心脏起搏器的发展与临床应用-1.ppt

* Atrial fibrillation occurred in 24.2 percent of the study population, including 4.8 percent in whom it developed for the first time. The incidence of atrial fibrillation after randomization was significantly lower in the dual-chamber group (hazard ratio, 0.79; 95 percent confidence interval, 0.66 to 0.94; P=0.008) (Figure 1 and Table 2). Of 487 patients in whom atrial fibrillation developed after randomization, 105 (21.6 percent) had chronic atrial fibrillation (15.2 percent of patients with dual-chamber pacing, as compared with 26.7 percent of patients with ventricular pacing; hazard ratio for chronic atrial fibrillation in the overall study population, 0.44; 95 percent confidence interval, 0.29 to 0.67; P<0.001). Patients receiving dual-chamber pacing who had no history of atrial fibrillation had a 50 percent lower incidence of atrial fibrillation after randomization (hazard ratio as compared with ventricular pacing, 0.50; 95 percent confidence interval, 0.32 to 0.76; P=0.001), whereas patients receiving dual-chamber pacing who had a history of atrial fibrillation had a smaller, nonsignificant 14 percent reduction (hazard ratio, 0.86; 95 percent confidence interval, 0.70 to 1.04; P=0.12). Hospitalization for heart failure occurred in 10.3 percent of the patients receiving dual-chamber pacing and 12.3 percent of the patients receiving ventricular pacing (hazard ratio, 0.82; 95 percent confidence interval, 0.63 to 1.06; P=0.13). Adjusted Analyses Multivariable analyses were performed to control for slightly higher proportions of patients with a history of myocardial infarction, diabetes, congestive heart failure, and supraventricular tachycardia in the group receiving dual-chamber pacing. Adjusted analyses had minimal influence on the estimate of the effect of treatment on the primary end point. However, the adjusted hazard ratio was 0.73 (95 percent confidence interval, 0.56 to 0.95; P=0.02) for hospitalization for heart failure and 0.85 (95 percent confiden