Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151814 (coronary occlusion)
 3,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of verapamil on epicardial ST segment elevation, regional myocardial metabolism and collateral blood flow were studied in open-chest anesthetized dogs following left anterior descending coronary artery occlusion. Collateral blood flow was measured by radioactive microspheres (15 +/- 5 micron diameter) and regional metabolism was studied by measuring lactate concentration in venous blood draining the infarcting myocardium. Verapamil (0-2 mg/kg intravenously) produced a significant reduction (50-60%) in the epicardial ST elevation when it was given before coronary occlusion; when administered 15 minutes after coronary occlusion and infusion continued for two hours, it minimized (30-40%) ST segment elevation, and prevented the fall in cardiac index and rise in systemic resistance found in the untreated animals in which the ST segment remained persistently elevated. Changes in epicardial ST segment occurred without alterations in the QRS duration. Verapamil had no effect on either the total collateral blood flow or the relative distribution of flow to the endocardial and epicardial halves of the ischemic ventricular myocardium. No significant differences were found between the levels of lactate in blood sampled from small epicardial veins at the center of the infarct when the control animals were compared with those treated with verapamil.
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PMID:The effect of verapamil on experimental myocardial ischaemia with a particular reference to regional myocardial blood flow and metabolism. 26 65

Coronary bypass surgery performed after more than 3 or 4 hours of coronary occlusion may results in serious derangements of cardiac metabolic, contractile, and electrical functions, and lead to extensive myocardial infarction, as well as to an unacceptable mortality. If the operation can be performed within the first 1 to 2 hours of acute coronary occlusion, hospital mortality rate is acceptably low. Although the average infarct size was usually reduced by reperfusion after 3 hours of experimental occlusion, in about 30 percent of cases there appeared to be no salvage of jeopardized myocardium.
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PMID:Is early revascularization following acute coronary occlusion a safe and effective surgical procedure? 30 Feb 82

Coronary hemodynamics were studied intraoperatively in 65 patients undergoing aortocoronary bypass grafting. Poststenotic coronary pressure and graft flow hyperemia were measured. Patients without coronary collateral vessels on arteriography (class A) were compared with patients with collateral vessels (class B). Patients in class A were grouped according to the angiographically determined degree of coronary stenosis. Eight of these patients with moderate coronary stenosis underwent intraoperative studies with transient complete coronary occlusion and were classified in the "acute" occlusion group. In class B all patients had complete coronary occlusion with good retrograde filling of the distal segment. In class A patients there was good correlation between the degree of stenosis and poststenotic pressure or hyperemic response. Stenosis had to be at least 80 percent before it produced a significant pressure gradient or graft flow hyperemia. In class B patients (those with complete "chronic" coronary occlusion), poststenotic pressure was significantly greater than in the class A patients with "acute" occlusion, significantly less than in the class A groups with 71 to 80 percent and 81 to 90% stenosis but not significantly different from values in the class A group with 91 to 99 percent stenosis. The hyperemic response was significantly less than in the "acute" occlusion group of class A, significantly greater than in the class A groups with 71 to 80 percent and 81 to 90 percent stenosis, but not significantly different from values in the class A group with 91 to 99 percent stenosis. It is concluded that (1) under basal conditions a coronary stenosis must be at least 80 percent to be hemodynamically significant, and (2) well developed collateral vessels produce in a completely occluded coronary artery hemodynamic changes that simulate those of a 90 percent coronary stenosis without collateral vessels.
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PMID:Intraoperative evaluation of the functional significance of coronary collateral vessels in patients with coronary artery disease. 30 6

William Heberden (1710--1801), in 1768, described angina pectoris, the classic symptom of ischemic heart disease, 150 years after the discovery of the coronary circulation by William Harvey (1578-1657). Another 110 years had elapsed before the first antemortem diagnosis (confirmed at autopsy) of coronary thrombosis was reported by Adam Hammer in 1878. The patient was a 34 year old man who died some 19 hours after a sudden collapse. Although the patient's clinical features were atypical (such as the absence of angina and the presence of complete heart block) and the autopsy showed vegetative aortic endocarditis that appeared to be causally related to the thrombotic coronary occlusion, Hammer's astute and carefully reasoned bedside diagnosis was history-making and deserves to be so recognized.
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PMID:Centenary of the first correct antemortem diagnosis of coronary thrombosis by Adam Hammer (1818--1878): English translation of the original report. 36 Aug 11

Limitation of myocardial injury after coronary occlusion is an exciting, recently recognised, but as yet unconfirmed, possibility in the treatment of myocardial infarction. Review of the experimental basis for the concept indicates that although manipulation of the ST segment of the electrocardiogram is not sufficient proof that myocardial necrosis can be limited, more robust experimental methods have confirmed the efficacy of a variety of interventions in experimental coronary occlusion. The effect of myocardial infarct size in determining acute prognosis and complications has been confirmed in clinical studies though the importance of infarct size lessens after recovery. Reported attempts at limiting myocardial necrosis in patients with myocardial infarction have so far not been sufficiently convincing to merit universal clinical application. Results of large scale randomised trials currently underway are awaited with interest.
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PMID:Limitation of myocardial infarct size: review of experimental basis and clinical trials. 37 10

Although oral contraception (OC) offers reliable and esthetic contraception for 40-50 million women in the world today, serious complications do occur with its use and must be considered in a basic risk-benefit equation. Thorough knowledge of these complications and their predisposing factors may guide the selection of patients for OC use and management of its use. The following complications are reviewed: Vascular thrombosis (cerebrovascular disease, coronary artery disease), hypertension, carbohydrate metabolism, lipid metabolism, neoplasms (cervical tumors, breast tumors, endometrial carcinoma, benign tumors of the uterus and ovary, liver tumors), subsequent reproductive function (outcome of pregnancy), subjective effects (emotional state), gallbladder disease, liver function, and other effects. The incidence of complications may be decreased by proper prescribing and selection of patients. OC use in hypertensive or diabetic patients is not recommended. They should be used with caution in the younger obese patient and not used in the obese patient over age 35. OC may be prescribed for women over age 35 who do not smoke or have any other risk factor and who are apprised of the possible but uncertain degree of increased risk of coronary occlusion from pill use alone. Women with headaches developing or increasing with OC use should discontinue this method of contraception. It is recommended that women with any of these risk factors who have completed their desired families should be offered surgical sterilization.
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PMID:Oral contraception. 38 49

Widely distributed throughout the heart is a network of fibers connected to the medullary cardiovascular centers by nonmedullated vagal afferent fibers. When the traffic in these fibers is interrupted by vagal cooling, and the input from the arterial baroreceptors is prevented, the arterial blood pressure increases. Thus, these receptors act to inhibit tonically the vasomotor center. The receptors in the atria alter their rate of discharge with changes in atrial transmural pressure and contractility and are most active during end-inspiration and early expiration when the transmural pressure is maximal. The receptors in the ventricles respond to changes in ventricular end-diastolic pressure (preload), to the pressure generated during systole (afterload) and to changes in ventricular contractility. The cardiac mechanoreceptors have an equal or greater effect on the renal bed than the arterial mechanoreceptors and this effect is enhanced by hypercapnia. In animals, the cardiac mechanoreceptors have less control of the muscle vessels than the arterial mechanoreceptors, but the reverse is true in man. Both the cardiac and arterial mechanoreceptors can modulate the output of renin from the kidney, but the cardiac mechanoreceptors are more sensitive to small changes in blood volume. During coronary occlusion, in association with the bulging of the ischemic myocardium, the rate of discharge of these cardiac receptors is greatly increased.
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PMID:Cardiac receptors: normal and disturbed function. 38 68

The widespread use of cardiac ventriculography has focused interest on the frequency with which asynergy accompanies coronary heart disease as well as on its clinical and prognostic implications and dynamic nature. Recently, "intervention ventriculography" using nitroglycerin or postextrasystolic potentiation has indicated that asynergic zones may be more accurately classified as reversible (implying viable myocardium) or irreversible (nonviable or scarred myocardium), and thus the ventriculographic definition of aneurysm must reflect not only the severity of asynergy but its contractile reserve. Surface electrocardiogram Q waves, the severity of asynergy, and degree of coronary occlusion all adversely affect the potential for reversibility, whereas coronary collaterals enhance it. Important clinical applications include assessment of the potential utility of coronary bypass surgery in improving asynergy and of vasodilators in the treatment of patients with left ventricular failure. With refractory sequelae of aneurysms (heart failure, ventricular tachyarrhythmias, and systemic emboli) and a discrete aneurysm, surgical resection has been increasingly used with generally good results.
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PMID:Asynergy in coronary heart disease. Evolving clinical and pathophysiologic concepts. 41 Mar 36

The effects of myocardial reperfusion have been examined following a 1 h coronary occlusion and compared to a permanent coronary ligation in pigs. Haemodynamic investigations were carried out throughout the surgical intervention and repeated after 7 days. Cellular injury was estimated by serial serum enzyme determinations (creatin phosphokinase, alpha-hydroxybutyric dehydrogenase, aspartate aminotransferase, lactic dehydrogenase) during the first 5 postoperative days; infarct size was assessed morphometrically by a histochemical staining procedure 1 week after the temporary or permanent coronary occlusion. A linear correlation was found between the logarithmically plotted peak serum activity of AST, HBDH, CPK and the morphometrically determined infarct size. Based upon enzyme and morphometrical studies no significant difference could be detected between the two experimental groups. In the animals subjected to transient coronary occlusion, however, the development of a ventricular aneurysm had been prevented to early and sustained reperfusion. Early re-establishment of coronary circulation appears to accelerate the proliferation of a more resistant granulation tissue into the infarcted area. Cardiac performance was not improved by myocardial reperfusion.
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PMID:Consequences of myocardial reperfusion following temporary coronary occlusion in pigs; effects on morphologic, biochemical and haemodynamic findings. 41 74

Changes in the ECG of a rhesus monkey during a classical aversive conditioning trial conducted 10 minutes after occlusion of the marginal branch of the left circumflex coronary artery have been observed. This appears to reflect an instance where myocardial ischemia following coronary occlusion was exacerbated by presentation of a conditional stimulus.
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PMID:A note on ECG changes observed during Pavlovian conditioning in a rhesus monkey following coronary arterial occlusion. 41 87


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