Search PubMed⌕ Search

Biomedical subjects

H Fukuzaki

Publications and source records attributed to H Fukuzaki.

At least 163 records · Page 9Linked to original sources
PubMed1987

Reduced chronotropic reserve to the metabolic requirement during exercise in advanced heart failure with old myocardial infarction.

We studied the metabolic and cardiac responses to exercise by expiratory gas analysis in 40 patients with old myocardial infarction and 33 normal sedentary males. On the basis of exercise energy metabolism, the elevation of the respiratory quotient (RQ; RQ = VCO2/VO2) during exercise is caused by the increase of blood lactate due to the augmented anaerobic metabolism. Functional aerobic impairment (FAI) in our study was significantly advanced in the control group and the NYHA functional class I, class II and class III groups, that is, -2.3 +/- 11.2%, +14.8 +/- 10.4%, +27.8 +/- 13.8% and +49.4 +/- 2.8%, respectively. The delta RQ values were similar among all groups; 0.29 respectively. The delta RQ values were similar among all groups; 0.29 +/- 0.06, 0.28 +/- 0.07, 0.27 +/- 0.07 and 0.29 +/- 0.09, respectively. Functional chronotropic impairment (FCI) for the same groups was -0.9 +/- 7.0%, +1.4 6.1%, +3.8 +/- 4.8% and +8.7 +/- 6.0%, and that of the class III group was significantly larger than that of the control group. Thus, in the class III congestive heart failure group, the chronotropic response to the metabolic requirement was impaired in comparison to the control group. It was concluded that the reduced chronotropic reserve was present in NYHA class III patients with old myocardial infarction, and that this mechanism might contribute to a decrease in the pump reserve of the heart, resulting in further impairment of physical capacity in these patients.

Adult↗
PubMed1987

Impaired right ventricular filling in old myocardial infarction.

To evaluate ventricular filling and interactions between right and left ventricles in patients with old myocardial infarction, right and left ventricular time-volume curves were analyzed from a cineangiographic study of 10 normal subjects (Group 1), 10 patients with old anterior myocardial infarction (Group 2) and 10 patients with old inferior myocardial infarction (Group 3). Volumes of both ventricles were calculated from each frame over an entire cardiac cycle using Simpson's method. From time-volume curves, peak ejection rates, peak filling rates and atrial kick rates were obtained for both ventricles and these parameters were normalized by end-diastolic volume. All patients were in sinus rhythm with heart rates less than 80 beats/min. There were no significant differences among the 3 groups in end-diastolic pressure of both ventricles and mean pulmonary artery pressure. Left ventricular ejection fractions were significantly lower in Groups 2 and 3 than in Group 1 (p less than 0.001, p less than 0.005, respectively), although there were no significant differences in end-diastolic volume indexes of either ventricle among the 3 groups. Peak left ventricular ejection rate and peak filling rates of the left and right ventricles were lower in Group 2 than in Group 1 (p less than 0.01, p less than 0.05, p less than 0.01, respectively) and peak filling rate of the right ventricle in Group 2 correlated with the peak filling rate of the left ventricle and left ventricular ejection fraction (r = 0.64, r = 0.64, respectively). Peak filling rate of the right ventricle in Group 2 correlated inversely with left ventricular peak negative dp/dt (r = -0.72), but no correlation was found between peak filling rate of the right ventricle and left ventricular end-diastolic volume index or mean pulmonary artery pressure. Peak ejection rate of the left ventricle and peak filling rates of both ventricles in Group 3 were lower than in Group 1 (p less than 0.02, p less than 0.02, p less than 0.01, respectively) and no correlation was found between peak filling rates of both ventricles. Wall motion of the right ventricular septal portion was slightly reduced in 5 patients in Group 2. In all patients in Group 3, right ventricular wall motion centering around the right ventricular diaphragmatic portion was reduced. These results suggest that in old inferior myocardial infarction, right ventricular wall motion abnormality results in impaired right ventricular filling, whereas in old anterior myocardial infarction, right ventricular filling is reduced indirectly due to impaired left ventricular filling.

Cardiac Volume↗
PubMed1987

The role of parasympathetic nerve activity in the pathogenesis of coronary vasospasm.

To evaluate the role of the autonomic nervous system, especially the parasympathetic nervous system, in the initiation mechanism of vasospastic angina pectoris (AP), the coefficient of R-R interval variation (CV) on the electrocardiogram (ECG) and plasma catecholamine concentration were measured in 25 patients with vasospastic AP, 10 patients with effort AP and 12 control subjects. CV which has been recognized as reflecting parasympathetic nervous system activity was calculated from 100 consecutive heart beats on the ECG and represented as the percentage of standard deviation of the R-R interval per mean R-R interval. Repeated measurements of plasma catecholamine concentration revealed higher values at any sampling point throughout a day in patients with vasospastic AP than those in control subjects. A distinctly higher CV was observed at night in the vasospastic AP group. This elevated CV was abolished by atropine sulfate (1.5 mg/day per os). Pilocarpine injection (1.3 mg/10 kg B.W. subcutaneously) induced a marked increase in CV that preceded the occurrence of chest pain and/or ischemic ECG changes in 5 patients with vasospastic AP. The increment in CV at 10 min after pilocarpine administration was greater in vasospastic AP than in control subjects (p less than 0.05). It is concluded that enhanced parasympathetic activity may play a role in the initiation of coronary vasospasm associated with sympathetic hyperactivity.

Angina Pectoris, Variant↗
PubMed1987

The effects of isosorbide dinitrate on exercise-induced ST-segment elevation at the infarcted area in old myocardial infarction.

To clarify the clinical significance and therapeutic implication of exercise-induced ST elevation at the infarcted area in old myocardial infarction (OMI), 30 patients with exercise-induced ST elevation underwent treadmill exercise testing. The patients with transient perfusion defects at the infarcted area on thallium-201 stress myocardial scintigraphy (group I: n = 12) revealed a decreased rate of ST elevation expressed as delta ST/delta HR X 10(2) after 10 mg of isosorbide dinitrate (ISDN), compared to the results of treadmill exercise testing under no medication (3.1 +/- 2.5 vs. 4.7 +/- 2.6, p less than 0.001). Exercise capacity and anginal threshold were improved after ISDN in group I. In contrast, the patients without transient perfusion defects (group II: n = 18) revealed an increased rate of ST elevation after ISDN (2.4 +/- 1.1 vs. 2.0 +/- 0.8, p less than 0.05). It is concluded from the above results that if exercise-induced ST elevation at the infarcted area reflects transient myocardial ischemia, ISDN can decrease it by its anti-anginal effect. Additionally, treadmill exercise testing with ISDN is a useful means of clarifying the underlying pathophysiology and management in OMI cases with this effect on exercise-induced ST elevation at the infarcted area.

Adult↗
PubMed1987

[Myocardial perfusion assessed by dynamic computed tomography before and after percutaneous transluminal coronary angioplasty].

A method for quantitatively and visually assessing myocardial perfusion using a new transmission computed tomography scanner and contrast media injection was devised. Myocardial perfusion was assessed before and after percutaneous transluminal coronary angioplasty (PTCA). Six patients with left anterior descending coronary artery stenosis undergoing PTCA were successfully studied. Dynamic scans, each with a scan time of one sec, were performed at the mid left ventricular level using bolus injections of contrast medium from the inferior vena cava. Regions of interest (ROIs) were located in the left ventricular cavity and in the myocardium perfused by the left anterior descending coronary artery, and gamma-variate fitted time density curves were recorded within the first pass phase, excluding recirculation. Cardiac outputs calculated from the ventricular curves of the ROIs in the left ventricular cavity correlated well with the thermodilution measurements using Swan-Ganz catheters (r = 0.90, p less than 0.01). The ratios of myocardial blood flow (F) to the tissue element volume (V) were calculated (F/V) from the myocardial curves of the ROIs in the myocardium as parameters of myocardial perfusion, according to the Zierler's principle. The F/Vs in the myocardium perfused by the left anterior descending coronary artery before PTCA were significantly less than those of the control subjects (4.4 x 10(-2) +/- 1.2 x 10(-2) vs 8.1 x 10(-2) +/- 2.9 x 10(-2): p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1987

[Pathogenesis of dilated cardiomyopathy: a study based on comparison of the clinical features with other related conditions].

To investigate the pathogenesis and pathophysiology of dilated cardiomyopathy (DCM), we studied 28 patients with DCM by echocardiography and endomyocardial biopsy, and compared their findings with those of 34 patients including eight with myocarditis, seven with alcoholics, 12 with hypertensives and seven patients with hypertrophic cardiomyopathy. All 12 patients in the hypertensive group had congestive heart failure without accompanying high blood pressure, and prominent dilatation and uniform wall motion abnormality of the left ventricle observed echocardiographically on admission. After medical management, both heart failure and the echocardiographic abnormalities gradually resolved. Those in the alcoholic group had larger left ventricles and uniform wall motion abnormality compared to those in the other groups. The myocarditis and hypertrophic cardiomyopathy groups had smaller left ventricles, non-uniform wall motion and larger % myocardial fibrosis. Both ventricles in the hypertrophic cardiomyopathy group were thicker than those of the other three groups. Each patient with DCM had individual echocardiographic abnormalities, which could be categorized as two subsets depending on the degree of left ventricular dilatation and uniformity of the wall motion. The one was characterized by a prominently dilated left ventricle and uniform wall motion abnormality similar to the alcoholic group, and the other had less marked left ventricular dilatation and heterogeneous wall motion abnormality similar to the myocarditis group. From these findings, it was suggested that there are common factors to specific myocardial disease in the pathogenesis and pathophysiology of DCM, and thus, DCM might include many subsets of different etiologies.

Adult↗
PubMed1987

[Relationships between segmental left ventricular wall motion abnormalities and pathological findings in patients with dilated cardiomyopathy].

Relationships between segmental left ventricular wall motion abnormalities and myocardial fibrosis at autopsy were examined in 12 patients who died of dilated cardiomyopathy. In each case, wall motion abnormalities were assessed by two-dimensional echocardiograms for 11 segments, and semiquantitatively evaluated as normokinesis (N) to hypokinesis (H), severe hypokinesis (SH) or akinesis (A). From the necropsy specimens, the myocardial fibrosis ratio was histologically quantitated using a point-counting method in each segment corresponding to the echocardiographic segment. Wall motion abnormalities and the fibrosis ratio correlated significantly in a total of 132 segments of the 12 patients, but there were some discordances. The cases were then categorized in uniform and non-uniform groups based on the patterns of myocardial fibrosis. Wall motion abnormalities correlated much better with the fibrosis ratio in a total of 44 segments among four cases with non-uniform fibrosis, whereas no significant correlation was found in a total of 88 segments in eight cases with uniform fibrosis. The latter group had more severe segmental wall motion abnormalities in the interventricular septum than in the left ventricular free wall; and in the apical portion rather than in the basal portion, although no significant difference was observed in the fibrosis ratio among these regions. Patients with non-uniform fibrosis had higher incidences of chest pain and sudden deaths and a significantly larger left ventricular end-diastolic dimension on M-mode echocardiogram as compared to those with uniform fibrosis. Pathologically, in the former group, the heart was heavier, the mean left ventricular fibrosis ratio was significantly higher, and there was a greater incidence of infiltration of the myocardium by mononuclear cells, but there was no difference in the mean left ventricular wall thickness. These results suggest that myocardial fibrosis mainly contributes to the wall motion abnormalities in cases with non-uniform fibrosis which may be caused by chronic myocarditis, but not in cases with uniform fibrosis. In the latter group, other factors such as reduced contractility of the myocardial cells or lack of a compensatory mechanism for wall stress seem to play important roles in causing left ventricular wall motion abnormalities.

Adult↗
PubMed1987

[Effect of valve replacement on left ventricular function in chronic aortic regurgitation].

To ascertain the optimal time for surgery in chronic aortic regurgitation (AR), 66 patients with and without surgical correction were reviewed from the standpoint of left ventricular (LV) function based on their serial echocardiographic studies. Aggravation of the clinical status was usually associated with enlarged LV dimension, decreased %fractional shortening (%FS), and increased LV end-systolic meridional stress (sigma m). Fourteen patients developed congestive heart failure during follow-up periods of up to five years, and most of their echocardiographic findings showed %FS less than 27%, and LV end-systolic dimension (LVD) greater than 50 mm. Thirty-two patients underwent surgery. Preoperatively, sigma m and %FS were closely correlated, including cases whose %FS was decreased. This linear regression equation became steeper with dobutamine administration; however, in patients, whose mean preoperative LVD value exceeded 50 mm, the %FS remained depressed (delta FS less than 6%) and sigma m did not significantly decrease during dobutamine administration. Marked or moderate resolution of LV dilatation and hypertrophy was observed in all patients postoperatively. Compared to patients with preoperative %FS greater than or equal to 27%, much more time was required for recovery of patients with %FS less than 27%, though their %FS and their exercise capacity improved within two years of surgery. Immediate postoperative recovery was observed in cases with excellent preoperative response to dobutamine (delta FS greater than or equal to 6%). However, in patients with severely depressed preoperative %FS less than 20%, postoperative improvement was not so marked and the surgical results were unsatisfactory. From these results, we concluded that the optimal time for surgery for AR is when %FS = 27% and LVDs = 50 mm.

Adult↗
PubMed1987

[Hypertrophic non-obstructive cardiomyopathy assessed by dipyridamole thallium single photon emission computed tomography: comparisons with hypertrophic cardiomyopathy with a dilated heart].

Thallium-201 (Tl) single photon emission computed tomography (SPECT) after dipyridamole infusion (0.56 mg/kg) was performed in 23 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and in seven patients with HCM simulating dilated cardiomyopathy (HCM-DCM) to clarify the mechanism and clinical significance of decreased coronary vasodilatory reserve. The coronary vasodilatory reserve in the hypertrophied area assessed by SPECT was compared with the findings of echocardiography, left ventriculography and endomyocardial biopsy. 1. Eleven patients with HNCM had no perfusion defects in the hypertrophied area (group I), but the other 12 patients (52.2%) had such defects (group II). All seven patients with HCM-DCM had perfusion defects in the anterior or septal walls (group III). Redistribution was observed in 11 of the 12 patients in group II and in three of the seven patients in group III. 2. The regional washout rate was relatively low in the upper septum in group II and in the anterior wall and upper septum in group III. Thus, coronary vasodilatory reserve in the hypertrophied area was decreased in groups II and III. 3. Echocardiographically, the degree of hypertrophy did not differ between groups I and II, but the latter had significantly greater left ventricular diastolic dimension (42.3 mm vs 49.5 mm: p less than 0.05) and lower percent fractional shortening (%FS) (43.7% vs 35.6%: p less than 0.05). However, group III showed thinner left ventricular wall, much greater diastolic dimension (60.9 mm vs 49.5 mm: p less than 0.05), and lower %FS (24.0% vs 35.6%: p less than 0.05) than did those of group II. 4. On left ventriculography, those in group II showed larger left ventricular end-diastolic volume index (93.9 ml/m2 vs 79.7 ml/m2: p less than 0.05) than that of group I. Left ventricular ejection fraction showed the same tendency, but this was not statistically significant. 5. On endomyocardial biopsy, the specimens of the patients in group II had significantly higher percent fibrosis than did those of group I (11.4% vs 6.8%: p less than 0.05). These findings suggest that the mechanism of decreased coronary vasodilatory reserve in the hypertrophied area may be related to myocardial fibrosis, and this decrease may induce left ventricular dysfunction and compensatory dilatation.

Adult↗
PubMed1987

[Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion].

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.

Cardiomyopathy, Dilated↗
PubMed1987

[Exercise echocardiography and clinical features in patients with mitral valve prolapse].

To assess left ventricular (LV) functional reserve and prognosis in patients (pts) with idiopathic mitral valve prolapse (MVP), we performed ergometer exercise echocardiography for 10 normal subjects and 30 MVP pts without or with mild mitral regurgitation (MR). These 30 pts were followed for 2-8 years (mean 4.5). Percent changes (delta%FS) of % fractional shortening (%FS) during exercise at initial study in MVP pts and normal subjects were 7 +/- 7 and 11 +/- 3%, respectively. Based on delta%FS, MVP pts were divided into two groups; Group I: 13 cases with delta%FS less than 5%, Group II: 17 cases with delta%FS greater than or equal to 5%. The incidence of cardiac symptoms was higher in Group I than in Group II (85 vs 41%, p less than 0.05). ST-T changes on standard 12 lead ECG and life-threatening arrhythmias on Holter ECG were more frequently observed in Group I (38 vs 18%, 58 vs 20%). During follow-up period, M-mode echo measurements did not change in Group II, but LV end-diastolic dimension, LV end-systolic dimension and left atrial dimension significantly increased (p less than 0.05, p less than 0.01, p less than 0.01, respectively), and %FS significantly decreased (p less than 0.01) in Group I without any changes of MR severity. Thus, some MVP pts with impaired cardiac reserve detected by exercise echo may develop progressive deterioration of cardiac function even without significant MR.

Adult↗
PubMed1987

[Pulsed Doppler echocardiographic findings in 117 professional cyclists].

To investigate the effect of long-term athletic training on the heart, pulsed Doppler echocardiography was performed in 117 male professional cyclists (Group C: 20-59 years of age), and 40 age- and sex-matched untrained normal controls (Group N). According to age, the subjects in each group were categorized in two subgroups: 74 cyclists (Group CI), 20-39 years of age and 43 cyclists (Group CII), 40-59 years of age; 24 control subjects (Group NI), 20-39 years of age and 16 control subjects (Group NII), 40-59 years of age. The average durations as professional cyclists were eight years in Group CI and 29 years in Group CII. The ratios of pre-ejection period to ejection time (LV-PEP/ET, RV-PEP/ET) as obtained from Doppler flow velocity patterns of the left and right ventricles (LV, RV) were used as parameters of systolic function. The peak flow velocities during rapid filling (LV-R, RV-R) and atrial systole (LV-A, RV-A), and the ratio of A to R (LV-A/R, RV-A/R) were used as parameters of diastolic filling dynamics. The parameters of systolic function of both ventricles and those of diastolic filling dynamics of the RV did not differ between Group C and Group N, Group CI and Group NI, and Group CII and Group NII. Study of the diastolic filling dynamics of the LV disclosed that Group C had a significantly higher LV-A/R (p less than 0.05) than did Group N; therefore, no significant differences between Group CI and Group NI, and Group CII had a significantly lower LV-R (p less than 0.005) and a higher LV-A/R (p less than 0.005) than did Group NII. Twenty-four hour ambulatory ECG monitoring was performed for 49 cyclists. Thirty cyclists aged 20-39 years were categorized in two groups according to their LV-A/R values: eight cyclists (Group A) with the LV-A/R greater than the mean + SD value (0.69) in Group NI and 22 cyclists (Group B) with the LV-A/R lower than or equal to 0.69. Nineteen cyclists aged 40-59 years were separated into two groups according to the LV-A/R value: 11 cyclists (Group A) with the LV-A/R values greater than the mean + SD value (0.89) in Group NII, and eight cyclists (Group B) with the LV-A/R equal to or less than 0.89.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

[A trial diagnosis of latent dilated cardiomyopathy].

To diagnose latent dilated cardiomyopathy (latent DCM), we performed loading echocardiography with Angiotensin II and ergometer exercise in 41 patients. Twenty-one patients were suspected of having latent DCM because of histories, of heart failure of myocarditis; 10 patients had DCM; and 10 normal persons served as controls. On angiotensin II loading, cardiac function deteriorated in the DCM group, but it was maintained in the normal controls. Nine patients in the latent DCM group showed the same pattern as normals (L1-group), and 12 did as the DCM group (L2-group). Although % fractional shortening, end-diastolic and end-systolic dimensions of the left ventricle did not differ between the L1 and L2-groups, the A/R, the ratio of the pulsed Doppler echocardiogram at the left ventricular inflow tract, was larger and the exercise change of the % fractional shortening and exercise tolerance were less in the L2-group than in the L1-group. Furthermore, the biopsy findings of the L2-group were similar to those of the DCM group in terms of myocardial degeneration, myocardial hypertrophy and interstitial fibrosis. Thus, patients in the L2-group were thought to have a risk for DCM, and were cases of latent DCM. Angiotensin II loading is thought to be useful for diagnosing such cases.

Angiotensin II↗
PubMed1987

[Regression of mitral valve prolapse to a state masquerading as dilated cardiomyopathy: a case report].

A 40-year-old man was admitted to our hospital in May 1982 for evaluation of a heart murmur. A standard 12-lead electrocardiogram (ECG) showed an abnormal Q wave in lead III. Echocardiography revealed prolapse of the anterior mitral valve leaflet (MVP), but neither dilatation nor wall motion abnormalities of the left ventricle (LV) were observed. Thallium-201 scintigraphy revealed an abnormal thallium uptake at the apex and inferior wall. He had no episode of acute myocardial infarction or myocarditis, but complete right bundle branch block suddenly appeared, and he was hospitalized in October 1984. He had no coronary artery lesions, and only mild mitral regurgitation on left ventriculography. The motion of the interventricular septum and apex was reduced on echocardiography and a persistent perfusion defect was observed at the inferior wall and the interventricular septum on T1-201 scintigraphy. In December 1985, he experienced an Adams-Stokes attack due to complete atrioventricular block. Echocardiographically, the left ventricle became enlarged and the wall motion abnormality and a perfusion defect on T1-201 scintigrams were of relatively severe degree. Thus, left ventricular dilatation and wall motion abnormality may progress in some cases of MVP as it did in this one. We consider this case a very interesting one in speculating on the relationship between MVP and DCM.

Adult↗