Abstract 10387: Left Ventricular Diastolic Dysfunction is a Pathophysiologic Mechanism for the Development of Late Atrial Fibrillation After Coronary Artery Bypass Surgery: A Community-Based Study
Introduction Late atrial fibrillation (AF) remains a frequent occurrence after CABG and increases the risk of stroke and mortality. LV diastolic dysfunction, which reflects abnormalities in LV relaxation, has been reported to be a strong risk factor for early postoperative AF (POAF). We hypothesized that the severity of LV diastolic dysfunction would also predict the development of late AF following CABG. The objective was to examine the association of LV diastolic dysfunction severity on the risk of late AF after CABG.
Methods We conducted a study of all Olmsted County, MN residents who underwent isolated CABG surgery with had complete diastolic function assessment preoperatively (integrating mitral E/A waves, deceleration time, mitral annulus velocity (e’) and left atrial volume into 4 diastolic function grades (DFG 0-3)] and were discharged from the hospital in sinus rhythm from January 1, 2000 to December 31, 2005 (n=196). Patients were followed up to the last clinical visit, repeat cardiac surgery or death for first documentation of late AF (AF after 30 days of surgery). We excluded patients with prior history of AF, pacemaker, or congenital heart disease.
Results The mean age of the population was 66±11 years. At 1 year, 5 years, and 10 years, late AF developed in 7.2%, 16.7, 33.5%, respectively. The median time from surgery to late AF was 1.87 years, (range 0.25, 3.9). By univariate analysis, patients who developed late AF were likely to be older (HR 1.04; p=0.006), develop early POAF (HR 2.93; p<0.001), have peripheral vascular disease (PVD) (HR 2.85; p<0.001), and abnormal LV DFG. DFG 1: HR 2.77; p=0.046, DFG 2: HR 3.84; p= 0.007, and DFG 3: HR 8.05; p<0.001); discharge medications had no effect. By multivariate Cox regression analysis, after adjusting for early POAF and PVD, severe diastolic dysfunction (DFG 3) remained independently predictive of late AF HR 3.26, 95% CI [1.25-8.51]; p=0.02).
Conclusions Diastolic dysfunction severity is also a strong independent predictor for the development of late AF after CABG. Increased LV stiffness and increased atrial pressure and stretch are believed to account for AF occurrence. Optimization of LV diastolic properties should be a logical strategy of prophylaxis against the development of late AF.
- © 2011 by American Heart Association, Inc.