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Biomedical subjects

T Bonzel

Publications and source records attributed to T Bonzel.

67 records · Page 4Linked to original sources
PubMed1984

[Prognostic significance of the QT-interval following myocardial infarction].

The prognostic value of QT prolongation was evaluated in 109 patients with myocardial infarction. Patients who suffered from reinfarction during the first month or developed ventricular fibrillation and sudden death did not have longer QT intervals than patients without these complications. On the other hand, QT prolongation was of prognostic value in the prediction of late reinfarction. The reasons for varying results from different investigators are discussed.

Adult↗
PubMed1984

[The significance of improved angiocardiography systems in the quantitative assessment of proximal coronary stenosis. Comparison of angiographic and hemodynamic measurements in vivo].

The use of high resolution X-ray techniques for biplane coronary angiography can improve the quantitative assessment of coronary stenoses when perpendicular projections in both views can be achieved. Angiograms thus obtained of coronary stenoses before (n = 17) and after (n = 14) coronary dilatation were evaluated for mean and minimal stenosis diameters of two planes and for percent narrowing of stenoses (caliper measurements). Comparisons with transstenotic pressure gradients showed significant or highly significant correlations for all dimensional parameters. It is concluded that quantitative angiographic analysis of coronary stenoses yields highly reliable results of hemodynamic relevance. In addition, a mean diameter of less than 1.6 mm could be identified as indicating hemodynamically significant stenosis.

Angiocardiography↗
PubMed1983

Two-dimensional echocardiographic measurements of left ventricular volume and stroke volume of endurance-trained athletes and untrained subjects.

The left ventricular volume (EDV), the left ventricular total volume (TDV), and the stroke volume (SV) of 40 male untrained subjects and 68 endurance athletes were determined using one-dimensional echocardiography, two-dimensional echocardiography, and a combined method. The accuracy of the volume and stroke volume measurements was checked by comparing them to ergometrically determined maximum oxygen pulse (max O2-P) and to radiographic heart volume (HV). There was clear improvement in the EDV, TDV, and SV measurements when using two-dimensional echocardiography and the combined method in comparison to one-dimensional echocardiography. The best correlation to the max-O2-P was reached by TDV2 (combined method, r = 0.8738). This method includes the myocardium of the left ventricle similar to heart volume measurements. The relationship is as close as between HV and max O2-P (r = 0.8665). The method suggested here is sufficiently accurate to be used in performance diagnosis to determine the size of the left ventricular volume and to classify pathological size changes or those due to training.

Adolescent↗
PubMed1981

[Non-invasive methods of investigation cardiology (author's transl)].

Non-invasive assessment of heart and chamber size employs various techniques which yield different information. Overall size as estimated by biplane chest roentgenogram in the upright or - better - supine position is a valuable quantitative method. Correlation with individual chamber size is, however, only fair. Information on wall thickness can currently be obtained only by ultrasound echocardiography. ECG and vectorcardiography as a means for determining ventricular hypertrophy have remained semi-quantitative techniques, but can probably be developed into more quantitative information by means of computer analysis. A method of predicting left ventricular muscle mass using the Frank orthogonal lead system is described. Regional disorder of contraction and contractility have been difficult to assess non-invasively. Kymographic techniques describe only motion of the lateral wall. Ultrasound techniques, even using a two-dimensional approach, rarely include the ventricular apical region. Systolic time intervals and radionuclide minimal transit times have remained of limited importance. The value of ECG-gated computertomography cannot be assessed as yet. The greatest promise can be expected from radionuclide techniques with gated blood pool scanning and myocardial scintigraphic techniques.

Angiocardiography↗
PubMed1977

[Non-invasive determination of cardiac pump function by respiratory gas exchange measurement during submaximal exercise -- comparison with hemodynamic (heart catheterisation) data (author's transl)].

The continuous measurement of respiratory gas exchange under linearly increasing work load allows a relatively exact and reproducible localization of the point of rise of the ventilatory equivalent for oxygen (ASV). On the basis of the values of oxygen consumption (V(O2)(ASV)), oxygen pulse (O2-pulse(asv)) and relative ventilatory equivalent (Vetn. Equivalent(asv)/V(O2(ASV)), measured at the point ASV, it is possible to divide patients with different severity of heart disease into 4 groups of cardiac response to exercise: group I = normal, group II = diminished, group III = definitely limited and group IV = severely limited cardiocirculatory capacity. Simultaneous cardiac output measurements (thermodilution method) as well as the comparison with hemodynamic and angiographic data acquired during separate heart catheterization reveal good correlations between V(O2(ASV) and O2-pulse(asv) on the one hand and exercise values of cardiac output and stroke volume on the other (r = 0.82). Consequently, definite relations exist between the absolute ASV values as well as the group classification (I--IV) based on these and further heart catheterization data such as left bentricular (LV) enddiastolic pressure, LV ejection fraction, contraction pattern of the left ventricle and coronary angiogram respectively. The described method of measuring respiratory gas exchange under submaximal unsteady state bicycle exercise represents a reliable and rapid non-invasive stress test of cardiac pump function without putting too much strain on the heart patient as is frequently the case with the more familiar steady state (maximal) tests.

Cardiac Catheterization↗
PubMed1976

[Pulmonary artery pressure and left ventricular late diastolic pressure in rest and during dynamic load. Comparative studies on pressure transmission in the pulmonary circulation during simultaneous determination].

Left ventricular enddiastolic pressure (LVEDP), mean pulmonary artery pressure (PAPM) and enddiastolic pulmonary artery pressure (PADP) were simultaneously recorded in 19 subjects with normal left ventricular (LV) function, and in 109 patients with LV-dysfunction, 83 of whom were also studied during exercise. Patients with valvular heart disease or atrial fibrillation were excluded from this study. LVEDP and mean pulmonary capillary wedge (PCW) pressure were simultaneously recorded in 81 patients at rest, andin 16 patients also during exercise; the LV diastolic pressure prior to atrial contraction (LVPpreA) could accurately be identified in 45 patients at rest and in 23 patients with exercise. In contrast to the widely accepted opinion of others, the PADP (mean 8.2 +/- 2.2 mm Hg at rest and 12.3 +/- 3.4 mm Hg with exercise) showed a close approximation of LVEDP (10.0 +/- mm Hg at rest and 16.2 +/- 3.5 mm Hg with exercise) only in normal subjects at rest (p less than 0.05 and p less than 0.01 respectively). In patients with LV dysfunction there was no significant difference between PADP (11.7 +/- 4.5 mm Hg and 23.0 +/- 8.9 mm Hg), PCW (11.6 +/- 5.1 mm Hg and 24.1 +/- 11.9 mm Hg) and LVPpreA (12.5 +/- 5.5 and 21.5 +/- 7.7 mm Hg) at rest and during exercise. LVEDP could be estimated with sufficient accuracy only from the PAPM (18.9 +/- 6.5 and 35.7 +/- 10.8 mm Hg). The increase in LVEDP (14.7 +/- 7.7 mm Hg) with exercise was not significantly different from the increase in PAPM (16.8 +/- 7.1 mm Hg). There were highly significant correlations (p less than 0.001) between LVEDP and PADP (r = 0.85) as well as PAPM (r = 0.86) at rest and during exercise with the regressionline being closest to the line of identity for LVEDP and PAPM. The pressure gradient between LVEDP and PADP (LVEDP - PADP = 6.3 mm Hg with exercise) equaled the pressure increase in LV by atrial contraction (LVEDP - LVPpreA = 6.3 and 13.3 mm Hg). The pressure difference between PADP or PAPM and LVEDP remained constant despite marked variation of other hemodynamic parameters, e.g. stroke volume index (SVI), heart rate (HR) and cardiac index(CI). These data suggest that an elevated LVEDP is caused mainly by an augmented atrial contraction in patients with LV dysfunction at rest and with exercise. This mechanism precludes an enddiastolic pressure equilibrium between pulmonary artery and left ventricel. PAPM allows the best estimation of LVEDP independent from other hemodynamic variables.

Adult↗