Torsades de Pointes electrical storm in children with KCNH2 mutations

Area of Science:

• Cardiology
• Genetics
• Pediatrics

Background:

• Congenital long QT syndrome (LQTS) is a genetic disorder causing dangerous heart arrhythmias, particularly in children.
• Misdiagnosis of LQTS as epilepsy can delay critical treatment, leading to severe cardiac events like Torsades de Pointes (TdP) and electrical storm (ES).

Purpose of the Study:

• To report two pediatric cases of LQTS misdiagnosed as epilepsy.
• To identify genetic mutations associated with these cases and highlight risk factors for cardiac electrical storm (ES).
• To emphasize the importance of cardiovascular evaluation in children with refractory epilepsy.

Main Methods:

• Whole exome sequencing (WES) was used to identify genetic mutations.
• Clinical data, including ECG findings (QT interval, T-wave patterns), were analyzed.
• Patient histories of misdiagnosis and cardiac events were reviewed.

Main Results:

• Two children, a 6-year-old boy and a 13-year-old girl, were found to have distinct KCNH2 mutations (c.1841 C>T and c.1838 C>T).
• Both patients exhibited significantly prolonged QT intervals and inverted T-wave patterns in specific ECG leads.
• These findings underscore KCNH2 mutations, QT prolongation, and T-wave inversion as key risk factors for ES in LQTS.

Conclusions:

• Patients with epilepsy, especially refractory cases with atypical features, require thorough cardiovascular assessment.
• Early identification of KCNH2 mutations and associated ECG abnormalities is crucial for preventing life-threatening arrhythmias.
• Treatment for LQTS with ES may involve Nadolol, left cardiac sympathetic denervation, and potentially an implantable cardioverter-defibrillator (ICD).