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Biomedical subjects

H Kreuzer

Publications and source records attributed to H Kreuzer.

At least 181 records · Page 10Linked to original sources
PubMed1989

Combined treatment with vitamins E and C in experimental myocardial infarction in pigs.

The effect of two different combined treatments with vitamin E acetate and vitamin C on infarct size and recovery of regional myocardial function was investigated in ischemic, reperfused porcine hearts. The left anterior descending coronary artery was distally ligated in 30 thoracotomized pigs for 45 minutes followed by 3 days of reperfusion. Infarct size was determined as the ratio of infarcted (tetrazolium stain) to ischemic (dye technique) myocardium. Regional myocardial function was assessed by sonomicrometry. Ten pigs received vitamin E acetate (12 gm intravenously three times for 1 week) before ischemic and vitamin C (4.4 gm intravenously) before reperfusion (therapy A). Another 10 pigs were treated with vitamin E acetate (12 gm intraarterially) and vitamin C (4.4 gm intravenously) during ischemia (therapy B). An additional 10 pigs served as a control group. Global hemodynamics did not differ significantly among the groups before and during ischemia. Mean plasma concentrations of vitamin E amounted to 107 micrograms/ml in group A, 16 micrograms/ml in group B, and 0.9 micrograms/ml in the control group at the onset of reperfusion. Therapy A reduced the size of the infarct from 73 +/- 12% to 47 +/- 16% of the region at risk (p less than 0.005) and improved regional systolic shortening from 0 +/- 7% to 11 +/- 6% at 3 days after reperfusion (p less than 0.01). Therapy B decreased the size of the infarct to 64 +/- 9% of the region at risk (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Treatment of reperfusion injury with intracoronary calcium channel antagonists and reduced coronary free calcium concentration in regionally ischemic, reperfused porcine hearts.

The effect of intracoronary diltiazem, EGTA (ethylene-bis-(beta-aminomethylether)-N,N'-tetraacetic acid), nifedipine, verapamil and isotonic saline solution as placebo on reperfusion injury was investigated in regionally ischemic, reperfused porcine hearts. The left anterior descending coronary artery was distally occluded for 45 min and was reperfused for 3 days. Intracoronary infusion was started immediately before reperfusion and continued during 45 min of reperfusion. Infarct size was determined as the ratio of infarcted (tetrazolium stain) to ischemic myocardium (dye technique). Regional systolic shortening was assessed by sonomicrometry. Apart from left ventricular end-diastolic pressure before ischemia and during 45 min of reperfusion, global hemodynamic values in the five treatment groups did not differ; in particular, calculated left ventricular oxygen consumption before and during ischemia was equally low. Intracoronary EGTA decreased coronary venous free calcium concentration to about 70% of baseline value. Infarct size was reduced from 76 +/- 10% (control group, n = 8) to 60 +/- 10% (p less than 0.01) by intracoronary diltiazem (n = 8) and to 55 +/- 15% (p less than 0.01) by intracoronary EGTA (n = 8). Insignificant reductions in infarct size were found after treatment with intracoronary verapamil (63 +/- 18%, n = 8) and intracoronary nifedipine (68 +/- 9%, n = 7). Regional systolic shortening of the risk region, which did not differ among the groups before occlusion and during ischemia, recovered to the greatest extent in the EGTA-treated pigs (p less than 0.01 compared with values in the control group). Treatment with intracoronary calcium antagonists resulted in only marginal improvement of systolic shortening.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Pros and cons of surgery of the left ventricular aneurysm--a review.

The prognosis for the patient with a left-ventricular aneurysm depends on the size of the aneurysm and the function of the remaining ventricle. Data in the literature suggest a 5-year-survival rate of 70-75% and a hospital mortality rate of 10% for aneurysmectomy with and without any additional aortocoronary bypass surgery. Medical treatment on the other hand is only credited with a markedly lower 5-year-survival rate of 45%. To date the only prospective data have been derived by the CASS Study, where no significant difference (67% for medical treatment, 69% for surgical treatment) was seen in the six-year-survival rate. However, considering only the patients with the combination of 3-vessel disease, coronary insufficiency, angina pectoris, and high age, the survival time after surgical treatment was significantly higher. The indication quoted for aneurysmectomy was angina pectoris in 46% of cases, acute or chronic coronary insufficiency in 33%, ventricular arrhythmias in 14%, and left ventricular thrombi in only 2.5%. The relative value of operative resection among the possible methods of treatment of the ventricular aneurysm is still a matter of controversy: there is a lack of larger-scale prospective studies comparing medical and surgical therapy.

Actuarial Analysis↗
PubMed1989

Will emergency coronary bypass grafting after failed elective percutaneous transluminal coronary angioplasty prevent myocardial infarction?

An emergency aorto-coronary bypass grafting operation was performed within 12 hours after the development of acute myocardial ischemia due to partial or complete vascular occlusion in 34 of 950 (3.6%) patients who had received elective percutaneous transluminal coronary angioplasty (PTCA). Of the 34 patients, three (= 8.8%) died postoperatively in irreversible cardiogenic shock. Half of the surviving patients developed a Q-wave infarction after the operation, whereas the other half remained without transmural infarct. With comparable clinical data and times of operation up to placement of the aorto-coronary bypass vessel, an adequate residual perfusion must still have been present in the cases with non Q-wave infarction. Since in many cases a myocardial necrosis is unavoidable despite relatively early operative revascularization, the decisive role will be played by the remaining perfusion of the vessel concerned and any collaterals. It follows that treatment of an early PTCA complication, occurring in the catheter laboratory, ought to be the earliest possible aorto-coronary bypass operation unless available cardiological methods can reliably assure reperfusion. Treatment of a PTCA complication occurring later, however, e.g. after hours in the intensive-care unit, should be a repeat PTCA attempt: surgery at this stage will not prevent the transmural infarction but will increase risk of lethal complications.

Adult↗
PubMed1989

Contrary effects of acetylcholine on coronary arteries and aortocoronary venous grafts in man.

The endothelium-dependent vasomotor responses differ in arteries and veins, and the transfer of veins into the arterial circulation by venous grafting may change their endothelial function. The purpose of this study was to examine the responses to acetylcholine in aortocoronary venous grafts of coronary arteries in man which may indicate differences in the endothelial function of these vessels. Five patients with venous grafts (12 to 72 months after implantation) and five patients without any angiographic evidence for coronary artery disease (controls) were examined. The effect of local infusions of acetylcholine (7-70 nmol min-1) on the vessel diameters was assessed by quantitative angiography. In controls, acetylcholine caused no consistent reaction, but in patients with venous grafts the arterial segments distal to the bypass anastomoses were contracted (7 nmol min-1: 82 +/- 2%; P greater than 0.01). We observed that aortocoronary venous grafts reacted differently to acetylcholine compared with the coronary arteries (P less than 0.05): a slight but not significant dilatation of the venous graft occurred (7 nmol min-1: 103 +/- 1%). The contraction of atherosclerotic coronary arteries of patients with aortocoronary venous grafts is in accord with the assumption of a loss of endothelium-dependent vasodilatation in coronary artery disease. The cholinergic influence on the vasomotor control of venous grafts seems to be either of little importance or less affected by atherosclerotic endothelial lesions than in coronary arteries.

Acetylcholine↗
PubMed1989

A randomized prospective study on anxiety reduction by preparatory disclosure with and without video film show about a planned heart catheterization.

Unfortunately, giving preparatory information to the patient is generally regarded as legally mandatory for obtaining his written consent to an invasive procedure. Disclosure, however, could be used to reduce his anxiety as well; we hypothesized that showing a preparatory video film might be helpful in this respect. Patients who were admitted for elective coronary angiography were eligible for the study. 65 were randomized to two groups: both groups received the same leaflet and personal interview with the doctor, but only one group (Group 2) additionally watched a 14 min preparatory video. Anxiety was assessed with the State-Trait Anxiety Inventory (STAI). The two groups did not differ with respect to initial anxiety levels and other important parameters. Group 1 patients, who did not watch the video had no significant reduction in anxiety score; group 2 patients showed a significant benefit. We conclude that disclosure with the additional aid of a video film may be an easy, yet effective way to reduce patients' anxiety.

Adult↗
PubMed1989

Effect of intracoronary superoxide dismutase on regional function in stunned myocardium.

This study investigates the ischemic-time dependency of dysfunction in reversibly ischemic myocardium and the effect of postischemic oxygen free radical scavenging thereupon. In open chest pigs, occlusion of the distal left anterior descending coronary artery (LAD) for 4 (n = 5), 8 (n = 5), or 12 min (n = 5) resulted in paradoxical systolic and diastolic regional function, measured by ultrasonic crystals. With onset of reperfusion, systolic shortening (SS) and diastolic lengthening (DL) normalized completely in the 4- and 8-min groups, followed by a significant decrease to 50% control in the 8-min group. In the 12-min group, recovery of SS and DL was only partial. In two further groups, animals received an intracoronary infusion of either recombinant human superoxide dismutase (SOD, n = 6) or placebo (n = 6), starting with reperfusion after an 8-min LAD occlusion. SOD improved recovery of SS compared with placebo (p less than 0.05), but DL and the depression of SS during later reperfusion were not influenced. Mitochondrial function after 90 min of reperfusion was not impaired in ischemic-reperfused compared to control myocardium. We conclude that the degree of postischemic dysfunction increases with the duration of ischemia. Oxygen free radical scavenging by SOD, starting not before reperfusion, fails to prevent myocardial stunning. Mitochondrial function is intact in such myocardium.

Adenosine Diphosphate↗
PubMed1989

Effect of alpha-tocopherol (vitamin E) in a porcine model of stunned myocardium.

Oxygen free radicals have been suggested to cause the myocardial damage resulting in the prolonged contractile depression following brief periods of regional ischemia. In pigs, we infused the natural antioxidant alpha-tocopherol as its water-soluble acetate [0.3 g/kg intravenously (i.v.), n = 6] three times during 1 week, prior to thoracotomy, 8-min distal left anterior coronary artery (LAD) occlusion and 90-min reperfusion. Plasma levels of alpha-tocopherol [high-performance liquid chromatography (HPLC)] on the experimental day were 148.91 +/- 21.47 micrograms/ml as compared to preinfusion control of 0.51 +/- 0.14 micrograms/ml. Myocardial levels of alpha-tocopherol were elevated to 93.15 +/- 14.78 micrograms/g as compared to 4.08 +/- 0.60 microgram/g in the control group (n = 6). Malondialdehyde levels in ischemic-reperfused myocardium of the treatment group were insignificantly lower (441.96 +/- 59.55 nmol/g) as compared to the control group (500.9 +/- 72.72 nmol/g). Heart rate was significantly higher in the treatment group by the end of the experiments (135 +/- 10 vs. 105 +/- 4 beats/min, p less than 0.01). Regional segment shortening (SS, sonomicrometry) became normal within 1 min of reperfusion in both the treatment and the control group. During the following 10 min, SS decreased to 52 +/- 6% of preischemic control in the alpha-tocopherol group and to 54 +/- 7% in the control group (NS). SS remained at these depressed values throughout the reperfusion period. Pretreatment with the antioxidant alpha-tocopherol resulted in a tendency to lower lipid peroxidation products but did not prevent development of contractile depression in reversibly ischemic reperfused myocardium.

Animals↗
PubMed1989

[Beneficial long-term effects of diltiazem on the course of dilated cardiomyopathy].

There is increasing evidence that chronic enhanced exogenic or endogenic catecholamine stimulation in patients with dilated cardiomyopathy may worsen hemodynamics and prognosis. The cause of this may lie in myocellular calcium accumulation and microcirculatory disorders. In a prospective study the calcium antagonist diltiazem was given to 22 patients with dilated cardiomyopathy (60-90 mg t.i.d.) in addition to conventional therapy of digitalis, diuretics, and vasodilators. Twenty-five patients received the conventional therapy and served as historical controls. Eight additional patients who were not originally included in the 25 controls changed over from conventional therapy to adjunctive diltiazem treatment. The patient groups compared were similar in all hemodynamic and anamnestic features. Further, only patients with reduced myofibril volume fraction in the myocardial biopsy were included in the trial, since hemodynamic deterioration could be expected in them. The mean survival rate was 29 months in the controls, while within a mean of 15.4 months no patient died in the diltiazem group (p less than 0.001). Mean left ventricular ejection fraction increased from 0.34 to 0.44 (p less than 0.001) and the New York Heart Association classification was significantly improved in the diltiazem group and during the diltiazem period in the crossovers, but deteriorated in the controls. Therefore, the results suggest that adjunctive diltiazem treatment in dilated cardiomyopathy has beneficial effects on letality, hemodynamics, and symptoms.

Adult↗
PubMed1988

[A decline in hospital mortality in acute myocardial infarct during the last 10 years. An effect of acute intervention?].

The decline in hospital mortality after myocardial infarction was analyzed retrospectively in a cohort of 2147 consecutive patients with acute myocardial infarction, admitted to an University Hospital between 1978 and 1987. During this period the percentage of patients who had acute active interventions (thrombolysis, aortocoronary bypass surgery, percutaneous transluminal coronary angioplasty) increased from 6% (in 1978/79) to 50% (in 1986/87). During that same period, conventional treatment of acute myocardial infarction and the provisions for emergency admission and intensive care remained unchanged. At the same time there was a significant reduction in overall mortality from 29% (1978/79) to 17% (1986/87) (P less than 0.001). This decrease was especially marked for males (from 27% to 13% in the respective periods), and in patients with anterior-wall infarction (34% and 16%, respectively). These changes cannot be explained by differences in group characteristics. The main cause for the distinct reduction in hospital mortality of this cohort was the introduction and expansion of acute interventions.

Age Factors↗
PubMed1988

[Observation of acenocoumarol-induced granulocytosis].

A male patient had been treated with acenocoumarol for 9 years. Raised white cell count returned to normal, when acenocoumarol was substituted by heparin, but rose again after reexposure. An analysis of variance showed that this effect is mediated by neutrophils only. The rise is quick and may therefore be caused by a redistribution of white cells rather than by increased cell production.

Acenocoumarol↗
PubMed1988

Local measurements of thrombus induced vasoconstriction in vivo.

No data is available describing the local effect of thrombus formation on the vessel's diameter in vivo. As platelet or thrombus induced vasoconstriction seems to be of clinical importance in various diseases, it is desirable to get insight into the interrelation of thrombus formation and local vasoactivity. With a contactless photochemical process, endothelial cells can be damaged and thrombogenesis may be initiated in vivo. After first platelets stick to endothelial cells, a strong vasoconstriction is observed in arterioles. In venules, no vascular reaction can be observed. Constriction is most pronounced at the site of thrombus formation and decreases at growing distance. The thrombus is squeezed by the vascular constriction and thus mechanically held in place and squeezed out. A slight relaxation follows 30-80 min later, but the vessel remains constricted during the following three hours. Thrombus induced vasoconstrictions can be reduced by papaverine, EP 092 (a thromboxane A2 antagonist) and phentolamine in dose-dependent manner in vivo. Papaverine was most effective followed by EP 092, Phentolamine was less effective, showing the minor importance of alpha-receptor stimulation in this model.

Animals↗
PubMed1988

[Monitoring of pacemaker patients by long-term ECG].

Long-term-ECG is an essential method for detecting transitory pacemaker-dysfunctions. Control of antitachycardia-pacemakers is possible as well as VVI-pacemakers and with restrictions DVI-, VDD- and DDD-pacers. Special pacemaker-control-modules increase the sensitivity for the recognition of dysfunctions. Regular check-ups are an important part of guiding the pacemaker-patient.

Arrhythmias, Cardiac↗
PubMed1988

Endocardial late potentials recorded during sinus rhythm in man: incidence in different cardiac disease states.

In a prospective study, 100 patients with various cardiac diseases not selected on the basis of previous ventricular arrhythmias underwent left ventricular endocardial mapping. With 10 different positions of the quadripolar catheter per patient, 90 of the 100 patients showed late potentials. These findings were documented in 50 of 52 patients with coronary heart disease compared to 26 of 34 patients with dilative cardiomyopathy (p less than 0.025). Late potentials in diastole were the most frequent type of abnormal electrogram, found in 82 patients. Fractionated electrograms were documented in 43 patients. They were seen in 27 (52%) coronary patients more often than in 8 (24%) patients with dilative cardiomyopathy (p less than 0.025). Onset of fractionated electrograms in coronary patients was somewhat later (301 +/- 177 ms after the QRS) than in the cardiomyopathy group (263 +/- 141 ms). The duration was longer (189 +/- 114 ms) in the former group than in the latter (148 +/- 87 ms). Thus, endocardial late potentials are not uncommon in patients with various cardiac diseases. The more frequent occurrence in coronary heart disease and the higher frequency of fractionated electrograms may indicate a more inhomogeneous, patchy type of fibrosis in the ischemically diseased myocardium.

Adult↗
PubMed1988

Coronary arterial embolism due to valvular debris after percutaneous valvuloplasty of calcific mitral stenosis.

A 74-year-old woman with refractory congestive heart failure due to long-standing calcific mitral stenosis who refused surgical intervention was treated with percutaneous balloon valvuloplasty. After an uneventful procedure, hemodynamic results were satisfactory with an increase in the mitral valve area from 0.4 to 1.1 cm2. Five hours after the procedure, the patient had a bout of vomiting followed by pulmonary aspiration. Electrocardiography, and in the further course, creatine kinase MB elevation, showed anterior myocardial infarction. Necropsy disclosed embolic material in the mid left anterior descending artery which unequivocally consisted of valvular material. This case demonstrates embolism of valvular debris as a life-threatening, procedure-related complication of percutaneous valvuloplasty of calcific mitral stenosis.

Aged↗