Magnesium in supraventricular and ventricular arrhythmias
The use of magnesium as an antiarrhythmic agent in ventricular and supraventricular arrhythmias is a matter of an increasing but still controversial discussion during recent years. With regard to the well established importance of magnesium in experimental studies for preserving electrical stability and function of myocardial cells and tissue, the use of magnesium for treating one or the other arrhythmia seems to be a valid concept. In addition, magnesium application represents a physiologic approach, and by this, is simple, cost-effective and safe for the patient. However, when one reviews the available data from controlled studies on the antiarrhythmic effects of magnesium, there are only a few types of cardiac arrhythmias, such as torsade de pointes, digitalis-induced ventricular arrhythmias and ventricular arrhythmias occurring in the presence of heart failure or during the perioperative state, in which the antiarrhythmic benefit of magnesium has been shown and/or established. Particularly in patients with one of these types of cardiac arrhythmias, however, it should be realized that preventing the patient from a magnesium deficit is the first, and the application of magnesium the second best strategy to keep the patient free from cardiac arrhythmias.
Zeitschrift fur Kardiologie (Germany), 1996; Source: www.mgwater.com
Effect of intravenous magnesium sulfate on cardiac arrhythmias in critically ill patients with low serum ionized magnesium
Magnesium effects cardiac function, although until the recent development of
a new ion selective electrode no method existed for measuring the physiologically
active form of magnesium, free ions (iMg2+), in the blood. We investigated the
antiarrhythmic effect of magnesium sulfate administered to critically ill patients
with cardiac arrhythmias and reduced iMg2+ as determined using the ion-selective
electrode. Eight patients with a low iMg2+ level (less than 0.40 mmol/L) were
given intravenous magnesium sulfate (group L). Magnesium sulfate was also administered
to patients with a normal iMg2+ level (more than 0.40 mmol/L) but who did not
respond to conventional antiarrhythmic drugs (group N). Intravenous magnesium
sulfate significantly increased the iMg2+ level in patients in group L from
0.35plus or minus0.06 mmol/L (mean plus or minus SD) to 0.54 plus or minus 0.09
mmol/L (p < 0.01), and had an antiarrhythmic effect in 7 of the 8 patients (88%).
However, in group N patients, intravenous magnesium sulfate had an antiarrhythmic
effect in only 1 of the 6 patients (17%) (p < 0.05 vs group L). These results suggest
that intravenous magnesium sulfate may be effective in the acute management of
cardiac arrhythmias in patients with a low serum iMg2+ level.
Japanese Circulation Journal (Japan), 1996; Source: www.mgwater.com