Abstract 15909: Co-administration of Magnesium and Serum Potassium Optimization Reduces Post Coronary Artery Bypass Graft Surgery Atrial Fibrillation Incidence
Background: Atrial Fibrillation (AF) is a frequent complication of Coronary Artery Bypass Grafting Surgery (CABGS). It’s associated with increased risk of stroke and hemodynamic deterioration. The pathophysiology of post-CABGS AF is not fully understood. It may involve increased catecholamines and electrolyte derangements including intracellular magnesium (Mg) depletion. The efficacy of Mg in reducing post CABGS AF varies. Optimal serum potassium (K) is cardioprotective and maintaining it requires adequate intracellular Mg. In this study we examined the hypothesis that combining an optimized serum K with Mg administration will be more effective in maintaining their serum levels and the impact on incidence of post CABGS AF more will be prominent.
Methods: In a double blinded placebo-controlled study, we examined the effects Mg (6 x 2 g doses), or optimized serum K (4.2 - 5.1 mmol/L) or both over 5 days vs. placebo on the incidence of post-CABGS AF in 200 patients undergoing isolated CABGS. Mg dose 1 was given the day before surgery, doses 2 & 3 on surgery day, doses 4-6 over the next 3 days. K optimization was initiated 1 day before surgery and continued 4 more days. ECG was continuously monitored and serum Mg/K frequently assessed.
Results: Mg and K administration significantly increased their serum levels during the study period without causing hypermagnesemia or hyperkalemia. Mg co-administration with K significantly lowered the needs to achieve optimal K levels compared to K administration alone. The incidence of post-CABGS AF in the four study groups was: 10/50 (20%) placebo, 7/50 (14%) optimized serum K, 5/50 (10%) Mg and 2/50 (4%) in the Mg plus optimized K group. Only the reduction in AF incidence in the Mg and optimized K group was statistically significant (p= 0.023). Mg and the combination Mg and K significantly reduced the length of hospital and ICU stay by 2.16 and 0.68 days respectively.
Conclusions: The findings of this study support the hypothesis as demonstrated by the combination's effectiveness in more efficiently attaining and maintaining optimal serum K levels and their safety and effectiveness in reducing post-CABGS AF incidence and the length of ICU stay. This approach may have potential as a cost-effective means of lowering post-CABG AF incidence.
- © 2012 by American Heart Association, Inc.