The extremely prominent negative U wave occasionally appears during a cardiac attack in variant angina pectoris. The clinical profile of the negative U wave was therefore studied in 80 patients with variant angina pectoris (VA) and 33 controls with resting angina pectoris (RA). The prominent negative U wave appeared in 55 of the patients with VA (68.8% of patients) and in 10 of the patients with RA (30.3%); thus, there was a significant difference in the appearance of the wave between the 2 groups of patients (p<0.001). The leads in which the negative U wave appeared were mostly consistent with those in which the ST segment was elevated. The negative U wave began to appear at about the time when ST-segment elevation began to improve; the wave then gradually became very prominent and then eventually disappeared. The patients with VA and also those with RA on whose ECGs the negative U wave appeared during exercise testing also had negative U waves during spontaneous episodes of angina. An investigation of the frequency of appearance of ST deviation and negative U waves during exercise testing, regardless of the type of angina pectoris, disclosed that the negative U wave appeared in 14 of 20 patients with ST-segment elevation (70% of patients), while the negative U wave appeared in only 52 of 519 patients with either no ST change or ST-segment depression (10.4%); thus, there was a significant difference in the appearance of the negative U wave between these 2 groups (p<0.001). Coronary cinearteriography failed to disclose any apparent difference between the appearance of the negative U wave and the presence of stenosis. The prognosis of VA and RA in patients with negative U waves was less favorable compared to those without negative U waves. In particular, we noted that of the 10 patients with RA associated with negative U waves, 4 died. Al-From the
SUMMARYIn order to clarify the clinical significance of a persistent negative U wave in patients with myocardial infarction, the clinical features and prognosis of a group of such patients were compared with a group without negative U waves. The persistent negative U wave was defined as the presence of a negative U wave at the time of discharge. The subjects were classified into 2 groups: group A-55 patients (50 males and 5 females, 5910 years) with negative U waves; group B-70 patients (55 males and 15 females, 619 years) without negative U waves. The average follow-up periods were 4921 months in group A and 4218 months in group B. Negative U waves appeared in leads where r or R waves were present, but were not observed in leads with a QS pattern. The incidences of a diseased left anterior descending artery, multi-vessel disease, left ventricular wall motion abnormality and left ventricular ejection fraction below 50% were higher in group A than in group B. The recurrence of myocardial infarction was 18.2% in group A and 7.1% in group B, and the number of patients treated with antianginal drugs was higher in group A than in group B. The rate of recurrence of myocardial infarction at 1, 3 and 5 years was 6%, 17% and 26%, respectively in group A and 6%, 8% and 11%, respectively in group B. Thus, it was concluded that patients in group A require more active treatment than those in group B. Additional Indexing Words: Recurrent myocardial infarctionClinical course of myocardial infarction Aortocoronary bypass graft Mechanism of negative U wave Genesis of U wave
SUMMARYThe purpose of the present study was to clarify the characteristics of myocardial ischemic attacks in patients with exertional angina (EA, 56 cases), exertional and rest angina (ERA, 28 cases), rest angina (RA, 4 cases), and variant angina (VA, 39 cases). The Holter electrocardiographic findings were compared among the four types of angina pectoris. The frequency of symptomatic ischemic attacks in descending order was 46.0% in EA, 29.0% in ERA, 28.1% in RA, and 21.6% in VA, while the frequency of asymptomatic ischemic attacks was in the reverse order. The maximal heart rates during symptomatic ischemic attacks were in descending order, EA, ERA, RA, and VA. The maximal heart rate during ischemic attacks was significantly lower in patients with spontaneous angina than in those with exercise-induced ischemia for all types of angina (p<0.05, respectively). Further, the difference in maximal heart rate during ischemic attacks between the ambulatory electrocardiogram and exercise test was greater in patients with RA and VA than in those with EA. Therefore, this suggests that increased coronary vascular tone is a cause of spontaneous ischemic attacks in each type of angina pectoris.
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.
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