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Magnesium Therapy in Ventricular Arrhythmias
Author(s) -
KEREN ANDRE,
TZIVONI DAN
Publication year - 1990
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1990.tb02131.x
Subject(s) - medicine , digitalis , diuretic , myocardial infarction , afterdepolarization , cardiology , cardiotoxicity , digitalis toxicity , pharmacology , anesthesia , heart failure , toxicity , repolarization , electrophysiology
Magnesium (Mg) is the known activator of 300 enzymes which govern energy utilization, cell permeability, and ionic membrane currents in the cardiac conducting cells. This may explain the antiarrhythmic efficacy of Mg in specific clinical settings, despite its only modest electrophysiological effects. This review summarizes the effect of Mg administration in four clinical conditions: in digitalis toxicity; in drug‐induced torsade de pointes; in patients with chronic diuretic therapy; and in acute myocardial infarction. Mg effectively abolished ventricular tachyarrhythmias associated with digitalis intoxication. This effect of Mg is related to the activation of sodium‐potassium ATP‐ase, which is inhibited by digitalis. Drug‐induced torsade de pointes was promptly abolished by Mg sulfate in the clinical setting. Experimental studies showed that Mg suppresses the early after depolarizations and the triggered activity responsible for occurrence of the arrhythmia. In diuretic‐treated hypertensives, potassium depletion has been associated with increased ventricular ectopy and sudden death. Mg has been found to be an important adjuvant for intracellular repletion of potassium in these patients. Several randomized, double‐blind studies in patients with acute infarction showed that Mg administered on admission improved survival or reduced the incidence of complex ventricular arrhythmias. Thus, Mg should be employed as first‐line therapy in digitalis intoxication and drug‐related torsade de pointes, and should be considered an important adjuvant therapy in hypertensives treated with diuretics and patients with acute myocardial infarction.