Intravenous infusion of potassium/magnesium solution for the treatment of postoperative atrial fibrillation after coronary artery bypass graft: a randomized, double-blinded, parallel controlled trial
Authors: Masoudkabir F , Mohammadi Z , Jameie M , Jalali A , Salarifar M , Bagheri J , Mansourian S , Ahmadi Tafti H 
Published: November 2023

Abstract

Background
Postoperative atrial fibrillation (POAF) afflicts 18% of patients following coronary artery bypass graft (CABG), increasing the risk of cerebrovascular events and all-cause mortality by more than three folds. POAF prevention and treatment have remained challenging. Correcting the hydroelectric imbalance before initiating antiarrhythmics (especially potassium and magnesium) is imperative for POAF prevention and management. Nevertheless, the implications of electrolyte infusion among patients with normal electrolyte levels have remained debatable.

Methods
This randomized, double-arm, double-blind, and parallel clinical trial assessed all patients who developed POAF following isolated CABG for eligibility. Patients were included according to inclusion and exclusion criteria (Figure 1). Permuted block stratified randomization (1:1 ratio) was adopted for randomization. The intervention group received oral metoprolol 47.5 mg combined with the infusion of 10cc potassium (15%) and 4cc magnesium sulfate (50%) diluted in 250cc half-saline serum during 60 minutes. The control group received oral metoprolol 47.5 mg (the standard treatment) and 250 cc half-saline infusion as the placebo. Hemodynamic status and cardiac rhythm were monitored continuously following treatment. Those whose POAF persisted for 6 hours after treatment were administered intravenous amiodarone according to guideline-adherent protocols. Primary outcomes were AF persistence (during the first six hours) and AF recurrence (during 48 hours after cardioversion). Intention-to-treat (ITT) analysis was used to assess the intervention effects. Secondary outcomes included time to cardioversion (in the first six hours), rate control achievement (rate&lt;110 beats/min achieved in the first three hours), and time to cardioversion after amiodarone administration.

Results
Seventy-two patients were enrolled in the study, with 38 (65.05±7.65 years, 73.7% men) in the intervention and 34 patients (65.24±7.35 years, 67.6% men) in the control group. The two groups were comparable regarding demographics, medical history, electrolyte levels, and intra- and postoperative characteristics. In the intervention and control groups, 16 (42.1%) and 16 (47.1%) patients had AF persistence, respectively (P-value:0.67). Respective figures for AF recurrence were 10 (26.3%) and 13 (38.2%) patients (P-value: 0.28). ITT analysis indicated that potassium/magnesium infusion did not significantly reduce AF persistence (relative-risk (RR): 0.89, 95% confidence interval (CI): 0.53-1.49) or AF recurrence (RR: 0.68, 95%CI: 0.35-1.36). Likewise, secondary outcomes did not differ significantly between the intervention and control groups (all Ps&gt;0.2) (Figure 1).

Conclusion
Among patients with normal electrolyte levels, potassium and magnesium infusion did not reduce the risk of AF persistence or recurrence compared to the standard treatment (beta blockers).Figure 1.Study design and findings