although the development of advanced AV block was not unexpected, prolongation of atrial cycle lengths before the abrupt termination of the arrhythmia, and the subsequent transient, but total, suppression of all electrical cardiac activity were. The atrial arrhythmia reappeared when adenosine effects dissipated. The current tendency to use intravenous adenosine as the drug of first choice in the acute management and diagnosis of paroxysmal supraventricular arrhythmias, despite its lack of superiority over verapamil, will probably result in many more reports of unexpected adverse effects following its use.