Abstract 19544: Rate and Magnitude of Atrial Remodeling in Permanent Atrial Fibrillation

Abstract

Background: Atrial fibrillation (AF) is associated with progressive enlargement of atrial size. Yet, the rate of change in left atrial (LA) and right atrial (RA) size is poorly defined. Methods: This cohort study included 51 patients with a history of permanent AF who had serial transthoracic echocardiograms performed between 2005 and 2010 at Vancouver General Hospital in British Columbia, a large university-based tertiary care hospital. Each had at least 3 transthoracic studies completed and had adequate views for assessment of LA and RA volume. Echocardiographic measurements were performed offline by one person using standardized methodology. Apical 4-chamber LA and RA volume by Simpson’s method was used for assessment of atrial size. Linear mixed effects modeling was used in analyzing changes over time. Results: Of the 51 subjects who underwent 183 studies in total, 28 were men (55%). The mean age at study entry was 72±10 yrs (47-85 yrs). The mean follow-up time was 3.2±2.9 years. The findings for the first 3 consecutive studies for these patients are shown in the attached table. There was a significant increase in LA and RA volume; the increases were 2.98 mL/m2 per year (95% CI 1.23-4.73, P<0.0001) and 1.25 mL/m2 per year (95% CI 1.01-1.61, P<0.0001) respectively. In parsimonious models adjusting for age, sex, and length of follow-up, left ventricular ejection fraction of less than 50% at first study was associated with a significantly more rapid increase in LA volume over time (P<0.001). Conclusion: Both LA and RA volume increased over time in patients with permanent AF. The absolute magnitude of increase appeared greater, and the rate of change faster, for LA than RA volume. Further studies are needed to determine the factors that mediate these changes and their reversibility.