PACEMAKER THERAPY IN THE SICK SINUS SYNDROME

Between 1986 and 1992, pacemakers were implanted in 307 patients with symptoms caused by the sick sinus syndrome (SSS). 301 patients were regularly followed up (161 men, 146 women, mean age 72.9 [27-91] years) of whom 180 had a WI, 65 an AAI and 58 a DDD/DDI pacemaker. Mean follow-up period was 58.3 months for VVI-stimulated patients and 35.6 months for atrial paced patients. The data were analysed retrospectively to ascertain whether a change in pacemaker treatment to a more physiological system produced any lowering in the mortality rate, incidence of permanent atrial fibrillation (AF), and thromboembolic phenomena. The annual mortality rate of the VVI-stimulated patients was 6.9%, that of atrial paced patients 2.8%. Age, abnormal ventricular function, survived resuscitation and diabetes mellitus each correlated with a shortened Life expectancy already at the time of implantation, regardless of the pacemaker mode. Permanent AF was more frequent during VVI stimulation (16% vs 7%), especially if it had been preceded by intermittent AF (26% vs 13%). But there was no significant difference with regard to transitory cerebral ischaemic episodes and peripheral arterial emboli (15% vs 10%). Fewer patients with atrial pacing went into heart failure (20% vs 30%). Four patients developed a high-grade atrioventricular (a-v) block on AAI stimulation (annual incidence 2.4%). - These observations suggest that patients with SSS should always have atrial paced pacemaker systems. If a-v conduction is disturbed, a bifocal pacemaker is the system of choice.