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Biomedical subjects

T Kumada

Publications and source records attributed to T Kumada.

At least 199 records · Page 11Linked to original sources
PubMed1981

[Prediction of the location of left anterior descending coronary artery disease by anterior echocardiography and esophageal echocardiography (author's transl)].

In 11 normal subjects and 30 patients (pts) with left anterior descending coronary artery (LAD) lesion, the left ventricular anterolateral wall (LVAW) was investigated by esophageal echocardiography (Eso Echo) and the interventricular septum (IVS) by conventional anterior echocardiography (Ant Echo). The location of LAD obstruction, either proximal (20 pts; P-group) or distal (10 pts; D-group) to the first septal branch, was confirmed by coronary arteriography. Twenty-two of the 30 pts with LAD lesion had anteroseptal myocardial infarction (ASMI) and the remaining 8 had angina pectoris. Of the 30 pts, 20 pts including 13 pts with ASMI had normal systolic excursion of IVS. On the other hand, LVAW excursion was below 8 mm in 28 of the 30 pts with LAD lesion compared to the value of the normal subjects (10.8 +/- 1.7 mm; range = 8--13 mm). The sum of the values of IVS and LVAW excursions in the pts with ASMI was significantly lower in the P-group than those in the D-group (p less than 0.001). In the P-group, the beginning of both systolic IVS and LVAW excursion delayed significantly (IVS: 118 +/- 47 msec, LVAW: 121 +/- 44 msec from Q wave on ECG) than those of normal subjects, while in the D-group only LVAW excursion was delayed (142 +/- 23 msec) compared to that of IVS (84 +/- 32 msec). Thus, the analysis of the motion of IVS and LVAW obtained by Ant Echo and Eso Echo is useful in predicting the presence of absence as well as the location of LAD lesion.

Aged↗
PubMed1981

[Significance of non-invasive parameter (PSP/ESVI) in assessing left ventricular contractility (author's transl)].

Since myocardial pump function is affected by preload or afterload, it is difficult to assess left ventricular (LV) contractility independently from these in clinical cardiology. In this study, we performed inotropic intervention by isoproterenol or propranolol, and changed afterload by angiotensin or nitroprusside, to estimate the usefulness of peak systolic pressure/end-systolic volume index (PSP/ESVI) as a parameter of LV contractility. The data were obtained by cuff method or catheter-tip manometer and echocardiography. We calculated PSP/ESVI in various heart diseases, and results were analyzed for a significant change using the t test. Ejection fraction, mean VCF (mVCF) were calculated simultaneously, and compared with PSP/ESVI. The results were as follows: 1) PSP/ESVI ratio significantly reflected inotropic intervention with isoproterenol and propranolol. 2) PSP/ESVI ratio was less affected by the change of peak systolic pressure than EF or mVCF. 3) There was a significant difference in PSP/ESVI among congestive cardiomyopathy, valvular heart diseases and normal controls. 4) There was also a significant difference in PSP/ESVI between patients of NYHA I and those of NYHA II--IV. 5) PSP/ESVI ratio, measured by non-invasive method, was thought to be a useful parameter to assess LV contractility.

Adolescent↗
PubMed1981

[Exercise echocardiography: relationship between interventricular septal wall dynamics and electrocardiographic changes during ischemia (author's transl)].

The relationship between interventricular septal (IVS) wall motion assessed by the echocardiogram and surface electrocardiogram was investigated in 11 patients (pts) with proximal left anterior descending coronary artery disease (LADd) during ergometer exercise. A specially devises transducer was used to obtain the echocardiograms. During exercise, 6 pts had transient ST segment depression (Group 1), whereas 5 pts had transient ST segment elevation (Group 2). During exercise-induced ischemia, the ST segment depression occurred prior to abnormal wall motion in Group 1, and lasted longer than the latter. On the other hand, the ST segment elevation was preceded by abnormal wall motion in Group 2, and returned to the control earlier than the latter. In conclusion, exercise echocardiography is useful to assess the relationship between interventricular wall dynamics and electrocardiographic changes during ischemia.

Angina Pectoris↗
PubMed1981

[Left ventricular end-systolic pressure and wall thickness relation for the assessment of regional myocardial contractility in man (author's transl)].

In 28 patients (pts) (5 normal subjects (N), 12 pts with valvular heart disease, 6 with cardiomyopathy, and 5 with ischemic heart disease), left ventricular (LV) pressure was measured using Millar's catheter tip transducer simultaneously with LV posterior wall thickness (W) by echocardiography. After the control recording, LV peak systolic pressure was altered by about 30 mmHg from the control level by angiotensin (20 ng/kg/min) or nitroprusside (1 gamma/kg/min) to attain two (18 pts) or three (10 pts) different end-systolic pressure points, determined after the steady state was achieved. LV end-systolic pressure and wall thickness (P-W) relation a the three different end-systolic pressure points was found to be linear (r = 0.996) in each of the 10 pts, suggesting that end-systolic P-W relation is independent of afterload. Isoproterenol infused in 4 pts, which led to an increase in peak positive (+) dp/dt by a mean of 28%, increased the slope of the P-W relation by 43.4% of the control value (P less than 0.001), while propranolol, which led to a decrease in peak (+) dp/dt by a mean of 16.7%, reduced the slope by 27.3% (p less than 0.001). This indicates the sensitiveness of the slope of P-W relation to the inotropic change of the myocardium. In N, the slope of the P-W relation was -29.7 +/0 6.0 mmHg/mm (mean +/- SD), while the value in 4 pts with decreased functional capacity (NYHA III or IV) was significantly lower (-13.7 +/- 2.9 mmHg/mm; p less than 0.001). Thus, the present study suggests that the slope of the end-systolic P-W relation is useful in assessing regional myocardial contractility in man.

Adult↗
PubMed1980

Detection of latent coronary stenosis in conscious dogs: regional functional and electrocardiographic responses to isoprenaline.

A conscious animal model was developed in which coronary stenosis could be produced while regional myocardial function and local surface electrocardiograms were measured. Responses to isoprenaline stress in the presence of mild (latent) coronary stenosis were then examined. In the absence of coronary stenosis, isoprenaline produced increases in regional function and no change in the surface VCG; at higher doses, increases in the endocardial ST segments occurred. After partial coronary stenosis, which produced no apparent regional dysfunction or electrocardiographic changes, isoprenaline infusion for 3 min (0.02 microgram . kg-1 . min-1) rapidly produced decreases in percentage wall thickening (average 17 +/- 4%, mean +/- SE, P < 0.01) and increases in the mean sum of VCG ST segments by 0.23 +/- 0.06 mV (P < 0.05). 1 min after stopping isoprenaline, most dogs showed further significant deterioration of both measures of ischaemia, but by 5 min there was no significant mean change from control. We conclude that in the presence of latent partial coronary stenosis, stress due to mild sympathomimetic stimulation alone can rapidly induce regional myocardial ischaemia. Deterioration of regional myocardial contractile function during such stress can provide as sensitive means of detecting latent coronary obstruction.

Animals↗
PubMed1980

Improvement by isosorbide dinitrate of exercise-induced regional myocardial dysfunction.

Sonomicrometry was used in 10 conscious dogs to measure regional segment length and dynamic wall thickness by telemetry in a zone supplied by the left circumflex coronary artery after implantation of an ameroid constrictor. When coronary obstruction was nearly complete and collaterals had developed (24-42 days), control exercise and exercise runs after oral isosorbide dinitrate were carried out. During control runs, significant increases occurred in hemodynamic parameters, and percent shortening in normal segments increased (P < 0.01). During the repeat runs after isosorbide dinitrate, there were smaller increases in left ventricular systolic and end-diastolic pressures and significantly reduced end-diastolic dimensions. In addition, percent wall thickening and percent segment shortening in the ischemic zone did not deteriorate significantly during exercise. In this animal model, which appears to mimic chronic single-vessel coronary heart disease, isosorbide dinitrate can prevent exercise-induced deterioration of regional myocardial function.

Animals↗
PubMed1980

Significance of regional wall thickening abnormalities relative to transmural myocardial perfusion in anesthetized dogs.

In 15 open-chest, anesthetized dogs, regional systolic wall thickening (% delta WT) was measured with sonomicrometry and regional blood flow was determined with tracer microspheres (7-10 micron) before and after various degrees of coronary artery narrowing were created with a hydraulic occluder. The stenoses were categorized into four groups by the effect on % delta WT, and the corresponding myocardial blood flow (MBF) was determined in four layers across the ventricular wall (layer 1: subendocardium; layer 4: subepicardium). In group 1, % delta WT decreased 44 +/- 10% and only layer 1 MBF was significantly reduced (-28%); in group 2, % delta WT decreased 77 +/- 8% and MBF was reduced in both layers 1 and 2 (-52% and -36%, respectively); in group 3, % delta WT decreased 104 +/- 3% and MBF was reduced in the three inner layers (layer 1: -65%; layer 2: -58%; layer 3: -34%); in group 4, % delta WT decreased 145 +/- 9% (systolic wall thinning) and transmural reduction of MBF was found (layer 1: -74%; layer 2: -68%; layer 3: -55%; layer 4: -29%). We conclude that (1) up to 75% reduction in systolic wall thickening may occur when perfusion to only the inner one-half of the myocardium is decreased; (2) akinetic wall motion may be observed when perfusion remains normal in the subepicardial one-fourth of the wall; and (3) dyskinesia (wall thinning) occurs when blood flow is reduced transmurally.

Anesthesia↗
PubMed1980

Evaluation of left ventricular function by apex cardiography comparison of "t(dA/dt)/A" with hemodynamic indexes and with myocardial perfusion scintigraphy.

Left apex cardiograms (ACGs) were recorded in a total of 112 subjects; 32 normal individuals, 36 patients with ischemic heart disease, 19 patients with idiopathic cardiomyopathy and 25 patients with other cardiovascular diseases. The apex cardiographic index t(dA/dt)/A showed a good, positive correlation with t(dp/dt)/p (r = 0.81), p < 0.001) and also a positive correlation with Vmax (r = 0.76) as well as with ejection fraction (r = 0.65). It was weakly correlated with cardiac index and LV max dp/dt (r = 0.60 and r = 0.57, respectively) and had inverse correlations with LV end-diastolic pressure (r = -0.40) and LV end-diastolic volume (r = -0.59). There was no significant correlation between t(dA/dt)/A and LV peak systolic pressure. The t(dA/dt)/A value was significantly lower in the congestive cardiomyopathy group than in any other group investigated: ischemic heart disease, hypertrophic cardiomyopathy, occlusive thromboaortopathy or atrial septal defect (p < 0.001). Of the patients with ischemic heart disease examined by thallium-201 myocardial scintigraphy, those with imaging defects displayed significantly lower values for t(dA/dt)/A than those without imaging defects (p < 0.001), and the index tended to be lower in the patients with moderate to large imaging defects than in those with small defects. The results of the present study indicate potential usefulness of the ACG index of t(dA/dt)/A in noninvasive evaluation of the LV function and presumably of the mode of myocardial contraction.

Adult↗