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Biomedical subjects

I Ito

Publications and source records attributed to I Ito.

At least 199 records · Page 11Linked to original sources
PubMed1984

Adverse effect of nifedipine on left ventricular obstruction detected by pulsed Doppler echocardiography.

The effect of nifedipine on the ejection flow pattern in the left ventricular outflow tract was observed using pulsed Doppler echocardiography in 6 patients with hypertrophic cardiomyopathy. After sublingual administration of nifedipine (10 mg) to 1 patient, the turbulent ejection flow pattern became more marked and increased in duration compared with the initial state. An increase in turbulence in the left ventricular outflow tract may increase the pressure gradient between the left ventricle and the aorta. Nifedipine appeared to have the potential of adverse action on left ventricular outflow obstruction.

Blood Pressure↗
PubMed1984

Functional significance of coronary collateral vessels during exercise evaluated by radionuclide angiocardiography: the importance of supplying arteries.

To investigate the function of coronary collateral vessels, especially from view point of supplying arteries, radionuclide angiocardiography was performed before and during a symptom-limited ergometer exercise in 54 patients with effort angina. In single vessel disease, during exercise, left ventricular ejection fraction (EF) (%) increased in the cases with coronary collateral vessels (supplied from patent arteries) (72 +/- 7----77 +/- 8, p less than 0.025), but decreased in those without (66 +/- 10----61 +/- 10, P less than 0.001). In multivessel disease, EF decreased during exercise even in those with collaterals (supplied from stenosed arteries) (67 +/- 10----59 +/- 8, p less than 0.001). It is concluded that angiographic appearance of the coronary arteries supplying collateral vessels is a major predictive factor of the function of coronary collateral vessels and of left ventricle during exercise.

Adult↗
PubMed1984

[Pathophysiology of asymmetric septal hypertrophy with special reference to the response to isoproterenol administration].

To investigate the pathophysiological significance of asymmetric septal hypertrophy (ASH), echocardiograms were recorded in 25 patients with hypertension (HT) (12 with ASH, 13 with symmetric hypertrophy (SH), 19 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) (eight with ASH, 11 with SH), and 12 patients with hypertrophic obstructive cardiomyopathy (10 with ASH and two with SH). In eight patients with ASH, 12 patients with SH and eight normal controls, echocardiograms were also recorded during intravenous infusion of 0.02 mu/kg/min of isoproterenol. There were no significant differences in end-diastolic dimension (EDD), end-systolic dimension (ESD), percent fractional shortening (%FS), interventricular septal excursion (IVSE) and posterior wall excursion (PWE) between patients with ASH and patients with SH. Among patients with ASH, interventricular septal thickness (IVST) and its ratio to posterior wall thickness (IVST/PWT) were significantly larger in HOCM than in others. Before isoproterenol infusion, there was no significant difference in the normalized peak rate of change of left ventricular dimension during systole (pVs) between ASH and SH, and between ASH and NC. However, 5 min after isoproterenol infusion, pVs was significantly greater in ASH (7.0 +/- 2.4/sec) than in SH (4.9 +/- 1.3/sec) and in NC (4.5 +/- 1.1/sec) (p less than 0.05 and p less than 0.05, respectively). This study suggests that ASH is related to hyperfunction of the catecholamine-beta receptor system.

Adult↗
PubMed1984

[Two-dimensional pulsed Doppler echocardiographic estimates of cardiac output in man: sampling at the entrance to the main pulmonary artery].

To assess the feasibility and accuracy of measuring cardiac outputs (CO) by two-dimensional (2-D) pulsed Doppler echocardiography, taking samples at the main pulmonary artery just beyond the pulmonary valve, 62 cardiac patients were studied. The results obtained were compared with CO values determined by the thermodilution technique. 2-D Doppler echocardiograms suitable for computing CO were recorded in 37 (60%) of 62 patients. A significant correlation (r = 0.64) was observed between 2-D echocardiographic and angiographic pulmonary ring diameters (PRD), but the echocardiographic PRD was smaller than that of angiography by 0.4 +/- 0.2 cm. Thus, to compute the Doppler CO, the echocardiographic PRD had to be corrected by the difference between the angiographic and echocardiographic PRD. The angle between the ultrasound beam and the pulmonary blood flow was 7.8 +/- 6.1 degrees (0 approximately 18 degrees), and this was negligible for computing the Doppler CO. Even in cases with atrial fibrillation, the Doppler CO could be computed as is done in sinus rhythm. The correlation between the thermodilution and Doppler CO was highly significant (r = 0.92), and the regression equation was as follows: Thermodilution CO = 1.09 X (Doppler CO)-0.19 The difference between thermodilution and Doppler CO was 3.4 +/- 10.0% (-21 approximately +21%). Comparing the differences in CO between the thermodilution and dye-dilution techniques, those between thermodilution and the Fick methods, and those among thermodilution methods reported in the literatures, the difference in this study was not large and was acceptable. Thus, measurement of CO by pulsed Doppler echocardiography, with sampling entrance to the main pulmonary artery, can be used clinically.

Adult↗
PubMed1983

Dissociation between regional myocardial dysfunction and ECG changes during myocardial ischemia induced by exercise in patients with angina pectoris.

In order to investigate the relation between regional myocardial function and electrical changes during myocardial ischemia in humans, left ventricular echocardiogram and ECG were recorded during supine ergometer exercise in 16 patients with coronary artery disease until angina or ischemic ECG appeared. During exercise in 13 patients a decrease of left ventricular posterior wall excursion or of interventricular septum excursion occurred earlier than the appearance of ST-T change on ECG. In two patients the excursion decreased at the same time as the ST-T change. Significant regional myocardial dysfunction occurred at 30 +/- 15 seconds and ECG changes occurred at 90 +/- 60 seconds (p less than 0.001). Percent systolic wall thickening occurred in similar fashion. Results support the hypothesis that regional contractile abnormalities may provide a more sensitive indicator of myocardial ischemia than ST-T changes in humans.

Aged↗
PubMed1983

Myocardial mechanics of athletic hearts in comparison with diseased hearts.

Parameters of myocardial mechanics were measured by means of echocardiography in 31 competitive runners and 17 judo (Japanese wrestling) champions and were then compared with those in 25 normal control subjects, 15 patients with volume-overloaded (aortic regurgitation, AR) and 13 with pressure-overloaded (hypertension, HT) hearts, 14 patients with dilated cardiomyopathy (DCM), and 11 patients with hypertrophic cardiomyopathy (HCM). In runners, the ratio of left ventricular radius to wall thickness (R/Th) was maintained in the normal range, but fractional shortening (FS) and decreased slightly (p less than 0.01). Patients with decompensated DCM and AR had an increased R/Th (p less than 0.001) and a decreased FS (p less than 0.001). In judo champions, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). In patients with HT, R/Th had decreased slightly (p less than 0.05), but FS and peak systolic wall stress were maintained in the normal range. In patients with HCM, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). It is concluded that, at rest, hearts of runners are cardiomechanically similar to those of patients with compensated AR or DCM and probably have greater cardiac reserve, whereas hearts of judo champions are similar to those of HCM patients with inappropriate hypertrophy.

Adolescent↗
PubMed1983

Effect of exercise on left ventricular diastolic filling in athletes and nonathletes.

To evaluate the effect of exercise on left ventricular diastolic filling, the following were measured at rest and during exercise in 14 control subjects and 15 athletes, using digitized M-mode echocardiography: the peak early diastolic lengthening rate of the left ventricular dimension and the filling volume and the filling fraction during the first 0.10 s of diastole. During ergometer exercise performed at a level that increased the heart rate to 100 beats/min, there were significant increases in the peak normalized lengthening rate of the left ventricular dimension (control subjects, 4.2 +/- 1.3 vs. 6.1 +/- 1.1 s-1, mean +/- SD, P less than 0.001; athletes, 5.3 +/- 0.9 vs. 7.4 +/- 1.1 s-1, P less than 0.001), filling volume (control subjects, 15 +/- 12 vs. 33 +/- 10 ml, P less than 0.001; athletes, 21 +/- 12 vs. 63 +/- 18 ml, P less than 0.001), and filling fraction (control subjects, 21 +/- 14 vs. 42 +/- 17%, P less than 0.005; athletes, 21 +/- 13 vs. 54 +/- 12%, P less than 0.01). The peak lengthening rate of the left ventricular dimension, the filling volume, and the filling fraction were significantly greater in athletes than in control subjects during exercise (P less than 0.005, P less than 0.001, and P less than 0.05, respectively). Augmented early diastolic filling may be a mechanism to provide adequate filling for the ventricle at high heart rates produced by exercise, especially in athletes.

Adolescent↗
PubMed1983

[Randomized study on the long-term adjuvant chemotherapy with ftorafur and mitomycin C for stomach cancer: second report].

In view of the usefulness of long-term adjuvant chemotherapy, the Cooperative Study Group of Surgical Adjuvant Chemotherapy for Gastric Cancer adopted as the second cooperative study a prospective randomized trial on three groups; MMC alone, Futraful alone and a combination of MMC and Futraful. In the group of Futraful alone the survival and disease-free rate were improved in three years after operation, especially marked in patients with the advanced stage. Moreover, the survival and disease-free rate in the group of the combination therapy were higher than those in the group of Futraful alone, and the relapse rate was lower in the former. Therefore, a long-term combined adjuvant chemotherapy with MMC and Futraful seems to be one of the most effective chemotherapy regimens for resectable advanced gastric cancer.

Drug Therapy, Combination↗
PubMed1983

Evaluation of left ventricular reserve in left ventricular diseases: non-invasive analysis of its determinants by dynamic exercise echocardiography.

To analyze the determinants of left ventricular (LV) reserve non-invasively, LV echocardiograms were taken during ergometer exercise in 52 LV disease patients (19 with hypertension [HT], 22 with aortic regurgitation [AR] and 11 with dilated cardiomyopathy [DCM] with various severities. In mild cases [HT], at exercise, fractional shortening (FS) increased, and at higher-grade exercise, an increase of LV enddiastolic diameter (Dd) was added to more increase of FS, to increase stroke volume (SV). In moderately severe cases [HT, AR or DCM], FS did not change or decreased at exercise. In severe cases [AR or DCM], FS was low at rest, and at exercise decreased further with an increase of LV systolic stress and no significant increase of Dd, resulting in a decrease of SV. The responses of LV parameters in volume-overload (AR) or dilated myocardial (DCM) hearts were poorer than in pressure-overload (HT) hearts, in moderately severe cases. In conclusion, exercise echocardiography can show non-invasively that the interrelationship among the determinants of LV reserve is different by the severities and the types of LV diseases, and this method is useful, especially in discriminating mild cases objectively.

Adult↗
PubMed1983

Uneventful pregnancy and delivery in a case of multiple peripheral pulmonary stenoses.

The first case of multiple peripheral pulmonary stenoses undergoing uneventful pregnancy and delivery is described. The course of pregnancy in a patient with peripheral pulmonary stenoses may generally be uneventful, because increased pulmonary blood flow in pregnancy may cause little influence on pulmonary circulation in this disease by the same mechanism as in pulmonary stenosis, the course of which is known to be uneventful during pregnancy.

Adult↗
PubMed1983

The influence of exercise on left ventricular outflow tract obstruction, left ventricular performance and electrocardiogram in hypertrophic cardiomyopathy.

To investigate exertional changes in hypertrophic cardiomyopathy (HCM), 42 patients with HCM were studied by echocardiography and ECG at a supine ergometer exercise. In 12 cases with left ventricular (LV) outflow tract obstruction at rest (Group I), systolic anterior movement (SAM) of mitral valve was intensified during exercise; and among 30 cases without obstruction at rest (Group II), in 6 cases (Group IIA) SAM appeared during exercise. SAM might be further intensified 1 minute after exercise. Inverted T-wave was seen at rest especially in Group IIB (no SAM both at rest and during exercise), and tended to become less deep during exercise with an increase of LV wall motion. In conclusion, in HCM, LV outflow tract obstruction may be produced or intensified during exercise. Inverted T-wave in HCM may become less deep during exercise, with accelerated LV function.

Adolescent↗
PubMed1983

[Contrast echocardiography of the left heart by intravenous injection of perfluorochemical emulsion].

We evaluated a new method of contrast echocardiography of the left heart utilizing the intravenous injection of perfluorochemical emulsion (PFC emulsion: Fluosol-DA 20 W/V%: Green Cross Corp), which was prepared as artificial blood. Observations were made in 18 open-chest dogs. To assess the possibility of detection of mitral valve regurgitation and myocardial perfusion by this method, a small series of experiments were made. Results were as follows: Following the appearance of contrast echoes in the right heart after the injection of PFC emulsion (10 ml) into the inferior vena cava, the left heart contrast echo images were clearly obtained in 16 of the 18 dogs, and they were visible but weak in the remainder 2. The solution of surfactants (Pluronic F-68, yolk phospholipids, and glycerol), which were added to Fluosol-DA, was also used as contrast agent in 6 dogs. The left heart was also opacified by contrast echoes after intravenous injections. However, the density of the left heart contrast echoes appeared lower, as compared with that after the injection of PFC emulsion. When oxygen (95%) was mixed in PFC emulsion or inhaled through the intratracheal tube, the left heart contrast images were slightly enhanced. In 4 of 6 dogs with surgically created mitral valve regurgitation, systolic contrast echoes in the left atrial cavity were detected on the M-mode echograms after the intravenous injection of PFC emulsion (15 ml). These echoes appeared to move across the mitral valve from the left ventricle to the left atrium or away from the mitral valve in the left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Isoproterenol infusion stress two-dimensional echocardiography in detecting coronary artery disease].

Dynamic exercise two-dimensional (2-D) echocardiography has been utilized as a valuable method in the diagnosis of coronary artery disease (CAD). However, there are some limitations in this technique including inability to apply for patients whose physical capacity is limited. Moreover, appropriate echocardiographic recordings are frequently difficult because of bodily movements and/or hyperventilation during exercise. In order to overcome these limitations, we examined whether isoproterenol (ISP) infusion stress 2-D echocardiography could detect transient LV asynergy or not. The subjects consisted of 19 cases with angina pectoris (AP), 16 with old myocardial infarction (OMI), nine with atypical chest pain syndrome and six with miscellaneous heart disease. ISP stress test was performed prospectively as follows: ISP was infused at a rate of 0.02 microgram/kg/min until anginal pain occurred or significant ST depression (elevation) developed. Real time 2-D echocardiograms were obtained in the short-axis or apical RAO views of the LV before and every one minute during ISP infusion test. Coronary artery stenosis was considered to be present if the narrowing was 50% or more in the luminal diameter. The results were as follows: Adequate echocardiographic recordings were obtained in 86.1% of LV segments at rest, and in 82.2% during ISP infusion. Echocardiographic recordings during ISP infusion were feasible in almost all cases. LV wall motion abnormalities were detected in 12 (86%) of the 14 subjects with OMI and two (29%) of the seven subjects with AP at rest, while induced or exaggerated in nine (64%) of the 14 subjects with OMI and all of the 7 subjects with AP during ISP infusion. On the other hand, LV wall motion remained entirely normal during ISP infusion in 11 (92%) of the 12 subjects without CAD. In 4 (40%) of these 10 subjects without CAD, electrocardiographic judgements were positive in the ISP stress test. None had hazardous arrhythmias or severe anginal pain. ISP infusion stress 2-D echocardiography possessed feasibility of detecting LV wall motion abnormalities because this method could exclude difficulty of recordings due to bodily movements and/or hyperventilation seen in exercise echocardiography. Compared with ISP stress electrocardiography, 2-D echocardiography seemed to be superior with respect to the specificity in detecting CAD. In conclusion, ISP stress echocardiography is a safe and useful method in the diagnosis of CAD.

Adult↗