Dynamic Enigma: Exercise Induced Left Bundle Branch Block

EI-LBBB represents a rare phenomenon observed during electrocardiographic evaluation in response to exercise. We present an asymptomatic patient referred for cardiac fitness before tympanoplasty surgery. During the treadmill exercise test, the patient developed a left bundle branch block, which reverted spontaneously in the recovery phase. A coronary angiogram revealed double vessel disease involving the left anterior descending and left circumflex arteries. The occurrence of EI-LBBB during stress tests like the treadmill test (TMT) can be a direct marker of underlying ischemia and underlying coronary artery disease as seen in our case.