Changes in heart rate variability pre and postoperative coronary artery bypass grafting

Abstract

Introduction and objectives: Previous studies have shown that after coronary artery bypass grafting (CABG), heart rate variability (HRV) becomes decreased. The loss of the peripheral autonomic sympathetic and parasympathetic control in Sinoatrial Node in the form of an autonomic cardioneuropathy syndrome is the predictor of the pre and postoperative complications after CABG. The aim of this study was to establish the temporal pattern of change in the decrease of HRV observed after CABG. Methods: The study involved 119 consecutive patients who underwent the first CABG operation with sinus rhythm. All subjects underwent assessed with 24-hour Holter recordings 2 days preoperative and 7 days, 3 months, 6 months postoperative at Hanoi Heart Hospital from 6/2016 to 8/2018. Main results: All indicators of heart rate variability decreased to the lowest level after surgery 7 days, recovers to the preoperative values within three to six months of the procedure. The incidence of pre and postoperative low HRV varies from 28.6% (preop) to 51.8% (postop 7 days), 19.6% (postop 3 months) and 12.7% (postop 6 months). Conclusions: This study have showed that CABG surgery generally leads to significant reduction in HRV. HRV gradually recovers to the preoperative values within three to six months of the procedure.