Emergency Medical Minute

Contributor: Travis Barlock MD Educational Pearls: What is the ST segment? The ST segment on an ECG represents the interval between the end of ventricular depolarization (QRS) and the beginning of ventricular repolarization (T-wave).  It should appear isoelectric (flat) in a normal ECG. What if the ST segment is elevated? This is evidence that there is an injury that goes all the way through the muscular wall of the heart (transmural) This is very concerning for a heart attack (STEMI) but can be occasionally caused by other pathology, such as pericarditis What if the ST segment is depressed? This is evidence that only the innermost part of the muscular wall of the heart is becoming ischemic This has a much broader differential and includes a partial occlusion of a coronary artery but also any other stress on the body that could cause a supply-and-demand mismatch between the oxygen the coronaries can deliver and the oxygen the heart needs This is called subendocardial ischemia What else sho