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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eight patients who had surgical correction of coronary artery-cardiac chamber fistula at our center and 163 from a review of the literature are presented. The patients are usually asymptomatic, and the diagnosis is suspected by observing a continuous cardiac murmur. Electrocardiographic findings are nonspecific. Angina pectoris or electrocardiographic evidence of severe ischemia are surprisingly uncommon since coronary artery steal syndrome is also rare. Cardiac catheterization with angiocardiography is required to establish the diagnosis and identify the involved coronary artery and the cardiac chamber into which the fistula terminates. Left-to-right shunt flow is usually low (average Qp/Qs = 1.5). Indications for operation are not precise. If there should be a large shunt flow (2.0) and symptoms of heart failure are present, the decision to operate is clearly justified. This situation is unusual, and operation is nearly always performed in an asymptomatic patient in whom the fistula is closed to prevent future symptoms or complications. The operation chosen is generally interruption of the fistula by direct ligation. Sometimes cardiopulmonary bypass is required. The results are good, with low morbidity (3.6% myocardial infarction) and low mortality (2%) justifying the operation, to be carried out prophylactically even in asymptomatic patients.
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PMID:Congenital coronary artery- cardiac chamber fistula. Review of operative management. 118 Jun

Ischaemia in the entire left ventricular wall was induced in dogs by installment of ameroid constrictors on the left anterior descending (LAD) and left circumflex (LC) branches of the left coronary artery (series A). Ischaemia in the anterior left ventricular wall was induced by installment of an ameroid constrictor on LAD and ligation of all (series B) or part of (series C) the subepicardial intercoronary anastomoses between LC and LAD. The effect of the operation was studied by electrocardiography and coronary angiography and, post mortem by radiography of the coronary arteries and histopathology of myocardium and coronary arteries. The high early mortality rate in series A and B precludes the further use of these procedures. In series C the mortality rate was low and in half of the cases lasting myocardial ischaemia of the anterior wall of the left ventricle was produced. The development of a small myocardial infarction was inevitable, but it was healed by the time the sought after state of stable myocardial ischaemia was reached.
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PMID:Standardized induction of myocardial ischaemia in the dog. 118 Nov 90

Because of the importance of acute myocardial infarction, much effort has been made to develop a representative animal model. Clinical characteristics that have been sought in the models include sudden death, early and late tachyarrhythmias, slow cardiac rhythms and bundle blocks, and variable influence of location of infarction. Each of these characteristics has been found under some conditions and in some models, but it has not been possible to imitate the entire range of the human disease in a simple model. Each model has significant drawbacks in terms of nonhuman cardiac response to stress or drugs, different coronary artery physiology, convenience of study, or cost. In particular, the use of isolated tissue confuses the influences of hypoxia and ischemia. The models have been of great value to investigation in myocardial infarction, but more focus on physiological and biochemical mechanisms may help to avoid the errors inherent in the use of models.
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PMID:Validity of myocardial infarction models. 118 67

Approximately one-third of patients dying suddenly exhibit occlusive coronary artery thrombi, in contrast to the high frequency (90%) associated with transmural myocardial infarction. Such a discrepancy, along with other considerations, indicates that not all cases of sudden cardiac death are simply the result of myocardial ischemia or infarction in the traditional sense, and does, we believe, justify a rigorous search for alternative pathophysiological mechanisms. Some alternative mechanisms have been discussed, including disturbances in the cardiac conducting system, and the potentially very important role of platelet microembolism or microthrombosis in the genesis of focal ischemia and the lethal arrhythmias. Additionally, not all disturbances leading to the development of lethal arrhythmias may be reflected in light microscopic changes. There is a need for more sophisticated methodological approaches to the detection of early ischemia or other changes at a subcellular level. Although existing studies have provided a useful initial approach to an understanding of the pathology of sudden cardiac death, more questions remain unanswered than answered. In particular, no definitive comparison of deaths occurring in or out of hospital is currently possible, while much more information is necessary in relationship to the clinical status of patients dying suddenly. For example, one needs to know whether there are fundamental pathological differences in patients dying instantaneously relative to those surviving minutes or hours after the onset of terminal symptoms or signs; to what extent the pathologic findings are modified by therapy; whether there are any terminal symptoms specifically associated with particular pathological findings; what differences, if any, exist between patients with myocardial injury who die suddenly and those who do not; and how one can ensure a reasonable degree of comparability between different studies. Answers to these and many other questions will not, we believe, be forthcoming if we continue to be preoccupied with the epicardial arteries and light microscopy alone, but rather from well-conceived studies employing the collective resources of clinical cardiology, epidemiology, pathology, and experimental biology.
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PMID:Anatomical pathology of sudden unexpected cardiac death. 118 72

Vessels of the microcirculatory bed of the heart in myocardial infarction were studied on the basis of the material of 21 section observations using histological, histochemical methods and the technique of impregnation of films of the epicardium developed by V. V. Kupriyanov. In the ischemic stage in the zone of ischemia and in perifocal areas there were noted signs of increased vascular permeability and impairment of hemodynamics: plethora of the venous department of the microcirculatory system, stasis of the blood in capillaries, spasm and paresis of vessels of the microcirculation. In the necrotic stage in the zone of necrosis there were observed destruction of vessels of the microcirculatory bed; in the peri-infarction zone--drastic plethora of veins, venules and capillaries, higher vascular permeability, leucostasis, leucopedesis, perivascular cellular infiltrates, destruction of vessels of the microcirculatory bed, dilatation of lymphatic vessels; in the intact zone--venous plethora and elevated permeability. In cases of shocks and collapses in vessels of the microcirculatory bed of the heart beyond the zone of necrosis aggregations of erythrocytes were found. In the reparative stage newly formed vessels in the granulation tissue were observed; In the post-infarction scars sinusoid vascular cavities and arteries of the closing type were noted.
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PMID:[Vessels of the microcirculatory bed of the heart in myocardial infarction]. 122 73

In order to reduce the oxygen consumption of the myocardium and preserve the areas around the infarction, still alive but undergoing ischemia, 8 patients with early extension of their infarction were placed under circulatory assistance by intra-aortic counter-pulsation. In 8 patients, the pain disappeared and did not recur, permitting left ventriculography and coronary arteriogrpahy. This examination is often considered high risk, but in no patient in our series, during the acute phase of myocardial infarction, were there any complications. 6 patients underwent operation, and aortic counter-pulsation was used during the post-operative period. In all, eight coronary by-pass operations were carried out and, in one case, part of the ventricular wall was resected. All patients are still alive, none have heart failure or residual angina; the follow-up period is now 2 years for the first case.
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PMID:[Emergency myocardial revascularization with assisted circulation for early extension of infarction]. 122 51

Transversal epidemiologic investigations carried out in different populations from several regions of Romania : Gurghiu Valley (lumberjacks from a mountain region), Danube Delta and Razelm lagoon complex (fishermen), and Bucharest have shown that, in spite of the high caloric value of food and even of a high intake of saturated fats, mean serum cholesterol is lower in the rural areas than in Bucharest, probably owing to the strenuous physical work. However, except myocardial infarction, more frequent in the urban than in the rural regions, the other forms of coronary heart disease have a relatively higher frequency in villages, particularly atrial fibrillation and ECG signs of ischemia. These findings might be explained by a greater prevalence of hypertension in these populations. It is concluded that the risk factors, which act synergically, depend on the complex structure of the "ecologic niche".
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PMID:Coronary heart disease and risk factors in some special type collectivities. 124 94

Tricuspid regurgitation developed in two patients after inferior wall myocardial infarction. Neither patient had preexisting valvular heart disease or evidence of endocarditis, and neither had suffered chest trauma. Because abnormalities in right ventricular function may occur after inferior infarction, and because other known causes of tricuspid incompetence were not present, we postulate that these patients developed valvular regurgitation from dysfunction of the papillary muscle complex controlling tricuspid valve function, a mechanism similar to that proposed to explain mitral regurgitation seen with inferior wall ischemia.
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PMID:Tricuspid regurgitation following inferior myocardial infarction. 124 43

During a 3 year period, direct myocardial revascularization was performed on an urgent basis in 48 patients with intermittent resting chest pain which persisted more than 24 hours despite in-hospital medical therapy and was accompanied by electrocardiographic changes representative of ischemia. Sixteen patients had saphenous vein (SV) grafts exclusively, and 32 patients each had one or two internal mammary artery (IMA) grafts with or without additional vein grafts. Follow-up ranges from 5 to 41 months (mean, 22 months). Twelve patients had single grafts to the left anterior descending coronary artery (LAD), 18 had double grafts, 16 had triple grafts, and 2 had quadruple grafts. The LAD required grafting in every patient. There was one operative death (2 per cent) and one late death from noncardiac causes. There were two (4 per cent) early postoperative myocardial infarcts and no late infarcts. Actuarial analysis projects a survival rate of 96 per cent 3 years postoperatively. Eighty-one per cent of the survivors are in Functional Class I, 17 per cent are in Class II, and 2 per cent are in Class III. All patients had postoperative angiography 2 weeks after operation. Eighty-six per cent of the SV grafts and all IMA grafts were open. No significant differences were observed between mean preoperative and postoperative left ventricular end-diastolic pressures or ejection fractions, but these parameters were noted to improve after operation in several patients. The remarkably high early and late survival rates, the low incidence of myocardial infarction, and the excellent functional results after rather long follow-up indicate that emergency coronary revascularization provides an effective therapy for unstable angina. The use of IMA grafts, when feasible, is a safe and possibly preferable approach in these patients.
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PMID:Surgical treatment of unstable angina by saphenous vein and internal mammary artery bypass grafting. 124 66

Focal ischemia of the small intestine does not always lead to necrosis and perforation, but may induce fibrous stenosis which is evidenced clinically by acute or chronic intestinal occlusion. Among 8 intestinal stenoses 5 were revealed by the presence of an intestinal occlusion whereas the others were manifested by intestinal occlusions complicated by subsequent perforation of the intestinal wall. Annulo-tubular stenoses of ischemic origin are frequently accompanied by inflammatory mesenteric adenopathies due to mucosal ulcerations in the septic environment of the intestinal lumen. Their aspect is reminiscent of Crohn's disease or annular carcinoma. Histological examination of the resected loop frequently reveals the primary oschemic origin of the stenotic lesion, characterized by the presence of macrophages loaded with hemosiderin in the thickened inflamed mucosa. The tissue alterations observed resemble those found in myocardial infarction, but the inflammatory response is more pronounced due to the septic medium. Although such stenoses are relatively rare, they should be distinguished from other lesions provoking a narrowing of the intestinal lumen, since their treatment calls for certain therapeutic precautions. In some cases, angioplastic intervention is required in order to improve perfusion of the vascular bed irrigated by the superior mesenteric artery following resection of the stenotic loop and termino-terminal anastomosis. Furthermore, during any operation requiring revascularization of the mesenteric vessels for intestinal angina, it is important to carry out a very careful examination of the state of the small intestine.
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PMID:[Stenosis of the small intestine of ischemic origin in the adult (segmental and transmural lesions)]. 125 Nov 54


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