Yoshiaki Mikuriya

Effect of pravastatin (10 mg/day) on progression of coronary atherosclerosis in patients with serum total cholesterol levels from 160 to 220 mg/dl and angiographically documented coronary artery disease

To evaluate the effect of pravastatin on progression of coronary atherosclerosis in normocholesterolemic patients with coronary artery disease (CAD), 90 patients with CAD and serum cholesterol levels of 160 to 220 mg/dl were randomized into a pravastatin (10 mg/day) group (n = 45) and control group (n = 45) in a 2-year study. The proportions of patients with progression (an increase of > or = 15% in percent stenosis) and regression (a decrease of > or = 15% in percent stenosis) of coronary atherosclerosis were compared between the 2 groups. Of 90 patients, 80 (89%) had a final angiogram: the pravastatin (n = 39) and control group (n = 41). Percent changes in total cholesterol, low-density lipoprotein cholesterol, and apoprotein B levels were significantly greater in the pravastatin group than in the control group (total cholesterol -11 +/- 12% vs 3 +/- 15%, p < 0.01; low-density lipoprotein cholesterol -18 +/- 16% vs 4 +/- 21%, p < 0.01; apoprotein B -5 +/- 20% vs 6 +/- 20%, p < 0.05). The proportion of patients with progression of coronary atherosclerosis was significantly smaller in the pravastatin group than in the control group (21% vs 49%, p < 0.05). The proportion of patients with disease regression did not differ in the 2 groups (3% vs 2%, p = NS). In conclusion, this study indicates that cholesterol-lowering therapy with pravastatin can prevent the progression of coronary atherosclerosis even in normocholesterolemic patients with established CAD.

Significance of spontaneous normalization of negative T waves in infarct-related leads during healing of anterior wall acute myocardial infarction.

This study was conducted to elucidate the significance of spontaneous normalization of negative T waves in infarct-related leads during the chronic phase of anterior wall acute myocardial infarction. Results of this study indicate that patients with spontaneous normalization of negative T waves in infarct-related leads between 1 and 6 months after anterior wall acute myocardial infarction have smaller infarct size, decreased left ventricular dysfunction, and greater improvement in left ventricular wall motion in the infarct area, suggesting that T-wave normalization represents functional recovery of viable myocardium in the infarct area.

Massive ST-segment elevation in precordial and inferior leads in right ventricular myocardial infarction

This report describes a case of right ventricular infarction in which massive ST-segment elevation in the precordial and inferior leads was observed. The maximum magnitude of the ST-segment elevation in the precordial leads was 21 mm in lead V2 and that in the inferior leads was 10 mm in lead II. Angiography revealed a reduction of 90% in the diameter of the right coronary artery in its proximal portion and a normal left coronary system. Recent reports have shown that precordial ST-segment elevation may reflect right ventricular infarction. However, no previously reported instance except our case has shown massive ST-segment elevation in both the precordial and inferior leads. In right ventricular infarction, the current of injury is usually simultaneously present in the right ventricular free wall and left ventricular inferior wall, electrically opposed to each other. Thus, the diffuse and massive ST-segment elevation observed in this study seems to be a rare phenomenon.

Hemostatic changes induced by percutaneous mitral valvuloplasty

A study was conducted of hemostatic changes in 15 patients with mild-to-moderate rheumatic mitral stenosis who underwent percutaneous mitral balloon valvuloplasty (PMV). The patients were divided into two groups according to the degree of valve dilatation as evaluated by Doppler echocardiography before and 2 to 3 months after therapy: one group (n = 7) with suboptimal valvuloplasty (< 0.5 cm2) and one (n = 8) with optimal valvuloplasty (> or = 0.5 cm2). On the day of echocardiographic evaluation, hemostatic testing of the platelet, coagulation, and fibrinolytic systems was performed. Before PMV there were no differences in the hemodynamic and hemostatic variables between the two groups. No favorable hemostatic changes were achieved by PMV in the suboptimal group. In the optimal group, however, platelet-specific protein levels decreased after PMV; the mean levels of platelet factor 4 and beta-thromboglobulin were moderately elevated before and decreased after PMV from 38.5 +/- 22.2 to 8.13 +/- 5.08 ng/ml (p < 0.01) and from 132.5 +/- 78.6 to 38.8 +/- 19.5 ng/ml (p < 0.02), respectively. Coagulation and fibrinolytic systems were unchanged in this study. These data indicate that PMV produces favorable hemostatic effects when sufficient mitral valve dilatation is achieved. Analysis of our data also discloses that platelet activation plays an important role in the initial step of thrombus formation in patients with rheumatic mitral stenosis.

Relation of QT dispersion to infarct size and left ventricular wall motion in anterior wall acute myocardial infarction

Previous studies have shown that QT dispersion increases during acute myocardial infarction (AMI). However, the relation of QT dispersion to infarct size and left ventricular (LV) function in AMI has not yet been fully clarified. Accordingly, this study was conducted to elucidate this relation at 1 month after anterior wall AMI. We examined 94 patients with first anterior wall AMI (< or = 6 hours) who underwent coronary arteriography at admission, 1 month, and 6 months after AMI, and left ventriculography at 1 and 6 months after AMI. Mean QT dispersion on the chronic phase (about 1 month after AMI) electrocardiogram was 79 +/- 33 ms. There were no significant correlations between QT dispersion and peak creatine phosphokinase levels, LV ejection fraction, and regional wall motion in the infarct region at 1 month after AMI (r = 0.06, p = 0.57; r = 0.11, p = 0.29; r = -0.05, p = 0.63, respectively). In conclusion, the findings of this study suggest that QT dispersion on the resting electrocardiogram at 1 month after anterior wall AMI is unrelated to infarct size estimated by the peak creatine phosphokinase level and the degree of LV dysfunction.

Significance of Negative U Waves in the Precordial Leads During Anterior Wall Acute Myocardial Infarction

This study was conducted to clarify the clinical significance of negative U waves in the precordial leads during anterior wall acute myocardial infarction (AMI). In all, 141 patients with first anterior wall AMI (< or = 6 hours) were classified into 2 groups according to the presence (group A, n = 31) or absence (group B, n = 110) of negative U waves in the precordial leads on the admission electrocardiogram (ECG). The number of leads showing ST elevation > or = 1 mm on the admission ECG was smaller in group A than in group B (5.2 +/- 1.3 vs 6.2 +/- 1.7, p < 0.01). Emergent coronary arteriography revealed that group A had a higher incidence of good collateral circulation than group B (39% vs 19%, p < 0.05). Peak creatine kinase activity was lower in group A than in group B (1,708 +/- 1,271 vs 2,735 +/- 1,865 IU/L, p < 0.01). The number of abnormal Q waves on the predischarge ECG was smaller in group A (2.0 +/- 1.5 vs 3.4 +/- 2.0, p < 0.01). Group A had a greater left ventricular ejection fraction and better regional wall motion in the anterobasal, anterolateral, and apical regions in the chronic phase than group B. In conclusion, patients with anterior wall AMI having negative U waves in the precordial leads on admission had a relatively smaller mass of necrotic myocardium than those without the waves. Therefore, negative U waves during anterior wall AMI may be a useful marker for identifying patients with smaller infarction partly due to better collateral circulation.

ST Elevation in the right chest leads in anterior wall left ventricular acute myocardial infarction

Abstract Many studies 1,2 have reported the use of right chest leads for the evaluation of acute right ventricular (RV) infarction or proximal right coronary disease 2,3 in the presence of inferior wall left ventricular (LV) infarction. However, the characteristics of ST shift and the clinical usefulness of these leads in anterior wall LV acute myocardial infarction have been less fully evaluated. 4 Therefore, we compared the incidence, distribution and pattern of ST elevation in the right chest leads between the 2 conditions and assessed the clinical usefulness of these leads for evaluation of anterior wall LV acute myocardial infarction.

Emergent coronary angiographic findings of patients with ST depression in the inferior or lateral leads, or both, during anterior wall acute myocardial infarction

In conclusion, the present study indicates that there are several distinctive differences in emergent coronary angiographic findings according to the presence or absence of ST depression in the inferior or lateral leads, or both, and location of the leads showing ST depression on admission electrocardiograms in patients with anterior AMI. The coronary angiographic features of patients with this ECG finding greatly support a poor prognosis. In patients with anterior AMI, analysis of ST depression on an admission electrocardiogram should be routinely performed because it is useful in predicting coronary anatomy, the extent of infarction, and its prognosis.

Intraventricular conduction delay in acute right ventricular ischemia

Abstract After acute myocardial infarction, impairment of cardiac conduction may occur at different sites in the conduction system. Many reports have described conduction disturbances complicating left ventricular infarction. In right ventricular (RV) infarction, the frequency and significance of RV conduction delay are not established in humans, although Braat et al 1 have described the characteristics of atrioventricular conduction disturbance. We undertook this study to ascertain the frequency of RV conduction delay in patients with RV infarction or ischemia.

Relation between negative U waves in precordial leads on the admission electrocardiogram and time course of left ventricular wall motion in anterior wall acute myocardial infarction

This study indicates that patients with anterior wall acute myocardial infarction showing negative U waves in the precordial leads on the admission electrocardiogram have greater improvement in left ventricular wall motion in the infarct region between 1 and 6 months after acute myocardial infarction. This suggests that these patients have a larger amount of stunned myocardium in the infarct region.