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

Concurrent viral infection and myocarditis presumably indicate viral myocarditis. The electrocardiographic and pathologic changes developing during acute infection may, however, result from changes not produced by the infection itself, eg, fever, tachycardia, ischemia, potassium depletion, vitamin deficiencies, drugs. This qualification should be remembered in the evaluation of all alleged virus myocarditis. Viral infection seems to prefer the very young. Its localization in the heart is favored by general or local hypoxia, perhaps thus explaining a predilection for the subendocardium. It may be influenced by the strain of the organism or by the hormonal or immunologic state of the host. Intrauterine infection of the fetus with rubella, mumps, and perhaps coxsackievirus can induce congenital cardiac defects. The role of virus infection in precipitating acute myocardial infarction deserves further study. The value of treatment, including steroids, nonsteroidal immunosuppressive agents, and "antiviral" agents is not yet established.
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PMID:Virus myocarditis: a critique of the literature from clinical, electrocardiographic, and pathologic standpoints. 46 41

Eleven autopsy cases (average of 71 years) with complete right bundle branch block were examined histologically with serial sectioning of the conduction system. The results were as follows: 1) moderate to severe reduction of conducting cells in the right bundle branch (RBB) by fibrous replacement in all 11 cases, 2) a preponderance of main lesions in the first portion of the RBB in cases with R configuration in leads V1 and V2, and in the second to the third portion without significant lesion of the Purkinje cell network in the right ventricle in cases with rsR', and RSR' configuration in these leads, 3) as to the etiology, 1 case was assumed to have had rheumatic myocarditis and an another case, 1 chronic ischemia. In cases in which the cause could not be clearly established, reduction of the conducting cells in the first portion of the RBB was thought to be due to fibrosis of the upper ventricular septum. Lesions in the second portion of the RBB may be due to mechanical strain effected by muscle crossing of the trabecula septomarginalis and RBB.
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PMID:Histopathological study on the conduction system of complete right bundle branch block with references to configuration of QRS complex. 52 45

Five term and two premature newborn infants were referred for respiratory distress and congestive heart failure, and were found to have electrocardiographic Q or ST-T abnormalities suggesting ischemia. Echocardiographic and/or hemodynamic assessment excluded anatomic heart disease in six infants. In three infants, moderate or severe hemodynamic impairment within 36 hours of age was suggested by these studies. Myocardial perfusion images in all patients showed very poor myocardial uptake of thallium 201, compatible with global myocardial ischemia. Infants of similar age with myocarditis, or with congenital heart disease and congestive failure, had normal myocardial uptake. Rapid clinical improvement occurred within three to seven days. Two to five months later, all infants were well. Two had persistent electrocardiographic abnormalities but repeat thallium 201 imaging in six demonstrated almost normal myocardial uptake. These data provide further evidence that perinatal respiratory distress may be associated with myocardial dysfunction and congestive heart failure in some infants without anatomic heart disease, and suggest that myocardial dysfunction in these infants is associated with global myocardial ischemia, most of which is transient. The timing and nature of the insult causing the ischemia are unclear.
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PMID:Transient myocardial ischemia of the newborn infant demonstrated by thallium myocardial imaging. 76 22

It is clear that cocaine has cardiotoxic effects. Acute doses of cocaine suppress myocardial contractility, reduce coronary caliber and coronary blood flow, induce electrical abnormalities in the heart, and in conscious preparations increase heart rate and blood pressure. These effects will decrease myocardial oxygen supply and may increase demand (if heart rate and blood pressure rise). Thus, myocardial ischemia and/or infarction may occur, the latter leading to large areas of confluent necrosis. Increased platelet aggregability may contribute to ischemia and/or infarction. Young patients who present with acute myocardial infarction, especially without other risk factors, should be questioned regarding use of cocaine. As recently pointed out by Cregler, cocaine is a new and sometimes unrecognized risk factor for heart disease. Acute depression of LV function by cocaine may lead to the presence of a transient cardiomyopathic presentation. Chronic cocaine use can lead to the above problems as well as to acceleration of atherosclerosis. Direct toxic effects on the myocardium have been suggested, including scattered foci of myocyte necrosis (and in some but not all studies, contraction band necrosis), myocarditis, and foci of myocyte fibrosis. These abnormalities may lead to cases of cardiomyopathy. Left ventricular hypertrophy associated with chronic cocaine recently has been described. Arrhythmias and sudden death may be observed in acute or chronic use of cocaine. Miscellaneous cardiovascular abnormalities include ruptured aorta and endocarditis. Most of the cardiac toxicity with cocaine can be traced to two basic mechanisms: one is its ability to block sodium channels, leading to a local anesthetic or membrane-stabilizing effect; the second is its ability to block reuptake of catecholamines in the presynaptic neurons in the central and peripheral nervous system, resulting in increased sympathetic output and increased catecholamines. Other potential mechanisms of cocaine cardiotoxicity include a possible direct calcium effect leading to contraction of vessels and contraction bands in myocytes, hypersensitivity, and increased platelet aggregation (which may be related to increased catecholamine). The correct therapy for cocaine cardiotoxicity is not known. Calcium blockers, alpha-blockers, nitrates, and thrombolytic therapy show some promise for acute toxicity. Beta-Blockade is controversial and may worsen coronary blood flow. In patients who develop cardiomyopathy, the usual therapy for this entity is appropriate.
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PMID:The effects of acute and chronic cocaine use on the heart. 134 9

Cocaine abuse may lead to serious cardiac complications, including myocardial ischemia and infarction, myocarditis, cardiomyopathy and arrhythmias. With concomitant use of alcohol and cocaine, cocaethylene is produced by hepatic transformation. Cocaethylene is now thought to be primarily responsible for the deaths that occur among cocaine abusers. Treatment of cardiovascular complications focuses on cocaine-induced ischemia, hypertension and arrhythmias. The use of thrombolytic agents in myocardial infarction remains controversial. Concurrent detoxification with bromocriptine and norepinephrine is recommended.
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PMID:Cardiovascular complications of cocaine abuse. 846 3

Cocaine use has increased in recent years, in part as a result of the increased availability of "crack," the inexpensive freebase form. Although it is used medicinally and initially was considered a relatively safe street drug, cocaine clearly has addictive potential as well as adverse health consequences even in low doses. Some of its most serious adverse effects involve the cardiovascular system. Understanding the cellular mechanisms of the action of cocaine on the heart allows insight into the pathophysiology of its adverse effects. Blockade of sodium channels accounts for cocaine's anesthetic effects and acts directly on myocytes to impair action potential generation and conduction, predisposing to dysrhythmias. Blockade of neurotransmitter reuptake has many deleterious effects, including dysrhythmogenesis via increased intracellular calcium, myocardial ischemia via vasospasm and increased myocardial oxygen demand, and contraction band necrosis also via increased intracellular calcium. In addition, alterations in platelet-endothelial cell function predispose to coronary artery thrombosis and ischemia. Alterations in immune function of natural killer cells may, among other effects, predispose to the development of myocarditis, the etiology of which is probably multifactoral. Finally, a direct toxic effect of cocaine on myocytes may, in some cases, produce heart muscle dysfunction. These multiple mechanisms of action combined with the deleterious effects of often-present adulterants give rise to an unpredictable, variable, and potentially life-threatening cardiovascular response to cocaine administration.
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PMID:Cocaine-induced heart disease: mechanisms and pathology. 167 Dec 28

With regard to cardiac findings in cocaine abuse, at autopsy the vast majority of patients dying with cocaine toxicity have either no pathologic change in the heart or only minimal changes that could not account for the patient's death. The second most frequent finding is underlying, mild-to-moderate coronary atherosclerosis, with or without coronary thrombosis. There may be acute or healed myocardial infarction or a sudden cardiac death without myocardial changes of ischemia. A high incidence of contraction band necrosis has been reported in the absence of coronary artery disease and may cause a sudden arrhythmic death. Myocarditis also has been described in a few cases as either lymphocytic or lymphocytic and eosinophilic infiltrate in the presence of myocyte necrosis. Usually, the foci are sparse and not always associated with contraction band necrosis. The underlying mechanisms are thought to be either direct effects of norepinephrine on myocytes or through vasospasm of resistance vessels and secondary myocardial ischemia. Cocaine rarely has been associated with aortic dissection, which is probably a result of cocaine's hypertensive effects.
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PMID:Cocaine-associated cardiovascular disease: clinical and pathological aspects. 174 14

Fab fragments of antibodies specific for cardiac myosin have been labeled with indium-111 and injected intravenously into animals and into patients with heart transplants. The antibodies, developed by Khaw, Haber, and co-workers, localize in cardiac myocytes that have been damaged irreversibly by ischemia, myocarditis, or the rejection process. After clearance of the labeled antibody from the cardiac blood pool, planar imaging or single photon emission computed tomography is performed. Scintigrams reveal the uptake of the labeled antimyosin in areas of myocardium undergoing transplant rejection. In animal studies, the degree of antimyosin uptake appears to correlate significantly with the degree of rejection assessed at necropsy. In patients, the correlation between scans and pathologic findings from endomyocardial biopsy is not as good, possibly because of sampling error in the endomyocardial biopsy technique. The scan results at 1 year correlate with either late complications (positive) or benign course (negative). Current limitations of the method include slow blood clearance, long half-life of indium-111, and hepatic uptake. Overcoming these limitations represents a direction for current research. It is possible that from these efforts a noninvasive approach to the diagnosis and evaluation of cardiac transplantation may evolve that will decrease the number of endomyocardial biopsies required to evaluate rejection. This would be particularly useful in infants and children.
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PMID:Antimyosin imaging in cardiac transplant rejection. 188 96

Endomyocardial biopsy (EMB) is a valuable diagnostic procedure for rejection surveillance in heart allograft recipients and is widely used for evaluation of native heart disease. However, the spectrum and incidence of diagnoses encountered on a heart failure/cardiac transplant service deserve clarification. Of 2300 consecutive EMBs performed during a 2.5-yr period, 79.9% had been performed for rejection surveillance in heart allograft recipients. Of these, 1281 (69.7%) were negative for rejection; 536 (29.1%) were positive (18.9% mild, 9.7% moderate, 0.5% severe); 21 (1.1%) were not interpretable due to insufficient samples. Endocardial lymphocytic infiltrates ("Quilty" effect) were present in 86 (4.7%), ischemia in 12 (0.7%), myocardial calcification in five (0.3%), foreign body giant cells in two (0.1%), valvular tissue in two (0.1%), and liver tissue in one (0.05%). Of the 20.1% of EMBs performed in patients with native heart disease, 298 (64.5%) were abnormal. A total of 239 (51.7%) had myocyte hypertrophy and/or fibrosis, while 37 (8.0%) had active or ongoing myocarditis, two of which were of the giant cell type. Other diagnoses included anthracycline cardiotoxicity in 11 (2.4%), amyloidosis in five (1.1%), hemochromatosis in two (0.4%), healed infarct in two (0.4%), scleroderma in one (0.2%), and foreign body granuloma in one (0.2%). A total of 159 (34.4%) samples had no diagnostic abnormalities; five (1.1%) were insufficient samples. As the number of EMBs performed grows, pathologists must develop expertise in the detection of morphological features pertaining to various cardiac conditions which may have similar clinical presentations.
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PMID:Pathological findings in 2300 consecutive endomyocardial biopsies. 192 75

The diagnostic yield of endomyocardial biopsies in patients with chronic congestive heart failure of non-ischaemic aetiology remains questionable and, therefore, the use of endomyocardial biopsies under such circumstances is at stake. The present report documents the correlation between the histologic interpretation of endomyocardial biopsies and the corresponding cardiac explants in 13 patients who underwent cardiac transplantation. The biopsy diagnoses in these patients varied from 'compatible with dilated cardiomyopathy' (n = 6) to 'non-conclusive' (n = 4), 'ischaemia' (n = 2) and 'borderline myocarditis' (n = 1). Correlation with the corresponding cardiac explants revealed hypertrophy of myocytes as the leading histologic feature in the majority of cases. Because of the non-specific histopathology of dilated cardiomyopathy, the discrepancy between biopsy diagnoses and the leading explant diagnosis is mostly a matter of semantics. Ischaemia was present at high incidence, but is considered a result of imparied myocardial perfusion rather than the prime mechanism of heart failure. In four cardiac explants myocarditis was encountered, while the corresponding biopsies showed no cellular inflammation. In two, the cellular infiltrates suggested an early state of repair. One heart contained an active and extensive lymphocytic myocarditis. The fourth case showed an eosinophilic myocarditis, most likely acquired after the biopsy was taken. These discrepancies almost certainly relate to the sampling error and the time interval between biopsy and onset of symptoms. The immediate diagnostic yield of the biopsy, in this particular subset of patients, was minimal, particularly with respect to the diagnosis 'myocarditis'. Nevertheless, biopsy diagnoses such as 'compatible with' and 'non-conclusive' do contribute to the final categorization and management of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Chronic non-ischaemic congestive heart disease and endomyocardial biopsies. Worth the extra? 204 56


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