Risk factors for symptoms in long QT syndrome patients in a single pediatric center.

Background: Long QT syndrome (LQTS) is a leading cause of sudden cardiac death due to arrhythmia in the pediatric population. This study aimed to determine risk factors for the presence of LQTS-related symptoms in a single pediatric center.

Methods: Subjects were 146 consecutive LQTS patients (M:F = 72:74) who visited our hospital between April 2005 and August 2012 and during the preceding 24 months. A total of 103 subjects were discovered by the school-based screening, 15 subjects visited because of their symptoms, and the others were 28 subjects. One subject died.

Results: Risk factors for the presence of symptoms after diagnosis were longer QTc values (P = 0.01), the presence of history of LQTS-related symptoms (P = 0.04), and longer follow-up periods (P = 0.03). Non-compliance with medicine was the sole risk factor for frequent symptoms after diagnosis (P = 0.02). In subjects discovered by the school-based screening, nine subjects (9%) had LQTS-related symptoms after diagnosis. Longer follow-up periods were the sole risk for the presence of symptoms (P = 0.04). The mean period until the presence of symptoms after diagnosis was 3.1 ± 2.7 years (0.1-7.1 years).

Conclusion: Good compliance with medicine is essential to prevent recurrent episodes. A new strategy is required to prevent subjects, including school-based screened subjects, from dropping out of hospital visits.