Abstract 3242: Transient Post-Operative Atrial Fibrillation is Associated with an Increased Rate of All-Cause Mortality
Background: Atrial fibrillation (AF) is the most common arrhythmia observed following coronary artery bypass grafting surgery (CABG) and is associated with increased morbidity and mortality. While the majority of affected patients are discharged in sinus rhythm, little is known about their ultimate outcome. We evaluated the effect of transient post-operative AF (TPAF) on long-term outcome in this population.
Methods: The Cleveland Clinic Cardiothoracic Database was used to identify 5,205 consecutive patients who underwent first time, isolated CABG from January 1993 to December 2005. Patients diagnosed with post-operative AF (n=1560, 30%) were separated into two groups: transient AF (confirmed AF with discharge rhythm of sinus; n=1490, 28.6%) and persistent AF (confirmed AF with discharge rhythm of AF; n=70, 1.3%). These groups were compared to those patients that did not develop post-operative AF (n=3645). Endpoints of death, myocardial infarction (MI), and stroke were evaluated using the Chi squared and Fischer Exact tests. Long-term survival was evaluated with multivariate Cox proportional hazards methods to account for baseline differences.
Results: Overall rates of 1 year mortality, MI and stroke were 12.5, 2.2, and 3.3 % respectively. TPAF was associated with an increased risk of death at 1 year as compared to patients with persistent AF (6.4 vs 2.9%; p<0.001) or without post-operative AF (6.4 vs 2.7%; p<0.001) but was not associated with increased risk of stroke or MI. Multivariate analysis identified TPAF as an independent predictor of both death (HR 1.93 95% CI [1.45, 2.56]; p<0.001) and the combination of death, MI, or stroke (1.8 [1.37, 2.36]; p<0.001). Use of beta-blockers (0.52 [0.34, 0.80]; p<0.003) and statins (0.26 [0.11, 0.64]; p<0.003), but not antiplatlet agents or warfarin, were associated with a reduced risk of death.
Conclusion: In those undergoing first-time, isolated CABG, the presence of TPAF identifies patients at increased risk for all-cause mortality. In addition, the use of post-operative statins and beta-blockers appear to reduce this risk. These data suggest that morbidity unrelated to stroke or MI are responsible for the poor outcome in this population and warrant prospective investigation.