Magnesium Supplementation in Cardiac Health

Acute Cardiac Conditions

The American Heart Association recommends intravenous magnesium sulfate for acute cardiac emergencies, such as torsades de pointes, with a dose of 1-2 g bolus (Class IIb, Level of Evidence C-LD) 2, 3
For cardiac arrest with documented hypomagnesemia, the American College of Cardiology suggests IV magnesium 1-2 g bolus IV push (Class I, LOE C) 1, 4
In cases of ventricular fibrillation/pulseless VT associated with acute MI, 8 mmol bolus followed by 2.5 mmol/h infusion of magnesium may be considered 5, 6
Routine magnesium administration during cardiac arrest is not recommended, showing no benefit for survival to hospital discharge (Class III: No Benefit; Level of Evidence C-LD) 2, 3

The American Heart Association does not firmly recommend routine oral magnesium supplementation in patients with normal magnesium levels, but it may be considered for patients with documented or suspected hypomagnesemia 1, 4

The American College of Cardiology recommends maintaining serum magnesium concentration above 1.3 mEq/L (normal range: 1.3-2.2 mEq/L) 1, 4
Hypomagnesemia is defined as <1.3 mEq/L, and therapeutic levels for arrhythmia control are 3-6 mg/100 mL (2.5-5 mEq/L) 1

The American Heart Association warns of potential adverse effects of magnesium overload, including bradycardia, cardiac arrhythmias, respiratory depression, and cardiorespiratory arrest 1
IV calcium should be immediately available to reverse magnesium toxicity 4