Contribution of left atrial pressure and dimension to signal-averaged P-wave duration in patients with chronic congestive heart failure

Abnormalities in P-wave duration, as detected by signal-averaged electrocardiography, have shown to be predictors of the development of atrial fibrillation in recent studies.(1-5) Signal-averaged P-wave duration depends on several factors, such as intra-atrial conduction time, autonomic tone,(6) left atrial dimension, and pressure. Since the relative role of the last 2 factors in determining P-wave duration has received little attention, the goal of this study was to assess the relation between both the left atrial dimension by echocardiography and the pulmonary capillary wedge pressure (PCWP) by right-sided heart catheterization with P-wave duration as measured by QRS-triggered signal-averaged electrocardiography in patients with chronic congestive heart failure (CHF), a group of patients at high risk for atrial fibrillation.(7) Furthermore, the effect of acute pharmacologic reduction in PCWP on P-wave duration was evaluated.