Significance of resting U wave polarity in patients with atherosclerotic heart disease.

The aim of this study was to determine the value of U wave polarity in the electrocardiograms of patients with atherosclerotic heart disease. One hundred twelve consecutive patients with U waves were entered into the study. Forty-eight of them had unstable angina pectoris and 64 had prior myocardial infarction (MI) (20 patients had inferior MI, 35 had anterior MI, and 9 had non Q wave MI). Each of these subgroups was divided into two groups with positive (group 1) and negative (group 2) U waves. All patients in this study underwent routine left ventriculography and coronary angiography. The authors examined coronary arteries and calculated ejection fractions. The authors discovered that patients with unstable angina pectoris or anterior MI (group 2) had three-vessel disease more frequently (P < .05). Also, in these patients, there was more than 90% diameter narrowing in the left anterior descending vessel more frequently (P < .001 in unstable angina pectoris and P < .05 in anterior MI). In patients with unstable angina pectoris, inferior MI, or anterior MI, the authors observed that the ejection fraction was lower in group 2 than in group 1 (P < .001 in unstable angina pectoris, P < .05 in inferior MI, and P < .05 in anterior MI). The authors suggest that negative U waves in patients with unstable angina pectoris or anterior MI may indicate multivessel disease with a severe left anterior descending lesion. Also, in patients with unstable angina pectoris, inferior MI, or anterior MI who had negative U waves, ejection fraction was reduced.