Background: Channelopathies are conditions caused by dysfunctional ion channels, and includes both congenital long QT syndrome type 2 (LQT2) and idiopathic epilepsies. Essential potassium ion channels are coexpressed in the heart and the brain. Current theories suggest that patients with LQT2 may have a coexisting cerebral channelopathy. Purpose: The main objective was to describe the characteristics of syncopes and evaluate the electroencephalograms (EEG) of LQT2 patients. Methods: We included 14 patients (age: 45 (21-72) years, 12 women) with a genotyped diagnosis of LQT2. The patients underwent a standardized medical history with emphasis on the characteristics of previous loss of consciousness (LOC), a clinical neurological examination and a 1hr 64-channel awake EEG. Results: Of the 14 patients, 11 (79%) had experienced LOC, of which 6 (55%) had experienced motor activity and urine incontinence during previous LOC. In 1 of these 11 patients the LOC was considered a definite vasovagal syncope. Two patients (14%) had been diagnosed with epilepsy prior to the LQT2 diagnosis. Ten of 14 EEGs (71%) presented minor to moderate abnormalities. This includes 9 EEGs with increased frequency of intermittent theta activity and 1 EEG with paroxysmal generalized epileptiform activity. Conclusion: LOC in LQT2 patients was frequently associated with motor activity and urine incontinence and two patients were previously diagnosed with epilepsy. This underlines the difficulties in differentiating between cardiac syncopes and epileptic seizures clinically. Furthermore, minor to moderate changes were reported in the majority of the EEGs. Our results may indicate a possible co-expression of EEG abnormalities and arrhythmic heart disease in patients with potassium ion channel dysfunction.