Magnesium has a scientifically supported role in the management of certain types of cardiac arrhythmias, including atrial fibrillation and palpitations. Magnesium is an essential mineral that plays a key part in cellular electrical activity, particularly in the heart. Low magnesium levels (hypomagnesemia) are associated with increased risk of arrhythmias. Clinical studies have shown that magnesium supplementation can be beneficial in specific circumstances, such as in the acute management of torsades de pointes (a specific type of ventricular tachycardia), and in the prevention of postoperative atrial fibrillation, particularly after cardiac surgery.

Randomized controlled trials and meta-analyses suggest that intravenous magnesium may reduce the incidence of atrial fibrillation after cardiac surgery, with a modest effect size. However, evidence for its routine use in non-surgical atrial fibrillation or palpitations is less robust. For individuals with magnesium deficiency, supplementation is clearly indicated and may help correct arrhythmias. For those with normal magnesium levels, benefit is less certain, though the safety profile of magnesium is generally favorable when used appropriately.

In summary, magnesium is used with scientific justification in specific arrhythmias and when deficiency is present, but its universal application for all heart palpitations or fibrillation lacks strong evidence. Clinical guidelines generally recommend checking and correcting magnesium in patients with arrhythmias, especially in acute or hospital settings.