Hisato Nakamori

Relationship between redistribution on exercise thallium-201 scintigraphy and repetitive ventricular premature beats in patients with recent myocardial infarction

The relationship between myocardial ischemia detected by exercise thallium-201 scintigraphy and repetitive ventricular premature beats (VPBs) during ambulatory monitoring was evaluated in 57 patients with recent myocardial infarction. Multivariate analysis was performed to obtain the relatively important factor related to repetitive VPBs with the use of the following variables: age, redistribution, left ventricular ejection fraction, serum potassium and magnesium concentration, QRS score, left ventricular aneurysm, and the number of diseased vessels. Thirty-five patients had redistribution, but only three of them had repetitive VPBs during exercise testing. The average heart rate before 79% of 398 episodes of repetitive VPBs during ambulatory monitoring was in the range of 56 to 70/min. These data indicate that most of repetitive VPBs during ambulatory monitoring were not provoked by exercise-induced acute myocardial ischemia. However, redistribution was found to be an important factor associated with repetitive VPBs. The electrical abnormality relating to a substrate characterized by chronic reversible ischemia may explain the association between redistribution and repetitive VPBs.

Clinical Significance of S-T Segment Elevation in Lead aVR in Anterior Myocardial Infarction

The significance of exercise-induced S-T elevation in aVR was studied in 57 patients with recent anterior infarction and single-vessel disease. S-T elevation in aVR was found at peak exercise in 24 patients. Although the initial defect area was similar in the groups with and without S-T elevation in aVR, the redistribution area was larger in the former group (p < 0.01). When three electrocardiographic criteria were used in the multivariate analysis, S-T elevation in aVR was the significant variable related to redistribution in the anterior wall. Thus, S-T elevation in aVR may indicate ischemia of the anterior wall.

Difference in the residual left ventricular pump function between anterior and inferior myocardial infarctions.

To evaluate the left ventricular regional ejection fraction (EF) of noninfarcted area in relation to the left ventricular end-diastolic volume (EDV) in patients with recent myocardial infarction (MI), 75 patients with Q-wave MI (anterior: 51 patients; inferior; 24 patients) were studied. The regional EF of noninfarcted area was obtained by radionuclide angiocardiography 4 weeks after the onset of MI and was used to estimate the left ventricular regional function of the noninfarcted area. Peak creatine kinase and QRS scores were not significantly different between anterior and inferior MI in each left ventricular EDV (EDV < or = 100, 101-139 and > or = 140 ml). Global EF and regional EF of noninfarcted area in anterior MI with left ventricular EDV > or = 140 ml was significantly lower than in those with EDV < or = 139 ml (p < 0.01), whereas there were no significant differences in global EF and regional EF of noninfarcted area in the three groups of left ventricular EDV in inferior MI. Thus, the effect of left ventricular EDV on regional EF of noninfarcted area and on the total cardiac performance was more important in anterior than in inferior MI, because a similar degree of left ventricular dilatation resulted in more severe derangements after anterior MI.

Evaluation of Platelet and Leukocyte Functions in Effort Angina Patients Using High Shear Conditions in Small-Sized Collagen Bead Columns

This study used a small-sized collagen bead column system to investigate platelet functions under high shear stress in 28 patients with effort angina and 15 healthy controls. Soluble P-selectin and soluble L-selectin were also evaluated. Patients underwent stent insertion, followed by treatment with aspirin (100 mg/day) and ticlopidine (200 mg/day). High-shear-dependent platelet function was measured using small-sized collagen beads. The retention rate of platelets from patients with angina was higher than that in healthy controls (10.9% ± 3.9% versus 5.6% ± 1.7%, P < .01). Soluble P-selectin and soluble L-selectin levels of patients with angina significantly increased after passage through the columns. Levels of soluble P-selectin and L-selectin in healthy controls did not exhibit significant changes with passage through the columns. These results suggested that high shear stress caused abnormal activation of leukocytes or adhesive proteins in patients with effort angina, and ticlopidine failed to suppress hyperaggregability of platelets in these patients.

Significance of αIIbβ3 in Subacute Stent ThrombosisAfter Percutaneous Coronary Intervention

Soluble P-selectin and whole blood aggregation (WBA) were measured after percutaneous coronary intervention in patients who then received antiplatelet therapy. One had subacute thrombosis on day 7. This patient’s WBA exhibited time-dependent enhancement. In addition, the accentuation of WBA on day 3 was observed when anti-αIIbβ3 antibody was added. The remaining 22 patients were divided according to WBA results on day 3 with anti-αIIbβ3 antibody added (A group, WBA enhanced; B group, WBA did not enhance). WBA on day 3 was similar in the two groups. The ratio of WBA with and without anti-αIIbβ3 antibody was higher in group A than in group B. A significant time-dependent increase of soluble P-selectin was observed in the A group. These results suggest that enhancement of WBA with anti-αIIbβ3 antibody after percutaneous coronary intervention predicts subacute thrombosis.