EFFECTS OF PERMANENT PACEMAKER AND ORAL THEOPHYLLINE IN SICK SINUS SYNDROME - THE THEOPACE STUDY - A RANDOMIZED CONTROLLED TRIAL

Background Pacemakers and theophylline art currently being used to rel ieve symptoms in patients with sick sinus syndrome (SSS). However, the impact of either therapy on the natural course of the disease is unkn own. We conducted a randomized controlled trial to prospectively asses s the effects of pacemakers and theophylline in patients with SSS. Met hods and Results. One hundred seven patients with symptomatic SSS (age , 73 +/- 11 years) were randomized to no treatment (control group, n=3 5), oral theophylline (n=36), or dual-chamber rate-responsive pacemake r therapy (n=36). They were followed for up to 48 months (mean, 19 +/- 14 months). During follow-up, the occurrence of syncope was low er in the pacemaker group than in the control group (P=.02) and tended to b e lower than in the theophylline group (P=.07). Heart failure occurred less often in patients assigned to pacemaker therapy and theophylline than in control patients (both, P=.05), whereas the incidence of sust ained paroxysmal tachyarrhythmias. permanent atrial fibrillation, and thromboembolic events did not show ally apparent difference among the three groups. Heart rate was higher in the theophylline group than in the control group. Both pacemaker therapy and theophylline improved sy mptom scores alter 3 months of treatment; however. a similar improveme nt was observed in the control group. Conclusions In patients with sym ptomatic SSS, therapy with theophylline or dual-chamber pacemaker is a ssociated with a lower incidence of heart failure; pacemaker therapy i s also associated with 3 lower incidence of syncope. The therapeutic b enefits of pacemakers and theophylline on symptoms are partly a result of spontaneous improvement of the disease.