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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exercise myocardial-thallium scintigraphy plays a fundamental role in the diagnosis of coronary artery disease. Once exercise is not always feasible, pharmacological stress became a possible alternative. The authors review the mechanism of action, administrations protocols, indications and side effects of the drugs used for this purpose: dipyridamole, adenosine and dobutamine. Dipyridamole causes coronary hyperemia by increasing the interstitial levels of endogenous adenosine. Perfusion defects result from the mismatch of coronary reserve in different coronary territories. The drug administration is classically performed with a 0.142 mg/kg/min dosage e.v. for 4 minutes, total of 0.56 mg/kg. It is possible to use a greater dose of 0.84 mg/kg e.v. for 10 minutes, increasing sensitivity without loss of specificity for diagnosis of coronary artery disease. Oral dipyridamole protocols with 300 and 400 mg were used with similar results for sensitivity and specificity. The oral protocol has the disadvantage of delayed onset and longer action. Including several dipyridamole studies, 87% was obtained for sensitivity and 84% for specificity, in the diagnosis of CAD. Dipyridamole scintigraphy has been applied to myocardial infarction risk stratification, cardiac risk evaluation of patients proposed to noncardiac surgery and therapeutic efficacy evaluation of reperfusion techniques (angioplasty and surgery). The secondary effects of dipyridamole are frequent, however mild and well tolerated. They occur in half the patients, the most frequent, facial flushing (2%), dizziness (5%), nausea (4%), vomiting (1%), headaches (11%) and chest pain (26%). Some important complications were reported although rare: myocardial infarction, ventricular fibrillation and bronchospasm.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Role of pharmacologic stimulation with myocardial perfusion scintigraphy in the evaluation of patients with ischemic cardiopathy]. 129 Jun 55

The purpose of this study was to evaluate the significance of increased Tl-201 uptake by the lungs after oral dipyridamole testing. In conjunction with myocardial perfusion scintigraphy, intravenous dipyridamole has been recently approved as an alternative to exercise for the evaluation of coronary artery disease in patients who cannot adequately exercise, and it will largely replace oral dipyridamole testing. This study contributes to the understanding of the significance of increased lung thallium uptake during pharmacologic stress testing. Oral dipyridamole, 400 mg, was administered to 192 patients undergoing Tl-201 imaging for clinical indications. Mild adverse effects occurred in 31% of patients (chest pain, nausea, headache, or flushing). Dipyridamole had minimal hemodynamic effects. The lung/heart thallium activity ratio was determined in 152 patients. These were subdivided into four groups according to the presence or absence of ischemia, transient myocardial perfusion defect, or scar as indicated by a fixed myocardial perfusion defect. In 61 patients without transient myocardial perfusion defect or fixed myocardial perfusion defect (group 1), the lung/heart thallium activity ratio was 0.39 +/- 0.01 (mean +/- SEM). In 31 patients without transient myocardial perfusion defect but with fixed myocardial perfusion defect (group 2), the lung/heart thallium activity ratio was higher, 0.44 +/- 0.02 (P less than 0.05). In 27 patients with transient myocardial perfusion defect but no fixed myocardial perfusion defect (group 3) and in 33 patients with both transient myocardial perfusion defect and fixed myocardial perfusion defect (group 4), the lung/heart thallium activity ratio was 0.51 +/- 0.03 and 0.52 +/- 0.03, respectively, both significantly higher than either group 1 or group 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Significance of increased Tl-201 uptake by the lungs in patients undergoing oral dipyridamole-thallium myocardial imaging. 161 45

The use of pharmacologic stress testing for detecting and assessing ischemic heart disease (IHD) is reviewed. Methods of diagnosing IHD are designed to emulate conditions that increase myocardial oxygen demand in order to identify areas of ischemia and atherosclerotic lesions and to evaluate their functional or anatomical importance. Diagnostic methods can be divided into functional assessment with stress testing and anatomical assessment with coronary angiography. Physical stressors, such as exercise or atrial pacing, or pharmacologic stressors, such as vasodilators or beta-adrenergic-receptor agonists, can be used in stress testing. Electrocardiography, thallium planar scintigraphy, echocardiography, and other techniques are used to evaluate the response to stress testing. Unlike exercise stress testing, pharmacologic testing does not require physical exertion. Adenosine, dipyridamole, and dobutamine are the principal agents used in pharmacologic stress testing. Adenosine and dipyridamole mediate coronary artery vasodilation. Adenosine, a direct agonist, has a rapid onset and short duration of action. Dipyridamole, the only agent with approved labeling for use in stress testing, inhibits adenosine indirectly. Dobutamine increases cardiac output and heart rate as well as promoting coronary artery vasodilation. Clinical trials show that all three drugs can be used safely and effectively in patients after acute myocardial infarction or before vascular surgery and in individuals with risk factors for or symptoms of IHD. The sensitivity and specificity of pharmacologic stress testing for detecting IHD are at least as high as those of exercise testing. Minor adverse effects, including chest pain, headache, and facial flushing, are common, but major adverse effects are rare. Pharmacologic stress testing can be used in patients who cannot undergo exercise testing and offers a noninvasive alternative to coronary angiography.
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PMID:Pharmacologic stress testing: experience with dipyridamole, adenosine, and dobutamine. 816 Jun 85