Magnesium deficiency in adult rats promotes the induction of ventricular tachycardia by the administration of epinephrine

Abstract

The effects of magnesium deficiency on epinephrine-induced ventricular tachyarrhythmia were investigated in adult rats. Forty-two adult Wistar rats were fed a magnesium-deficient diet while 30 rats were fed a standard diet for 20 days. The plasma magnesium concentration was lower in the magnesium-deficient rats (0.22+/-0.01 mmol/l) than in the control rats (0.76+/-0.03 mmol/l, P < 0.001). Using a telemetry system, electrocardiograms and arterial blood pressure were recorded on a polygraph in an unrestrained condition. Epinephrine was infused intravenously starting at 5 microg/kg per minute. The QT interval was prolonged to 50+/-1 ms in the magnesium-deficient rats compared with 44+/-1 ms in the control rats (P < 0.001). Before the administration of epinephrine, no ventricular tachyarrhythmias or seizures were found in either the control or the magnesium-deficient rats. The incidence of epinephrine-induced sustained ventricular tachycardia (VT) was higher in the magnesium-deficient rats (86%) than in the control rats (43%, P < 0.01). However, this VT did not result in sudden death. Seizures always preceded death in both the magnesium-deficient and control rats while the arrhythmias observed immediately before death were mainly bradyarrhythmias. The present study in an adult rat magnesium-deficient model revealed that magnesium deficiency enhances the susceptibility to epinephrine-induced ventricular tachyarrhythmias.

Incidence and Risk Assessment of Cardiac Arrhythmias in Dogs with Respect to Age, Breed, Sex and Associated Biochemical Changes

“…Similarly the arrhythmias due to hypo or hypernatremia are rare in clinical conditions (GarciaPalmieri, 1962). The role of Mg ++ in production of arrhythmia is not clear though; the studies suggest that hypomagnesaemia may enhance the susceptibility for arrhythmia (Tomiyasu et al, 1998). However, magnesium proved to play a vital role in the management of atrial, junctional and ventricular arrhythmia (Ho, 2008).…”

The nerve-heart connection in the pro-oxidant response to Mg-deficiency

“…What role circulating catecholamines might have in MgD pathophysiology is still undetermined, although elevated catecholamine release could contribute to the enhanced response to stress seen in MgD [82]. Available studies suggest also that MgD enhances myocardial susceptibility to catecholamine-induced arrhythmias [83][84][85] and myocardial injury [36,86]. Furthermore, beta-adrenergic blockade therapy proved to be effective in reducing myocardial lesions secondary to severe MgD [38,40].…”

Magnesium Deficiency During Lactation as a Precipitant of Ventricular Tachyarrhythmias

“…Other studies have shown that magnesium deficiency enhances the susceptibility to epinephrine induced ventricular arrhythmias in an adult rat magnesium deficient model 5 and Mg 1 1 treatment significantly decreases the electrical requirement for defibrillation in dogs. 6 There is more controversy regarding the effectiveness of Mg 1 1 treatment to suppress arrhythmias in humans.…”