abnormal ST segment ST segment elevation 2026-05-04T17:51:39Z an upward deviation of the ST segment on an ECG, where the J-point is displaced above the isoelectric baseline MPheno.ontology ST elevation can signal urgent, transmural myocardial ischemia (STEMI). While associated with acute heart attacks, it can also be caused by benign conditions (early repolarization), pericarditis, or ventricular aneurysms. MP:0031732 elevated ST segment