Syncope is a common presentation to the ER with a lifetime incidence of >35%. Among cardiac causes, long QT syndrome (LQTS), characterized by QT prolongation and T-wave abnormalities, may commonly cause syncope but may also cause sudden cardiac death (SCD). LQTS is diagnosed by clinical presentation, family history, ECG with supporting cardiac evaluation and genetics. LQT2 patients are prone to auditory or emotional triggers and managed by lifestyle modification, beta-blockers and cardiac defibrillator.
We describe a healthy, athletic 12-year-old male admitted because of a syncope episode during sleep lasting several minutes. During the event, loud irregular breathing was appreciated followed by apnea, pallor, perioral cyanosis, rigidity and unresponsiveness. Upon recovery, he was tachycardic and lethargic for 15 minutes.
The Patient denies palpitations or exercise-related complaints but reports occasional dizziness before sleep. Family history is negative for epilepsy, arrhythmia or SCD. The cardiac and neurological examinations were normal as was laboratory testing. ECG showed prolonged corrected QT of 480msec. Sleep-Electroencephalogram (EEG) showed bilateral rolandic spikes. Echocardiography was normal. Ergometry and Holter-ECG with mild QT shortening during exercise and no arrhythmia. Beta-blockers were initiated, and athletic activity was withheld. Genetic testing revealed heterozygous KCNH2 mutation suggesting LQT2. Our patient was guided to minimize triggers, equipped with a defibrillator and allowed to participate in non-strenuous supervised sports.
Syncope requires a thorough evaluation. A cardiac etiology should not be misinterpreted as epilepsy in the presence of an abnormal EEG. Life-threatening arrhythmia in LQTS can mimic epilepsy and should not be missed.
