rate dependent bundle branch block -transition from left bundle branch block to intraoperative normal sinus rhythm

A chronic hypertensive patient with electrocardiogram [ECG] showing left bundle branch block [LBBB] was given general anesthesia for right modified radical mastectomy. Her ECG reverted to normal sinus rhythm intermittently during peri-operative period. This intermittent ratedependent LBBB is a rare entity. Though hypertension is one significant co-morbid condition, the risk evalution of LBBB during anesthesia only on an ECG finding, is not justifiable. Rather patient should be investigated further for any cardiac risk