[Idiopathic long QT syndrome. An underdiagnosed disease]

Two eleven-year old boys were referred to the medical department, division of cardiology, Aust-Agder Central Hospital, because of reported attacks of syncope during physical exercise. Idiopathic prolongation of the QT-interval was diagnosed and their families were examined. A total of 25 patients with long QT-syndrome were identified. Eight patients had attacks of syncope, six patients had dizzy spells and five persons were asymptomatic. Nine cases of sudden and unexpected death were assumed retrospectively to be due to QT-prolongation. All patients with syncopes of unknown cause should be examined for QT-prolongation, and the study confirms the importance of examining all family members of patients with idiopathic long QT-syndrome.