CLINICAL EFFECTS OF ORAL THEOPHYLLINE IN ELDERLY PATIENTS WITH SICK SINUS SYNDROME

Theophylline increases the heart rate in patients with normal sinus rh ythm and in patients with sick sinus syndrome. This effect is probably connected to the blockade of adenosine receptors by theophylline. Thi s study evaluated the efficacy of theophylline in 34 elderly patients with symptomatic sinus bradycardia (age 68 +/- 11 years). A resting el ectrocardiogramm, a 24-hour recording and threadmill test were perform ed both before and after administration of slow-release theophylline ( 700 mg/day). The drug increased resting heart rate (from 43 +/- 6 to 6 3 +/- 16 beats/min, p < 0.01), mean 24 hour heart rate (from 49 +/- 7 to 65 +/- 17 beats/min, p < 0.01), and minimal 24 hour heart rate (fro m 34 +/- 5 to 44 +/- 10 beats/min, p < 0.05). Cardiac pauses longer th an 2.5 seconds were present in 8 patients during control recordings, a nd disappeared after theophylline. Twenty-six patients were followed f or a period of 20 +/- 5 months. Suppression of symptoms was achieved i n 24 of them. Asthenia and easy fatigue were reduced markedly by the d rug. During long term therapy, the sinus rate was similar to that obse rved at the steady-state evaluation. In 6 of the 34 patients theophyll ine had to be discontinued because of gastric intolerance (in Ir cases at the end of the steady-state evaluation and in 2 during long-term t herapy). These data suggest that oral theophylline can represent an ef fective therapy in some elderly patients with symptomatic sinus bradyc ardia and can avoid or delay the need of a permanent pacemaker.