The ECG shown here is from a 58 year old male one day after an episode of poorly-defined and somewhat non-descript chest pain. It shows an atypical left bundle branch block pattern with a widened QRS complex (140 ms) and left axis deviation. Note also the ST depression in leads V5 and V6 and the inverted T waves in leads II, III, aVF, and V4-V6. While these ST segment and T wave changes are similar to those induced by ischemia, they could also be secondary to the conduction abnormality. Therefore, the tracing by itself could not be interpreted as indicating an acute or prior ischemia event.