Electrical axis and voltage criteria on left ventricular hypertrophy.

The voltage criteria of left ventricular hypertrophy were studied in 229 hypertensive patients undergoing treatment and 62 patients who were not treated. The limb-lead voltage criterion (R Lead aVL greater than or equal 11 mm.) was found more frequently in patients with radiographic evidence of cardiomegaly than other voltage criteria. This may have been due to a more negative axis in patients with cardiomegaly than in patients without cardiomegaly. It is possible that dilatation of the left ventricle to the left and posteriorly accentuates limb-lead criteria at the expense of V-lead criteria. Left anterior hemiblock occured in less than 10 per cent of the hypertensive patients. In 10 out of 16 patients with left anterior hemiblock, the hemiblock disappeared after treatment of the hypertension for 4 years whereas all five hemiblocks in untreated hypertensives persisted. Development of left anterior hemiblock subsequently occurred in only one patient with treatment and one without treatment over a 4-year period.