Magnesium deficiency in adult rats promotes the induction of ventricular tachycardia by the administration of epinephrine.
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.
D000818:Animals; D002118:Calcium / Q000097:blood; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000187:drug effects; D004837:Epinephrine / Q000008:administration & dosage*; D006339:Heart Rate / Q000187:drug effects; D007275:Injections, Intravenous; D008274:Magnesium / Q000097:blood; D008275:Magnesium Deficiency / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D008297:Male; D051381:Rats; D013566:Sympathomimetics / Q000008:administration & dosage*; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology