Impact of Magnesium L-Lactate on Occurrence of Ventricular Arrhythmias in Patients with Implantable Cardioverter Defibrillators: A Randomized, Placebo-Controlled Trial

BACKGROUND: We evaluated the antiarrhythmic efficacy and quality of life (QoL) impact of oral magnesium Llactate on patients with an implantable cardioverter defibrillator (ICD). METHODS: This prospective, double-blind, placebo-controlled trial randomized 70 patients with an ICD to receive oral magnesium L-lactate 3 tablets twice daily (504mg elemental magnesium daily) or matching placebo for 12 months. Patients were seen at baseline, 12, 24, 36, and 52 weeks. The primary endpoints were the cumulative occurrence of ICD therapy [either shock or anti-tachycardia pacing (ATP)] or QoL between the groups. RESULTS: Among the 70 randomized patients with a mean ± SD follow-up of 6.4 ± 4.1 months, 10 patients in the placebo group and 8 in the magnesium group experienced either ICD shock or ATP [HR 0.84, 95% CI 0.33 to 2.12; p=0.706]. Without significant arrhythmia suppression, only minimal effects on QoL were seen. Eighty six percent of all patients had serum intracellular magnesium deficiency. CONCLUSION: In our underpowered trial, patients with ICDs had intracellular magnesium deficiency but oral magnesium Llactate only nonsignificantly reduced the occurrence of ICD therapies and had little impact on HrQoL.