Yuka Wakayama

Right ventricular ejection fraction during exercise in patients with recent myocardial infarction: Effect of the interventricular septum

To investigate the effect of interventricular septum (IVS) on right ventricular function during exercise, radionuclide angiocardiography was performed in 50 patients with recent myocardial infarction. Twenty-five patients had involvement of IVS according to thallium uptake in IVS (group I), and 25 patients were free of IVS involvement (group II). Although there was no statistical difference between the two groups in right ventricular ejection fraction (EF) at rest (45% +/- 10% vs 48% +/- 8%), patients in group I had significantly lower left ventricular (LV) EF (40% +/- 11% vs 53% +/- 11%, p < 0.01) and larger LV end-diastolic volume (129 +/- 46 vs 106 +/- 31 ml, p < 0.05) than those in group II. All parameters increased significantly during exercise in both groups, but patients in group I had significantly lower exercise right ventricular EF (50% +/- 10% vs 56% +/- 9%, p < 0.05), LVEF (44% +/- 11% vs 56% +/- 13%, p < 0.01), and larger LV end-diastolic volume (155 +/- 44 vs 129 +/- 37 ml, p < 0.05) than those of group II. Significant correlations were observed between right ventricular EF and LV end-diastolic volume at rest and during exercise (r = -0.48, p < 0.05, and r = -0.68, p < 0.01, respectively) in group I, but right ventricular EF correlated with LVEF only at peak exercise (r = 0.65, p < 0.01). In contrast, right ventricular EF did not correlate with any variables at rest or during exercise in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Late potentials during left ventricular healing of acute myocardial infarction.

BackgroundLate potentials and left ventricular remodeling are important factors in the prognosis of acute myocardial infarction. However, the relationship between late potentials and ventricular remodeling has not been fully evaluated. MethodsWe evaluated clinical characteristics, coronary angiographie findings and radionucltde angiographie measures about 1 month after an acute myocardial infarction in patients with and without late potentials. ResultsAlthough the left ventricular ejection fraction of patients with late potentials was not different from that of patients without late potentials, the left ventricular end-diastolic volume of patients with late potentials was larger than that of patients without late potentials (P<0.05). There was a significant positive correlation between the left ventricular end-diastolic volume and the filtered QRS duration (r = 0.53, P< 0.001). The root mean square of the voltage in the terminal 40ms and the low-amplitude signal duration of 7lt;40 μV in the terminal QRS sequence were also correlated with the left ventricular end-diastolic volume (r = 0.40, P<0.02, and r = 0.39, P<0.02, respectively). Patency of the infarct-related vessel in the late phase of an acute myocardial infarction was an important factor associated with the occurrence of late potentials (P<0.01). ConclusionA larger left ventricular end-diastolic volume in patients with late potentials might be associated with left ventricular remodeling during the first month after an acute myocardial infarction.

Difference between women and men in left ventricular pump function during predischarge exercise test after acute myocardial infarction

To evaluate the difference in left ventricular (LV) pump function during predischarge exercise testing between postmenopausal women and age-matched men with myocardial infarction, global and regional ejection fraction, LV end-diastolic volume, and the ratio of systolic blood pressure to LV end-systolic volume were investigated using radionuclide angiography in 25 postmenopausal women and 37 age-matched men. There were no significant differences in the resting radionuclide angiographic indexes between women and men. Global and regional ejection fraction of noninfarcted area, and the ratio of systolic blood pressure to LV end-systolic volume decreased at peak exercise in women, but these indexes increased in men. Although there was no significant difference in the amount of change in LV end-diastolic volume during exercise between the 2 groups, the amount of increase in LV end-systolic volume was significantly larger in women than in men. The ratio of systolic blood pressure to LV end-systolic volume had a curvilinear relation with LV end-diastolic volume at rest and peak exercise, but the ratio of systolic blood pressure to LV end-systolic volume was larger at any LV end-diastolic volume in men than in women during exercise. Thus, lower global ejection fraction and the ratio of systolic blood pressure to LV end-systolic volume during exercise in postmenopausal women compared with age-matched men indicate that gender may have played an important role in the LV remodeling process.

Residual left ventricular pump function following acute myocardial infarction in postmenopausal diabetic women

BackgroundThe Framingham Study indicated that women with diabetes mellitus developed cardiac failure four times more often than those without diabetes mellitus after acute myocardial infarction. However, there is little information on residual left ventricular pump function after myocardial infarction in female diabetic patients. MethodsTo evaluate the difference between postmenopausal women and age-matched men in the impact of diabetes mellitus on left ventricular pump function during the first year after myocardial infarction, radionuclide angiography was performed during the third week after acute myocardial infarction and again 1 year later in 50 patients (21 women, 29 men) with diabetes mellitus and 62 patients (25 women, 37 men) without diabetes mellitus. ResultsAlthough the radionuclide angiographie indices did not change during the first year after myocardial infarction in non-diabetic patients, left ventricular end-diastolic volume increased, and the left ventricular ejection fraction, the regional ejection fraction of the non-infarcted area, and the ratio of arterial systolic blood pressure to left ventncular end-systolic volume (pressure:volume ratio) decreased in the diabetic patients. Furthermore, the degree of change in the left ventricular end-diastolic volume, the left ventricular ejection fraction, the regional ejection fraction of the non-infarcted area, and the pressure: volume ratio in diabetic women was larger than that in diabetic men. ConclusionThe increase in the left ventricular end-diastolic volume and the decrease in the regional ejection fraction of the non-infarcted area during the first year after myocardial infarction in postmenopausal women with diabetes mellitus indicate that female sex associated with diabetes mellitus may be important factors in left ventricular remodeling in postmenopausal women.

Left ventricular function during exercise after aortic valve replacement.

To evaluate the difference in left ventricular function during exercise after successful aortic valve replacement, left ventricular function was investigated using radionuclide angiography in 12 patients with normal resting left ventricular systolic function. Patients were divided into two groups: Group 1 was comprised of 5 patients after aortic valve replacement for aortic stenosis and group 2 was comprised of 7 patients for aortic insufficiency. Left ventricular ejection fraction increased significantly during exercise in both groups. The increase in systolic arterial pressure to left ventricular end-systolic volume was significantly larger in group 1 than group 2, whereas the increase in left ventricular end-diastolic volume was significantly larger in group 2 than group 1. Thus, increase in left ventricular contractility played an important role in regulating increased left ventricular ejection fraction during exercise in patients with aortic prostheses for aortic stenosis, whereas increase in left ventricular end-diastolic volume played an important role in patients with aortic prostheses for aortic insufficiency.