XIII. Prognostic Significance of Negative U Waves in the Electrocardiogram in Hypertension

Negative U waves were found in 23 per cent of 287 electrocardiograms of hypertensive patients. The group of patients with negative U waves showed higher average diastolic and mean blood pressures, more advanced congestive heart failure, a higher incidence of marked cardiomegaly and uremia, more serious cerebrovascular complications, and a higher mortality than the group with positive U waves. Normal heart size, normal electrocardiographic patterns, and absence of evidence of renal impairment or congestive heart failure occurred more commonly in the group with positive U waves. Negative U waves were found in 43 per cent of 114 cases of "left ventricular strain" pattern in hypertensive patients. In the presence of "left ventricular strain" pattern, the patients with negative U waves had more advanced congestive heart failure, a higher incidence of marked cardiomegaly and uremia, and a higher mortality than the patients with positive or isoelectric U waves. A concept has been advanced that in the evolution of the "left ventricular strain" pattern, the inversion of the U wave is a late event that follows the inversion of the T wave by a certain time lag. In the few cases in which an inverted U wave followed a positive T wave, the morbidity and mortality were very high. A negative U wave constituted the only abnormal finding in 1 case.