Left Axis Deviation: Prevalence, Associated Conditions, and Prognosis

Abstract

In Tecumseh, Michigan, 4,678 persons past 20 years of age participated in a series of comprehensive examinations in 1959 and 1960. The electrocardiograms of 248 participants showed a mean QRS axis of -30 deg or beyond in the frontal plane. Men had a higher prevalence of left axis deviation than women, and the frequency increased with age among both sexes. Fifty-nine percent of the persons with left axis deviation had other findings that suggested heart disease. Forty-one percent were free of such abnormalities (isolated left axis deviation). Those with isolated left axis deviation had no excess incidence of heart disease morbidity or mortality during an average observation period of 4 years. Their frequency of coronary heart risk factors was similar to that observed in the entire study population. Isolated left axis deviation appears to be a common electrocardiographic finding without unfavorable prognostic implications.