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Biomedical subjects

T Bonzel

Publications and source records attributed to T Bonzel.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Acute effects of nitroglycerin on the energetics of the human left ventricular myocardium].

We analyzed performance and efficiency of the left ventricular myocardium on the basis of two new energetic parameters. The myocardial energy consumed during one cardiac cycle is related to performed work on the one hand (E1) and to the stress-time-integral on the other (E2). E1 was obtained by analysis of the pressure-volume integral divided by left ventricular muscle mass. E2 was obtained as follows: the stress-time integral was analyzed from pressure-volume data and wall thickness using an ellipsoidal calculation model. In order to transfer the stress-time integral into energy units, the value was multiplied by a constant factor which was obtained in experimental myothermal studies. In ten patients with coronary heart disease undergoing diagnostic heart catheterization, angiocardiography was performed before and after oral administration of nitroglycerin (1.6 mg). Total energy consumption (2E1 + E2) per gram myocardium per beat decreased from 6.1 +/- 1.3 mcal/g to 4.7 +/- 1.4 mcal/g (P less than 0.01), and myocardial efficiency (E1/[2E1 + E2]) increased from 27.0 +/- 3.1% to 28.4 +/- 4.3% (N.S.) on the average. This analysis explains quantitatively the beneficial effect of nitro-preparations on myocardial function and energetics.

Adult↗
PubMed1987

Radiological prerequisites for spatial intracoronary orientation and quantitation in interventional cardiology.

The prerequisite for the safe performance of an intracoronary intervention is an optimal angiographic visualization. This includes high resolution film and video equipment and the acquisition of spatial information about anatomic details during the procedure. The geometric properties of modern biplane multidirectional X-ray equipment allow for exact spatial computations. These can be used for optimal portraying of coronary segments by computed triple orthogonal projections. In addition, an improvement in quantitative angiography is possible by calculation of the exact radiological magnification factor of coronary stenosis.

Angiography↗
PubMed1986

Coronary thrombolysis during acute myocardial infarction by intravenous BRL 26921, a new anisoylated plasminogen-streptokinase activator complex.

The safety and fibrinolytic efficacy of a new anisoylated plasminogen-streptokinase activator complex (APSAC) was tested in 50 patients with acute myocardial infarction (AMI) less than 4 hours in duration. APSAC (30 mg) was given intravenously as a bolus injection 151 +/- 47 minutes after clinical symptoms. Coronary angiography was then performed to assess coronary artery patency: 28 patients had an inferior AMI and 22 an anterior AMI. A patent infarct-related artery was found in 32 patients (64%) on first coronary angiography 66 +/- 21 minutes after administration of APSAC. Subsequent reperfusion was observed in 10 patients after 74 +/- 16 minutes (84%). Bleeding complications or hematomas were observed in 18 patients, of whom 3 required blood transfusions. Marked hypofibrinogenemia was observed within 24 hours in most patients. A control coronary angiogram was recorded in 37 patients (74%) after 25 +/- 19 days and showed reocclusion in 5 patients.

Adult↗
PubMed1986

[Acute and delayed aortocoronary bypass operations following transluminal angioplasty].

Since 1980 348 PTCAs and 1288 CABs were performed at our institution (relation 1:4). In 15 cases (4.3%) emergency CAB was necessary because of complications encountered with PTCA. Two patients died, i.e. a mortality rate of 43.3% out of the emergency CABs or 0.6% out of the PTCA group; in 46.6% myocardial infarction occurred. In the same period 12 patients received CAB because of unsuccessful PTCA after a mean time of 4.6 months without increased operative morbidity. Interdisciplinary indication and experience, operation permanence and temporary coronary perfusion may decrease the complication rate.

Angioplasty, Balloon↗
PubMed1986

Noninvasive evaluation of pulmonary hypertension by quantitative contrast M-mode echocardiography.

Although it has been shown that pulmonary flow velocity can be calculated from contrast M-mode echocardiographic tracings, the clinical value of this noninvasive method has not been established. We used contrast M-mode echocardiography to examine the flow velocity pattern at the pulmonary valve in 30 adults referred for diagnostic cardiac catheterization. In the 15 patients with normal pulmonary artery pressure (PAP) (mean pressure less than or equal to 20 mm Hg), midsystolic pulmonary flow velocity was significantly (p less than 0.001) higher (654 +/- 140 mm/sec) compared to the 15 patients with pulmonary hypertension (342 +/- 85 mm/sec, mean pressure greater than 20 mm Hg). Fourteen of the 15 patients with pulmonary hypertension exhibited an early systolic flow velocity peak, whereas all patients with normal PAP showed a dome-shaped systolic flow velocity profile with maximal flow velocity occurring in midsystole. A significant close correlation was found between the relative early to midsystolic flow velocity change and mean PAP (r = 0.96; p less than 0.001). Thus quantitative contrast M-mode echocardiography reliably differentiates patients with pulmonary hypertension from patients with normal mean PAP. In addition, this technique allows a noninvasive estimation of PAP.

Adolescent↗
PubMed1986

Quantitative assessment of temporal and spatial ventricular wall motion in normal and infarcted human left ventricles.

A new integrated method for quantitating temporal and spatial systolic wall motion heterogeneity was developed and applied in 15 normal subjects and 26 patients with previous myocardial infarction (MI). After frame by frame digitizing, right anterior oblique left cineventriculograms (LV) were analyzed with 90 spaced radii. For each radius shortening fractions at sequential systolic time points relative to end diastole were correlated with corresponding normalized time points using linear regression method, yielding the radial correlation coefficient (r) and the radial regression slope (b) for temporal and spatial information. High radial r values with small standard deviations were observed in normal LV (0.972 +/- 0.016) and in non-MI regions (0.964 +/- 0.018), indicating temporally homogeneous radial shortening. A significant temporal heterogeneity in wall motion was demonstrated in MI regions (0.480 +/- 0.304) (p less than 0.001). In comparison with normal b values (0.449 +/- 0.106), there were decreased b values in MI regions (0.203 +/- 0.211) (p less than 0.001) and increased b values in non-MI regions (0.695 +/- 0.213) (p less than 0.001), suggesting hypokinetic and compensative hyperkinetic contraction in corresponding regions. Thus, temporal and spatial wall motion throughout systole could be assessed quantitatively by the present computer-assisted method with two simple integrated parameters.

Adult↗
PubMed1986

Ventricular arrhythmias and Q-Tc interval during stress-ECG.

Q-T prolongation is well-known to be related to ventricular arrhythmias in a number of clinical circumstances. The purpose of this study was to determine whether heart rate corrected Q-T interval (QTc) may indicate susceptibility to ventricular arrhythmias during stress testing. QTc was determined at rest, during submaximal and maximal bicycle work load in normals and patients with remote myocardial infarction, documented coronary artery disease (CAD) and in a group of patients with different cardiac diseases and premature ventricular beats during exercise testing (PVC). Ventricular arrhythmias were graded according to Lown. Q-Tc interval significantly increased in all groups of those patients having complex ventricular arrhythmias (Lown greater than or equal to III). In patients with ischemic S-T segment depression during stress testing, QTc was only lengthened if complex ventricular arrhythmias were present. Q-Tc lengthening in stress testing is assumed to be associated with occurrence of ventricular premature beats rather than ischemia. There is evidence that abnormal repolarization due to imbalance of the autonomic nervous system induces ventricular arrhythmias. Monitoring of Q-Tc interval during stress testing is warranted and may be useful to predict future cardiac events such as sudden cardiac death.

Angina Pectoris↗
PubMed1986

Acute effects of nitrates on left ventricular performance and energetics.

Left ventricular myocardial performance and efficiency were analyzed on the basis of two new energetic parameters in patients with coronary heart disease. The myocardial energy consumed during one cardiac cycle is related on the one hand to the work performed (E1) and on the other to the stress-time integral (E2). E1 was obtained by analysis of the pressure-volume integral divided by the left ventricular muscle mass. E2 was obtained as follows: The stress-time integral was analyzed from pressure-volume data and wall thickness using an ellipsoidal calculation model. In order to transfer the stress-time integral into energy units, the value is multiplied by a constant factor which was obtained experimentally in myothermal studies. In patients with coronary heart disease, a single dose of nitroglycerin (1.6 mg s.l.) reduced the total energy sigma (E1 + E2) from 6.1 mcal/g to 4.7 mcal/g (n = 10; P less than 0.01). The efficiency of myocardial contraction (E1/sigma (E1 + E2] was not changed significantly. These data explain quantitatively the beneficial effect of preload and afterload reduction due to nitroglycerin.

Energy Metabolism↗
PubMed1986

Derivation of spatial information from biplane multidirectional coronary angiograms.

UNLABELLED: Modern biplane multidirectional isocentric X-ray equipment delivers the image information necessary for spatial computations from two simultaneous 2-dimensional coronary angiographic pictures. Using the tools of analytical geometry, the spatial position of well definable points in the fields of view of the two image-intensifiers can be calculated from their corresponding projections knowing the geometrical properties of the system stands. The method developed is independent of the angle between the projections and is applicable even if hemiaxial views are used. The mathematical formulas necessary for these spatial computations are derived. By means of calculating the radiological magnification factor, the method was validated using a wire with known diameter as reference object. 360-diameter measurements of the wire filmed in 18 different simultaneous biplane projections resulted in a mean error of 3.14%. In addition, catheter measurements of routine coronary angiograms yielded a mean diameter of 2.64 +/- 0.19 mm (mean +/- SD, real diameter 2.66 mm). CONCLUSION: Using this algorithm, a reliable determination of spatial coordinates of distinct points of interest is possible as prerequisite for absolute quantitative measurements from biplane angiograms.

Angiocardiography↗
PubMed1985

[Dilatation of epicardial coronary vessels by intravenous diltiazem in patients with coronary heart disease].

UNLABELLED: Coronary diameters and central hemodynamics were measured in 22 patients with stable coronary artery disease before and after 20 mg of intravenous diltiazem. Coronary diameters from high quality biplane coronary angiograms were calculated as mean values after caliper measurements of identical segments. Measurements were made in angiographically normal and abnormal proximal, middle and distal vessel segments. Central hemodynamics showed a significant decrease for heart rate, mean aortic pressure and peripheral resistance (p less than 0.001). Coronary diameters increased between 2 and 16% (proximal or distal segments). Diameter increases were statistically significant for all segments (p less than 0.001) except for proximal atherosclerotic segments. These hemodynamic and diameter changes were seen after 5, 10 and 20 minutes. CONCLUSION: Intravenous diltiazem shows an acute coronary dilative effect in patients with stable coronary artery disease. This effect is regarded as one of the essential antianginal actions of the drug.

Benzazepines↗
PubMed1985

[Value of contrast echocardiography in the diagnosis of pulmonary valve insufficiency].

The directional analysis of contrast echographic flow lines is routinely used for tricuspid insufficiency diagnosis. The value of this noninvasive technique for the assessment of pulmonic regurgitation is not yet established. Therefore we evaluated the contrast M-mode echocardiograms at the pulmonary valve in 55 patients. Echographic contrast was obtained by injection of 6-8 ml of indocyanin-saline solution into an antecubital vein. In all 5 patients with documented pulmonic insufficiency (3 patients after repair of tetralogy of Fallot, one with pulmonic endocarditis, one posttraumatic) typical diastolic retrograde directed flow lines crossing the pulmonary valve were recorded. In addition, 6 of 18 patients with primary or secondary pulmonary hypertension exhibited early to middiastolic retrograde flow lines at the pulmonary valve. In contrast, none of the normals (N = 13), and none of 19 patients with various cardiac diseases but unaffected pulmonary valve and normal pulmonary artery pressure, had contrast echographic evidence of pulmonary insufficiency. There were distinctive differences between the contrast flow patterns of the patients with organic pulmonary insufficiency and patients with functional pulmonic regurgitation due to pulmonary hypertension. It is concluded that the directional analysis of contrast echographic flow lines at the pulmonary valve allows a sensitive assessment of pulmonary regurgitation using standard echocardiographic equipment.

Adult↗
PubMed1984

Effect of cimetidine on the hepatic extraction of indocyanine green, the portal pressure and the systemic circulation in patients with cirrhosis of the liver.

The effect of cimetidine on hepatic and systemic haemodynamic parameters was studied in seven patients with portal hypertension due to alcohol-induced cirrhosis of the liver and in one patient with peliosis hepatis following oral contraceptive steroids. The intravenous administration of cimetidine (350 mg as bolus, followed by 2 mg/min over 60 min) reduced the hepatic extraction of continuously infused indocyanine green (ICG) by 27%; this was statistically significant (P less than 0.01). Since the ICG clearance, calculated independently of hepatic perfusion, was lowered by 19%, this effect seems to be mainly due to a reduced capacity of the liver to remove the dye from the blood, rather than due to changes in perfusion. Cimetidine did not influence the elevated portal pressure in the patients with cirrhosis, or the normal pressure in the patient with peliosis hepatis. No significant effect was observed on heart rate, mean arterial pressure, pulmonary artery pressure, pulmonary capillary pressure and cardiac output. These studies indicate that the reduction of the hepatic ICG extraction following cimetidine is more the result of an inhibited capacity of the liver to remove the dye than of changes in the hepatic perfusion or in the systemic circulation.

Adult↗
PubMed1984

[The effect of various cutaneously administered nitroglycerin preparations on coronary heart disease].

Sublingually administered nitroglycerin provides marked benefit in the treatment of angina pectoris due to occlusive coronary disease. Because of its brief duration of action, its usefulness as a prophylactic agent is limited. One way to prolong the beneficial effects is cutaneous administration of a nitroglycerin ointment, and the effects and duration of action of three different preparations of topical nitroglycerin on exercise performance have therefore been studied in a double-blind randomized manner in 44 patients with well documented coronary artery disease and stable angina pectoris. 30 mg 2% nitroglycerin ointment((Plantorgan Co.) produced significant improvement in maximal exercise capacity one and six hours after application; concomitantly there was a decrease in the sum of exercise induced ST-segment depression especially one hour, but less markedly six hours, later. 10 mg 2% nitroglycerin ointment (Pohl Boskamp Co.) also produced an increase in maximal exercise tolerance and a reduction in the degree of myocardial ischemia estimated by the magnitude of exercise-induced ST-segment depression one hour after application, but no clear effect could be measured four hours later. 25 mg nitroglycerin in the "transdermal therapeutic system" (Ciba Geigy) produced a significant improvement in maximal exercise capacity and a significant decrease in the sum of exercise-induced ST-segment depression one and five hours after cutaneous application. Side effects were not observed during these studies, and the topical compatibility of the different ointments was good.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1984

[Invasive diagnosis of coronary heart disease: recent developments in coronary angiography].

Coronary angiography as a diagnostic procedure has been increasingly perfected over the last 25 years. Technical and pharmacological developments have revealed several new aspects of coronary angiography. The optical and spatial resolution of coronary lesions has been enhanced by improvement of X-ray equipment and the introduction of biplane isocentric coronary angiography with hemiaxial views. Functional diagnosis of coronary arteries has been improved by the introduction of selective pharmacological methods, especially in the search for coronary spasms. The latest development is the introduction of coronary angiography as a therapeutic procedure for intracoronary thrombolysis in evolving myocardial infarction and percutaneous transluminal angioplasty.

Cardiac Catheterization↗