USE OF THE DUAL-CHAMBER PACING FOR TREATMENT OF SICK SINUS SYNDREME

Cardiac pacing is a safe and an established treatment for patients with symptomatic bradycardia due to atrioventriular conduction block and sick sinus syndrome. Until recently, however, cardiac pacing has been restricted to ventricular demand pacing at a constant rate. Ventricular demand pacing does not restore the normal electrical sequence of the cardiac cycle.with the availability of reliable transvenous atrial leads and advances in electronic and battery technology, pacing for the restoration of the atrioventricular sequence has become practical. In the last few years, 165 pacemakers were implanted in the Department of Cardiac Surgery of General Hospital of Chinese PLA. Four of them were Medtronic dual-chamber pacemakers model 7000. The diagnosis of these patients was sick sinus syndrome.The atrial and ventricular leads were inserted into the right cephalic vein. The Medtronic transvenous screw-in J lead was positioned in the right atrial appendage and a transvenous ventricular lead was positioned in the right ventricular apex. The dual-chamber pacemakers were implanted in the right pectoral region and paced in the DVI or DDD mode.The post-operative course was uneventful and exercise tolerance improved witin a few days following pacemaker implantation. The cardiac index were increased remarkably. In these 4 patients no complications were noted in the post-operative period. The hemodynamic and electrophysiologic benefits of dual-chamber cardiac pacing have been well documented. Physiologic pacing should therefore be applied as indicated.