Biomedical subjects
P Spiller
Publications and source records attributed to P Spiller.
[Left ventricular function at rest and by stress in patients with aortic valve diseases. Study using digital subtraction angiocardiography].
Using digital subtraction angiocardiography left ventricular (LV) function and mean pulmonary artery pressure (PPA) at rest and during exercise were examined in 49 patients with aortic valve disease, 23 patients with aortic stenosis (AS), 12 patients with combined aortic valve lesions (kAV) and 14 patients with aortic regurgitation (AI). Muscular hypertrophy was present in all patients. LV-mass-to-volume ratio was significantly higher in patients with AS and kAV than in patients with AI. There was no significant difference in heart rate at rest or during exercise among the three groups. During exercise PPA increased significantly in all groups. The increase was significantly higher in patients with AS than in those with AI. End-diastolic and end-systolic volumes increased significantly in patients with AS and kAV on the average, showing no change in patients with AI. Ejection fraction decreased significantly in patients with AS and kAV and remained unchanged in patients with AI. Due to the increase in heart rate cardiac index increased significantly during exercise in all groups. In patients with pressure overloaded left ventricles (AS and kAV) the increase in filling pressure partly results in a decrease of compliance caused by hypertrophy. Thus in these ventricles LV function cannot be judged by LV filling pressures alone. In those patients in whom the indication for valve replacement was given without knowing the results of the exercise test, the changes of LV volumes and ejection fraction were abnormal during exercise on the average.(ABSTRACT TRUNCATED AT 250 WORDS)
[Qualitative evaluation of myocardial perfusion using digital subtraction angiocardiography].
The purpose of this study was to discover whether the passage of contrast medium through the myocardium can be visualized by digital subtraction angiocardiography and whether myocardial perfusion can be determined qualitatively from the difference images. Cineangiograms (duration 20 s) were obtained during routine coronary angiography and analyzed by means of a computerized image processing system. The results show that the passage of contrast medium through the coronary artery system, myocardium and coronary veins can be visualized. In 10 patients myocardial perfusion at rest was classified qualitatively into four categories (well perfused, slightly reduced perfusion, markedly reduced perfusion and perfusion defect) from local contrast intensity and the time dependent wash-in phase of the contrast medium. Intra- and interobserver comparison of the qualitative estimation of myocardial perfusion showed a close correlation (p less than 0.001 to p less than 0.0001). In the same 10 patients myocardial perfusion at rest was evaluated from Tl-201 scintiscans by two independent observers. A comparison between the qualitative classification of local myocardial perfusion assessed by both methods revealed a close correlation (p +/- 0.049). These results indicate that myocardial perfusion at rest can be visualized by digital image processing and evaluated qualitatively from cineangiograms.
[Evaluation of myocardial perfusion based on digital subtraction angiocardiography measured contrast medium flow times].
The purpose of this study was to discover whether myocardial perfusion can be determined quantitatively by digital subtraction angiocardiography from the passage of contrast medium through the myocardium. Cineangiograms (duration 20 s) were obtained during routine coronary angiography and analyzed by means of a computerized image processing system. Regional myocardial contrast intensity was plotted versus time as a densogram for quantitative assessment. The parameter "medium rise time" showed a good reproducibility (r = 0.92). The average of medium rise time was 2.9 s in well-perfused areas, 3.7 s in less perfused areas, 5.2 s in areas with markedly reduced perfusion and 5.8 s for perfusion defects or scars using Tl-201 scintigrams as reference. The differences between the four groups were significant except between areas of markedly reduced perfusion and perfusion defects or scars (p less than 0.05). The correlation of medium rise time to the extent of the stenosis of the coronary vessel supplying the corresponding myocardial region revealed that the medium rise time on an average was 3.2 s distal to unstenosed vessels, 3.2 s distal to slightly stenosed vessels, 5.4 s distal to highly stenosed vessels and 4.7 s distal to vessel occlusion. The differences between the groups were not significant except between the groups of patients with low and high-grade coronary stenoses. These results indicate that the parameter "medium rise time" of the intensity-time curves determined by digital image processing provides a quantitative assessment of myocardial perfusion from cineangiograms.
[Digital subtraction angiocardiography--an alternative to traditional angiocardiography?].
Intravenous (i.v.) digital angiography has been extensively and successfully used for studying peripheral arterial vessels. Its application in the heart now results in high resolution images of the cardiac chambers. Accuracy and reproducibility of left ventricular volume determination equal that of conventional cineangiocardiography. Thus, left ventricular regional and global function can be analyzed quantitatively at rest and during exercise with higher simplicity and lower risk even on an outpatient basis by i.v. digital subtraction angiocardiography. To date, however, the coronary artery system cannot be visualized by digital image processing using i.v. injection of contrast medium, i.e., in patients win whom the coronary arteries have to be examined, selective arteriography for the future, too, will be combined with direct left ventricular angiocardiography. Regarding clinical experience till now, digital subtraction angiocardiography must be characterized as a complementary rater than an alternative method to conventional cineangiocardiography.
[Left ventricular function at rest and during exercise in patients with arterial hypertension. Studies using digital subtraction angiocardiography].
Using digital subtraction angiography, left ventricular function and pulmonary artery pressure at rest and during submaximal exercise (98 +/- 33 watts) were examined in 25 patients with systemic hypertension. All patients had normal coronary arteries and a normal left ventricular function at rest. Heart rate increased in all patients (from 82 +/- 14 to 134 +/- 20 min-1, p less than 0.001). Systolic blood pressure also increased significantly in all patients (from 153 +/- 12 to 190 +/- 14 mmHg, p less than 0.001). End-diastolic and end-systolic volumes did not change on average (89 +/- 22 and 87 +/- 19 ml/m2, 28 +/- 8 and 28 +/- 10 ml/m2, respectively), neither did stroke volume nor ejection fraction (61 +/- 18 and 59 +/- 16 ml/m2, 68 +/- 7 and 67 +/- 9%, respectively). The increase in end-systolic volumes and concomitantly the decrease in ejection fraction during exercise in 8 patients points to an impairment of left ventricular function. This effect is frequently found in ventricles with less distinct hypertrophy. Cardiac index increased in each patient (from 5.1 +/- 2.1 to 8.2 +/- 2.9 I/min/m2, p less than 0.001). This is caused by the increase in heart rate while stroke volume remains unchanged. Mean pulmonary artery pressure increased in all patients from 19 +/- 6 to 35 +/- 10 mmHg on average (p less than 0.001). A pathologic increase could be observed in 18 patients. There was no correlation to angiographic parameters of left ventricular function. The exercise test was stopped in 12 patients mainly because of dyspnea. In 11 of these patients a pathologic increase of mean pulmonary artery pressure was found. As in these patients the angiographic parameters of left ventricular function were normal, the increase in pulmonary pressure is related to an impairment of diastolic function caused by hypertrophy.
[Digital subtraction angiocardiography: accuracy of measuring left ventricular wall thickness and wall volume during intravenous contrast media injection].
A comparison of left ventricular wall thickness and wall volume determined by intravenous digital subtraction angiocardiography and by conventional left ventricular angiocardiography was performed by linear regression analysis: wall thickness: WDDSA = 0.90 X WDLV , Syx = +/- 0.16 cm, r = 0.74; wall volume: WVOLDSA = 0.87 X WVOLLV , Syx = +/- 48 ml, r = 0.85. Compared to the deviation and scatter of corresponding data measured from two consecutive beats in conventional left ventricular angiocardiographies , the error of determination of wall thickness and wall volume, determined by intravenous digital subtraction angiocardiography, is more pronounced. The regression analysis of wall volumes under rest and bicycle exercise evaluated by digital subtraction angiocardiography revealed a similar inaccuracy ( Syx = +/- 46 ml). This is due to faults in recognition of the inner and outer contours of left ventricular wall. Our results show that measurements of left ventricular wall thickness and wall volumes by means of intravenous digital subtraction angiocardiography can only be performed with greater deviations compared to conventional left ventricular angiocardiograms.
[Digital subtraction angiocardiography--a new semi-invasive technic of heart function determination].
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Results of surgical therapy in patients with left ventricular aneurysm.
The clinical, angiographic and haemodynamic findings in 87 patients with left ventricular aneurysm were investigated before and after different surgical interventions. Thirty-four patients underwent aneurysmectomy alone (group I), 35 patients had additional coronary revascularization (group II), and 18 patients had revascularization alone because of the findings during operation (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 (predominantly one-vessel disease) had no angina pectoris, with no significant change early and late (more than 12 months) after operation. The patients in groups II and III (with more two- and three-vessel diseases) showed an improvement in angina pectoris. Preoperatively, most patients had experienced exertional dyspnoea. Overall, there was no significant change after operation, but most patients showed an improvement in angina and dyspnoea when these symptoms had been the major indication for surgical therapy. Heart rate, systolic and end-diastolic pressures in the three groups did not change significantly after surgery. End-diastolic and end-systolic volumes decreased and ejection fraction increased significantly in groups I and II. In group III these variables did not change. Circumferential fibre shortening velocity in the residual ventricle increased significantly only in group I. Haemodynamic studies during exercise were performed in a total of 32 patients. In group I the increase of mean pulmonary pressure was significantly lower postoperatively; there was no significant change in groups II and III.(ABSTRACT TRUNCATED AT 250 WORDS)
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.
[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.
[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.
[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.
[Hemodynamic rest and stress studies following implantation of various aortic valve prostheses].
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[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)
[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).
Radiological methods in left ventricular hypertrophy.
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[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.