Heart Failure Hospitalizations and All-Cause Mortality
Heart failure hospitalization rates were slightly lower among patients implanted with a leadless VVI pacemaker compared to transvenous in the overall patient cohort (adjusted, 19.9% vs. 22.0%, P=0.005) as well as among patients without prior history of heart failure (adjusted, 11.2% vs. 13.6%), P=0.003) (Appendix Table 4 ). In the time-to-event models, patients with a leadless pacemaker had a slightly, but significantly lower, rate of heart failure hospitalization compared with patients implanted with a transvenous pacemaker through 3 years (Figure 1C ; unadjusted HR 0.90; 95% CI 0.84–0.97, P=0.006; adjusted HR 0.90; 95% CI 0.83–0.97, P=0.005). Among patients without history of heart failure, the lower rates among patients implanted with a leadless VVI pacemaker were more pronounced (unadjusted HR 0.83; 95% CI 0.72–0.94, P=0.005; adjusted HR 0.81; 95% CI 0.71–0.93, P=0.003) (Appendix Figure 2 ).
The unadjusted 3-year all-cause mortality rate was significantly greater in the patients implanted with a leadless VVI pacemaker compared with the transvenous (HR, 1.09; 95% CI, 1.03-1.15, P=0.003); however, there was no difference in the adjusted 3-year all-cause mortality rate between leadless and transvenous (Figure 1D ; HR, 0.97; 95% CI, 0.92-1.03, P=0.32) after accounting for differences in baseline characteristics.
For the composite endpoint of time to heart failure hospitalization or death, there was no difference in the unadjusted rates for either the full cohort or those patients without history of heart failure (full cohort: unadjusted HR 1.03; 95% CI 0.98-0.1.08, P=0.28; sub-cohort: unadjusted HR 1.00, 95% CI 0.93-1.08, P=0.98). After statistical adjustment, there were small differences, with patients implanted with a leadless VVI pacemaker having slightly lower rates than transvenous (full cohort: adjusted HR 0.94; 95% CI 0.89-0.99, P=0.01; sub-cohort: adjusted HR 0.92, 95% CI 0.85-0.99, P=0.03) (Appendix Figures 3A and 3B ).