text_1: There was a patient (50-year-old man) with left bundle branch block (questionably new or old) who had chest pain.  I set him up for a stress echocardiogram, but the cardiologist said he could not do the stress echocardiogram due to the left bundle branch block.  He wanted to do a pharmacologic stress echocardiogram (rather than exercise).  "Why is that?"
text_2: Why should you do a pharmacologic stress echocardiogram in a patient with left bundle branch block?