Abnormal electroencephalograms in patients with long QT syndrome.
BACKGROUND
The long QT syndrome (LQTS) is an inherited cardiac channelopathy associated with syncope and sudden cardiac death due to ventricular arrhythmias. It is most frequently caused by potassium channel mutations. Potassium channels are also expressed in brain tissue and play an important role in idiopathic epilepsies. Recent reports have indicated that related potassium channel mutations may coexpress as concomitant epilepsy and LQTS.


OBJECTIVE
The purpose of this study was to explore cerebral activity by means of EEG recordings in individuals with LQTS related to potassium channel mutations.


METHODS
Seventeen individuals with confirmed LQTS related to potassium channel mutations (11 LQT1 and 6 LQT2) were prospectively studied with 21-channel electroencephalography (EEG) LQTS -related symptoms, comorbidity, medication, and QTc (12-lead ECG) were recorded. Sixteen healthy individuals previously studied with EEG served as a control group. All EEGs were reviewed by two independent neurophysiologists.


RESULTS
EEG recordings were abnormal in 12 of 17 patients (71%) in the LQTS group, whereas abnormalities were present in only 2 of 16 healthy controls (13%; P <.01). In the LQTS group, all abnormal EEGs showed a combination of theta activity and sharp waves. Two patients showed additional delta activity. None of the patients had definite epileptic activity (spikes, spike waves).


CONCLUSIONS
Abnormal electrical cerebral activity was identified more frequently in subjects with LQTS secondary to a potassium channel mutation compared with healthy controls. This result indicates a possible link between cardiac and cerebral channelopathy.
Department of Cardiology, Oslo University Hospital-Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Electronic address: kristina.haugaa@rr-research.no.
Kristina H
KH
Haugaa
Tommy Tveit
TT
Vestervik
Stein
S
Andersson
Jan Peder
JP
Amlie
Ellen
E
Jørum
Leif
L
Gjerstad
Erik
E
Taubøll
D000328:Adult; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D004827:Epilepsy / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D055815:Young Adult
ECG; EEG; Electroencephalogram; Epilepsy; Ion channels; LQTS; Long QT syndrome; QTc; SUDEP; Ventricular arrhythmias; electrocardiogram; electroencephalography; heart rate-corrected QT interval; long QT syndrome; sudden unexplained death in epilepsy