Background: Post-operative atrial fibrillation (POAF) is associated with worse long-term cardiovascular outcomes.
Objectives: This study hypothesized that injecting calcium chloride (CaCl2) into the major atrial ganglionated plexi (GPs) during isolated coronary artery bypass grafting (CABG) can reduce the incidence of POAF by calcium-induced autonomic neurotoxicity.
Methods: This proof-of-concept study randomized 200 patients undergoing isolated, off-pump CABG to CaCl2 (n = 100) or sodium chloride (sham, n = 100) injection. Two milliliters of CaCl2 (5%) or sodium chloride (0.9%) was injected into the 4 major atrial GPs during CABG. All patients received 7-day continuous telemetry and Holter monitoring. The primary outcome was incidence of POAF (≥30 s) in 7 days. Secondary outcomes included length of hospitalization, POAF burden, average ventricular rate during AF, plasma level of inflammatory markers, and actionable antiarrhythmic therapy to treat POAF.
Results: The POAF incidence was reduced from 36% to 15% (hazard ratio: 0.366; 95% confidence interval: 0.211 to 0.635; p = 0.001). Length of hospitalization did not differ between the 2 groups. POAF burden (first 7 post-operative days), the use of amiodarone or esmolol, and the incidence of atrial couplets and nonsustained atrial tachyarrhythmias were significantly reduced in the CaCl2 group. Heart rate variability data showed a decrease in both high-frequency and low-frequency power in the CaCl2 group with a preserved low-frequency/high-frequency ratio, suggesting that the sympathetic/parasympathetic balance was not perturbed by CaCl2 injection.
Conclusions: Injection of CaCl2 into the 4 major atrial GPs reduced the POAF hazard by 63%. Inhibition of GP function by Ca-mediated neurotoxicity may underlie the therapeutic effect. (Calcium Autonomic Denervation Prevents Postoperative Atrial Fibrillation; ChiCTR1800019276).
Keywords: autonomic nervous system; calcium-mediated neurotoxicity; ganglionated plexi; post-operative atrial fibrillation.
Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.