Magnesium and Heart Failure

Research examined the effect of intravenous magnesium sulfate in patients with congestive heart failure who also had arrhythmias [1]. Magnesium was administered intravenously to patients with congestive heart failure and serum magnesium levels below 2.0 mg/dL. All patients had at least 10 premature ventricular depolarizations per hour, as determined by a six-hour ambulatory electrocardiographic recording. Treatment with magnesium resulted in a significant reduction in premature ventricular depolarizations.

Low magnesium status appears to be common in this population. One study found that 19% of 199 patients with congestive heart failure had low serum magnesium levels [2]. Given that serum magnesium is tightly regulated and often fails to reflect intracellular status, the true prevalence of magnesium deficiency in these patients is likely higher.

Magnesium supplementation has also been associated with improved clinical outcomes. A double-blind, placebo-controlled study followed 79 patients with severe congestive heart failure for one year. Subjects were randomly assigned to receive either magnesium orotate or placebo. Survival was significantly higher in the magnesium group (75.7%) compared to the placebo group (51.6%). In addition, symptoms improved in 38.5% of patients receiving magnesium, while symptoms worsened in 56.3% of those receiving placebo [3].

Medication use may further contribute to magnesium depletion in heart failure patients. Research published in Magnesium Bulletin (1994;16(3):98–100) demonstrated that treatment with ACE inhibitors can deplete magnesium, raising the possibility that commonly prescribed cardiac medications may exacerbate an already prevalent deficiency.