Effect of Diuresis on P‐Wave Duration and Dispersion

Study Objective. To evaluate the effects of changing volume status on P‐wave duration and dispersion in patients with decompensated heart failure. Design. Prospective analysis. Setting. Hospital cardiology unit. Patients. Twenty‐one patients with symptoms of decompensated heart failure who were treated with diuretics on admission. Intervention. Twelve‐lead electrocardiograms were obtained at baseline and after diuresis. Average, minimum, and maximum P‐wave duration and P‐wave dispersion (minimum minus maximum duration) were determined. Measurements and Main Results. P‐wave duration was measured manually in all 12 leads by using a 0.5‐mm‐scale precision ruler and magnifying lens. After 40 ± 23 hours of diuresis, 3 ± 1 L of fluid was removed. A significant correlation was found between average P‐wave duration and amount of fluid removed (r = −0.59, p=0.015). Also, average and maximum P‐wave duration were significantly decreased with diuresis (p=0.001 and 0.022, respectively). No other P‐wave variables were significantly affected. Conclusions. Diuresis may attenuate electrophysiologic changes caused by fluid overload.