Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 25 cases (12 men, 13 women) of complete left bundle branch block (LBBB) were found among 1,400 consecutive autopsy in the aged. Their ages ranged from 70 to 86 years (average 78.9). ECG was analyzed as for the occurrence of LBBB and myocardial infarction (MI). Pathological examinations included observations of the conduction system by serial sections. They were divided into group A with MI and group B without MI. Duration of LBBB was 1 to 3 days in 4 cases, more than 1 month in 7, and more than 1 year in 14. From the temporal sequence of LBBB and MI in group A, cases were classified into (1) MI preceding LBBB in 5, (2) both coexistent in 5, and (3) LBBB preceding MI in 1. There were 8 cases of normal electrical axis, 17 left axis deviation, 7 first degree A-V block, and 2 atrial fibrillation. Various heart diseases were underlying in 21 cases, including hypertension, MI, mitral and aortic regurgitation, and primary myocardial disease, and there were 4 cases with no cardiac diseases. Cause of death was cardiac in 12; MI, congestive heart failure, and sudden death. Heart weight was 410 Gm on the average (240 to 550 Gm). MI was found in 11, with stenotic index of 12/15, while it was 9/15 in group B. Lesions of the conduction system were slight to moderate (1.5 to 2.4) except left bundle branch, which showed marked changes in posterior (4.9) and anterior (4.8) fascicles. Site of interruption of the left bundle branch was the junction between the branching portion of the A-V bundle and the left bundle branch (Junctional type) in 17, and peripheral portion of the left bundle branch about 10 mm or more below the junction in 8 (Peripheral type). In conclusion, 2/3 of cases of LBBB belonged to the junctional type and most of them were not related to MI, but to the lesions caused by mechanical injuries at the septal summit. One third of the cases were as peripheral type, which was mainly related to the various types of lesions including septal ischemia (necrosis and fibrosis).
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PMID:A clinicopathological study on 25 cases of complete left bundle branch block. 44 51

Sixty-five patients were studied with stress electrocardiography and thallium-20 1 relative myocardial perfusion scintigraphy. Results were correlated with selective coronary angiography. Scintigraphy was more sensitive (85 versus 67 percent), more specific (89 versus 63 percent) and significantly more accurate (87 versus 65 percent) than stress electrocardiography for the diagnosis of significant coronary arterial lesions in patients with isoelectric S-T segments at rest. Stress scintigraphy helped clarify the equivocal stress test due to left bundle branch block, left ventricular hypertrophy, drugs, hyperventilation and other conditions and was more accurate than the stress electrocardiogram (89 versus 53 percent) even in the presence of a depressed S-t segment at rest. Thallium-20 1 scintigraphy is a safe and simple noninvasive method for identifying abnormal myocardial perfusion, stress-induced ischemia and, indirectly, significant coronary arterial lesions.
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PMID:Thallium-20 1 myocardial perfusion scintigraphy for the clinical clarification of normal, abnormal and equivocal electrocardiographic stress tests. 62 4

Fractionated His bundle potentials were induced by ischemia or trauma in 30 anesthetized dogs, in vivo. Functional dissociation, i.e., alteration of the activation sequence of portions of these His bundle potentials was demonstrated in vivo as well as in 10 in vitro preparations of the His-Purkinje system. In vivo, plunge wire and electrode catheters were utilized to record from portions of the His bundle. During vagal-induced slowing of the heart rate, atrial pacing or His bundle pacing, His-Purkinje conduction as measured by the H-V interval was constant over a wide range of heart rates, 50-300/min. One or two hours after anterior septal artery ligation, His bundle damage manifested as split His bundle potentials (H, H'). Atrial pacing or proximal His bundle pacing induced H-H' delays with concomitant right or left bundle branch block patterns in ECG leads. However, distal His bundle pacing at comparable or even higher rates produced normal QRS complexes. In other cases, during atrial pacing or with progressive ischemia at a constant rate, H' progressively delayed during the H-V interval or even disappeared into the QRS complex with a concomitant occurrence of right or left bundle branch block. In vitro, a dissected septal preparation was studied containing the His bundle, proximal and distal right bundle and left bundle branches. Normal conduction throughout the His-Purkinje system was observed at pacing rates of 30-220/min. Punctate lesions, anatomically placed above the branching His bundle caused tachycardia-dependent, complete bundle branch blocked with concurrent temporal reversal of proximal and distal His bundle action potentials. These data suggest that ischemic or traumatic lesions in the His bundle may manifest on the electrocardiogram as bundle branch block patterns. From a clinical point of view, a critical site of lesion would markedly increase the liability for A-V blocked although the electrocardiogram alone would not indicate the actual site of lesion. Predestination of fiber tracts and alternative proposals to the pedestination theory are considered to explain QRS aberration due to exclusive His bundle lesions.
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PMID:The significance of dissociation of conduction in the canine His bundle. Electrophysiological studies in vivo and in vitro. 71 85

Noninvasive myocardial imaging with potassium-43 and rubidium-81 has been used successfully to identify areas of infarction and exercise-induced ischemia as regions of decreased radioactivity. The image defects observed are believed to be due to a decreased radionuclide uptake in regions of myocardial scar or to heterogeneous myocardial accumulation of tracer as a result of regional ischemia. Of 27 patients with left bundle branch block studied with noninvasive imaging at rest and during exercise, 25 manifested at rest reduced radioactivity in the region of the interventricular septum. This pattern is similar to that seen in patients with anteroseptal myocardial infarction. Sixteen of the 27 patients underwent diagnostic coronary arteriography and left ventriculography. Only five of these patients had evidence of either previous infarction or significant obstructive coronary artery disease as assessed with clinical or angiographic criteria, or both. Although the image defect was routinely demonstrated at rest in patients with left bundle branch block, this defect was generally normalized or less distinct with exercise in patients with no anatomic heart disease. In contrast, a larger, more distinct or new image defect with exercise correctly identified the presence of significant obstructive coronary artery disease in patients with left bundle branch block. In the clinical application of noninvasive myocardial imaging, these image defects observed at rest can lead to the false pasitive radionuclide interpretation of anteroseptal myocardial infarction.
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PMID:Noninvasive myocardial imaging with potassium-43 and rubidium-81 in patients with left bundle branch block. 97 Mar 29

An attempt has been made to demonstrate morphological equivalents of electrocardiographically determined conduction disturbances in the human heart. In 50% of our cases an authentic morphological change was found. In 25% the correlation remained doubtful, and in another 25% there was no connection. The highest coincidence was found in chronic left bundle branch block and in dissecting aneurysms causing hemopericardium. The correlation between function and morphology is very loose in patients who have undergone cardiac surgery. Etiology is discussed only marginally; ischemia is the predominant feature.
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PMID:[Morphological studies on the human heart conduction system]. 99 17

The prognosis of left bundle branch block is determined by associated cardiovascular disease. Exercise electrocardiography is not helpful in detecting ischemia in these patients. Exercise thallium-201 scintigraphy has been widely accepted for that purpose. The authors made an overview of several studies suggesting that exercise thallium-201 scintigraphy has low specificity regarding left anterior descending coronary artery disease. They also review the mechanisms of perfusion defects in patients with left bundle branch block without coronary artery disease. One important question to be clarified is weather small defects are unrelated to coronary artery disease. Finally the authors analyse a few methods to increase diagnostic accuracy of perfusion scintigraphy in left bundle branch block. First the employment of a new criterium that requires the apex to be abnormal to indicate left anterior descendent artery disease. Second Pharmacological Stress with Dipyridamole or Adenosine. Third imaging with Tc-99m-MIBI.
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PMID:[What is the value of myocardial perfusion studies with isotopes in patients with complete left bundle branch block?]. 129 Jun 46

Three hundred forty consecutive patients (mean age 69 +/- 9 years) were evaluated with adenosine tomographic thallium-201 scintigraphy for suspected coronary artery disease. Minor side effects occurred in 91% of patients. Out of 28 patients (8%) with potentially serious side effects, 28 had significant atrioventricular (AV) block (second-degree, 24 patients; third-degree, four patients; syncope occurred in two patients). Acute bronchospasm and severe refractory angina pectoris occurred in one patient each. All side effects were transient and without sequelae. One hundred twenty-one patients underwent coronary angiography within 9 days of adenosine thallium imaging. The predictive accuracies of adenosine thallium imaging for identifying and localizing ischemia to a specific coronary distribution were: left anterior descending = 88%, left circumflex = 84%, right coronary = 88%. The predictive accuracy of adenosine thallium imaging in patients with left bundle branch block was 91%, and was higher than the 71% predictive accuracy noted in 39 patients who underwent exercise thallium testing (p = 0.04). It is concluded that adenosine thallium-201 myocardial scintigraphy was (1) highly accurate for the detection and localization of significant coronary artery disease; (2) it was more accurate at detecting ischemia in patients with left bundle branch block than exercise thallium testing, and (3) subjective side effects were common and were of no diagnostic importance; transient AV block occurred occasionally.
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PMID:Safety and diagnostic accuracy of adenosine thallium-201 scintigraphy in patients unable to exercise and those with left bundle branch block. 151 88

Extensive clinical research has demonstrated that the administration of indium-111 antimyosin antibodies is useful in the diagnosis of acute myocardial infarction. It is specific for acute myocardial necrosis, as opposed to ischemia or chronic infarction, and therefore identifies patients who have had an acute MI. It is most useful in patients whose ECGs are indeterminate for the diagnosis of acute myocardial infarction (eg, left bundle branch block or permanent pacemaker) or those with inconclusive CK or CK-MB. Diagnostic accuracy and safety of antimyosin imaging has been established. This new cardiac imaging agent holds great potential for future clinical use in the diagnosis and management of patients with known or suspected acute myocardial infarction. Presuming FDA approval, the critical care nurse will see antimyosin used as an innovative and viable alternative in the diagnosis of acute myocardial infarction. Critical care nurses need to continually increase their knowledge of technologic advances and clinical applications for their own professional development, as well as to provide accurate information to patients and their families. In the area of nuclear cardiology, this includes antimyosin imaging and other state-of-the-art imaging techniques such as magnetic resonance imaging, positron emission tomography and computed tomography.
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PMID:Indium-111 antimyosin antibody imaging: a promising new technique in the diagnosis of M.I. 152 57

The clinical development of taxol, a new antimicrotubule agent with a unique mechanism of cytotoxic action, has proceeded slowly due to serious hypersensitivity reactions (HSRs) and shortages in its supply. Nevertheless, large-scale phase II trials have been initiated as taxol has recently demonstrated impressive activity in advanced and cisplatin-refractory ovarian carcinoma. Furthermore, the incidence of HSRs has been reduced substantially with premedications and modifications in the administration schedule. However, various manifestations of potential cardiotoxicity have been observed in several patients who participated in four phase I and II studies of taxol. Asymptomatic bradycardia has occurred in a high proportion of patients, including 29% of ovarian cancer patients who were treated with maximally tolerated doses of taxol in a phase II study. More profound cardiac disturbances, including a range of atrioventricular conduction blocks, left bundle branch block, ventricular tachycardia (VT), and manifestations of cardiac ischemia, have been observed in seven of 140 patients (5%) who received taxol. Descriptions of these events are presented in this report to alert investigators to the potential for these adverse effects. Although these disturbances did not result in serious sequelae in most patients, investigators should continue to maintain a high degree of caution until precise risk factors, frequency, and clinical significance of these adverse cardiac effects are determined.
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PMID:Cardiac disturbances during the administration of taxol. 167 81

This study reports on the frequency and clinical significance of false-positive thallium studies in the interventricular septum in patients with left bundle branch block. In a 3-year period, 93 studies were performed on patients with complete left bundle branch block and sinus rhythm. Of these, 29 had a reversible septal defect; 17 are scored false-positive although only six had angiographic proof of normal left anterior descending coronary arteries. We conclude that thallium scintigraphy is indicated in patients with left bundle branch block, but caution is justified when reversible ischemia is demonstrated scintigraphically.
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PMID:False-positive Tl-201 SPECT studies in patients with left bundle branch block. Frequency and clinical significance. 161 54


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