Abstract 2494: Long-term Outcomes for Pacemaker-Requiring Bradyarrhythmias After Cardiac Transplantation: Analysis of the UNOS Registry
Background - Pacemaker-requiring bradyarrhyhmias after cardiac transplantation are common, and can lead to sudden cardiac death. The long-term prognosis for pacemaker recipients in this population has not been established.
Methods and Results - We analyzed the UNOS registry (n=35,987) of sequential cardiac transplant recipients [Age 46.1±18.3 yrs, 76% Male] between October 1997–2007 with mean 6.3±4.7 yrs follow-up. The primary endpoint was all-cause mortality. Bradyarrhythmias requiring a pacemaker occurred in 3,940 patients (9.1%). Pacemaker recipients demonstrated improved survival (median 8.0 yrs vs. 5.2 yrs; p<0.001), decreased 5 year mortality (13.8% vs. 17.7%, p<0.001) and overall crude mortality (42.9% vs. 45.9%; p<0.001). Multivariable analysis demonstrated improved survival among pacemaker recipients (adjusted HR 0.86 [CI 0.82–0.90]; p<0.001) after adjustment for donor/recipient age, UNOS listing status, donor heart ischemic time, VAD bridging, surgical technique, graft rejection, and other common co-morbidities. In this analysis, transplant recipients who did not survive to hospital discharge were censored (n=1,160) to avoid selection bias against those whom might have been too systemically ill to be considered for pacemaker implantation. Fewer than 5% of these patients had received a pacemaker.
Conclusion - Cardiac transplant recipients with bradyarrhythmias receiving a pacemaker have excellent long-term survival. The observed increased mortality in the non-pacemaker group suggests the possibility of acquired bradyarrhythmias that go under-diagnosed or treated.