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The aim of this study was to evaluate the relation between thallium-201 scintigraphic indices and left ventricular size after acute myocardial infarction. Forty-seven patients with acute myocardial infarction underwent rest-redistribution thallium-201 scintigraphy at 2 weeks and left ventriculography at 4 weeks, after the onset of myocardial infarction. Percent (%) fixed defect, %redistribution and %reverse redistribution, calculated as a percentage of whole left ventricular area, were quantified with computer-generated unfolded map method of the myocardial radioactivity. Despite no significant difference in peak plasma creatine phosphokinase between the two groups, patients with anterior myocardial infarction (28 patients) had larger %fixed defect (p < 0.01), which was associated with higher end-diastolic pressure (p < 0.05) and larger end-diastolic volume index (p < 0.01) than those with inferior myocardial infarction (19 patients). End-diastolic volume index was not related to %redistribution and %reverse redistribution, but there was a good relation between end-diastolic volume index and %fixed defect in anterior (r = 0.79, p < 0.001) and in inferior (r = 0.73, p < 0.001) myocardial infarction. However, left ventricular end-diastolic volume index in anterior myocardial infarction was larger than that of inferior myocardial infarction at any given %fixed defect. Thus, site as well as size of fixed defect at 2 weeks after the onset of acute myocardial infarction was related to left ventricular end-diastolic volume at chronic phase.

Cardiovascular responses to static-dynamic exercises were studied in 27 patients with recent myocardial infarction. Patients with ischemic electrocardiographic changes at peak weight carrying exercise (group 1 = 8 patients) had a significantly larger left ventricular end-diastolic volume than those without (group 2 = 19 patients). A higher tension time index and shortening of diastolic time/min was observed in group 1 compared to group 2 during weight carrying. Thus, in addition to the increased myocardial oxygen demand, shortening of the diastolic perfusion time was observed during static-dynamic exercise in patients with dilated heart after myocardial infarction.

To evaluate the effects of gender and isometric handgrip exercise on left ventricular diastolic function in normal individuals, atrial and rapid filling fraction were investigated using M-mode echocardiography in 35 postmenopausal women and 31 age-matched men. There were no significant differences in heart rate, mean blood pressure, atrial filling fraction, and rapid filling fraction at rest between women and men. When the amount of change in hemodynamic variable during exercise was compared, there were no significant differences in heart rate and mean blood pressure between women and men. But the increase in atrial filling fraction and the decrease in rapid filling fraction were significantly larger in women than in men. These data suggest that left ventricular diastolic function is restricted in postmenopausal women, and left atrial booster pump action is mobilized when afterload is increased during isometric handgrip exercise.

Changes in left ventricular (LV) ejection rate were evaluated during supine bicycle exercise and recovery in 12 patients with anterior myocardial infarction. Pulmonary artery wedge pressure (34 +/- 9 to 14 +/- 5 mm Hg) and plasma norepinephrine level decreased at 2 min recovery from peak exercise, whereas plasma lactate tended to increase. As a result, LV ejection rate reached the highest value at 2 min of recovery. Thus, both cardiac (optimal filling pressure) and peripheral factors (reduced vascular resistance) caused the increase in LV ejection rate at early recovery.

To study the ventriculoarterial coupling in diabetic patients with myocardial infarction (MI), 26 diabetic and 34 nondiabetic patients were investigated using radionuclide angiography in the 3rd week after acute MI. Effective arterial elastance was nearly one half of left ventricular end-systolic elastance in nondiabetic patients. On the other hand, effective arterial elastance was twice left ventricular end-systolic elastance in diabetic patients. These data suggest that a decrease in left ventricular contractility and an increase in effective arterial elastance lead to increased potential energy and decreased work efficiency in diabetic patients.