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Biomedical subjects

H Klepzig

Publications and source records attributed to H Klepzig.

At least 91 records · Page 5Linked to original sources
PubMed1986

[Hemodynamic side effects of an ionic and a nonionic roentgen contrast medium in patients with heart valve diseases and pulmonary hypertension].

The purpose of this study was to compare the hemodynamic side effects of an ionic and a nonionic contrast medium intra-individually. 20 patients with valvular heart disease (NYHA III-IV) and pulmonary hypertension (PPAsyst greater than or equal to 40 mm Hg) received injections of 40 ml iopamidol (0.8 osmol/kg) and 40 ml amidotrizoate (2.1 osmol/kg) into the right atrium. Heart rate and cardiac output, as well as right atrial, pulmonary-artery, pulmonary-capillary, and aortic pressures were measured. Peripheral and pulmonary vascular resistance and stroke volume were calculated. Right atrial pressure increased more after amidotrizoate (p less than 0.001). Pulmonary artery pressure was elevated with both contrast media to the same extent. An increase in aortic pressure was seen after iopamidol, while a decrease occurred after amidotrizoate (p less than 0.01). Amidotrizoate caused a more marked increase in heart rate (p less than 0.001) and cardiac output (p less than 0.001). Stroke volume was increased with both contrast media. Pulmonary vascular resistance decreased after amidotrizoate as well as after iopamidol, but systemic vasodilatation was more pronounced following injection of amidotrizoate (p less than 0.001). In general, iopamidol caused less hemodynamic side effects than amidotrizoate. Thus, nonionic low osmolality contrast media provide decreased risks in patients with valvular heart disease and elevated pulmonary artery pressures undergoing angiocardiography and intravenous digital subtraction angiocardiography.

Adult↗
PubMed1985

Combined first-pass and equilibrium radionuclide ventriculography and comparison with left ventricular/right ventricular stroke count ratio in mitral and aortic regurgitation.

Effective and total left ventricular (LV) stroke volume were assessed in 31 patients with verified aortic or mitral regurgitation, or both, and in 22 patients with normal valvular function using combined first-pass and equilibrium radionuclide ventriculography. The difference between these 2 volumes as a fraction of LV stroke volume was taken as the radionuclide regurgitant fraction. The results were compared with the LV/right ventricular (RV) stroke count ratio and with the angiographic regurgitant fraction according to the method of Sandler and Dodge. Radionuclide regurgitant fraction derived from 2 determinations with a time interval of 1 week showed good reproducibility (n = 15, r = 0.96, SEE = 9.1). Sensitivity was 100% for radionuclide regurgitant fraction and 87% for LV/RV stroke count ratio at equal specificity (100%). Radionuclide regurgitant fraction was more sensitive, especially in severely ill patients, in whom additional RV volume overload led to false-low or false-negative ratios. Angiographic and radionuclide regurgitant fraction showed linear correlation (r = 0.79, p less than 0.001). In contrast, because 5 patients had RV volume overload, only a weak correlation could be noticed between angiography and LV/RV stroke count ratio (r = 0.47, p less than 0.05). Excluding these patients, correlation substantially improved (r = 0.74, p less than 0.001). The combination of first-pass and equilibrium radionuclide ventriculography is a sensitive, specific and well reproducible method for the evaluation of mitral and aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Sectoranalysis of left ventricular function by fully automated equilibrium radionuclide ventriculography.

We describe a fully automated method for quantification of left ventricular performance by equilibrium radionuclide ventriculographic studies, based on subdivision of the left ventricular region into 9 equiangular sectors. The precise identification of the left ventricular contours is achieved by the use of morphological and functional criteria in a sequential edge detection algorithm with a success rate of 96%. In addition to left ventricular global and sectorial ejection fraction the first harmonic of the corresponding Fourier spectrum is approximated to each sectorial time-activity curve and to the global one. Sectorial phase is calculated as the difference between the phase of the sectorial and global first Fourier component. Computerized comparison between the sectorial parameters at rest and during peak exercise localizes and classifies the degree of global and regional impairment in response to exercise. The processing time of 60 sec makes this method suitable for routine use. The validity of our procedure has been tested in 34 patients before and after successful transluminal coronary angioplasty. In these patients, 73% of the stenosed vessels before dilatation were localized by sectorial ejection fraction, 77% by sectorial phases, and 88% by the combination of both.

Angioplasty, Balloon↗
PubMed1985

[Follow-up studies in chronic aortic insufficiency].

In order to study the course of chronic aortic regurgitation 17 patients with various degrees of aortic valve incompetence were investigated twice with a time interval of 1.5 +/- 0.4 years. The following parameters were evaluated: NYHA class; electrocardiographic sum of the largest R-wave in V4-V6 plus the largest S-wave in V1-V3 (RS index); echocardiographic left ventricular end-diastolic diameter (EDD); roentgenographic heart volume (HV); scintigraphic left ventricular end-diastolic volume (EDV), regurgitated blood volume (RBV) and ejection fraction (EF). During the period of observation functional deterioration occurred in 5 cases, all suffering from moderate to severe aortic regurgitation. While EF did not change significantly (55 +/- 12% vs. 55 +/- 11%), all other parameters showed a significant increase: RS index 5.4 +/- 1.4 mVolt to 6.0 +/- 1.7 mVolt (p less than 0.01); EDD 6.3 +/- 0.7 to 6.8 +/- 0.9 cm (p less than 0.001); HV 1017 +/- 151 ml to 1099 +/- 261 ml (p less than 0.01); EDV 371 +/- 131 ml to 441 +/- 175 ml (p less than 0.001); RBV 117 +/- 57 ml to 151 +/- 77 ml (p less than 0.001). Cases with functional deterioration showed a higher initial EDV and EDD (487 +/- 143 vs. 322 +/- 93 ml, p less than 0.05; 7.1 +/- 0.7 vs. 6.1 +/- 0.5 cm, p less than 0.01). The increase of HV, EDV and RBV during the time of observation was higher than in the remaining patients (166 +/- 137 vs. 39 +/- 95 ml, p less than 0.05; 133 +/- 75 vs. 44 +/- 29 ml, p less than 0.01; 66 +/- 22 vs. 22 +/- 31 ml, p less than 0.01). On average it was less pronounced in cases with mild initial left ventricular dilation than in those with marked dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

Prolonged application of pressure in transluminal coronary angioplasty.

We investigated the morphologic structure and fluid content of atherosclerotic specimens of fresh human postmortem artery segments before and after application of a pressure of 5 atmospheres simulated by a weight of 5 kg per 1 cm2. After applying pressure in nonorganized atheromata, we noticed a marked reduction in thickness while in fibrotic atheromata we observed only smaller differences in thickness. Reduction in fluid content was significantly more pronounced in nonorganized atheromatous tissue. Reduction in thickness was closely related to reduction in weight (i e, fluid content). The time of pressure application necessary to achieve the optimal result averaged 60 sec. The conclusions drawn from these experiments were incorporated into clinical application of coronary angioplasty. Prolonged balloon inflation was applied to the last 400 out of a total of 600 coronary angioplasty procedures, performed between October 1977 and October 1983. Stenoses not sufficiently responsive to balloon inflation periods of 5-10 sec were exposed to periods of 60 sec (30-120 sec). The number of "non dilatable" stenoses was 15% with the standard short pressure procedure, but only 5% with the prolonged pressure application. No serious complications related to prolonged pressure application were observed. Thus, from experimental data and clinical experience the application of longer pressure periods appears justified and beneficial.

Angioplasty, Balloon↗
PubMed1984

Volumetric evaluation of aortic regurgitation by combined first-pass/equilibrium radionuclide ventriculography.

In 16 men with normal valvular function (group 1) and 23 men and one woman with isolated aortic regurgitation (group 2) effective stroke was determined by first-pass radionuclide ventriculography. Total left ventricular stroke volume was derived from equilibrium radionuclide ventriculography using a geometric approach for the end-diastolic volume multiplied by the ejection fraction. The difference between the two stroke volumes as a fraction of total left ventricular stroke volume was taken as radionuclide regurgitant fraction. Radionuclide lv/rv stroke count ratio was calculated as the ratio of end-diastolic-end-systolic count-rate differences from the left and right ventricles. All patients underwent left heart catheterization. Angiographic regurgitant fraction was evaluated by the method of Sandler and Dodge in 16 patients of group 2. In the others, aortic regurgitation was quantified in 5 grades of severity. Group l was classified correctly by both radionuclide regurgitant fraction and lv/rv stroke count ratio (specificity 100%). In group 2 the radionuclide regurgitant fraction was elevated in all (from + 20% to +88%, sensitivity 100%), radionuclide lv/rv stroke count ratio in 19 of 24 cases (from 0.6 to 5.6, sensitivity 79%). The angiographic regurgitant fraction correlated well with the radionuclide regurgitant fraction (r = 0.78), whereas no significant correlation was found between the angiographic stroke volume ratio (i.e. left ventricular stroke volume/cardiac output per beat) and radionuclide stroke count ratio (r = 0.10) due to the high rate of false-negative results of the latter method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Behavior of atheromatous vessel segments during pressure application of 5 kg/cm2 for various periods of time].

In this study changes in weight and thickness of atheromatous vessel wall segments in relation to a varying duration (2-60 sec.) of a constant pressure application (5 kg/cm2) were investigated. Vessel wall segments were taken shortly postmortem from human femoral and external iliacal arteries. According to the type of atherosclerotic changes the samples were divided into 2 types (lipoidosis/sclerosis) before the experiments. As standard served non-atheromatous segments. During pressure application all specimens showed rapid decrease in weight and thickness within the first 40 seconds. After 50 seconds no further change could be seen. Atheromata predominantly containing lipids and few collagen fibres showed higher decrease in weight and thickness than those predominantly containing collagen and the control group. A positive correlation was shown between decrease in weight and thickness of the specimens. Is is concluded that squeezing out tissue fluid by pressure application may lead to a decrease in thickness of the atheromata; the enlargement of the luminal diameter achieved by balloon catheters may be attributed to this mechanism.

Angioplasty, Balloon↗
PubMed1984

[Limitations of scintigraphically determined left-ventricular/right-ventricular stroke volume in the evaluation of the severity of aortic valve insufficiency].

Noninvasive evaluation of aortic regurgitation can be performed by the radionuclide determination of the left/right ventricular stroke volume ratio. This ratio proved to have a relatively low sensitivity. Therefore, we conducted a study comprising 25 patients with angiographically verified aortic regurgitation in order to look for characteristics of patients with false-negative results. In 5 patients with aortic regurgitation the scintigraphically determined left/right ventricular stroke volume ratio was within normal range. In 3 other patients with severe regurgitation the radionuclide ratio was distinctly lower when compared with the angiographic stroke volume ratio (calculated from the left ventricular stroke volume and effective stroke volume). Left heart failure was observed in all these 8 patients, 7 of 8 patients showed additional right heart failure. Only 2 of the other 17 patients had signs of left heart failure. In the 8 patients with discrepant results, the roentgenographically determined heart volume was increased (1617 vs 1057 ml; 2p less than 0.001), left ventricular ejection fraction decreased (31 vs 60%; 2p less than 0.001), and mean pulmonary artery and right atrial pressure were elevated (38 vs 18 mm Hg; 2p less than 0.001; 11 vs 6 mm Hg; 2p less than 0.001). We conclude that in patients with aortic regurgitation, congestive heart failure associated with functional pulmonic and tricuspid regurgitation and geometric reasons can lead to a reduced sensitivity of the radionuclide left/right ventricular stroke volume ratio.

Aortic Valve Insufficiency↗
PubMed1984

[Central venous injection of large amounts of contrast media--advantages of a low osmolar contrast medium in experimentally-induced pulmonary hypertension].

Intravenous administration of contrast material is a prerequisite for the imaging of the cardiovascular system with computed tomography and digital subtraction techniques. Fatal side effects after intravenous contrast injection, particularly in patients with pulmonary hypertension, have been reported repeatedly. The object of this study was to compare hemodynamic side effects of a conventional, ionic contrast medium (amidotrizoate; 2.1 osmol/kg) and a modern, non-ionic compound (iopamidol; 0.8 osmol/kg) after intravenous bolus injection (1.5 ml/kg). Experiments were carried out in 10 open-chest dogs with pulmonary normotension and hypertension induced by embolisation. Under control conditions (PPA = 19.9 mm Hg) both contrast media produced marked pulmonary and peripheral vasodilation. Major effects were seen after amidotrizoate (RPULM 60.3%, RPERI 32.1% vs 72.5% and 70.4% of controls). In pulmonary hypertension (PPA = 44.2 mmHg), iopamidol had similar hemodynamic effects compared to control conditions. In contrast, amidotrizoate initially led to a significant increase in pulmonary pressure and resistance (PPA = 118.6%; RPULM = 141.7%) followed by a delayed depression of right ventricular function (dP/dt = 65.3%; PRVED = 180.9%). Resuscitation was required in 3 dogs with pulmonary hypertension after amidotrizoate injection. Because of these unfavorable hemodynamic side effects of the conventional high osmolality contrast medium in animal experiments, it can be expected that modern compounds with low osmolality pruduce smaller side effects during diognostic interventions in patients with pulmonary hypertension.

Animals↗
PubMed1983

Noninvasive assessment of left ventricular performance following transluminal coronary angioplasty.

We studied 36 patients with successful transluminal coronary angioplasty (group 1) noninvasively using exercise electrocardiography, exercise T1-201 myocardial scintigraphy and equilibrium radionuclide ventriculography before and 3-5 days after the procedure. Six patients who underwent aortocoronary-bypass surgery (group 2) and 10 patients with stable angina pectoris (group 3) served as controls. All patients had arteriographically documented coronary artery disease at least in one major coronary vessel (stenosis greater than or equal to 70%). In group 1, average coronary stenosis was 81.1 +/- 8.4% before dilatation and 44 +/- 13.7% after the procedure (P less than 0.001). Ischemia score in the exercise electrocardiography decreased from 2.4 +/- 2.7 before dilatation to 0.4 +/- 0.8 after the procedure (P less than 0.001). Myocardial perfusion in computerized T1-201 myocardial scintigraphy 5-10 min after exercise expressed as vitality index (the ratio of T1-201 uptake in the ischemic region to the region of maximal uptake in the same image analyzed carefully in the same view in 2 studies) increased from 72.9 +/- 8.4% before dilatation to 79.9 +/- 11.7% after the procedure (P less than 0.001). Ejection fraction at rest increased from 47.2 +/- 9.2% to 51.0 +/- 9.7% (P less than 0.001) and during exercise from 39.9 +/- 10.5% to 49.4 +/- 10.9% (P less than 0.001) before and after the procedure. In group 2, noninvasive studies showed a tendency to improvement after surgery. In group 3 no significant changes were noted. We conclude that transluminal coronary angioplasty improves both coronary perfusion to ischemic areas supplied by critical coronary artery stenoses and left ventricular function, especially during exercise, if luminal diameter is dilated by greater than 20%.

Adult↗
PubMed1982

[Coronary circulations in patients with valvular aortic stenoses (author's transl)].

This study was done to substantiate the observation that there is a high coincidence of predominant left coronary circulations in patients with valvular aortic stenoses, Between 1973 and 1980, 506 patients, who underwent coronary angiography and ventriculography, were investigated: patients with mitral stenosis (group I; n = 77), mitral regurgitation and combined mitral valve dysfunction (group II; n = 50), aortic regurgitation with or without mitral valve disease (group III; n = 61), pure aortic stenosis (group IV; n = 49) and the combination of aortic stenosis and insufficiency with mitral valve disease group V; n = 69). Patients with coronary heart disease (group 6; n = 200) served as control. Predominant left circulation was present in a comparable frequency in the valve-patient group 1 (8%), group 2 (10%) and group 3 (8%) and with patients with coronary heart disease (7.5%). A distinctly higher frequency was observed in group 4 (33%; p less than 0.001) and in group 5 (19%; p less than 0.01). We conclude that valvular aortic stenosis and predominant left coronary circulation might have the same genetic or developmental background.

Adult↗