1981 Volume 48 Issue 3 Pages 410-427
Since the prominent negative U wave is frequently observed during the attack of variant angina, relationships between its appearance and clinical features were studied in 54 patients with variant angina (VA) and 33 patients with resting angina showing ST depression (RA). The negative U wave was observed in 71.4% of VA, while only in 30.0% of RA. There was a significant difference. In VA, it appeared in the same leads as those showing ST elevation. No significant relationships were observed between the appearance of the negative U wave and the history of hypertension, the size of cardiothoracic ratio, occurrence of arrhythrnias, and repetitive tendency of attacks, but its incidence was higher in patients showing left ventricular hypertrophy pattern in the period without attack and in those with longer duration of the attack and marked elevation of blood pressure during attack. ST elevation and increase of amplitude of the R wave were more prominent inpatients showing negative U wave.
Incidence of the negative U wave on exercise test was morefrequent in VA than RA. In both VA and RA, which showed the negative U wave on the exercise test, the negative U wave was observed also in the spontaneous attacks. Its incidence on the exercise test was significantly higher in patients with exertional angina showing ST elevation than in those showing ST depression.
There were no relationships between the incidence of the negative U wave and the severity of coronary artery narrowing and the number of the diseased branches in coronary arteriogram in both VA and RA. However, patients with multivessel disease were found more frequently in patients with exertional angina with negative U wave than those without it. Although in most patients with VA the negative U wave was observed in the leads corresponding to the sites perfused by coronary artery having organic stenosis or spasm, a closer correspondence was found to the portion showing abnormal ventricular wall motion in left ventriculogram. These findings suggest that the negative U wave in VA reflects the abnormal left ventricular wall motion produced by ischemic change rather than the ischemic change per se.
No significant relationships were present between theappearance of the negative U wave and the effects of the drugs or prognosis in both VA and RA. Calcium antagonists were effective in 84.8% of VA and in 85.7% of RA.
