P-wave measurements and left atrial function were investigated to predict the maintenance of sinus rhythm. after cardioversion of atrial fibrillation. Left atrial dimension <45 mm (p = 0.02) and P-wave dispersion <46 ms (p<0.001) were independent predictors of sinus rhythm maintenance, with a sensitivity of 89% and 96%, respectively. Duration of atrial fibrillation, maximum P-wave duration, and no spontaneous echocardiographic contrast were also univariate predictors. (C) 2004 by Excerpta Medica, Inc.