In certain patients, pulmonary venous flow pattern obtained by the pulsed wave Doppler during transesophageal echocardiography shows a notching on the atrial reversal (A) wave. However, the incidence or the mechanism of this notched A wave has not been described. After transthoracic echocardiographic evaluation for the chamber sizes, wall thickness, and left-ventricular function, transesophageal echocardiography was performed in 100 patients with in sinus rhythm. Discernible pulmonary venous A wave was observed in 46 patients. Among these 46 patients, notched A wave was observed in 11 (31%). In 4 patients with notched A wave, left-atrial pressure waveforms could be obtained during mitral balloon valvuloplasty. In all these patients, left-atrial pressure waveforms showed prominent c waves. In 2 patients, transesophageal echocardiography was repeated after mitral balloon valvuloplasty. Late peak of the notched A wave decreased with the decrease in the magnitude of rise in left-atrial c wave. Among the transthoracic echocardiographic parameters, patients with notching (n = 11) had significantly larger left atriums than patients without notching (n = 35)(49.3 +/- 6.2 vs 37.3 +/- 4.4 mm, P <.0001). There were no significant differences in left-ventricular dimensions, wall thickness, and ejection fraction. In conclusion, notched pulmonary venous A wave indicates the presence of left-atrial c wave; and presence of left-atrial c wave may represent decreased left-atrial compliance.