Spontaneous remission of left bundle branch block immediately after denitrogenation with inhalation of 100% oxygen prior to anesthetic induction.

Complete left bundle branch blocks have focused our attention, primarily because they are a sign predictive of mortality and a predictor of coexisting cardiovascular disease. Left bundle branch block (LBBB) is usually permanent but may occur transiently or intermittently. Spontaneous remission of LBBB rarely occurs during anesthesia. We present two patients in whom chronic LBBB reverted to normal sinus rhythm shortly following denitrogenation with inhalation of 100% oxygen during induction of anesthesia.