Differential diagnosis of epilepsy and syncope may be difficult. Arrhythmias such as asystole, or ventricular fibrillation, may lead to cerebral hypoperfusion mimicking partial or secondary generalized tonic-clonic seizures. While performing an electroencephalogram (EEG) for epilepsy diagnosis, simultaneous electrocardiogram (ECG) recording may detect cardiac pathology. In this article, through 2 cases, who had cardiac asystole during the EEG, we demonstrate the importance of ECG during EEG. To rule out cardiac pathology in syncope cases, all necessary investigations must be done.