Aminophylline induced atrial fibrillation.

Atrial fibrillation (AF) with a rapid ventricular response was induced by intravenous (i.v.) aminophylline during treatment for symptomatic pulmonary disease in three patients who had no evidence of underlying heart disease or previous cardiac arrhythmia. Serum theophylline concentration was therapeutic in two patients and toxic in the third. Previous reports of AF related to aminophylline have underscored its association with toxic serum theophylline concentration. Conversion to sinus rhythm occurred at a time interval (9-14 hours) appropriate to the serum decay of aminophylline, after its cessation. A shortened atrial refractory period and dispersed recovery of excitability consequent to aminophylline may engender multiple reentrant circuits and lead to AF. i.v. diltiazem was more effective than digoxin in the ventricular rate control of AF prior to conversion to sinus rhythm.