Stress Test-Induced Left Bundle Branch Block.

Left bundle branch block (LBBB) is an uncommon complication of myocardial perfusion imaging using Regadenoson, a vasodilatory agent. The mechanism is poorly understood at this time but could be related to ongoing ischemia. The use of a Regadenoson with the subsequent occurrence of LBBB could be a predictor of coronary artery disease or conduction abnormalities and should be understood by the physician to diagnose and risk stratify patients undergoing myocardial perfusion imaging properly.