Effectiveness of magnesium sulphate for prevention of atrial fibrillation after coronary artery bypass grafting

Abstract

Introduction and background: Postoperative atrial fibrillation is the most common complication that develops after cardiovascular surgery and is associated with adverse outcomes. Magnesium is an essential element in the body, which is required as a cofactor for over 300 enzymatic reactions and reduced levels of magnesium in the blood have been found related with an increased risk of AF, both in ambulatory setting and after cardiac surgeries. Our study was aimed at determining role of prophylactic magnesium sulphate in preventing postoperative AF in subjects undergoing CABG. This would eventually improve the overall outcome of patients undergoing cardiovascular surgeries. Objective: To compare efficacy of magnesium sulphate with control group for prevention of atrial fibrillation after coronary artery bypass surgery. Study duration and setting: 6 months from November 2019 to April 2020 at Department of Cardiac surgery, Cardiac Center PIMS Islamabad. Materials and methods: In the present study, enrolled a total of one hundred and twenty eight (n=128) patients of both gender between age 50-70 year who were planned for coronary artery bypass surgery. The trial was conducted in compliance with the international on Harmonization guidelines for good clinical practices and according to the declarations of Helsinki. All the patients were randomized by lottery method into group A, who were given intravenous injection of 200 mEq MgSO4 in 100 ml of normal saline/day for 03 days and group B, who were given intravenous injection of 100 ml of normal saline only for 03 days. All the patients had continuous cardiac monitoring performed for 72 hours to observe for occurrence of AF. Occurrence of postoperative AF was compared in both groups by applying chi-square test, a p-value of <0.05 was considered as significant. Results: There were 93.8% (n=60/64) males and 6.3% (n=4/64) females in group A and 90.6% (n=58/64) males and 9.4% (n=6/64) females in group B. Mean age of subjects in group A was 59.9 years ± 6.7 SD while it was 58.6 years ± 6.3 SD in group B. Mean baseline LVEF was 52.7% ± 8.1 SD in group A while it was 53.4% ± 5.9 SD in group B. Postoperative AF was observed in 12.5% (n=8/64) patients in group A while it was observed in 45.3% (n=29/64) patients in group B (p=0.001). When stratified for age and gender magnesium sulphate was found more effective in preventing postoperative AF in younger males (p=0.001). Conclusion: In the present study, postoperative AF was developed in significantly lesser number of patients who received prophylactic magnesium sulphate as compared to placebo group. Magnesium sulphate was found more effective in preventing postoperative AF among younger males. Significance of the study: AF was most commonly assessed post-operatively after cardiac surgery. Findings of our study suggest that Magnesium sulphate administration during CABG serves a prevelantive strategy for post-op AF.