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)

To determine the incidence and significance of transient intraventricular conduction abnormalities occurring in association with myocardial ischemia during exercise testing, the recordings of 2,200 consecutive exercise tests were reviewed. Ten patients (0.45%) were identified as having both ischemia and intraventricular conduction abnormalities that developed transiently during the exercise test. In all 10 patients both typical angina and electrocardiographic evidence of ischemia developed during exercise. Among the 10 patients, left anterior hemiblock developed in 4, left posterior hemiblock in 2, right bundle branch block (RBBB) in 2, RBBB with left axis deviation in 1, and left anterior hemiblock progressing to complete left bundle branch block (LBBB) in 1. All 10 patients had cardiac catheterization showing significant obstruction of the left anterior descending (LAD) coronary artery at or before the origin of the first septal branch. Eight patients were treated surgically and 2 medically, all with relief of ischemic symptoms. Nine of the 10 had repeat exercise stress testing without angina or electrocardiographic evidence of ischemia and without recurrence of the transient intraventricular conduction disturbance. It is concluded that the development of transient intraventricular conduction abnormalities associated with myocardial ischemia during exercise testing is an uncommon occurrence (0.45%). When such conduction disturbances do develop, the existence of significant disease in the proximal portion of the LAD coronary artery is strongly suggested. With control of myocardial ischemia, the transient conduction disturbances during exercise are ameliorated.
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PMID:Ischemia-associated intraventricular conduction disturbances during exercise testing as a predictor of proximal left anterior descending coronary artery disease. 683 53

The differential diagnosis of VTs with LBBB morphology includes several well-defined syndromes. Although the majority of cases are attributable to acquired structural heart disease, including ischemia, prior infarction, or dilated cardiomyopathy, consideration of specific right ventricular processes is essential to proper evaluation and treatment. The approach to older patients or those with evidence for heart disease should begin with an evaluation for coronary artery disease and an assessment of biventricular function. Careful evaluation for bundle branch reentry should be performed during electrophysiological study, especially when there is underlying conduction system disease. Younger patients, those without overt heart disease, or those with isolated right ventricular disease, should receive a complete noninvasive evaluation of right and left ventricular size and function. An abnormal SAECG or identification of intracardiac late potentials suggest right ventricular dysplasia or cardiomyopathy, whereas responsiveness to adenosine and absence of detectable heart disease support the diagnosis of idiopathic right VT. Newer techniques, including MRI, show promise in identifying subtle right ventricular disease not otherwise detectable even in the setting of presumed idiopathic right VT. Following surgical repair of selected congenital heart defects, particularly tetralogy of Fallot, symptoms of recurrent palpitations, near syncope, syncope, or aborted sudden death may be attributable to recurrent VT, and diagnostic electrophysiological study should be considered for these patients. Finally, SVTs with LBBB morphology, particularly cases associated with right-sided or septal accessory pathways, should always be considered in this differential diagnosis.
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PMID:Ventricular tachycardias with left bundle branch block morphology. 773 82

Ischaemia has been the suggested mechanism of simultaneous left bundle branch block and chest pain on effort with normal coronary angiography. This hypothesis is very controversial and was not the mechanism in the two new cases of this syndrome. The two patients in whom effort pain and left bundle branch block were observed had been treated for paroxysmal supraventricular tachycardia with flecaine. Withdrawal of the anti-arrhtymic resulted in the disappearance of this syndrome. In these cases, the ischaemic mechanism could be excluded without ambiguity. The flecaine was the only cause of rate-related LBBB by slowing conduction in the left bundle branch with no effects on coronary reserve. It would seem that LBBB alone was the cause of chest pain. The absence of coronary artery disease was confirmed in the first patient and the diagnosis was highly improbable in the second.
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PMID:[Flecainide exercise induced left bundle branch with chest pain]. 781 Nov 45

Evaluation of operative risk in coronary artery disease patients before non-cardiac surgery is a frequent problem concerning 100,000 patients each year in France. Perioperative cardiac morbidity is the first cause of death associated with non-cardiac surgery, with infarction rates of the order of 1 to 2% in coronary disease patients. These infarcts are followed by the death of the patient in 25 to 50% of cases. Evaluation of anesthetic risk is based upon three points: type of surgery, clinical findings and results of investigations. The risk is markedly increased in emergency surgery, and in thoracic, intraperitoneal and above all vascular surgery, in particular when clamping of the aorta is involved. From a clinical standpoint, only a history of infarction and signs of peripheral cardiac failure are independent predictive factors of postoperative complications. Other criteria, e.g. age, uncontrolled hypertension, diabetes and above all the severity of angina are also associated with the onset of perioperative-complications. This evaluation can be refined by electrocardiogram (Q wave, ST segment anomalies, ventricular hypertrophy and left bundle branch block) and chest X-ray. The usefulness and predictive value of exercise tests, when possible in a preoperative context, are particularly precious when the result is positive at low work-load. Many publications have studied the value of myocardial isotope scan, in particular before vascular surgery. They report the excellent negative predictive value (95 to 100%) of this investigation. Furthermore, the predictive value of isotope scan is all the greater when the clinical risk factors seen in the patients and the number of areas with ischemia are taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Evaluation of the anesthetic risk in patients with coronary disease prior to non-cardiac surgery]. 812 64

In a patient with left bundle branch block exercise/rest SPECT using 99mTc-MIBI revealed exercise-induced ischemia. After exclusion of significant coronary artery stenosis by angiography early dilated cardiomyopathy was assumed. Scintigraphic findings using 99mTc-MIBI SPECT in patients with left bundle branch block are discussed.
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PMID:[False-positive findings in the 99mTc-MIBI SPECT of left bundle branch block and angiographic excluded coronary artery disease]. 813 87

A 37-year-old man with atypical chest pain and complete left bundle branch block showed a marked exercise induced septal defect on Tc-99m sestamibi stress testing. A repeat examination at rest the next day revealed complete reversal of the previous septal defect. Coronary angiography two days later showed a normal coronary artery system. Left bundle branch block has been associated with false-positive results of exercise (and more recently, dipyridamole) TI-201 examinations for septal ischemia. The case presented here may be the first reported example of a false positive Tc-99m sestamibi examination for septal ischemia in the presence of left bundle block.
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PMID:False-positive Tc-99m sestamibi SPECT in a patient with left bundle branch block. 842 18

A patient with an established LBBB suffered an acute septal myocardial infarction complicated with a 2:1 infranodal AV block. As the ventricular rate decreased, the preexisting LBBB disappeared, and, in its place, a RBBB bradycardia-dependent appeared. Later on, an escape rhythm emerged, and competition between the two rhythms evolved. These disturbances were short-lived, and took place in the first 24 h. It is postulated that an increase in the rate of diastolic depolarization, ischemia related, may cause, in the same area, impairment of conduction and increased automaticity accounting for the findings previously mentioned. In an acute septal infarction conduction disturbances usually are progressive; ischemia rarely may induce hypopolarization rise giving to complex, but reversible, phenomena.
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PMID:[Depressed conduction and increased automaticity in acute septal myocardial infarction]. 902 47

In choosing a pharmacologic agent for stress testing, the clinician must keep a number of things in mind, such as the diagnostic utility of the agent or in what situations a vasodilator or catecholamine will be the better choice. Although all stress agents produce similar diagnostic accuracy for CAD, vasodilators have a higher cardiac uptake than catecholamines, and the addition of exercise improves the heart/background contrast ratios. With regard to physiologic comparisons, exercise or dobutamine will double coronary perfusion compared with baseline flow, but vasodilators produce a threefold or fourfold increase. The clinician should also keep in mind that adenosine will produce the shortest duration of hyperemia, whereas dobutamine and arbutamine produce a longer effect, and dipyridamole has the longest duration. If electrophysiologic considerations are important, exercise and catecholamines accelerate sinoatrial and atrioventricular conduction and are not typically associated with heart block. In contrast, adenosine can cause transient atrioventricular block, but this rarely occurs with dipyridamole. Clinical factors also must be considered. Although clinical utility of pharmacologic stress agents in the first 24 hours after infarction has not been demonstrated, the prognostic utility of vasodilators in the subsequent 2- to 4-day period has been shown. With patients with pulmonary disease (asthma) who do not have wheezing, dipyridamole can be used, but dobutamine or arbutamine should be used in patients with recent respiratory failure or bronchospasm before testing. In patients with left bundle branch block, vasodilators are the preferred stress agents rather than synthetic catecholamines or dynamic exercise. In the first crossover thallium imaging, there was good overall agreement in segmental perfusion comparing adenosine and dipyridamole, but there was a tendency for adenosine to detect more ischemia. The clinical significance (if any) for these findings has yet to be determined.
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PMID:Comparison of pharmacologic stress agents. 898 83

Exercise-induced left bundle branch block is a relatively rare finding during exercise tolerance testing. A 36-year-old female with intermittent exercise-induced left bundle branch block, a MIBI study suggesting anterior ischemia and normal coronary arteries is reported. A review of the English and French language literature published from January 1985 to January 1996 is presented. Exercise-induced left bundle branch block has been reported in association with and without structural heart disease. Pooled mortality in the group with structural heart disease was 2.7% per year, and mortality was 0.17% per year when no structural heart disease was identified. Exercise-induced left bundle branch block has been reported to resolve with therapy. Noninvasive testing appears to have limited ability to detect or exclude coronary artery disease in this group. If a definitive cardiac diagnosis is required, strong consideration should be given to coronary angiography.
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PMID:Exercise-induced left bundle branch block: a case report of false positive MIBI imaging and review of the literature. 917 91

Left bundle branch block does not permit an easy diagnosis of coronary heart disease (CAD) with provocative non-invasive test such as bicycle or treadmill stress test. Echocardiography allows the identification of segmental wall motion by evaluating the movement as well the thickness of the segment examined. Due to its agonist action on beta 1 receptors, dobutamine causes an increase in myocardial oxygen consumption and, as a consequence, may reveal myocardial ischemia; on this basis, we evaluated the sensibility, specificity and diagnostic accuracy of dobutamine stress-echo in identifying CAD in patients with left bundle branch block, and compared results with those obtained from coronary catheterization. From February 1994 to September 1995 we observed 25 patients with left bundle branch block (17 men, 8 women, mean age 61.8 +/- 8.4 years, range 43.75), affected or suspected for CAD. All patients underwent dobutamine stress-echo test and coronary arteriography. We divided patients into two groups: the first one (11 patients) with acute myocardial infarction, the second one (14 patients) without previous ischemic episodes. Diagnostic accuracy, specificity and sensibility of the stress-echo test were evaluated in order to identify significant stenosis of the left anterior descending (LAD), right coronary (RCA), and/or circumflex artery (CA). Dobutamine stress echocardiography showed in all patients, from basal to peak, an increase in blood pressure (from 121.2 +/- 17.4 to 141.8 +/- 23.6 mmHg), heart rate (from 81.3 +/- 10.9 to 140.7 +/- 8.9 b/min), and double product (from 9861.1 +/- 1898.1 to 19976.6 +/- 3603.6). In 8 (32%) patients who had typical chest pain, 7 had CAD. In 17 (68%) patients without chest pain, 5 had CAD and 12 had normal coronary arteries. Dobutamine stress echocardiography showed segmental wall motion variations only in 13 patients; 12 of them had a significant stenosis of coronary artery relative to the ischemic area, the other 1 was a false positive. Coronary arteriography showed stenosis of LAD in 10 and of RCA and/or CA in 12 patients, in both groups dobutamine stress-echo test had 1 false negative. Dobutamine stress echocardiography showed high diagnostic value as a provocative non-invasive test for CAD in patients with left bundle branch block. In conclusion, or study shows that no statistical difference exists in identifying ischemia in identifying ischemia in the LAD territory compared to RCA and/or CA. Further investigations are need to confirm the higher diagnostic accuracy in patients with left bundle branch block and to establish whether lower specificity in patients with a previous myocardial infarction is due to the smaller number of patients or to methodology.
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PMID:[Stress echocardiography with dobutamine in the identification of coronary disease in patients with left bundle branch block]. 928 78


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