Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002962 (angina)
 21,142 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alternans of the elevated ST segment (STEA) was found in 8 of 21 patients (38%) with Prinzmetal's variant angina. In addition to STEA, all eight patients had varying cardiac arrhythmias: multiple premature ventricular depolarizations in eight, ventricular tachycardia in five, and ventricular fibrillation in three. There was no consistent temporal relationship between the occurrence of STEA and the cardiac arrhythmias. Alternans occurred during periods when no arrhythmias were present. All eight patients underwent coronary angiography. Spontaneous coronary artery spasm was documented angiographically in three patients including two who had minimal or no coronary atherosclerotic disease. Six patients had severe, fixed, occlusive coronary artery disease. Possible mechanisms for STEA include: 1) failure of regions of myocardium to depolarize on alternate beats due to variation in conduction and refractoriness between ischemic and nonischemic zones of myocardium, and 2) electrical alternans of the transmembrane action potential during phase 2 and 3 (repolarization) caused by changes in the rate and extent of electrolyte transfer across cell membranes during ischemia. It is postulated that STEA is an electrocardiographic sign in the surface ECG of a dysequilibrium of refractory periods during ischemia and reflects an unstable electrical state of the myocardium.
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PMID:Alternans of the ST segment in Prinzmetal's angina. 83 98

Elevated electrical alternans of the elevated ST segment (STEA) was documented in a patient with non-Prinzmetal's or classical angina and severe atherosclerotic coronary artery disease. STEA was precipitated during graded exercise testing. The disappearance of this phenomenon after aortocoronary bypass surgery suggests that the coronary obstructions were the etiologic factors. These findings emphasize that the STEA may occur in myocardial ischemia caused by conditions other than Prinzmetal's angina.
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PMID:Electrical alternans of the ST segment in non-Prinzmetal's angina. 616 57