title: Antiarrhythmic effects of increasing the daily intake of magnesium and potassium in patients with frequent ventricular arrhythmias. Magnesium in Cardiac Arrhythmias (MAGICA) Investigators.
abstract: OBJECTIVE
  This study sought to assess potential antiarrhythmic effects of an increase in the daily oral intake of magnesium and potassium in patients with frequent ventricular arrhythmias.
  
  
  BACKGROUND
  Magnesium and potassium contribute essentially to the electrical stability of the heart. Despite experimental and clinical evidence for the antiarrhythmic properties of the two minerals, controlled data in patients with stable ventricular arrhythmias are lacking.
  
  
  METHODS
  In a randomized, double-blind study, 232 patients with frequent ventricular arrhythmias (> 720 ventricular premature beats [VPBs]/24 h) confirmed at baseline and after 1 week of placebo therapy were subsequently treated over 3 weeks with either 6 mmol of magnesium/12 mmol of potassium-DL-hydrogenaspartate daily or placebo.
  
  
  RESULTS
  Compared with placebo pretreatment, active therapy resulted in a median reduction of VPBs by -17.4% (p = 0.001); the suppression rate was 2.4 times greater than that in patients randomized to 3 weeks of placebo therapy (-7.4%, p = 0.038). The likelihood of a > or = 60% (predefined criterion) or > or = 70% suppression rate (calculated from the placebo-controlled run-in period) was 1.7 (25% vs. 15%, p = 0.044) and 1.5 times greater in the active than in the placebo group (20% vs. 13%, p = 0.085), respectively. No effect of magnesium and potassium administration was observed on the incidence of repetitive and supraventricular arrhythmias and clinical symptoms of the patients.
  
  
  CONCLUSIONS
  To our knowledge, this study is the first to provide controlled data on the antiarrhythmic effect of oral administration of magnesium and potassium salts when directed to patients with frequent and stable ventricular tachyarrhythmias. A 50% increase in the recommended minimum daily dietary intake of the two minerals for 3 weeks results in a moderate but significant antiarrhythmic effect. However, with the given therapeutic regimen, repetitive tachyarrhythmias and patient symptoms remain unchanged.
authors.affiliation: Abteilung für Kardiologie, Innere Medizin III, Universitatsklinik Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Zehender
authors.forename: T
authors.initials: T
authors.lastname: Meinertz
authors.forename: T
authors.initials: T
authors.lastname: Faber
authors.forename: A
authors.initials: A
authors.lastname: Caspary
authors.forename: A
authors.initials: A
authors.lastname: Jeron
authors.forename: K
authors.initials: K
authors.lastname: Bremm
authors.forename: H
authors.initials: H
authors.lastname: Just
mesh_terms: D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D004311:Double-Blind Method; D005260:Female; D005527:Food, Fortified; D006321:Heart / Q000187:drug effects; D006801:Humans; D008274:Magnesium / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D011188:Potassium / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D008274:Magnesium; D011188:Potassium