[ECG diagnosis of left ventricular hypertrophy associated with a left anterior fascicular block].

The hitherto available ECG indices for the detection of left ventricular hypertrophy in the presence of left anterior fascicular block do not provide a reliable diagnosis. We have therefore constructed a new ECG index, based on vectorcardiographic considerations, and assessed its value by echocardiographic measurements. The new ECG index SIII + (R + S)max precordial greater than or equal to 30 mm, applied to the ECGs of 50 patients without myocardial infarction and without right bundle branch block, showed a specificity of 87.5%, a sensitivity of 96.1% and a positive predictive value of 89.2%.