Clinical Significance of Acute Coronary Syndrome with Transient ST-Segment Elevation Significado clínico del síndrome coronario agudo con elevación transitoria del segmento ST

The electrocardiographic evidence of injury appears in the presence of evident diastolic depolarization due to an important reduction in blood supply or other non-ischemic causal factors. This in turn leads to a ‘‘defective’’ transmembrane action potential reflected upon the ECG tracing as an ST-segment deviation. When diastolic depolarization occurs at subendocardial level, an ST-segment descent appears on the ECG, while depolarization at subepicardial (or transmural) level gives rise to ST-segment elevation.1 In patients with acute coronary syndrome (ACS), the ST-segment elevation pattern is associated to rupture or fissuring of an unstable atheroma plaque, with acute thrombotic occlusion of an epicardial artery in a patient without previous important ischemia (ACS with ST-segment elevation [ACSSTE]). When occlusion is incomplete or distal flow is present thanks to collateral circulation, ST-segment elevation is not observed (ACS without ST-segment elevation [ACSWSTE]).1--4 The initial management of ACSSTE involves emergency aperture of permeation of the affected artery through pharmacological (thrombolysis) or mechanical means (percutaneous revascularization). In contrast,