Evaluation of the Role of Magnesium in Prevention of AF Post Cardiac Surgery

Atrial fibrillation (AF) is a common complication after cardiac surgery. Most studies suggest that the frequency ranges between 25-40%.

Several reports have indicated that postoperative AF is associated with an increased length of in-hospital stay (LOS) and consequently a greater utilization of health care resources.

Postoperative AF is also associated with higher rates of postoperative stroke, compromised cardiac function, and adverse effects from drugs used to prevent AF.

Despite many years of clinical experience and a large amount of investigation, prevention, and treatment of postoperative AF remain controversial. Many questions about the mechanisms and pathophysiology of AF remain unanswered, further contributing to the ambiguity in reaching consensus about appropriate treatment. Increasing patient age, valvular lesion and dilated atrial diameter is generally considered the greatest risk factor for postoperative AF and an aging population suggest that postoperative AF will continue to be a considerable problem in the future.

Magnesium (Mg) is an important intracellular ion with electrophysiological properties. It is essential for optimal metabolic cell function. Mg has proven effective for treating eclampsia, preeclampsia, and torsade's de pointes. Other therapeutic applications such as adjunctive therapy in acute asthma exacerbations, acute coronary syndromes, acute cerebral ischemia, and postoperative pain control are under discussion.

Some studies have shown that serum hypomagnesaemia is common after coronary artery bypass grafts (CABG) and other types of cardiac surgery. and is associated with postoperative morbidity such as atrial tachyarrhythmia.

Some clinical trials have assessed the efficacy of magnesium as a method of intervention to reduce the incidence of postoperative AF. Though this study is a negative one, other studies showed that magnesium sulfate has a body of evidence supporting its anti-arrhythmic effects and safety profile in AF prevention post-surgery.

A Phase III trial is necessary to further validate the efficacy and safety of magnesium sulfate because the previous studies, while promising, have shown varying results and may have methodological limitations such as small sample sizes, lack of rigorous randomization, or not accounting for long-term outcomes. This study aims to provide definitive evidence through a well-powered randomized controlled trial, using more rigorous study designs, thereby filling an important gap in clinical evidence.

The currently considered standard preventive care for AF after cardiac surgery includes the use of beta-blockers, amiodarone, or other antiarrhythmic drugs. These measures can then be contrasted with the magnesium sulfate intervention, highlighting its potential advantages and rationale for testing in this study.

A placebo group is used in this study since magnesium sulfate has shown some benefit in previous studies, the evidence is not definitive. Therefore, a placebo group is necessary to ensure that any observed effects of magnesium sulfate are due to the treatment and not other confounding factors.

Inclusion criteria

• • Elective open heart surgeries for coronary bypass grafting CABG,valvular lesion single or multiple replacement, combined CABG and valvular; with EF in preoperative echo is more than or equal 40%

Exclusion criteria

• Patients refuse to give informed consent.
• Emergency open heart surgeries
• Redo cases.
• Patients with preoperative serum creatinine level ≥ 1.8 mg/dL
• Patients with reduced intra/post operative urine output ≤ 1 ml/kg/hour.
• Patients with Chronic Kidney disease, Renal failure on dialysis
• Patients with rhythm defects as proved by ECG before administration of Mg/Placebo.