Electrocardiographic diagnosis of left atrial enlargement in patients with mitral stenosis: the value of the P-wave area

Objective - To investigate the value of the P-wave area in diagnosing left atrial enlargement in patients with mitral stenosis. Methods - We measured the P-wave area from lead 11 of a standard 12-lead ECG in 136 consecutive patients with mitral stenosis. We also measured the left atrial diameter with two-dimensional echocardiography. Results - Left atrial enlargement was identified in 120 (88.2%) patients. There was an excellent correlation between P-wave area and left atrial diameter in these patients (r = 0.739, p = 0.001). A P-wave area of greater than or equal to 4 ms(.)mv had an 85.8% sensitivity and 93.7% specificity for left atrial enlargement. There was also a smaller but significant correlation between left atrial diameter and the total P-wave duration (r = 0.635, p < 0.01) or P-wave amplitude (r = 0.683, p < 0.0 1) in these patients. However, the P-wave area had a better overall sensitivity than the P-wave duration (43.3%) or amplitude ( 10.8%) in diagnosing left atrial enlargement. Conclusions - Left atrium enlargement can be estimated by P-wave area measured from ECG lead 11 in patients with mitral stenosis. A P-wave area A ms-mv serves as a new criterion of left atrial enlargement.