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

Although coronary obstruction due to atherosclerosis is the most common cause of myocardial ischemia, a significant proportion of patients have myocardial ischemia in the absence of obstructive epicardial coronary artery disease (CAD). This finding is more common among women and alternative causes can mediate myocardial ischemia. Abnormalities in vascular structure, alterations in coronary vasomotion and dysfunction of the coronary microcirculation can all cause ischemia in the absence of obstructive CAD due to atherosclerosis. In this review, we provide an update on three alternative causes of myocardial ischemia: spontaneous coronary artery dissection (SCAD), vasospastic angina (VSA) and coronary microvascular dysfunction (CMVD). We review pathophysiology, clinical presentation, diagnosis, treatment and outcomes related to these important clinical entities. There is increasing interest in better defining this patient population with use of advanced imaging and testing tools. Despite the increased associated risk with future cardiac events, evidence-based treatments for these diagnoses remain under-studied and poorly defined. These alternative diagnoses should be kept in mind when evaluating women with myocardial ischemia without obstructive CAD due to atherosclerosis.
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PMID:Alternative causes of myocardial ischemia in women: An update on spontaneous coronary artery dissection, vasospastic angina and coronary microvascular dysfunction. 2842 64

Acetylcholine is widely used for a diagnostic provocation test of coronary spasm in patients with vasospastic angina. Acetylcholine usually induces coronary vasodilatation mediated by muscarinic receptor activation, but sometimes it evokes vasoconstriction of coronary arteries where the endothelium is damaged. Early repolarization syndrome is characterized by a J wave observed at the end of the QRS complex in a surface electrocardiogram. The J wave is attributed to the transmural voltage gradient at the early repolarization phase across the ventricular wall, which stems mainly from prominent transient outward current in the epicardium, but not in the endocardium. Transient high-dose application of acetylcholine into the epicardial coronary arteries provides a unique opportunity to augment net outward current, selectively, in the ventricular epicardium and unmask the J wave, irrespective of the cardiac ischemia based on coronary spasm. Acetylcholine augments cardiac membrane potassium conductance by enhancing acetylcholine-activated potassium current directly and by activating adenosine triphosphate-sensitive potassium current, in addition to the reduced sodium and calcium currents in the setting of severe ischemia due to vasospasm. However, the role of acetylcholine as an arrhythmogenic probe of the J wave induction in patients with suspected early repolarization syndrome warrants future prospective study.
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PMID:Intracoronary acetylcholine application as a possible probe inducing J waves in patients with early repolarization syndrome. 2902 44

Vasospastic angina results from temporary spasm of one or more coronary segments. Although prognosis of patients presenting with coronary vasospasm appears to be generally good, multivessel coronary vasospasm may increase the risk of life-threatening cardiac events. We present a case of a 51-year-old man admitted to the emergency room due to severe retrosternal pain, who was documented with multifocal coronary vasospasm. <Learning objective: The case described illustrates the importance of recognizing coronary vasospasm as a cause of reversible ischemia. Although vasospastic angina is associated with a favorable prognosis, multivessel involvement may increase the risk of life-threatening cardiac events.>.
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PMID:Acute coronary syndrome in a patient with multifocal coronary vasospasm. 3053 30

Prinzmetal angina, also known as vasospastic or variant angina, is defined as an intermittent focal coronary artery spasm often associated with an atherosclerotic lesion near the site of spasm. It is caused by a focal or diffuse spasm of the smooth layer of the arterial wall of an epicardial coronary artery. Acute infarctions or malignant arrhythmias may develop during spasm-induced ischemia. Evaluation includes observation of echocardiogram (EKG) for transient ST elevations during discomfort; diagnosis is confirmed with coronary angiography using provocative testing. We describe two cases of patients who presented for non-cardiac complaints, but had episodes of vasospastic angina during their hospitalization. Both underwent cardiac catheterization with differing results, demonstrating the importance of catheterization in patients who experience vasospastic angina.
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PMID:Vasospastic Angina and Role of Cardiac Catheterization. 3169 6

Patients with coronary microvascular dysfunction represent a widespread population, and despite the good prognosis, many of them, because of the angina symptoms, have a poor quality of life with strong limitations in their daily activities. In 2017, a new classification of microvascular dysfunction as well as a new definition of ischemia in patients with no obstructive coronary artery disease became available. This new definition improves Kemp's initial work, where cardiac X syndrome was initially described. This work summarizes the last updates on the subject with particular attention to the new classification of microvascular dysfunction, with particular attention to microvascular and vasospastic angina definition and diagnostic criteria.
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PMID:Ischemia in patients with no obstructive coronary artery disease: classification, diagnosis and treatment of coronary microvascular dysfunction. 3207 18


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