Left atrial enlargement: an electrocardiographic misnomer? An electrocardiographic-echocardiographic study.

The agreement between electrocardiography and echocardiography for diagnosing left atrial (LA) enlargement has been studied in 100 unselected consecutive adult patients with a variety of cardiac diseases. In only 4 did both methods agree with respect to the diagnosis of LA enlargement. Mainly as a result of supraventricular arrhythmia, the P wave of the ECG could not be analyzed in 19 patients. In 13 of these, the echocardiogram showed enlargement of the LA. Four of the remaining 81 patients had positive ECG criteria for LA enlargement and 20 patients showed LA enlargement on their echocardiogram. It appears from our results that there is no agreement between the ECG diagnosis of LA enlargement and the LA cavity size as measured from the echocardiogram. Echocardiography may be considered as a reference method for assessing left atrial size.