Long-QT Syndrome

Abstract

After a 13-year-old girl dies suddenly while playing basketball, her family comes to the clinic for medical evaluation. Her parents' resting electrocardiograms (ECGs) are normal, but her 9-year-old sister's ECG has an abnormally long QT interval. The family history is notable for recurrent syncope in the maternal grandmother's female relatives. How should family members be evaluated and treated?