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Biomedical subjects

J Jehle

Publications and source records attributed to J Jehle.

At least 55 records · Page 3Linked to original sources
PubMed1983

Measurement of systolic and diastolic flow rates in the coronary artery system by x-ray densitometry.

The reliability of a modified videodensitometric and photodensitometric sampling technique for measuring phasic flow rates in the coronary artery system was examined. Electromagnetic flow measurements were performed in a circulatory model with continuous and pulsatile flow and intraoperatively in aortocoronary bypass grafts; cineangiograms were made simultaneously. Based on the front velocities of injected boluses of contrast medium, the densitometric measurement overestimated the electromagnetically measured flow systematically by about 20%. Systolic and diastolic flow rates in aortocoronary bypass grafts and coronary arteries determined from biplane cineangiograms in 34 patients generally revealed the typical pulsatile flow pattern familiar from electromagnetic and ultrasonic flow measurements. Flow velocities in unstenosed coronary arteries were nearly identical before and after branchings of the vessels, whereas the corresponding flow rates were higher in proximal than in distal segments. The identical flow velocities in different branches of the same vessel and the low variability of this parameter in different patients may be a suitable index of the effect of stenoses on coronary arterial blood flow.

Absorptiometry, Photon↗
PubMed1983

[Digital subtraction angiocardiography: accuracy of left ventricular volume determination using intravenous injection of contrast medium].

The usefulness and accuracy of intravenous digital subtraction angiography of the left ventricle was proved by comparison with conventional left ventricular angiocardiography. During heart catheterization two cineangiograms were performed in 20 patients at rest: one with direct injection of contrast medium into the left ventricle and the other with intravenous injection. The intravenous angiocardiograms were processed by a hardwired digital image-processing system designed by our own group. Image enhancement was obtained by subtracting a mask image from the contrasted image of the left ventricle. The utility of four different mask modes was examined by correlating end-diastolic and end-systolic volumes determined from conventional and intravenous digital subtraction angiocardiograms of the left ventricle respectively. Reliable quantitative results could only be achieved by obtaining mask and contrasted images from the same phase of the cardiac cycle. Using these special mask modes, the standard deviations of the residuals amounted to +/- 33 and +/- 36 ml respectively. The results show that intravenous digital subtraction angiocardiography allows a quantitative determination of left ventricular volumes at rest.

Angiocardiography↗
PubMed1983

[Reliability of digital subtraction angiocardiography for the evaluation of left ventricular function and physical stress].

The reliability of determinations of left ventricular dimensions from digital subtraction angiocardiographies during exercise using intravenous injection of contrast material was proved in 20 patients. All angiocardiograms could be analyzed qualitatively and quantitatively only by means of the time-interval-difference (TID-) mode. Compared with other mask modes the superiority of the TID-mode results from the close temporal relationship between mask and contrasted frame. Thus, changes in position and brightness of the background structures are small, and left ventricular contours can be determined accurately despite intense respiratory movements. The intra-observer variability of determinations of end-diastolic and end-systolic volumes was +/- 12 ml (i.e. 7.5% of the mean value), corresponding inter-observer variability was +/- 24 ml (i.e. 17% of the mean value), respectively. Intra-observer deviation in determining ejection fraction was 2.8% (i.e. 4.5% of the mean value). The intra-observer variability in determining left ventricular axes was basal +/- 0.40 cm (i.e. 7% of the mean value), equatorial +/- 0.73 cm (i.e. 13% of the mean value) and apical +/- 0.34 cm (i.e. 8% of the mean value). Deviations of corresponding circumferential fiber shortening rates were basal +/- 0.22 s-1 (i.e. 14% of the mean value), equatorial +/- 0.32 s-1 (i.e. 22% of the mean value), and apical +/- 0.18 s-1 (i.e. 13% of the mean value). The results show that left ventricular dimensions can be determined accurately from intravenous angiocardiograms during exercise using digital subtraction angiocardiography.

Adult↗
PubMed1983

[Relations between ventricle function, myocardial oxygen consumption and coronary circulation following sublingual administration of nitroglycerin].

The relationships between ventricular function, coronary blood flow, and myocardial oxygen consumption after sublingual administration of 1.6 mg nitroglycerin (TNG) were investigated in 12 patients. Left ventricular volumes, determined from cineventriculograms (enddiastolic volume index and endsystolic volume index), decreased (p less than 0.005) after TNG, as did left ventricular peak pressure (p less than 0.01), left ventricular enddiastolic pressure (p less than 0.005), mean aortic pressure (p less than 0.005), and mean pulmonary artery pressure (p less than 0.001). Due to the decrease in enddiastolic volume and the insignificant change in stroke volume, ejection fraction increased (p less than 0.05). Heart rate did not change significantly. In spite of an increase in the vessel diameter (13%, p less than 0.005), systolic and diastolic coronary blood flow, measured by means of a photodensitometric technique, decreased insignificantly by an average of approx. 15%. Similarly the change in myocardial oxygen consumption, calculated according to Bretschneider, decreased insignificantly by an average of approx. 10%. The correlation of changes in coronary blood flow and myocardial oxygen consumption was evaluated statistically by the use of the 2 X 2 contingency table in conjunction with the chi 2 McNamar test: patients with a decrease in myocardial oxygen consumption also showed a decrease in coronary blood flow (p less than 0.05). This implies that coronary blood flow is determined by myocardial oxygen consumption, which is altered by the systemic effects of TNG.

Adult↗
PubMed1983

[Value of the floating catheter test in cardiologic diagnosis].

This study had two aims: a) to investigate the diagnostic value of right heart catheterization at rest and during exercise in patients with angina pectoris and dyspnea, and b) to find out whether right heart catheterization during exercise provides additional diagnostic information when the correct diagnosis has been established by invasive means. The findings in 109 patients with coronary or myocardial heart disease (average age 50 years) were investigated retrospectively. Right heart catheterization is a semiinvasive measure which permits the differentiation of normal ventricles from ventricles with impaired function during exercise; further diagnostic information cannot be obtained, however. In patients with angina pectoris, right heart catheterization has no greater diagnostic value than the ECG during exercise. The patients were divided into five groups according to the final diagnosis: 55 with coronary heart disease, 11 with dilatative and 6 with latent cardiomyopathy, 26 with systemic hypertension, and 11 without heart disease. The results show that right heart catheterization during exercise is absolutely necessary in addition to invasive measures in patients with normal function of the left ventricle at rest and without coronary heart disease, as these patients show either a normal (patients with systemic hypertension, patients without heart disease) or an abnormal increase in pulmonary artery pressure during exercise (patients with systemic hypertension, patients with latent cardiomyopathy). Patients without coronary heart disease but with impaired left ventricular function even at rest always show a pathological increase in pulmonary artery pressure during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

The distribution of alterations in energy metabolism in the rat brain produced by apomorphine.

The effects of the putative dopaminergic agonist, apomorphine (0.15-5 mg/kg, i.v.), on glucose utilization in 43 anatomically discrete regions of the rat brain have been examined by the quantitative autoradiographic 2-deoxyglucose technique. Apomorphine failed to alter the rates of glucose utilization in 25 of these regions (for example, primary auditory areas, regions of white matter, hippocampal areas, nucleus accumbens and caudal regions of the neocortex). Dose-dependent alterations in glucose utilization were observed following apomorphine administration in a number of regions known to contain dopaminergic receptors (viz: caudate nucleus, substantia nigra, amygdala, subthalamic nucleus and anterior cingulate cortex). Moreover, dose-dependent alterations in glucose utilization were produced by apomorphine in a number of regions thought to contain few specific dopaminergic receptors (e.g., cerebellar hemisphere and vermis, lamina VI of rostral neocortical areas, and ventral nucleus of the thalamus). The distribution of alterations in glucose utilization following apomorphine administration are considered to reflect the functional involvement of the region in the overall response to apomorphine, and not simply the topography of dopaminergic receptor mechanisms.

Animals↗
PubMed1982

[Determination of phasic flow speeds in the coronary vessels by means of a simple photodensitometric technique (author's transl)].

Systolic and diastolic flow rates in coronary arteries were determined from cineangiograms using a photodensitometric measurements system. The front velocity of a bolus of contrast medium was evaluated by two different methods. Measurements in aortocoronary bypass grafts showed that the photodensitometric determination of flow rates overestimated the electromagnetically measured flow by about 20%. Measurements in coronary arteries proved a good reproducibility (r=0.98) and the typical pattern of phasic flow. The velocity of flow in coronary arteries was nearly identical before and after branchings of the vessels (r=0.96).

Blood Flow Velocity↗
PubMed1982

Local cerebral glucose utilization in hypothermic and hyperthermic rats.

Local rates of glucose utilization in 38 regions of the CNS were measured in conscious, lightly restrained rats during normothermia (rectal temperature, 37.4 +/- 0.1 degrees C, hypothermia (31.8 +/- 0.1 degrees C), and hyperthermia (40.2 +/- 0.3 degrees C). In 34 of the 38 regions examined (the four exceptions being primary auditory nuclei in the lower brainstem), a significant relationship could be demonstrated between the rate of glucose utilization and body temperature. The magnitude of temperature-related alterations in glucose use displayed considerable regional heterogeneity. In hypothermic rats the reductions in glucose use were proportionately most marked (reduced 35-50% from normothermic) in thalamic nuclei, extrapyramidal and motor areas, septohippocampal formation, and some areas of neocortex and white matter; they were least pronounced in anterior hypothalamus (reduced by 13%), habenula (by 16%), and amygdala (by 22%). In hyperthermic rats, significantly increased glucose utilization was observed in only 16 of the 38 areas examined (e.g., hypothalamus, hippocampus, extrapyramidal system, and raphe nucleus), whereas in a number of major areas (such as the neocortex and thalamus) glucose use was minimally altered with hyperthermia. The regional heterogeneity in the alterations in glucose utilization suggests that caution must be exercised in the interpretation of autoradiographic 2-deoxyglucose investigations in which body temperature disturbances occur.

Animals↗
PubMed1982

[Clinical course of patients with aneurysms of the left ventricle following conservative and surgical therapy].

The angiographic and hemodynamic findings as well as the symptoms of a total of 128 patients (mean age 45, range 22 to 67 years) with left ventricular aneurysm were investigated retrospectively. The patients were assigned to three groups: Group op (69 patients): aneurysmectomy with and without revascularisation; Group kons-op (28 patients): indication for surgery, but operation not performed; Group kons (31 patients): no indication for operation. The size of the aneurysm was not significantly different in the three groups. Patients of group op and kons-op revealed more two- and three-vessel diseases than patients of group kons. Heart rate and left ventricular systolic pressure were not significantly lower than in the other groups which showed no significant difference. Enddiastolic volume differed not significantly in all groups, endsystolic volume was significantly lower in group kons than in group kons-op. Hence ejection fraction was significantly higher in group kons. The circumferential fiber shortening velocity in the residual part of the contracting ventricle was not different in all groups. Hemodynamic studies during exercise with pressure measurements in the pulmonary artery (floating catheters) revealed a significantly higher work load and a smaller increase of mean pulmonary artery pressure in group kons than in the other groups. In group kons the clinical symptoms (angina pectoris, dyspnea) were less distinct. The surviving patients of the medically treated groups showed no changes between the first and last clinical examination, whereas patients of group op revealed a significant improvement after surgery. Mortality was 13% in the group op, four patients died perioperatively. In Group kons-op the mortality was 50% during the observation period, in group kons only two patients died. In most cases the patients died for cardiac reasons. The results show that surgery is indicated in patients with left ventricular aneurysm with severe clinical symptoms, pathological hemodynamics at rest and/or during exercise not only because of the symptomatic improvement after surgery, but also because of the high mortality rate in patients without operation.

Adult↗
PubMed1981

[Long-term results of coronary revascularization--clinical, angiographic and hemodynamic findings (author's transl)].

Clinical angiographic, and hemodynamic examinations were performed in 37 patients (mean age 54 +/- 6.5 years) with coronary heart disease 5.4 +/- 5.3 months and 57.0 +/- 15.3 months after coronary revascularisation. The results were compared with those of a preoperatively performed examination (8.1 +/- 5.9 months). Early postoperatively 57 per cent of the patients were free of angina and 32 per cent had marked relief, whereas preoperatively 73 per cent had severe angina (class III and class IV). Late postoperatively 51 per cent had no angina and 49 per cent had only slight or moderate angina. The patency rate of the aorto-coronary bypass grafts was 90 percent early and 83 per cent late postoperatively. Occlusions of the native coronary arteries proximal to the anastomosis were found in 26 per cent preoperatively, in 55 per cent early and in 84 per cent late postoperatively. The parameters of left ventricular function showed no significant alterations early and late postoperatively. The results demonstrate that the relief of angina, the patency rate of the aorto-coronary bypass grafts and the resting function of the left ventricle are approximately unchanged five years after coronary revascularisation.

Adult↗
PubMed1981

[Examination of the effect of aorto-coronary revascularisation by means of exercise tests (author's transl)].

The purpose of this study was to determine the value of exercise tests in the examination of the effect of aorto-coronary revascularisation. 48 patients (mean age 52 +/- 6 years) were examined 5.0 +/- 1.9 months before and 4.9 +/- 3.0 months after coronary revascularisation by means of coronary and left ventricular angiography. Left ventricular function at rest was unchanged. 122 grafts were constructed, the patency rate was 86%. Preoperatively two exercise tests with a bicycle ergometer were performed, some days before angiography and some days before operation, respectively. A third test was performed postoperatively (again some days before angiography). During exercise at identical work load, heart rate and systolic blood pressure did not change significantly pre- and postoperatively. At the second preoperative examination, pulmonary artery pressure (31.6 +/- 11.3 mm Hg) was significantly lower than at the first examination (36.3 +/- 10.8 mm Hg). Postoperatively there was a further decrease of mean pulmonary artery pressure (27.6 +/- 6.5 mm Hg). At the highest work load, mean pulmonary artery pressure was significantly lower at the second preoperative and at the postoperative examination (34.4 +/- 11.6 and 31.3 +/- 8.1 mm Hg versus 39.6 +/- 9.8 mm Hg). The explanation of the preoperative reduction of pulmonary artery pressure is not clear. The pressure decrease must be considered in the examination of the effect of aorto-coronary revascularisation by means of exercise tests.

Coronary Angiography↗
PubMed1981

[Experimental studies of the effects of contrast medium on left ventricular function (author's transl)].

The influence of contrast medium (0.63 ml/kg body weight Natrium-Methylglucamin-Jothalamat, Conray 70) on pressures and volumes of the left ventricle were studied in six anesthetized mongrel dogs (mean body weight 36 +/- 6 kg). Under closed-chest conditions radiopaque markers were implanted into the endocardium of the left ventricle by means of a special catheter via the right carotid artery. The positions of the markers were calibrated in terms of volume by injections of contrast medium during diastole (flow rate 14 ml/s). Thus it was possible to determine left ventricular volumes without additional administration of contrast medium. Before and during injection, volumes determined from the position of the markers and pressure (catheter-tip manometer) were evaluated in each cycle. After injection, the parameters were determined every minute over a period of ten minutes. Immediately after injection of contrast medium there was a short period in which the following parameters changed: decrease of ventricular systolic pressure, of mean aortic pressure, of maximal dp/dt, of minimal dp/dt, and, after a short increase, of enddiastolic pressure. About one minute after the end of injection, the parameters were about the initial values. These transitory changes were explained by the initial negative and vasodilating effect of the contrast medium. The chamber volumes and stroke volume did not change during and after injection. Because of the constant heart rate cardiac output did not change. The ejection fraction was diminished even before injection, no further changes were found. These experimental results show that, even in ventricles with reduced function, contrast medium injected with a slow flow rate during diastole only leads to small and transient changes of left ventricular hemodynamics.

Animals↗
PubMed1981

[Clinical and hemodynamic results in patients with left ventricular aneurysm after surgical therapy (author's transl)].

The clinical and hemodynamic results of 87 patients (average age 49 years, range 22 to 65 years) with left ventricular aneurysm were retrospectively investigated before and after (1-87 months) surgical treatment. 34 patients underwent aneurysmectomy only (group 1), 35 patients additionally underwent coronary revascularisation (group II), and 18 patients underwent--because of findings during operation--coronary revascularisation only (group III). The size of aneurysm was not significantly different in the three groups. Postoperatively it decreased only in groups I and II. The majority of the patients in group I (with predomination of one-vessel disease) had no angina pectoris. There was no significant change early and late (more than 12 months) after the operation. The patients in groups II and III (the majority with multi-vessel disease) showed an improvement of angina pectoris. Preoperatively most of all the patients claimed to have exertional dyspnea. On the whole, there was no significant change after operation. The majority of the patients showed an improvement in their angina pectoris and dyspnea when those symptoms were the major indications for the operation. Heart rate, systolic and end-diastolic pressure in the three groups did not significantly change after the operation. End-diastolic and end-systolic volumes decreased significantly in groups I and II. The ejection fraction increased significantly. In group III these parameters did not change. Circumferential fiber shortening velocity in the residual ventricle significantly increased only in group I. Hemodynamic studies during exercise were performed in total on 32 patients. In group I, there was a significant smaller increase of the mean pulmonary artery pressure, no significant change in groups II and III. At rest, only the patients with aneurysmectomy showed an improvement of the global and residual left ventricular function. The patients with an angiographically presumed aneurysm and viable myocardium found intraoperatively showed no improvement in function at rest or during exercise even after coronary revascularisation. The hospital mortality was 6%. Three patients died during the follow-up period because of ascertained cardiac reasons. The high mortality of non-operated patients with similar clinical and hemodynamic findings as in operated patients warrants an indication for aneurysmectomy without even taking into account the symptomatic and functional improvements.

Adult↗
PubMed1980

[Maximum rate of left ventricular volume change--a parameter of ventricular function (author's transl)].

Peak left ventricular ejection rate (dV/dtsyst) and peak left ventricular filling rate (dV/dtdiast) were determined from biplane cineangiographies in patients with normal left ventricular function (n = 8), pressure overload (n = 11), aortic regurgitation (n = 7), mitral regurgitation (n = 9), mitral stenosis (n = 6), hypertrophic obstructive cardiomyopathy (n = 10), congestive cardiomyopathy (n = 9) and coronary heart disease (n = 17). dV/dtsyst (normal 642 +/- 187 ml s-1) was reduced in mitral stenosis (447 +/- 77 ml s-1) and was increased significantly in aortic regurgitation (1085 +/- 162 ml s-1) and mitral regurgitation (744 +/- 232 ml s-1). dV/dtsyst/EDV was correlated linearly with ejection fraction and was reduced significantly in mitral stenosis, aortic and mitral regurgitation, congestive cardiomyopathy and coronary heart disease. Ventricles with pressure overload and coronary heart disease could be separated better from normal ventricles by dV/dstsyst/EDV than by ejection fraction. dV/dtdiast (normal 549 +/- 205 ml s-1) was decreased significantly in mitral stenosis and increased in aortic regurgitation (1141 +/- 557 ml s-1) and mitral regurgitation (946 +/- 349 ml s-1). Peak left ventricular filling rate and diastolic stiffness were correlated by a hyperbolic function. The results show that peak left ventricular ejection and filling rates allow a more detailed analysis of ventricular function than the usually applied parameters. Quantification of the factors which determine the rate of change of left ventricular volume was only partially possible.

Aortic Valve Insufficiency↗