<prompt> What is diagnostic of fresh myocardial infraction in ECGQT interval prolongationP mitraleST segment elevationST segment depression  <response>: diagnostic changes of acute or evolving ischemia are often masked by the presence of left bundle branch block, electronic ventricular pacemaker patterns, and Wolff- Parkinson-White preexcitation. However, clinicians continue to over- diagnose ischemia or infarction based on the presence of ST-segment elevations or depressions; T-wave inversions; tall, positive T waves; or Q waves not related to ischemic hea disease pseudoinfarct pat- terns. Ref Harrison 20th edition pg 1435 