Background: Only a few studies were devoted to analysis of clinical, genetics and ECG features in toddlers with the LQTS and risk of life-threatening events (LTE).
Methods: Clinical and ECG features were examined in 136 pts with confirmed LQTS aged from 1-18 years (13.0±5.2). Group I included 43 pts (57% males) diagnosed at age 1-3 years with follow up duration from 1-16 years (4.8±4.2). Group II included 93 pts (56% males) diagnosed at age 3-12 years (6.0±3.1). Conventional risk factors were assessed at 1st clinical examination. LTEs (all pts were at full-dose of beta-blockers) were defined either arrhythmic syncope, aborted cardiac arrest, or ICD appropriate shock.
Results: Pts of group I have significantly higher prevalence of Jerwell-Lange-Nielsen syndrome (JLN), QTc>500 ms, T-wave alternans (AltT) and syncope (Table). They were predominantly diagnosed during family examination and ECG screening while nearly half pts of the older group were more frequently diagnosed due to syncope (p < 0.002). Within the groups, LTEs were negatively associated with age at diagnosis: OR=0.75 (0.61-0.93, p=0.01). Beta-blockers were significantly less effective in the older group.
Conclusions: In recent years, the results of ECG screening and examination of family members increasingly allow to recognize inherited LQTS among infants and very young children. The study confirms higher prevalence of risk factors among younger group. There is a need for longitudinal studies, which could permitting to follow up children with LQTS from early age until the onset of adulthood.