Study on the diagnostic accuracy of left atrial enlargement by resting electrocardiography and its echocardiographic correlation.

M-mode echocardiography has been accepted as gold standard for measuring left atrial (LA) size. Electrocardiography (ECG) offers a simple, non-invasive, cost-effective and reproducible method to assess LA size and it is mostly in agreement with echocardiography though discrepancies exist. ECGs and echocardiograms were obtained in 100 consecutive patients suspected of having left atrial enlargement due to different underlying heart diseases. The diagnostic accuracy of six ECG criteria of LA enlargement were evaluated comparing with LA size in M-mode echo study. Various criteria were found to be poor to mildly sensitive (8% to 78%) but highly specific (85% to 100%) for left atrial enlargement. Morris Index (PTFV1) was found to be the best criterion having 76% sensitivity and 92% specificity. Combination of criteria enhances the sensitivity at the cost of specificity. Overall predictive index of electrocardiogram for left atrial enlargement is not encouraging.