Cardiac Implications in Dravet Syndrome: Can Electrocardiogram and Echocardiography Detect Hidden Risks?

Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy associated with loss-of-function variants in the SCN1A gene. Although predominantly expressed in the central nervous system, SCN1A is also expressed in the heart, suggesting a potential link between neuronal and cardiac channelopathies. Additionally, DS carries a high risk of sudden unexpected death in epilepsy (SUDEP). This study investigates electrocardiographic (EKG) and echocardiographic findings in patients with DS to assess potential cardiac risks.

This prospective study recruited 34 patients with DS with confirmed SCN1A pathogenic variants during the 2024 family meeting of the Dravet Syndrome Foundation Spain. Participants underwent standard 12-lead EKG, high-lead EKG for Brugada pattern detection, and a standing test to evaluate QT interval response. When available, echocardiogram data were collected. QTc and P wave dispersion were calculated. To establish a basis for comparison, cases were matched with age- and sex-matched epileptic patients without DS.

No significant EKG abnormalities suggesting long QT syndrome or Brugada syndrome were detected. However, QT and P wave dispersion, previously reported as markers of autonomic dysfunction associated with arrhythmias and SUDEP risk, were elevated. Echocardiograms in 21 patients showed normal cardiac structure, even in those on fenfluramine.

Although no significant EKG or echocardiographic abnormalities were identified, elevated QTc and P wave dispersion, along with the elevated risk of SUDEP and past reports of arrhythmias, suggest the need for continued cardiac surveillance. Further studies are essential to explore the predictive value of QTc and P wave dispersion in assessing SUDEP and arrhythmia risk, and to identify other potential cardiac markers.