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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
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↗
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↗
PubMed1975

Abnormal regional metabolism and mechanical function in patients with ischemic heart diseases: improvement after successful regional revascularization by aortocoronary bypass.

Left ventricular anterior wall metabolism was investigated concurrently with global myocardail metabolism by simultaneous preoperation sampling of anterior interventricular venous (AIV) and coronary sinus (CS) as well as arterial bloods in seven patients with severe obstructive lesions of the major coronary arteries, including left anterior descending. Postoperative study was performed two weeks to six months following successful aortocoronary artery bypass surgery. All grafts including the aorto-left anterior descending artery grafts were patent. Preoperatively in three of the seven patients, anterior wall lactate extraction (R%L) was negative at rest. The average R%L at rest (7 +/- 14%) was abnormal and was negative (-49 +/- 26%) at a maximum supraventricular pacing rate (MPR) of 137 +/- 4.6 beats/min. Postoperatively, not only was resting R%L (39 +/- 4;4%) normal but also it remained normal during atrial pacing (32 +/- 8.5%) even though the postoperative MPR (164 +/- 4.4 beats/min) was much higher than the preoperative MPR; Postoperatively AIV pO2 both at rest (21 +/- 1.1 mm Hg) and at MPR (22 +/- 1.3 mm Hg) and directly determined O2 saturations (resting: 34 +/- 3.0%; MPR:35 +/- 2.1%) tended to be higher than the preoperative values (AIV pO2, resting: 18 +/- 1.7; MPR: 19 +/- 1.7 mm Hg; AIV O2 saturation resting: 30 +/- 2.7; MPR: 33 +/- 3.3%), although only differences in pO2 were statistically significant. In five of the seven patients in whom the pre and postoperative left ventricular angiograms could be compared, systolic wall motion of the left ventricular anterior wall improved markedly postoperatively. Average global myocardial lactate extraction (G%L) preoperatively was normal (19 +/- 4.8%) at rest but was negative (-22 +/- 12%) at MPR. Postoperatively however, G%L both at rest (44 +/- 5.5%) and at MPR (34 +/- 7.9%) were normal. Coronary sinus pO2 and O2 saturation were also higher postoperatively compared to the preoperative values. Over-all left ventricular performance indicated by increase in ejection fraction also improved postoperatively. This improvement was not caused by increased coronary blood flow. Postoperative coronary sinus blood flow both at rest (114 +/- 19 ml/min) and at MPR (199 +/- 27 ml/min) however were less than the preoperative values (resting 136 +/- 24, MPR 261 +/- 40 ml/min), There was also no increase in global O2 delivery and O2 consumption despite higher heart rate and rate-pressure product achieved during postoperative pacing stress and the patients did not develop angina. These findings suggest that improved regional and global metabolism and mechanical functions observed postoperatively in these patients may be due to redistribution of blood flow to the ischemic and nonischemic myocardium following successful aortocoronary artery bypass surgery.

Adult↗
PubMed1975

Improved angina threshold and coronary reserve following direct myocardial revascularization.

Angina threshold, coronary reserve, and global myocardial lactate metabolism were studied by atrial pacing in 18 patients with obstructive coronary artery disease before and after aortocoronary artery bypass (ACB) surgery. In 3 of these 18 patients, regional (anterior wall) metabolism was also studied. Following ACB, 16 of the 18 patients did not develop angina at the maximum pacing rate (MPR). One patient developed angina postoperatively at a similar rate as before surgery. In the other patient, postoperative angina threshold was much higher. In the group as a whole, postoperative MPR (159 +/- 3.5 beats/min) was much higher than the preoperative angina rate (124.9 +/- 4.9 beats/min; P less than 0.001). Rate-pressure product (RP) at MPR postoperatively (21.5 +/- 0.89 mm Hg/min X 10(-3)) was also higher than RP at angina rate preoperatively (18.8 +/- 0.92 mm Hg/min X 10(-3); P less than 0.01). Although coronary sinus blood flow (CSBF) both at rest (152 +/- 16.2 ml/min) and at MRP (266 +/- 27.5 ml/min) postoperatively was higher than preoperative CSBF at rest (111 +/- 10.7 ml/min; P less than 0.05) and at angina rate (202 +/- 19.9 ml/min; P less than 0.05), arterial-coronary sinus O2 content (Art.-CSO2) difference was significantly lower postoperatively both at rest (8.9 +/- 0.37 ml/min) and at MPR (9.1 +/- 0.44 ml/min) compared with the preoperative Art.-CSO2 at the rest (12.7 +/- 0.40 ml/min; P less than 0.01) and at angina rate (12.4 +/- 3.8 ml/min; P less than 0.01)...

Adult↗