Relation of Prolonged Pacemaker Dependency After Cardiac Surgery to Mortality

Permanent pacemaker implantation (PPI) represents a rare complication after cardiac surgery, with no uniform agreement on timing and no information on follow-up. A multicenter retrospective study was designed to assess pacemaker dependency (PMD) and long-term mortality after cardiac surgery procedures. Between 2004 and 2016, PPI-patients from 18 centers were followed. Time-to-event data were evaluated with semi-parametric regression Cox models and semi-parametric Fine and Gray model for competing risk framework. Of 859 (0.90%) PPI-patients, 30% were pacemaker independent (PMI) at 6 months. PMD showed higher mortality compared to PMI (10-year survival 80.1% ± 2.6% and 92.2% +2.4%, respectively, log-rank p-value < 0.001) with an unadjusted hazard ratio for death of 0.36 (95% CI 0.20 - 0.65, p< .001 favoring PMI) and an adjusted hazard ratio of 0.19 (95% CI 0.08 - 0.45, p< .001 with PMD as reference). Crude cumulative incidence function (CIF) of restored pacemaker independent rhythm at follow-up at 6 months, 1 year and 12 years were 30.5% (95% CI 27.3% - 33.7%), 33.7% (95% CI 30.4% - 36.9%) and 37.2% (95% CI 33.8% - 40.6%) respectively. PMI was favored by preoperative sinus rhythm with normal conduction (SR) (HR 2.37, 95% CI 1.65 - 3.40, p< .001), while coronary artery bypass grafting and aortic valve replacement were independently associated with PMD (HR 0.63, 95% CI 0.45 - 0.88, p = 0.006 and HR 0.807, 95% CI 0.65 - 0.99, p = .047 respectively). Time-to-implantation was not associated with increased rate of PMI. While 30% of PPI-patients are PMI after 6 months, PMD is associated with higher mortality at long term