Abstract 715: Diastolic Dysfunction is a Major Profibrillatory Substrate for the Initiation of New-onset Atrial Fibrillation Following Cardiac Surgery
Background Atrial fibrillation (AF) is a frequent complication after cardiac surgery and is associated with adverse cardiac outcomes. However, the precise mechanism underlying the development of new-onset postoperative AF (POAF) remains unclear. We hypothesize that preexisting alterations of myocardial diastolic properties are a contributing pathophysiologic substrate predisposing patients to the genesis of POAF.
Methods We identified all Olmsted county, MN residents who were free of any history of preoperative AF and had complete echocardiographic LV diastolic function assessment (integrating mitral E/A waves, deceleration time, mitral annulus velocity (e’) and left atrial volume) prior to coronary bypass and/or valvular surgery between January 1, 2000, and December 31, 2005 (n=351). We aimed to investigate the relationship between diastolic dysfunction (DD) and the risk of POAF (any AF episodes ≤30 days of surgery)
Results The incidence of POAF was 38.5% (n=135). Patients with POAF were older (mean age 72.5±10.3 vs 63.1±14.1 years; p<0.0001) and more likely to have abnormal DD (OR 17.4 (95% CI [6.99–58.26]; p<0.0001). The rate of POAF increased exponentially across diastolic function grade (DFG). By multivariate analysis, after adjusting for age, sex, clinical and surgical risk factors, age (OR 1.05; p=0.0002), BMI (OR 1.05; p=0.049) and DFG (OR 3.1; p<0.0001) were independently associated with the development of POAF.
Conclusions DD is a powerful predisposing substrate for the initiation of POAF after cardiac surgery. Selective preoperative measures to improve LV compliance and reduce LV filling pressure may help to lessen the clinical and economic burden of POAF.