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

Starting from general assumptions on the clinical aspects of homeostasis and on the functional correlations lung-heart in physiological and pathological states, the difficulty to diagnose an individual pulmonary heart disease is stressed, as well as the necessity to differentiate it from the cases of coronary heart disease, when respiratory failure aggravates the latent cardiac ischemia and induces a global cardiac failure. The diagnosis criteria of the two distinct pathological pictures are established, emphasizing the importance of this differentiation for clinical practice and epidemiological research.
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PMID:Clinical aspects of cardio-respiratory homeostasis. 66 38

Ischemia is traditionally considered a cause of intermittent left bundle-branch block (LBBB), and some patients have right precordial T-wave inversion in the normally conducted beats. Clinical correlates of T-wave abnormalities were examined in 46 consecutive patients with intermittent LBBB. Thirty-three patients (72%) had at least transient right precordial (V-14) T-wave inversion suggesting ischemia in normally conducted beats. Seventeen such patients had no evidence of coronary heart disease, including five with normal arteriograms. During LBBB conduction, T-wave abnormalities (upright T-waves I, aVL, V5-6) were frequent (48%) and more common than among patients with permanent LBBB (p less than 0.005). The T-wave abnormalities during LBBB conduction occurred in the absence of coronary heart disease in nine patients, including two with normal arteriograms. Thus, right precordial T-wave inversion may result from recent LBBB itself, associated with T-wave abnormalities during the LBBB, in the absence of coronary artery disease.
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PMID:T-wave abnormalities of intermittent left bundle-branch block. 67 81

The electrocardiogram was monitored in 51 patients during fiberoptic bronchoscopic procedures and was compared to recordings made before premedication. Sixteen of the patients had heart disease. During the bronchoscopic procedure, the heart rate increased by 154 "/- 5 percent (+/- SE). The frequency of atrial ectopic beats was minimally increased, by an average 0.15 +/- 0.12 beats per minute (not significant). Ventricular ectopic beats became less frequent during the bronchoscopic procedure (-0.17 +/- 0.41 beats per minute; not significant), and there was no ventricular tachycardia. Frequent ventricular ectopic beats were seen mainly during bronchoscopic procedures in patients with coronary heart disease, but even in this group, ventricular ectopic beats became less frequent than at rest (-1.13 +/- 1.46 beats per minute; not significant). The nearly uniform sinus tachycardia that was observed was well tolerated but could predispose coronary patients to ischemia; however, the fiberoptic bronchoscopic procedure per se does not enhance prior ectopy.
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PMID:Arrhythmias from fiberoptic bronchoscopy. 67 41

The majority of deaths from coronary heart disease (CHD) occur before the victims receive medical attention. Chronic ventricular ectopic activity (VEA) is a well-established predictor of coronary mortality as well as sudden death. Evidence that chronic VEA is independently and causally related to sudden death, however, remains equivocal. Only more advanced grades of chronic VEA appear to be significant. Arrhythmias are clearly more common in patients with advanced coronary obstruction, and therefore prone to new ischemic events and their associated electrical disturbances. Autopsy studies are limited in their ability to identify an acute myocardial infarction in patients who die suddenly, but experience with the mobile coronary care units has reemphasized the role of acute ischemia. The prospective, randomized trial, including reliable assessment of VEA, offers the only definitive means of identifying the contribution of chronic VEA to the incidence of sudden death from CHD.
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PMID:Chronic ventricular ectopic activity and sudden death. 69 44

New-generation high-performance aircraft can produce levels of high sustained +Gz which may exceed man's physiological capacity to withstand such stress. The severity of this stress has led to concern that sudden incapacitation due to coronary heart disease could occur during sustained +Gz. This report presents results obtained from an apparently asymptomatic miniature swine with a severe stenosis of the left anterior descending branch of the left coronary artery. Regional coronary blood flow was measured with the radiolabeled microsphere technique using 9 +/- 0.8 microgram diameter microspheres. Under resting conditions, myocardial blood flow was marginally depressed in the areas distal to the coronary stenosis. When the animal was exposed to +7 Gz, a large portion of the heart became acutely ischemic due to a redistribution of coronary blood flow. After 49 x of exposure to +7 Gz, the animal developed fatal ventricular fibrillation. Histologically, the areas of myocardium supplied by the stenosed vessel showed a variety of ischemia-induced lesions, including infarction and patchy myocardial fibrosis.
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PMID:Regional coronary blood flow at rest and during high sustained +Gz in a miniature swine with subclinical, ischemic, coronary heart disease due to coronary stenosis. 71 74

A man with known coronary heart disease underwent treadmill exercise testing to determine his functional capacity. The test was negative for ischemia. Ventricular ectopic activity was noted at rest and in the recovery period. On the same day, while viewing a sporting event at home, the patient died suddenly. An ambulatory electrocardiographic recording documented ventricular fibrillations as the terminal mechanism. Ventricular ectopic activity and heart rate increased in the two hours prior to death, and ischemic ST-segment depression was noted at the time of the terminal arrhythmia. It is postulated that myocardial ischemia and catecholamine response lowered the threshold to ventricular fibrillation, thus facilitating the emergence of the fatal arrhythmia.
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PMID:Sudden death during ambulatory monitoring. Clinical and electrocardiographic correlations. Report of a case. 83 Feb 11

Six men, clinically diagnosed as having coronary heart disease, had postexertional ventricular fibrillation after maximal exercise testing. The common featureof their treadmill performance was "exertional hypotension," that is, a decrease or a limited increase (10 mm Hg) in systolic blood pressure. All six men were successfully resuscitated with electircal defibrillation. The major indication for electrocardiographic monitoring is the detection of major ventricular arrhythmias and changes in QRS-ST-T of acute myocardial infarction or severe ischemia, all of which are urgent indications for stopping exertion. Close supervision both during and after exercise testing is essential, particularly in men with severe coronary artery disease; monitoring of changes in systolic pressure during and shortly after exercise testing is as important as searching for changes in the -S-T segment.
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PMID:Exertional hypotension and postexertional ventricular fibrillation in stress testing. 86 Jun 95

The consequences of ischemia for the affected myocardium are highly variable. As a result, in chronic coronary heart disease there is little correlation between coronary arterial obstruction and myocardial dysfunction. Dysfunction can be permanent and related to replacement fibrosis or fixed disruption of the chain of events leading to effective contraction. Dysfunction can also be transient, as a direct consequence of acute myocardial ischemia. The mechanical lesions include generalized and localized myocardial dysfunction, mitral incompetence, and rarely, a left-to-right shunt through loss of integrity of the interventricular septum. Diagnosis per se is not difficult, but deciding on the true contribution of any given lesion to the overall symptoms and disability of the patient is. Therapy must be individually planned according to the total set of factors in each patient.
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PMID:Impaired myocardial contraction in the chronic stage. 97 42

The relationship of left ventricular relaxation and compliance to the mechanism of elevation of left ventricular enddiastolic pressure during ischemia was investigated. Isovolumic left ventricular contraction, relaxation, and diastolic pressure-volume relationship were studied in controls and in coronary heart disease patients. Patients were studied at similar heart rates during ergometric exercise and pacing. Diastolic aortic, left ventricular systolic, and incisural pressure were not significantly different in both groups at rest, pacing, and exercise. Left ventricular dP/dtmax increased during pacing and exercise in controls (P smaller than 0.05; P smaller than 0.01) and in coronary heart disease patients (P smaller than 0.01 for both); whereas left ventricular dP/dtmin increased only in controls during exercise (P smaller than 0.01). Peak measured velocity of shortening (Vpm) and of lengthening (Vpmr) of the contractile elements was calculated as (dP/dt)/p. Vpm and Vpmr increased in controls during both pacing (P smaller than 0.05; P smaller than 0.02) and exercise (P smaller than 0.01 for both). In coronary heart disease patients Vpm increased during pacing (P smaller than 0.01) while Vpmr did not differ significantly. During exercise both Vpm and Vpmr were unchanged. In patients with coronary heart disease paced to angina, diastolic logarithmic pressure-volume relationship showed change in slope (P smaller than 0.05) of the regression line and upward shift in intercept b (+0.25; P smaller than 0.001). Ischemia produced an impaired contractile state, delayed relaxation and generation of active diastolic tone in the intact ventricle.
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PMID:Left ventricular contraction and relaxation in patients with coronary heart disease. 113 9

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


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