Congenital long QT syndrome (LQTS) is a potentially life-threatening inherited heart rhythm disorder. Neuropsychiatric disorders are described in adults, but outcomes in children remain unknown. We investigated neurodevelopmental and mental health outcomes and their risk factors in children with LQTS.

This is a cross-sectional multicenter study. Mean scores for neuropsychological assessment (Full-Scale IQ, verbal comprehension, visual-spatial reasoning, working memory, fluid reasoning and processing speed), executive function, and symptoms of anxiety and depression were compared to normative values. The proportions with scores at-risk ( i.e. , 1SD from the mean) were analyzed. Multivariate regression was applied to identify risk factors.

Twenty-three children with LQTS (mean age = 11 years, 3.5 mo; 70% male) were enrolled. Despite normal cognitive scores including IQ (98.4 ± 12.2, p = 0.55) and executive functions, verbal skills were lower than expected ( i.e. , Vocabulary, 8.9 ± 2.2, p = 0.02), with 26% of patients scoring at least 1SD below expected norms for verbal comprehension, and 31% for executive functioning. Anxiety and depression were frequent, particularly among females. Multivariable analyses showed that early age at LQTS diagnosis was related to higher cognitive risk (ORadj [95% CI] = 0.98 [0.95;1.00]) and that older age at assessment was linked to higher executive function risks (ORadj [95% CI] = 1.45 [0.99;2.12]). Finally, females were particularly vulnerable regarding mental health for both anxiety (54.7 ± 8.5 versus 44.7 ± 10.0, p = 0.04) and depression (55.8 ± 11.5 versus 41.9 ± 10.3, p = 0.04).

Pediatric LQTS is associated with specific cognitive vulnerabilities and higher rates of mental health symptoms. Neurodevelopmental care is critical in pediatric LQTS.