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

The indices of central hemodynamics and myocardial contractile function were studied in 35 dogs before and in different periods after the administration of drugs which block beta-receptors: propranolol, pindolol, and talinolol. The drugs blocking the beta-adrenergic receptors were administered against the background of an intact myocardium to 15 dogs and against the background of acute coronary insufficiency to another 15; acute ischemia was induced in 5 dogs to which the drugs were not given. It was established that beta-adrenergic blocking agents have a beneficial effect in the acute stage of myocardial ischemia; they exert a marked influence on the consumption of oxygen by the myocardium, intramyocardial tension, and the contractile capacity and rhythm of the heart. Talinolol produced the most favourable effect.
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PMID:[Effect of blockaders of cardiac beta-adrenergic structures on the central hemodynamics and contractile function of the myocardium in acute experimental coronary insufficiency]. 4 59

The quantitative potassium and sodium contents in the separate regions of the heart and m. rectus abdominis in cases of sudden and violent death were investigated. The disturbances of the electrolyte metabolism of potassium and sodium were established to be the earliest changes in coronary disease (acute coronary insufficiency resulting from functional disturbances of the coronary circulation and myocardial infarction). The decrease of the quantitative potassium contents and sodium increase in myocardium depend on the ischemia duration and the stage of the myocardial lesion. The highest potassium decrease was observed in the left ventricle and right auricle. Not very high but even decrease of potassium and sodium contents in the separate heart regions was observed in the deceased by electrocution and strangulation, the decrease being most negligible in the deceased by electrocution. The changes observed in potassium and sodium contents are not pathognomic signs of coronary disease. Only the sharp, focal decrease of the contents of those element is a reliable sign of myocardial infarction.
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PMID:[Quantitative K and Na levels in different parts of the heart in cases of sudden death from coronary disease, acquired heart valve defects and violent death]. 13 71

Fluorescence analysis was used in comparison with other methods to study the morphologic-functional changes in the intact parts of the myocardium in 48 persons who had died of infarction and acute coronary insufficiency. The irregular intensity of primary and secondary cardiomyocyte fluorescence, the diversity of fluorescence, and the character of its colour and dynamics of its replacement are manifested in the earliest stages of ischemia. Quantitative measurements reveal diminution of primary fluorescence intensity at the onset of the disease and its gradual increase eventually.
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PMID:[Fluorescence of "intact" human myocardium in myocardial infarct]. 45 18

In 13 patients with acute coronary insufficiency (intermediate syndrome, postinfarction angina, and progressive angina), samples of the ischemic area of the myocardium were studied with the electron microscope and by morphometric methods in order to describe quantitatively the mitochondrial population. Three indices were measured: the fractional volume of the mitochondrial compartment of the cytoplasm, the number of mitochondria per unit volume of heart tissue, and the average individual mitochondrial volume. As a control, the same study was performed on samples obtained from patients with chronic coronary insufficiency and mitral stenosis. In all the ischemic hearts the most conspicuous ultrastructural modification of the muscle cells consisted in an irregular distribution of the mitochondriranules. Generally, odd shaped mitochondria were found. The modifications were not diffuse, and almost normal heart muscle cells were seen alongside deeply altered ones. In addition a definite decrease in the fractional volume of the mitochondrial compartment was found, which was apparently due to a decrease in the number of mitochondria per unit volume of cytoplasm. The average individual mitochondrial volume was similar in acute coronary insufficiency and in the control cases. On the basis of this evidence it is postulated that in sublethal ischemia definite ultrastructural modifications of the heart muscle cells are associated with a decrease in the number of mitochondria per unit volume of cytoplasm.
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PMID:Ultrastructural and morphometric study of the human heart muscle cell in acute coronary insufficiency. 52 66

Effects of coronary constriction on the flow reserve of regional myocardium were studied in the anesthetized open-chest dogs. Regional myocardial blood flow (RMBF) was continuously measured using heated crossthermocouple method. Left circumflex coronary artery (LCX) was constricted gradually with a screw type constrictor. The coronary constriction decreased subendocardial myocardial blood flow, while subepicardial myocardial blood flow was not affected until reactive hyperemia in LCX nearly disappeared. Recovery and arrival to peak flow rate of RMBF following the release of 15-second's occlusion of LCX were progressively delayed with an increase in the constriction, especially in the subendocardial myocardium. Repayment of flow debt, however, was remained relatively well since the duration of reactive hyperemia in RMBF was prolonged by an increment of the constriction. From these findings, it might be concluded that in the heart with coronary stenosis recovery from ischemia was caused by prolonged duration of reactive hyperemia, and is suggested that the time required for recovery from ischemia or ischemic abnormalities after the cessation of stress might be an important marker for the severity of coronary insufficiency.
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PMID:Effect of graded coronary constriction on the flow reserve in regional myocardium in dog. 57 29

Ischemic cardiopathies in Eastern Africans at Djibouti are frequent: 2.9 % of the in patients and 73 % of the cardiac diseases. Male prevalence is marked. Coronary insufficiency is most often demonstrated by the usual symptomatology. Three groups of electrocardiopathic manifestations have been individualised: ischemia proving angor (288 cases), anginose syndromes revealing a myocardic infarct (81 cases), acute myocardic infarcts (62 cases). The patients come for the most part from Djibouti and belong to any social class. The part played by a food mainly constituted of complex glucids, refined sugar and lipids is pointed out. Arterial hypertension, diabetes, essential hypercholesterolemia and tobacco intoxication are the most frequent risk factors. This coronary pathology is closer the one met with in the Near East than ischemic cardiopathies observed in tropical Africa which begin to emerge.
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PMID:[Ischemic cardiopathies in Africans in Djibouti. Study of 431 cases in 5 years]. 58 Sep 20

Modern clinicians encounter considerable difficulties in the diagnosis and treatment of ischemic heart disease which is first of all due to insufficient knowledge of the main mechanisms of the development of coronary insufficiency, myocardial dystrophy, myocardial necrosis, and cardiosclerosis. From the point of view of molecular cardiology, myocardial hypoxia cannot be considered as the foundation for ischemic disease. Metabolic insufficiency of the heart both of coronary and non-coronary origin should also be taken into account. Apart from ischemic (coronary) disease, ischemia of the myocardium alongside with metabolic disorders occurs in most diverse conditions and diseases. Therefore, in future this diagnosis will be reconsidered towards a more accurate determination of the causes of these disorders. Examples from clinical practice are presented for the discussion os such causes and mechanisms. A classification of the causes of metabolic heart deficiency and its outcomes is proposed.
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PMID:[Pathogenesis and classification of ischemic heart disease]. 68

In the open-chested dog, coronary flow reduction results in a decrese of regional myocardial temperature (T). We assessed the contribution of T decrease to changes in refractoriness and conduction delay attributed to ischemia. The independent effect of regional hypothermia on effective refractory period (ERP) was a linear function of the temperature (ERP = -b T +a) with a -r = 0.97 0.02 in 11 dogs. The effect on conduction time of a ventricular premature beat was a linear function of the dog T at both endocardium (-r = 0.95 +/- 0.02) and epicardium (-r = 0.96 +/- 0.01). A 75% reduction in coronary flow resulted in a mean T decrease of 1.0 +/- 0.3 degrees C. The T decrease was sufficient to mask the effects of ischemia on shortening of the ERP. Furthermore, the conduction delay of ventricular premature beats during 75% coronary flow reduction could be accounted for by the decrease in T alone in five of seven dogs. We conclude that changes in refractoriness and conduction during acute coronary flow reduction in the open-chested dog are due to the composite effects of ischemia and the decrease in regional temperature. The open-chested model may have important limitations in understanding the electrophysiologic effects of acute coronary insufficiency. However, it may have important applications in defining the electrophysiologic environment at the time of coronary artery surgery.
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PMID:Electrophysiologic effects of partial coronary flow reduction in the exposed canine heart. Effects of ischemia and ischemic-induced regional hypothermia on refractoriness and conduction delay. 68 78

The possible relationship between the cardiac volume, as determined radiologically in the supine position in 119 patients with angiographically proven coronary artery disease, and the results of ergometry and balloon catheterization was investigated. There was no relationship between the heart size on the one side and the maximum exercise tolerance and the maximum cardiac output on the other, except for the fact, that these parameters tended to decrease with increasing heart size. This was especially true in patients with angina. The maximum cardiac output of patients with angina was always below the value of patients without angina but comparable heart size. Reduced cardiac output under exercise (exertional cardiac insufficiency) was present in 50% of patients with enlarged hearts but already in 22% of patients with heart volumes in the lower range of normal. The diastolic pulmonary artery pressure, determined under exercise, was the only parameter with a significant relationship to the heart size: The larger the heart size, the higher the diastolic pulmonary artery pressure. On the other hand: the diastolic pulmonary artery pressure at rest was abnormal with significant frequency only, when the heart was enlarged. Our data suggest, that the hemodynamics are determined by 2 factors: Myocardial scarring secondary to infarction and coronary insufficiency (ischemia). Of these two factors only the former influences cardiac size. Therefore, determination of the heart volume helps evaluating the respective role of these two factors in individual cases.
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PMID:[Heart size and left ventricular function in coronary artery disease: I. Heart size, exercise tolerance, cardiac output and filling pressures (author's transl)]. 92 89

Actively contracting segments, preoperatively akinetic, were found in 8 of 63 patients, evaluated 6-12 months after aortocoronary surgery by coronary angiography. Ejection fraction was increased from 48.1% (S.D. 15.7) to 68.3% (S.D. 11.4). These patients are characterized by two simple clinical parameters: 1. All patients had angina pectoris at rest or at minimum exercise except for one; 2. preoperatively, there was a discrepancy between severe ventriculographic and discreet Ecg findings. These findings prove that myocardial function in coronary artery disease can be impaired at rest by ischemia, without clinical signs of coronary insufficiency, such as angina pectoris. Even severe impairment of left ventricular function is no contraindication for coronary artery surgery, if caused by reversible myocardial ischemia.
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PMID:[Function improvement in levography following aortocoronary bypass]. 108 30


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