Cardiac Arrhythmias in Magnesium Deficiency

To clarify malignant arrhythmias in magnesium (Mg) deficiency, we used weanling rats in study 1 and an adult rats in study 2. In study 1, weanling rats were fed either an Mg-deficient diet or a control diet for approximately 2 weeks and then electroencephalogram (EEG) and electrocardiogram (ECG) were recorded during auditory stimulation until death. EEG changes were abrupt attenuation of EEG background activity at the onset of tonic convulsion and then spike-wave complex at the falling down stage in association with marked bradyarrhythmias. When flattening of EEG became after generalized seizures, death occurred within a few minutes but consistent ventricular tachyarrhythmias were not observed. NMDA receptor blockers given intraperitoneally prevented significantly seizure occurrence and sudden death. These results may suggest that sudden death in weanling Mg-deficient rats results from a neurologic trigger.