Long-term effects of theophylline in patients with symptomatic atrial fibrillation and a slow ventricular response

The purpose of the present study was to investigate the long-term effects of oral theophylline in patients with atrial fibrillation (AF) and a slow ventricular response. In 17 patients (age: 78 ± 9 years) with symptomatic AF and a slow ventricular response not related to drugs, resting electrocardiogram and 24-hour Holter recording were performed before and 5-6 days after the administration of slow-release theophylline (700 mg daily) and successively every 3 months during the long-term phase. Fourteen patients had organic heart disease, 13 complained of syncope or presyncope and 4 of asthenia and easy fatigue. At the steady-state evaluation, theophylline significantly increased resting heart rate (HR) by 42%, mean 24-hour HR by 31% and minimal 24-hour HR by 34%. Cardiac pauses > 2500 ms disappeared or markedly decreased. The daily number of wide QRS complexes increased. Serum theophylline level was 13 ± 5 ng/ml. During the follow-up period (20 ± 18 months) the mean daily theophylline dosage was 450 mg and the mean serum theophylline level 9 ng/ml. Seven patients died: 1 because of heart failure and 6 because of non cardiac death. One patient complained of a syncopal episode during one visit. The drug markedly reduced asthenia and easy fatigue. During the long-term phase, HR increased spontaneously in 3 patients and the treatment was interrupted. In 2 patients theophylline had to be discontinued because of gastric intolerance. During long-term therapy, the HR was similar to that observed at the steady-state evaluation despite the reduction in the daily dosage. These data suggest theophylline as an effective therapy in most patients with symptomatic AF and a show ventricular response.