DELETERIOUS EFFECTS OF LONG-TERM SINGLE-CHAMBER VENTRICULAR PACING IN PATIENTS WITH SICK SINUS SYNDROME - THE HIDDEN BENEFITS OF DUAL-CHAMBER PACING

Nine hundred fifty patients who received three modes of primary pacemaker systems (581 dual-chamber universal [DDD], 84 atrioventricular-sequential ventricular-inhibited [DVI] and 285 ventricular-inhibited [VVI]) over 12 years were studied retrospectively to determine the effect of pacing mode on patient longevity and the subsequent development of chronic atrial fibrillation or flutter. All patients were followed up continuously for 7 to 8 years. Patients were classified according to indication for permanent pacing (sick sinus syndrome or other indication), age at pacemaker implantation (less-than-or-equal-to 70 or >70 years) and history of atrial tachyarrhythmia. Fourteen percent of patients developed atrial fibrillation at some time during the study period. Of those, 4% had a DDD pacemaker, 8% had a DVI pacemaker and 19% had a VVI pacemaker. At 7 years, atrial fibrillation was significantly more frequent in the VVI group than in the DDD and DVI groups. In patients with sick sinus syndrome, the incidence rate was even higher in the VVI group but approximately the same in the DDD and DVI groups. Patients in the VVI and DVI groups who had had previous atrial tachyarrhythmia had a significantly higher incidence of atrial fibrillation at 7 years than did those in the DDD group. During the entire period there were 130 deaths in the study group, including 22% of patients with a DDD pacemaker, 38% of those with a DVI pacemaker and 50% of those with a VVI pacemaker. Patient survival at 7 years was lower in the VVI group than in the DDD or DVI groups. Survival also was poorer in the VVI group in comparison with the DDD group for all patients >70 years of age. Thus, death occurred more frequently with VVI pacing than with DDD pacing regardless of age at pacemaker implantation or initial diagnosis. These results suggest that the DDD mode is preferable to VVI pacing from the standpoint of patient longevity and the development of atrial fibrillation, especially in patients who undergo permanent pacemaker implantation because of sick sinus syndrome and those >70 years of age at the time of pacemaker implantation.