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Biomedical subjects

K Tsuiki

Publications and source records attributed to K Tsuiki.

At least 109 records · Page 6Linked to original sources
PubMed1981

Quantitative evaluation of treadmill test induced ST-T changes using body surface mapping.

Using the ST difference map after the treadmill exercise test, the 26 patients with coronary artery disease were studied. 1) The extent and the speed of complete recovery of ST depression or negative area were well correlated with the severity of coronary artery disease. 2) ST elevation or positive area was correlated with regional asynergies. 3) ST elevation area disclosed regional defect of 201 T1 scintigram at rest, while ST depression area could disclose it infrequently.

Adult↗
PubMed1981

Treadmill exercise test using body surface mapping. A quantitative diagnostic method for coronary artery disease.

In order to evaluate coronary artery disease quantitatively we recorded body surface maps before and after treadmill exercise in 27 patients suspected of having coronary artery disease. Electrocardiograms were recorded from 87 points on the anterior and posterior chest wall. The pre-exercise ST level was subtracted from post-exercise ST level at each lead point and an ST difference MAP was constructed. The ST level at 60 msec from J point was used for the construction of the ST difference MAP. By means of ST difference MAP, the area with ST changes which was induced by treadmill exercise could be evaluated. the size of the ST-depression area in the ST difference MAP was considered to be proportional to the severity of the coronary artery disease and the ST-elevation area was closely correlated to the motion abnormality of the corresponding left ventricular wall. Treadmill exercise test using body surface mapping has provided a measure of quantitative diagnosis of coronary artery disease especially in symptomatic patients.

Adult↗
PubMed1980

Alterations of myocardial function during early stages of mild experimental ischemia in dogs determined by left ventricular pressure-wall thickness loop.

Alternations of regional left ventricular myocardial function immediately after coronary artery branch ligation as related to the total left ventricular function were determined by utilizing left ventricular pressure-wall thickness loop in 6 anesthetized open-chest dogs. End-diastolic wall thickness was decreased immediately from 11.54+/-0.50 mm (standard error of the mean) of control to 10.99+/-0.50 mm in 5 to 10 min after ligation (p<0.05), while regional myocardial work calculated as the loop area, was also decreased from 27.5+/-6.1 to 19.3+/-5.8X10(3) dyn/cm (p<0.05), indicating that the local Frank-Starling curve at the myocardium was depressed during ischemia. At the site where the ligation did not have effect, end-diastolic wall thickness and the regional work did not change significantly. Analysis of the shape of the loop revealed that the myocardial shortening was incomplete during the systolic ejection phase, and that the myocardial relaxation occurred very early in the ventricular relaxation phase after ischemia without alterations in the isovolumic contraction phase. These findings are compatible with those reported on isolated cardiac muscle strips during anoxia. The left ventricular pressure-wall thickness loop is superior to the pressure-length loop in that the former can be applied easily for clinical purposes and that the former utilizes a more direct relationship of pressure to its generator than the latter. Thus, primary alterations of myocardial function during ischemia were clarified accurately by utilizing the present method in the left ventricle in situ.

Animals↗
PubMed1980

Direct evidence that left ventricular myocardium is incompressible throughout systole and diastole.

Incompressibility of left ventricular myocardium was tested utilizing isolated canine working left ventricular preparations. This ventricle functioned at levels comparable to the intact heart. The ventricular muscle volume was calculated with the videometric border recognition technique, which is probably the most satisfactory among the presently available techniques to measure left ventricular volume. The calculated wall mass throughout the cardiac cycle varied ranging between about +/- 5%. The difference between the calculated and weighed myocardial mass was within +/- 7% of the true weight. These findings warrant the idea that myocardial muscle mass is incompressible throughout systole and diastole; the assumption used to calculate some variables of left ventricular function.

Animals↗
PubMed1978

Dependency of transcoronary circulatory transport function on coronary perfusion pressure and flow.

Transcoronary circulatory transport function was computed from the dye-dilution curves recorded simultaneously at the entrance (aortic root) and exit (coronary sinus) of the coronary circulation after the injection of dye bolus into the femoral vein in open-chest dog. The effect of coronary perfusion pressure and flow on the first (delta-t) and second (deltapi2) moments of the transport function was examined before and during intra-aortic angiotensin infusion. It was observed that the relative dispersion (deltapi2 1/2/delta-t) in the canine coronary circulation is the largest among the organ-circulations that have been examined by the investigators, suggesting that cardiac wall is highly heterogeneously perfused, and that the relative dispersion was variable depending on the coronary perfusion pressure and flow. It is concluded that sole measurement of the moment of transcoronary transport function such as -t cannot be a reliable indicator of the coronary circulatory disturbances. The underlying mechanisms for the dependency of the relative dispersion on the perfusion was discussed.

Animals↗
PubMed1977

Pulmonary arterial pressure-flow characteristics in atrial septal defect: comparative study with ventricular septal defect and patent ductus arteriosus.

Pulmonary arterial pressure-flow relation was studied in 142 patients with artrial septal defect (ASD) and was compared with that of 139 patients with ventricular septal defect (VSD) and was compared with that of ductus arteriosus (PDA). The incidence of pulmonary arterial mean pressure (PAm) over 25 mmHg was 21 percent in ASD, 36 percent in VSD and 43 percent in PDA, and that over 40 mmHg was 3 percent, 23 percent and 19 percent, respectively. Large left to right shunt over 50 percent was found more frequently in ASD (58 percent) than in VSD (22 percent) and PDA (30 percent). When patients were separated into 2 groups at a PAm of 40 mmHg, lower pressure group showed a positive correlation between PAm and left-to-right shunt in each disease, although the correlation was poor in ASD (r equals 0.23) as compared with VSD (r equals 0.49) and PDA (r equals 0.47). The slope of the regression line was less steep in ASD (0.08) than in VSD (0.17) and PDA (0.14). It is considered that pulmonary hypertension in ASD develops on the basis of pulmonary vascular changes caused by prolonged hyperkinetic circulation.

Adolescent↗
PubMed1977

Determination of transcoronary circulatory transport function.

A method is described to determine the transcoronary circulatory transport function (h(t)) from input (Ci'(t)) and output (Co'(t)) dye-dilution curves obtained at the inlet and outlet of the coronary circulation. Assuming the mathematical linearity and stationarity of the coronary circulation, it is demonstrated that h(t) can be computed in terms of lagged normal density curve as a model from the sole measurement of the first to third moments of Ci'(t) and Co'(t) when recorded by a pair of our dye sampling systems that have shown to have identical response to step function. The method is useful because of its simplicity in practice. The physiological meaning of the determination of h(t) is discussed. It could be helpful to the estimation of the change in coronary path-length distribution under some conditions, although the method is still of limited value at present, because the averaged path-length through the coronary circulation cannot be evaluated correctly.

Animals↗
PubMed1976

Regional difference of respiratory changes in pleural pressure between left and right thoraxes in dogs.

Respiratory changes in pleural pressure were recorded simultaneously from the left and right pleural spaces in 6 anesthetized closed-chest dogs in the supine, prone, left lateral and right lateral positions. Saline-filled radiopaque catheters connected to strain-gauge manometers were inserted percutaneously in the left and right pleural spaces by an air tight technique and their tips were placed in the mid-thoracic plane. The esophageal pressure was also recorded with the saline-filled system. The value of respiratory pressure amplitude (deltap, the difference between end-expiratory and minimal inspiratory pressures) in the pleural spaces was significantly greater in the left thorax than in the right in the supine, prone and right lateral positions. In 4 body positions, deltap in pleural pressure was significantly greater than in esophageal pressure. It is concluded that respiratory variations in pleural pressure of the left and right thorax are not the same and that postural change does not produce significant regional difference of the respiratory variations.

Animals↗
PubMed1975

A method for quantitative detection of tricuspid regurgitation with double injection--single sampling dye-dilution technique.

A method for quantitative detection of tricuspid regurgitation is proposed. In cases without tricuspid insufficiency or intracardiac shunt, 1/slope (ts-fv) of the earpiece dye-dilution curve after injection of dye into the femoreal vein (fv curve) was significantly correlated with that (ts-pa) of the curve after injection into the pulmonary artery (PA curve) within each range of right heart blood volume (rbv) calculated as a product of cardiac output and mean transit time difference between FV curve and PA curve. The relationship among the 3 parameters was expressed as a statistically significant regression equation; log (tsfv) equals 0.9858 log (ts-pa) plus 0.2980 log (RBV) minus 0.6418 (p small than 0.005, sd of predicted ts-fv equals plus or minus 0.591). The assumption was made that tricuspid regurgitation caused prolongation ot ts-fv without any changes in ts-pa or RBV, being based on the concepts of the indicator dispersion and of the path-length distribution. The ratio of tricuspid regurgitation to cardiac output was calculated from (observed ts-fv-predicted ts-fv)/predicted ts-fv, in which predicted ts-fv is the value calculated from ts-pa and RBV using the equation shown above. In 2 patients who manifested clinical tricuspid insufficiency, large amount of tricuspid regurgitant fraction was determined by this method. It is suggested that the present method utilizing double injections--single sampling dye-dilution technique is useful for clinical quantitation of tricuspid regurgitation.

Adolescent↗