[Magnesium deficiency and magnesium substitution. Effect on ventricular cardiac arrhythmias of various etiology].

During recent years there has been an increasing but still controversial discussion on the antiarrhythmic effects and overall benefit of magnesium when directed to patients with various types of ventricular tachyarrhythmias. While magnesium is considered to be a simple, safe and cost-effective approach and many casuistic and empiric reports have indicated antiarrhythmic properties of magnesium in patients with suspected or manifest ventricular arrhythmias, controlled studies proving the antiarrhythmic and overall benefit and justifying a broader use of magnesium in treating various types of ventricular arrhythmias are missing or rare. At present, antiarrhythmic properties and clinical benefit of magnesium application has only been established in patients with torsade de pointes and digitalis-induced ventricular tachyarrhythmias. In perioperative patients at risk for ventricular tachyarrhythmias and in patients suffering from manifest heart failure, data may also indicate some antiarrhythmic properties of magnesium, however, in this case with a wide consensus that the prevention of magnesium deficit is more effective and preferred in most patients over the therapeutic application of magnesium. Another group of patients who may profit from such a therapeutic approach are patients with frequent ventricular arrhythmias and stable underlying heart disease, in whom a recently published double-blind, randomized study documented an antiarrhythmic effect of a 3 week treatment with potassium and magnesium. For all other types of ventricular tachyarrhythmias, the therapeutic use of magnesium can be considered as not harmful, but also as not proven to be effective.