[Diagnosis of left atrial enlargement with electrocardiogram. A misplaced reliance]

Abstract

We analyzed the performance of the electrocardiogram in the diagnosis of left atrial enlargement in 1000 unselected consecutive patients (585 men and 415 women, mean age 46 +/- 17 years) with different cardiovascular diseases or clinically normal. Echocardiography was used as reference method to assess left atrial dimension. The following electrocardiographic criteria were considered: total P-wave duration in leads D1, D2 or D3 > or = 110 ms; P terminal force in lead V1 equal to or more negative than -0.04 mm-s, and P-wave notching in leads D1, D2 or D3 with a peak to peak interval > or = 40 ms. A total of 89 subjects (8.9%) fulfilled the echocardiographic criteria for left atrial enlargement, defined as a left atrial dimension above the upper limit of the normal 95% predicted interval calculated as a function of age and body surface area. In the whole group 67 subjects (6.7%) had at least one of the electrocardiographic criteria for left atrial enlargement. In only 23 patients there was agreement between electrocardiogram and echocardiogram in the diagnosis of left atrial enlargement. The three electrocardiographic indexes had specificity > or = 97%, however sensitivity was unacceptable (< or = 18%). Negative predictive value was high (> or = 91%) but positive predictive value was poor (< or = 35%).(ABSTRACT TRUNCATED AT 250 WORDS)