Peri-Operative Magnesium Infusion to Prevent Atrial Fibrillation Evaluated

Post‐operative atrial fibrillation (POAF) is commonly observed in patients post cardiacsurgery without a previous history of atrial fibrillation (AF) or other arrythmias. (1)Within this population, AF is considered to be multifactorial in origin (2) butassociated with significant postoperative complications including infection, bleedingreoperation, increased hospital length of stay (LOHS) and mortality. (3,4) Multipleinterventions have been tried before including anti‐arrhythmic drugs (amiodaron,verapamil, sotalol) and rate reducing agents like beta‐blockers. (5‐7) Althoughencouraging results have been found with different regimes, adaptation in clinicalpractice has been hampered by toxicity (amiodarone) and therapeutic index. Magnesium hasbeen identified as a potentially interesting compound with easy access and low toxicity;besides, hypomagnesemia has been observed frequently immediately after cardiac surgery.(8,9) Both reduction of abnormal activity of atrial myocardium and prolongation of theatrial refractory period caused by administration of magnesium may prevent AF. (10)Magnesium metabolism has identified that less then 1% of the total magnesium content isintravascular and serum levels don't always correlate with intracellular concentrations.(11) Hypomagnesaemia is associated with increased ventricular tachycardia and atrialfibrillation which is likely caused by a reduction in membrane triphosphate (ATP)activity. This results in reduced membrane stabilization due to a reduction inintracellular potassium compared to extracellular concentrations thus increasingelectrical excitability. (12) Also measuring the intracellular concentration is difficultand especially in a routine fashion as loading tests followed by 24 hour urine analysis(13) and energy‐dispersive X‐ray analysis are not available. (14) Administration ofmagnesium sulphate does however correlate to higher intracellular magnesium concentrationcompared to placebo. (14) Several studies in different populations have shown a reductionin arrhythmias post magnesium supplementation. (15) Previous studies suggest thatmagnesium administration after cardiac surgery is effective in reducing the incidence ofAF. (16) However, uncertainty remains regarding optimal dose/blood levels, duration andmethod of magnesium administration. (17) In a recent study using a protocol foradministration of magnesium aiming for blood levels between 1.5 and 2.0 mmol/L anabsolute reduction of POAF of 15.1% (OR 0.49, 95% CI 0.27‐0.92) was demonstrated. (18)Based on this study, we designed the POMPAE trial (Peri‐Operative Magnesium infusion toPrevent Atrial fibrillation Evaluated). The POMPAE trial is a double blinded randomizedclinical trial to investigate the efficacy of magnesium supplementation and the reductionof POAF.