Electrocardiographic prediction of the severity of aortic valvular stenosis.

The ECG at rest and at 4 min after a symptom-limited exercise test was studied in 52 patients who were catheterized because a significant aortic valvular stenosis was suspected. The calculated valve area ranged from 0.2 to 1.1 cm2/m2 BSA. QRS amplitude criteria did not discriminate between slight and severe stenoses but a negative or biphasic T wave in lead V6 did, especially after exercise. Thirty-three of the 37 patients with an area of less than or equal to 0.5 cm2/m2 BSA showed negative/biphasic TV6 after exercise but only 4 of the 15 with an area of greater than or equal to 0.6 cm2/m2 BSA. Thus, this criterion had a sensitivity for stenoses less than or equal to 0.5 cm2/m2 BSA of 89%, a specificity of 73% and a predictive value of a positive test of 89% (the pre-test likelihood being 71%). The left ventricular pressures measured during supine exercise in 38 patients did not correlate to the TV6 patterns after exercise.