Significance of the initial R wave in lead aVR of the electrocardiogram in the diagnosis of myocardial infarction.

no significant effect of age, sex, or race on the mean initial R-wave amplitude in lead aVR or its distribution, or on the upper 98% normal limit of the initial R wave, a decrease of the mean R amplitude in aVR with clockwise rotation of the transitional zone, and a highly significant correlation of R amplitude in aVR to that of R in V1, Q3, and Q in aVF, but too low for reliable prediction. Right ventricular hypertrophy, anterior wall myocardial infarction, and hypertensive heart disease have no effect on the amplitude or prevalence of the initial R in aVE. Posterior and anterior plus posterior wall infarction significantly increased amplitude and incidence of the initial R in aVR.