Epidemiological study of the electrocardiographic diagnosis of left ventricular hypertrophy.

Electrocardiograms from 5,129 examined persons, 2,449 men and 2,680 women, 16 years of age or older, were classified according to the Minnesota code of Blackburn and associates. The R wave amplitude criteria for possible left ventricular hypertrophy were fulfilled in 193 tracings from 135 men and 58 women. Age and sex matched controls were randomly selected from the remainder of the examined population for similar measurement. Those with high amplitude R waves and their controls were grouped according to age, sex, and possible cause for anatomical left ventricular enlargement. Precise measurements were made of all the amplitudes and intervals necessary for the application of a variety of other differential items from current diagnostic criteria. The prevalence of the various differential items in the high amplitude and control groups and the frequency with which each was associated with a cause for enlargement indicated their relative sensitivity and specificity. Among the individuals with electrocardiographic evidence of left ventricular hypertrophy according to the Minnesota criteria, there were more persons in the upper and lower quintiles of the relative weight distributions, more hypertensives, more persons with roentgenographic evidence of cardiomegaly, and fewer persons in congestive heart failure than among the controls, but the differences were slight. Most QRS amplitude items were too nonspecific to be of much diagnostic value among young men, and the same items apparently lack sensitivity when applied to the tracings from older women. The items which constitute the Minnesota criteria are useful for screening purposes. Single items are unreliable for the detection of left ventricular hypertrophy and certain combinations are suggested to improve diagnostic accuracy. Still the electrocardiogram is often an inexact method for the recognition of left ventricular hypertrophy and the diagnosis should be based on careful physical and roentgenographic examinations as well.