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Biomedical subjects

F Yuasa

Publications and source records attributed to F Yuasa.

At least 19 recordsLinked to original sources
PubMed2001

Clinical significance of ST-segment elevation in lead V1 in patients with acute inferior wall Q-wave myocardial infarction.

BACKGROUND: This study was designed to determine the clinical significance of ST-segment elevation in the precordial leads (leads V1 and V2) in acute Q-wave inferior wall myocardial infarction. METHODS AND RESULTS: One hundred fifty-eight consecutive patients with acute Q-wave inferior wall myocardial infarction were classified into 3 groups on the basis of the initial ST-change in V1 (group 1 = 29 patients with ST elevation, group 2 = 97 patients with ST depression, and group 3 = 32 patients with no ST-segment change). The right coronary artery was the infarct-related artery in all the patients in group 1. Although there was no significant difference between groups 1 and 2, the number of left ventricular asynergic segments was larger and the incidence of major in-hospital arrhythmias was higher in groups 1 and 2 compared with group 3. Patients in group 1 had a significantly higher incidence of proximal lesion (86%) and right ventricular infarction (69%) than the other 2 groups did. When ST elevation in leads V1 and V2 was considered, 14 of 15 patients (93%) with ST elevation only in V1 had right ventricular infarction, whereas 6 of 14 patients (43%) with ST elevation in both V1 and V2 had right ventricular infarction (P =.011). CONCLUSIONS: ST-segment elevation in V1 on admission in patients with acute Q-wave inferior wall myocardial infarction indicates a right coronary artery lesion associated with a larger infarct size and a higher incidence of major in-hospital arrhythmias.

Adult↗
PubMed2001

Clinical significance of coronary flow to the infarct zone before successful primary percutaneous transluminal coronary angioplasty in acute myocardial infarction.

STUDY OBJECTIVE: To assess the effect of coronary flow to the infarct zone before primary coronary angioplasty on hospital complications in patients with acute myocardial infarction (MI). DESIGN: Consecutive case series analysis. SETTING: Coronary-care unit in a university hospital. PATIENTS: Two hundred sixty-four consecutive patients with ST-elevation acute MIs who had successful primary percutaneous transluminal coronary angioplasty. INTERVENTIONS: Coronary angiography on hospital admission and serial echocardiography. MEASUREMENTS AND RESULTS: The status of infarct-related artery flow before primary angioplasty was evaluated on hospital admission. Left ventricular wall motion and pericardial effusions were studied by echocardiography. One hundred ninety patients had total occlusions (Thrombolysis in Myocardial Infarction [TIMI] flow grade, 0 to 1) in the infarct-related artery (group 1), and 74 patients had antegrade flow (TIMI flow grade, 2 to 3) [group 2] before undergoing primary angioplasty procedures. When group 1 was subdivided into two groups (for the presence and absence of collateral flow), the patients with total occlusions and no collateral flow had a higher incidence of left ventricular aneurysmal wall motion (11% vs 1%, respectively; p = 0.03) and pericardial friction rub (15% vs 3%, respectively; p = 0.03) than did those in group 2. Moreover, those patients with total occlusions and no collateral flow had higher incidences of pericardial effusion (34% vs 17%, respectively; p = 0.02; and 34% vs 9%, respectively; p < 0.01) and in-hospital mortality (8% vs 1%, respectively; p = 0.04; and 8% vs 1%, respectively; p = 0.06) than did those patients in the other two groups. CONCLUSIONS: Despite successful primary angioplasty, the absence of antegrade flow in the infarct-related artery and collateral flow to the infarct zone before angioplasty resulted in a higher incidence of in-hospital complications.

Aged↗
PubMed2000

Effect of angiotensin-converting enzyme inhibitor on cardiopulmonary baroreflex sensitivity in patients with acute myocardial infarction.

We evaluated the effect of angiotensin-converting enzyme inhibition (quinapril) on cardiopulmonary baroreflex sensitivity in 30 patients with uncomplicated myocardial infarction (quinapril group, 15 patients; placebo group, 15 patients) at 5 and 10 days after the onset of myocardial infarction. This study indicates that quinapril improved cardiopulmonary baroreflex and thus reduced sympathetic outflow in patients with acute myocardial infarction.

Administration, Oral↗
PubMed1998

Pericardial effusion after primary percutaneous transluminal coronary angioplasty in first Q-wave acute myocardial infarction.

To evaluate the incidence and clinical significance of infarction-associated pericardial effusion in patients with successful primary percutaneous transluminal coronary angioplasty, we studied 214 consecutive patients with a first Q-wave acute myocardial infarction. Based on 9 clinical variables, multivariate analysis was performed to determine the important variables related to the occurrence of pericardial effusion. Pericardial effusion was detected by echocardiography in 45 patients (21%); pericardial rub (p <0.001), number of advanced asynergic segments (p <0.001), ventricular aneurysmal motion (p = 0.03), and pulmonary capillary wedge pressure (p = 0.04) were found to be the important variables related to pericardial effusion. Among 45 patients with pericardial effusion, 29 patients with no pericardial rub had significantly higher pulmonary capillary wedge pressure than those with pericardial rub, whereas 16 patients with pericardial rub had a higher incidence of angiographic no reflow and ventricular aneurysmal motion than those without pericardial rub. Patients with pericardial effusion and a pericardial rub had a higher mortality rate than those without pericardial effusion (19% vs 3%; p = 0.02). Thus, pericardial effusion is still a relatively common clinical finding after primary percutaneous transluminal coronary angioplasty, and those with pericardial effusion and a pericardial rub were associated with more severe transmural myocardial damage and higher in-hospital mortality.

Aged↗
PubMed1998

Importance of intrinsic calf vasodilator capacity in determining distribution of skeletal muscle perfusion during supine bicycle exercise in patients with left ventricular dysfunction.

BACKGROUND: Distribution of skeletal muscle perfusion during exercise is an important factor in determining exercise capacity and is markedly impaired in patients with cardiac disease. This study examined the importance of intrinsic calf vasodilator capacity in determining distribution of skeletal muscle perfusion during supine bicycle exercise in patients with left ventricular dysfunction. METHODS: We studied 19 patients with left ventricular dysfunction (left ventricular ejection fraction <45%) after myocardial infarction. All the patients underwent cardiopulmonary exercise testing with measurements of central hemodynamics, leg blood flow (LBF), and the percentage of cardiac output distributed to both legs (%LBF). Calf reactive hyperemic flow (RH) was measured by venous occlusive plethysmography at supine rest. RESULTS: LBF at peak exercise was closely related to peak cardiac output and RH. Furthermore, %LBF at peak exercise had modest correlation with peak cardiac output and good correlation with RH. Although peak cardiac output and RH were independent determinants of LBF at peak exercise by multiple regression analysis, RH had higher correlation with %LBF at peak exercise than peak cardiac output. Despite marked changes in other hemodynamic variables, nonleg blood flow during exercise was constantly maintained at a level identical to resting value. CONCLUSIONS: Calf vasodilator capacity, which was the major determinant of distribution of skeletal muscle perfusion during exercise, may have contributed to maintaining perfusion of important nonexercising regions during exercise in patients with left ventricular dysfunction.

Adult↗
PubMed1997

Importance of left ventricular diastolic function on maintenance of exercise capacity in patients with systolic dysfunction after anterior myocardial infarction.

To investigate the role of left ventricular (LV) diastolic function in the maintenance of exercise capacity in patients with systolic dysfunction, symptom-limited cardiopulmonary exercise testing combined with radionuclide ventriculography was performed in 24 patients with an LV ejection fraction < 35% after anterior myocardial infarction. The ratio of pulmonary artery wedge pressure (PAWP) to LV end-diastolic volume (EDV), an index of global diastolic function, correlated significantly with peak oxygen consumption at peak exercise (r = -0.55; p = 0.006), whereas ejection fraction at peak exercise did not. The change in PAWP/EDV ratio from rest to peak exercise was related to the increases in stroke volume (r = -0.54; p = 0.006) and cardiac output (r = -0.51; p = 0.01) during exercise, but the change in ejection fraction was not. Resting hemodynamics did not differ between patients with preserved exercise capacity (group 1, n = 8) and those with exercise impairment (group 2, n = 16). At peak exercise, stroke volume, cardiac output, and EDV were significantly higher, and PAWP and PAWP/EDV ratio were significantly lower in group 1 than in group 2, but ejection fraction and end-systolic volume were similar in both groups. Although the incidences of hypertension, LV hypertrophy, and infarct-related coronary artery lesions did not differ between the two groups, group 2 had a significantly higher incidence of non-infarct-related coronary artery lesions than group 1 (p < 0.05). Thus in patients with LV systolic dysfunction after anterior myocardial infarction, the major cause of exercise impairment and failure to increase LV performance during exercise was diastolic dysfunction associated with the presence of non-infarct-related coronary artery lesions with the potential for exercise-induced ischemia of the noninfarcted areas.

Adult↗
PubMed1997

Effects of left ventricular peak filling rate on exercise capacity 3 to 6 weeks after acute myocardial infarction.

STUDY OBJECTIVES: To investigate the importance of early left ventricular (LV) diastolic filling on maintenance of exercise performance, we examined peak filling rate and its relation to exercise capacity during upright bicycle exercise in patients with recent myocardial infarction. DESIGN: Retrospective analysis of data of cardiopulmonary exercise testing characteristics in patients with recent myocardial infarction. SETTING: Coronary care unit in a university hospital. PATIENTS: Fifty-one patients 3 to 6 weeks after acute myocardial infarction. INTERVENTIONS: Upright bicycle exercise using a symptom-limited graded exercise protocol. MEASUREMENTS AND RESULTS: Peak filling rate increased significantly from 1.55 +/- 0.52 at rest to 3.43 +/- 1.1 end-diastolic volume per second at peak exercise. Despite no significant relation between peak filling rate at rest and peak oxygen consumption, peak filling rate at peak exercise correlated significantly with peak oxygen consumption (r = 0.50; p < 0.002), stroke volume (r = 0.51; p < 0.002), and cardiac output (r = 0.56; p < 0.002) at peak exercise. Although both end-systolic and end-diastolic volumes increased from rest to peak exercise, the increases in end-systolic volume correlated inversely with the changes in peak filling rate during exercise (r = -0.45; p < 0.02), but the increases in end-diastolic volume did not. CONCLUSIONS: During maximal upright bicycle exercise, exercise capacity and exercise hemodynamic responses were mainly dependent on early LV diastolic filling, and preserved LV systolic contraction, resulting in a cardiac suction effect following early diastole, seemed to have an important role in the enhancement of early LV diastolic filling in patients with recent myocardial infarction.

Cardiac Output↗
PubMed1997

Left atrial function as a reliable predictor of exercise capacity in patients with recent myocardial infarction.

STUDY OBJECTIVE: To examine the relation between left atrial (LA) function and exercise performance. DESIGN AND SETTING: Retrospective study at a referral cardiopulmonary exercise laboratory in a university hospital. PATIENTS: Forty-one patients with recent myocardial infarction. INTERVENTIONS: M-mode echocardiography and cardiopulmonary exercise testing combined with radionuclide ventriculography. MEASUREMENTS AND RESULTS: Hemodynamic measurements were obtained at rest and peak exercise. LA fractional shortening at rest was used as an index of global LA function. LA fractional shortening had fair correlations with peak oxygen consumption (r=0.67, p<0.01) and exercise duration (r=0.71, p<0.01). Although there were no significant relations between LA fractional shortening and hemodynamic measurements at rest, LA fractional shortening was positively related to peak cardiac output (r=0.61, p<0.01) and peak stroke volume (r=0.57, p<0.01), and negatively related to peak pulmonary arterial wedge pressure (r=-0.44, p<0.05). In addition, LA fractional shortening correlated significantly with an increase in left ventricular (LV) end-diastolic volume from rest to peak exercise (r=0.48, p<0.02), but did not correlate with the changes in ejection fraction and end-systolic volume during exercise. An increase in LV end-diastolic volume during exercise was significantly related to peak oxygen consumption (r=0.46, p<0.02), peak cardiac output (r=0.60, p<0.01), and peak stroke volume (r=0.53, p<0.01), whereas the changes in ejection fraction and end-systolic volume during exercise were not related to these indexes. CONCLUSIONS: Exercise capacity and LV performance during exercise were mainly dependent on LV diastolic filling rather than systolic contraction during exercise. LA fractional shortening at rest reflected LV diastolic filling during exercise and, therefore, predicted cardiac output and stroke volume responses to exercise and exercise capacity in patients with recent myocardial infarction.

Adult↗
PubMed1996

Skeletal muscle hypoperfusion during recovery from maximal supine bicycle exercise in patients with heart failure.

Leg blood flow (LBF) and its relation to central hemodynamics were examined during recovery following maximal supine bicycle exercise in 11 patients with heart failure and 20 patients with normal exercise capacity after myocardial infarction. The results indicate that LBF was markedly reduced in patients with heart failure, and that decreased cardiac output response and enhanced peripheral vasoconstriction, which functioned to prevent hypoperfusion in the nonexercising vital regions and to maintain arterial blood pressure, were responsible for the reduced LBF during recovery in heart failure.

Adult↗
PubMed1996

Influence of intrinsic limb vasodilator capacity on exercise tolerance in patients with recent myocardial infarction.

To investigate the influence of intrinsic limb vasodilator capacity on exercise performance, limb reactive hyperemic flows and their relations to exercise capacity during upright bicycle exercise were examined in 52 patients with recent myocardial infarction. Reactive hyperemic flow was measured in the forearm and the calf by venous occlusive plethysmography after 5 min of arterial occlusion. Calf reactive hyperemic flow correlated significantly with cardiac output, systemic vascular resistance, and oxygen consumption at peak exercise, whereas flow in the forearm did not. In patients with preserved exercise capacity (group 1, n = 20) compared with those with exercise impairment (group 2, n = 32), calf reactive hyperemic flow was significantly augmented, but forearm flow was similar in the two groups. There were no significant differences in hemodynamic parameters at rest between the two groups. At peak exercise, however, cardiac output was lower and systemic vascular resistance was higher in group 2 than in group 1, whereas arterial blood pressure was maintained identically in the two groups. Thus, intrinsic calf but not forearm vasodilator capacity was linked to exercise hemodynamic responses and exercise capacity in patients with recent myocardial infarction. In addition, reduced calf vasodilation and concomitant enhanced vascular tone seemed to be useful for preserving arterial blood pressure in the setting of decreased cardiac output response to exercise in patients with exercise impairment.

Adult↗
PubMed1995

Effects of left ventricular diastolic dysfunction on exercise capacity three to six weeks after acute myocardial infarction in men.

To examine the effects of left ventricular (LV) diastolic dysfunction on exercise capacity, hemodynamic and radionuclide responses were measured at rest and during exercise in 50 patients with recent myocardial infarction. The ratio of an increase in pulmonary arterial wedge pressure (PAWP) to an increase in LV end-diastolic volume (EDV) from rest to peak exercise (delta PAWP/delta EDV) was used as an index of LV diastolic function, delta PAWP/delta EDV had modest and negative correlations with peak oxygen consumption (VO2), cardiac output, and stroke volume in all patients. Among patients with peak VO2 > or = 20 ml/min/kg (group I, n = 24) and those with peak VO2 < 20 ml/min/kg (group II, n = 26), there were no differences between the 2 groups with regard to resting LV ejection fraction, EDV, PAWP, cardiac output, and stroke volume. Although there was no significant difference in LV ejection fraction at peak exercise, group II had significantly reduced EDV, increased PAWP, and decreased cardiac output and stroke volume than those in group I. As a result, delta PAWP/delta EDV was significantly higher in group II. These results suggest that LV diastolic dysfunction has a key role in determining exercise capacity in patients with reduced exercise capacity after recent myocardial infarction.

Adolescent↗
PubMed1994

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.

Aged↗
PubMed1993

Increase in left ventricular ejection rate during recovery from exercise in patients with myocardial infarction.

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.

Acid-Base Equilibrium↗
PubMed1993

Ventriculoarterial coupling during low-level exercise testing after myocardial infarction.

To evaluate the change of ventriculoarterial coupling during low-level exercise in patients after myocardial infarction, the ratio of systolic blood pressure to left ventricular end-systolic volume (P/V ratio) and the ratio of systolic blood pressure to stroke volume (effective arterial elastance) were investigated using radionuclide angiography in 73 consecutive patients with a negative predischarge exercise test. The patients were divided into three groups according to their resting left ventricular ejection fraction: group A (n = 12) > or = 60%; group B (n = 32) 41-59%; group C (n = 29) < or = 40%. The ejection fraction increased significantly during exercise in all three groups. There was no significant difference in the change of the P/V ratio during exercise between groups A and B, but it was significantly smaller in group C. The effective arterial elastance increased during exercise in group A, did not change in group B, and decreased in group C. Thus, the augmentation of myocardial contractility was an important factor related to the increase in ejection fraction during exercise in patients with normal or slightly reduced cardiac function, whereas the decrease in effective arterial elastance was important in patients with poor cardiac function.

Adult↗
PubMed1993

Overshoot in mixed venous oxygen saturation during recovery from supine bicycle exercise in patients with recent myocardial infarction.

During recovery from dynamic exercise, systemic oxygen extraction rapidly decreases below the resting level in patients with heart failure, which leads to a subsequent increase in mixed venous oxygen saturation (SvO2) above its resting value (postexercise SvO2 overshoot). To evaluate the pathophysiologic basis of this phenomenon, postexercise SvO2 overshoot was evaluated in relation to hemodynamic, metabolic, and neurohumoral responses during recovery from maximal supine bicycle exercise in 22 patients with recent myocardial infarction. Postexercise SvO2 overshoot closely correlated with increased systemic vascular resistance (r = 0.79, p < 0.001) and reduced cardiac output (r = -0.74, p < 0.001), suggesting that SvO2 overshoot is primarily due to increased peripheral arteriovenous shunting caused by an enhanced peripheral vasoconstriction in the setting of reduced cardiac output. Postexercise SvO2 overshoot and systemic vascular resistance were significantly higher and cardiac output was significantly lower in New York Heart Association functional class 3 and 4 (8 patients) compared with class 1 and 2 (14 patients), whereas systemic arterial blood pressure was maintained at normal levels in both groups. Thus, postexercise SvO2 overshoot and, hence, decreased systemic oxygen extraction during recovery represent a compensatory response of an enhanced peripheral vascular tone that maintains systemic arterial blood pressure in the setting of reduced cardiac output by linking central and peripheral blood flow.

Adult↗
PubMed1993

Effect of infarct site on diastolic time during exercise.

To assess the difference in left ventricular performance during exercise between anterior (11 patients) and inferior (10 patients) myocardial infarction (MI) of equivalent size, patients performed a supine bicycle exercise 6 to 8 weeks after the first acute MI. All patients had negative exercise test results and despite no significant differences in HR, blood pressure and stroke volume index at peak exercise, pulmonary artery wedge pressure was significantly higher in anterior (35 +/- 7 mm Hg) than in inferior MI (27 +/- 9 mm Hg). Although there were no significant differences in electromechanical systole (QS2) and diastolic time (DT) at rest, a significant prolongation of QS2 with consequent shortening of DT (p < 0.01) was observed at peak exercise in anterior MI. In addition to decreased subendocardial coronary blood flow from increased left ventricular end-diastolic pressure, a disproportionate shortening of DT in anterior MI may initiate subendocardial ischemia in the noninfarcted segments, which may further impede subendocardial blood flow.

Blood Pressure↗
PubMed1991

Oxygen utilization, carbon dioxide elimination and ventilation during recovery from supine bicycle exercise 6 to 8 weeks after acute myocardial infarction.

The pattern of oxygen (O2) consumption (VO2), carbon dioxide (CO2) production (VCO2), ventilatory and metabolic responses during and in recovery from supine bicycle exercise was examined in 18 patients with recent myocardial infarction. An increase in VO2 with increasing work load was accomplished by proportional increases in both cardiac output and the arteriovenous O2 difference. During recovery, however, the arteriovenous O2 difference rapidly decreased below levels at rest, whereas VO2 and cardiac output remained elevated, indicating that VO2 during recovery further depended on relatively high cardiac output. The ratio of VCO2 to VO2 further increased after exercise, suggesting that such cardiac output contributed to the remaining high CO2 flow to the lung and therefore enhanced ventilation. Increased arterial catecholamines during exercise remained elevated for the first 5 minutes of recovery. Arterial lactate during this period continued to increase and resulted in profound metabolic acidosis, causing alveolar hyperventilation after exercise. These results suggest that during recovery from exercise, cardiopulmonary responses remain enhanced because of continuing high cardiac output, resulting in subsequent high CO2 flow to the lung and metabolic acidosis, and that this may be associated with profound fatigue or dyspnea after exercise.

Acidosis, Lactic↗