Pericardial Fat is Associated With Atrial Conduction: The Framingham Heart Study

Background-Obesity is associated with altered atrial electrophysiology and a prominent risk factor for atrial fibrillation. Body mass index, the most widely used adiposity measure, has been related to atrial electrical remodeling. We tested the hypothesis that pericardial fat is independently associated with electrocardiographic measures of atrial conduction. Methods and Results-We performed a cross-sectional analysis of 1946 Framingham Heart Study participants (45% women) to determine the relation between pericardial fat and atrial conduction as measured by P wave indices (PWI): PR interval, P wave duration (P-duration), P wave amplitude (P-amplitude), P wave area (P-area), and P wave terminal force (P-terminal). We performed sex-stratified linear regression analyses adjusted for relevant clinical variables and ectopic fat depots. Each 1-SD increase in pericardial fat was significantly associated with PR interval (beta=1.7 ms, P=0.049), P-duration (beta=2.3 ms, P<0.001), and P-terminal (beta=297 mu V.ms, P<0.001) among women; and P-duration (beta=1.2 ms, P=0.002), P-amplitude (beta=-2.5 mu V, P<0. 001), and P-terminal (beta=160 mu V.ms, P=0.002) among men. Among both sexes, pericardial fat was significantly associated with P-duration in analyses additionally adjusting for visceral fat or intrathoracic fat; a similar but non-significant trend existed with P-terminal. Among women, pericardial fat was significantly associated with P wave area after adjustment for visceral and intrathoracic fat. Conclusions-Pericardial fat is associated with atrial conduction as quantified by PWI, even with adjustment for extracardiac fat depots. Further studies are warranted to identify the mechanisms through which pericardial fat may modify atrial electrophysiology and promote subsequent risk for arrhythmogenesis.