Any epileptic seizure, through affecting the autonomous system, may result in cardiac arrhythmia. In turn, arrhythmia by producing hemodynamic disturbances in the cardiovascular system may lead to a loss of consciousness with convulsions due to a prolonged insufficient oxygen supply to the brain. Cases of sudden death are more frequent among those suffering from epilepsy than in the general population. The risk of sudden death is to a large extent due to cardiac arrhythmias of which bradycardia is the most dangerous although not the most frequent variety. The best protection against sudden death is the heart pacemaker grafting, supported by pharmacotherapy with antiepileptic drugs. The most useful techniques in the differential diagnosis of epilepsy, cardiac arrhythmia and their interrelations are simultaneous 24-hour ECG and EEG monitoring, as well as video EEG.