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Biomedical subjects

W Ganz

Publications and source records attributed to W Ganz.

At least 91 records · Page 5Linked to original sources
PubMed1980

The relationship of vascular injury and myocardial hemorrhage to necrosis after reperfusion.

Early reperfusion may salvage ischemic myocardium; late reperfusion often intensifies morphologic changes of necrosis and causes hemorrhage. To determine whether hemorrhage after reperfusion increases the extent of myocardial infarction, six closed-chest, anesthetized dogs underwent balloon occlusion of the left anterior descending coronary artery for 5.5 hours, followed by 30 minutes of reflow. Colloidal carbon was injected distal to the balloon before reperfusion to label injured vessels. After sacrifice, the area of myocardial necrosis was measured by planimetry of 1-cm-thick serial slices of left ventricle stained with triphenyl tetrazolium chloride. Areas of hemorrhage and vascular injury were also measured. In all hearts, the extent of hemorrhage and vascular injury was less than the extent of necrosis (10.2 +/- 4.6% vs 19.8 +/- 8.6% [mean +/- SD], p < 0.01). Further, hemorrhage was always within the area of necrosis, primarily in the subendocardial portion. Hemorrhage after reperfusion occurred only in necrotic tissue where carbon labeling indicated severe vascular injury before reperfusion, suggesting that the hemorrhage was the consequence of preexisting microvascular injury, not its cause.

Animals↗
PubMed1979

Nitroglycerin in acute myocardial infarction. X. Effect of small and large doses of nitroglycerin on sigma ST segment deviation -- experimental and clinical results.

The purpose of the present study was to investigate the effect of the dose of nitroglycerin (NTG) on myocardial ischemic injury. In 20 closed chest dogs the anterior descending branch of the left coronary artery was occluded by inflating a balloon in its lumen. Compared with the untreated control group the sigma ST elevation was significantly lower when NTG was applied at a rate of 0.02 mg/min, but significantly higher when NTG was administered at a rate of 0.10 mg/min. In 12 patients with acute myocardial infarction NTG was infused at a rate of 3 mg in the first hour (0.05 mg/min) and 6 mg in the second hour (0.1 mg/min). Sigma ST elevation and sigma ST depression decreased during the lower infusion rate (p less than 0.001). When the rate of NTG infusion was raised to 6 mg/hr, the improvement in ST segment deviation was partially reversed. This effect, particularly evident in patients not in heart failure, was associated with a significant rise in heart rate (p less than 0.05) and a fall in diastolic arterial pressure (p less than 0.025). Patients with left ventricular failure were less sensitive to higher doses of NTG than those without failure. Thus, the effect of NTG on myocardial ischemic injury depends on the NTG dose and on the functional state of the injured left ventricle.

Animals↗
PubMed1979

Haemodynamic and electrocardiographic accompaniments of resting postprandial angina.

The early postprandial changes in 10 patients with angiographically proven coronary artery disease and history of postprandial angina were studied by the continuous recording on magnetic tape of the electrocardiogram and haemodynamic variables. The significant changes 20 minutes after a meal not followed by angina included increases in cardiac index and stroke index, with a decrease in systemic vascular resistance. When angina developed after a meal, there were significant increases in mean systemic arterial blood pressure, heart rate, pulmonary capillary wedge pressure, and systemic vascular resistance with decreases in stroke index at the onset of pain rather than at the onset of ischaemic electrocardiographic abnormalities. The first haemodynamic variable to change was pulmonary capillery wedge pressure which tended to increase coincident in time with the electrocardiographic abnormalities. In all cases, postprandial angina occurred within 25 minutes after a meal. In every instance, there was little or no change in the product of heart rate and systolic arterial blood pressure at the onset of the ischaemic electrocardiographic abnormalities at a time when the pulmonary capillary wedge pressure had begun to rise. Postprandial angina, like many cases of rest angina, may rise on the basis of a primary decrease in myocardial perfusion, the nature of which is unclear but merits further investigation.

Aged↗
PubMed1978

Metabolic effects of glucose-insulin-potassium in the ischemic myocardium.

This investigation was designed to explore the metabolic, hemodynamic, and electrocardiographic effects of glucose-insulin-potassium (GIK) solution in a model of segmental myocardial ischemia with significant but incomplete restriction of coronary blood flow. An open-chest anesthetized canine model was utilized including 11 GIK and 6 saline control experiments. The anterior descending coronary artery (LAD) was partially occluded causing an average 71% reduction in its blood flow. Thirty min following occlusion GIK or saline was infused for 30 min at 3 ml/min into a femoral vein. Statistically significant effects of GIK included: increased glucose uptake by the ischemic myocardium, reduced arterial free fatty acid (FFA) concentration, reduced myocardial FFA uptake, decreased coronary arterio-venous oxygen content difference, increased myocardial lactate extraction, decreased myocardial potassium egress, and reduced epicardial ST segment elevation. Heart rate, aortic and left ventricular end-diastolic pressures, and developed force in the ischemic area were unchanged. The results indicate a potentially favorable effect of GIK on the metabolism of the ischemic myocardium which may be due to the shift of substrate utilization from free fatty acids to glucose.

Animals↗
PubMed1978

Quantification of myocardial injury during coronary artery bypass graft.

Serial intraoperative myocardial-specific creatine-kinase (MB-CK) samples were obtained in 32 patients undergoing coronary artery bypass graft (CABG). Based upon their postoperative ECG and technetium pyrophosphate SCAN results, each patient was classified as either Group A (MI), B (normal), or C (equivocal). Peak MB-CK was reported for each group. The mean value for Group A (75 +/- 17 IU/L) is higher than for Group B (18 +/- 1 IU/L) or Group C (30 +/- IU/L). The concept of measuring and a formula for calculation of intraoperative myocardial injury are presented. The mean value for Group A (MI, 10,709 +/- 5885) is higher than either groups B (normal) or C (equivocal) by a test of proportionality (P < 0.001). Likewise, Group C (898 +/- 159) is higher than B (466 +/- 71) (P < 0.05). This index, while in need of further validation, corresponds closely to the clinical status of the 32 patients studied and should provide a means more refined than mortality or incidence of MI upon which to judge efficacy of any proposed means of operative myocardial preservation.

Aged↗
PubMed1977

The effect upon coronary blood flow of coronary ostial intubation with an angiographic catheter.

Fifty-two patients undergoing cardiac catheterization were studied to determine whether intubation of the coronary ostium in the course of coronary angiographic studies interferes with coronary blood flow. Pressure at the tip of the catheter and coronary sinus blood flow were measured continuously during insertion of a No. 7.2 French Judkins' catheter into the left coronary ostium and during withdrawal of the catheter from it. In 48 of the 52 patients, there was no change in blood flow related to manipulation of the catheter. In four patients, either a drop in flow following insertion of the catheter or a rise following withdrawal or both were recorded. Two of these four patients had high-grade obstruction of the main left coronary artery, and in the other two the catheter inadvertently advanced and became wedged. In all four cases, reduction in coronary flow was indicated by a drop in or "ventricularization" of the catheter-tip pressure. It is concluded that in the large majority of instances, intubation of the coronary ostium during coronary angiographic studies causes no interference with resting coronary blood flow, but that monitoring of catheter-tip pressure is an important, as well as a valid, procedure for detecting such an interference if it should occur.

Cardiac Catheterization↗
PubMed1975

Hemodynamic and metabolic effects of isosorbide dinitrate in chronic congestive heart failure.

To assess the potential beneficial effects of a nonparenteral vasodilator, sublingual isosorbide dinitrate (5 to 15 mg.) was administered in 12 patients with chronic congestive heart failure refractory to conventional therapy. Hemodynamic measurements were performed before and at 15 minute intervals after drug administration for 90 minutes. Venous capacitance was measured at 5 minute intervals. Myocardial metabolism was also studied in five patients before and after drug administration. Hemodynamic effects were characterized by a modest decrease in mean arterial pressure (85 +/- 3 to 78 +/- 2 [S.E.M.] mm. Hg) and substantial decrease in right atrial (10 +/- 1 to 6 +/- 1), pulmonary arterial (39 +/- 4 to 30 +/- 4) and pulmonary capillary wedge pressures (28 +/- 2 to 21 +h- 2). These changes were accompanied by an increase in venous capacitance (2.46 +/- 0.16 to 3.99 +/- 0.24 c.c./100 c.c. of tissue). Along with a decrease in left ventricular filling pressure, cardiac index increased (1.99 +/- 0.13 to 2.37 +/- 0.15 L./min/M.2). No significant effect on heart rate was seen. Delta P/delta t, an index related to left ventricular dp/dt, increased in all but one patient (253 +/- 31 to 298 +/- 39 mm. Hg/sec.) (p less than 0.02 for all changes) in the face of decreased preload and afterload and unchanged heart rate, suggesting improved contractile state. A decrease in coronary blood flow (165 +/- 13 to 131 +/- 15 c.c./min.) and myocardial oxygen consumption (18.1 +/- 1.6 to 14.5 +/- 1.6 c.c./min.) was noted (p less than 0.02). No change in arterial-coronary sinus oxygen difference or lactate extraction was observed. These data demonstrate that the objectives of therapy in congestive heart failure, namely improved forward output and decreased ventricular filling pressures, can be achieved without metabolic deterioration by using sublingual isosorbide. The mechanisms responsible are related to diminished impedence to ventricular ejection and peripheral pooling of blood. Since the duration of action does not usually exceed 90 minutes, frequent drug administration may be a source of patient inconvience.

Administration, Oral↗
PubMed1975

Use of a balloon-tipped flotation electrode catheter for cardiac mounting.

A new balloon-tipped flotation catheter equipped with two pairs of electrodes has been developed for simultaneous monitoring of cardiac rhythm and hemodynamics as well as for temporary emergency atrial, ventricular and atrioventricular sequential pacing. Experience in 43 patients demonstrates the following: (1) The catheter can be passed and positioned with the tip in the pulmonary artery or its branches at the bedside with the use of fluoroscopy as easily as the standard (Swan-Ganz) catheters. (2) With the catheter in the proper position ans with the use of appropriate filters (proximal, 50 to 300 hertz; distal, 15 to 300 hertz), the intracavity electrograms recorded from the proximal and distal pair of electrodes provide characteristic high right atrial and right ventricular signals, virtually free of noise artifact, baseline drift and respiratory variation, that are particularly suitable for automated on-line monitoring of cardiac rhythm. (3) When indicated, atrial, ventricular or atrioventricular sequential pacing can be initiated without delay. (4) Large artifact-free right ventricular intracavitary signals can be used for reliable and consistent operation of any device requiring QRS triggering mechanisms. (5) Monitoring of pulmonary arterial or pulmonary capillary wedge pressure and withdrawal of blood samples from the central circulation is possible. This device can be particularly useful in patients with hemodynamic difficulties as well as arrhythmias.

Arrhythmias, Cardiac↗
PubMed1975

Use of balloon flotation catheters in critically ill patients.

In summary, balloon flotation catheterization of the central circulation provides data in patient management which are meaningful and important. It has allowed the application of sound physiologic principles to the understanding of the circulatory abnormalities characterizing an illness in an individual patient, and provides a rational basis for selection of therapy with objective, quantitative assessment of patient response. The procedures are simple, the complication rate is low, and the information highly relevant to clinical care.

Arrhythmias, Cardiac↗
PubMed1975

The effect of intracoronary injection of contrast medium upon coronary blood flow.

The changes in coronary blood flow in response to intracoronary injection of 3 ml of 76% Renografin were studied in 47 patients using the thermodilution technique for continuous measurement of coronary sinus blood flow. Within seconds after left coronary injection, an increase in coronary sinus flow began which peaked at an average of 53% above control in 5-10 seconds. There was a corresponding decrease in coronary resistance. Flow returned to control level in almost all patients within one minute of injection. Twenty-four of 35 patients had no change in coronary sinus flow in response to right coronary injection. This can be explained by the fact that most of the venous flow from the right coronary artery returns in such a way that it cannot be measured by the coronary sinus catheter. Of the eleven patients who did show an increase, seven had angiographically documented right to left collaterals, suggesting that the increase in flow was the result of vasodilatation of the left coronary bed by contrast arriving via the right to left collaterals. The percent changes in flow and resistance in response to left coronary injection were isgnificantly greater in the 13 normals than in the 34 with obstructive disease of the left coronary artery (P lessthan 0.01). Flow rose 70 plus or minus 27% (mean plus or minus standard deviation) in the normals versus 46 plus or minus 25% in the patients with coronary artery disease, while resistance fell 44 plus or minus 9% versus 33 plus or minus 11%. The differences, however, were not sufficient for these changes to be of value in the assessment of the degree of impairment of the coronary arterial bed in the individual patient.

Blood Flow Velocity↗