Reversal of left bundle branch block-induced cardiomyopathy by His bundle pacing.

A 61-year-old woman was referred to our institution for evaluation of severe nonischemic dilated cardiomyopathy and left bundle branch block (LBBB). After permanent His bundle pacing, the LBBB was immediately corrected; however, the right bundle branch was injured during the procedure. Subsequent recovery of the right bundle branch block and normalization of heart function were observed during follow-up. This case indicates that LBBB might result in the development of nonischemic cardiomyopathy and emphasizes the necessity of a temporary pacemaker during His bundle pacing for patients with LBBB.