Genotype Predicts Outcomes in Fetuses and Neonates With Severe Congenital Long QT Syndrome.
OBJECTIVES: This study sought to determine the relationship between long QT syndrome (LQTS) subtype (LTQ1, LTQ2, LTQ3) and postnatal cardiac events (CEs). BACKGROUND: LQTS presenting with 2:1 atrioventricular block or torsades de pointes in the fetus and/or neonate has been associated with risk for major CEs, but overall outcomes and predictors remain unknown. METHODS: A retrospective study involving 25 international centers evaluated the course of fetuses/newborns diagnosed with congenital LQTS and either 2:1 atrioventricular block or torsades de pointes. The primary outcomes were age at first CE after dismissal from the newborn hospitalization and death and/or cardiac transplantation during follow-up. CE was defined as aborted cardiac arrest, appropriate shock from implantable cardioverter-defibrillator, or sudden cardiac death. RESULTS: A total of 84 fetuses and/or neonates were identified with LQTS (12 as LQT1, 35 as LQT2, 37 as LQT3). Median gestational age at delivery was 37 weeks (interquartile range: 35 to 39 weeks) and age at hospital discharge was 3 weeks (interquartile range: 2 to 5 weeks). Fetal demise occurred in 2 and pre-discharge death in 1. Over a median of 5.2 years, there were 1 LQT1, 3 LQT2, and 23 LQT3 CEs (13 aborted cardiac arrests, 5 sudden cardiac deaths, and 9 appropriate shocks). One patient with LQT1 and 11 patients with LQT3 died or received cardiac transplant during follow-up. The only multivariate predictor of post-discharge CEs was LQT3 status (LQT3 vs. LQT2: hazard ratio: 8.4; 95% confidence interval: 2.6 to 38.9; p < 0.001), and LQT3, relative to LQT2, genotype predicted death and/or cardiac transplant (p < 0.001). CONCLUSIONS: In this large multicenter study, fetuses and/or neonates with LQT3 but not those with LQT1 or LQT2 presenting with severe arrhythmias were at high risk of not only frequent, but lethal CEs.
Moore, JP; Gallotti, RG; Shannon, KM; Bos, JM; Sadeghi, E; Strasburger, JF; Wakai, RT; Horigome, H; Clur, S-A; Hill, AC; Shah, MJ; Behere, S; Sarquella-Brugada, G; Czosek, R; Etheridge, SP; Fischbach, P; Kannankeril, PJ; Motonaga, K; Landstrom, AP; Williams, M; Patel, A; Dagradi, F; Tan, RB; Stephenson, E; Krishna, MR; Miyake, CY; Lee, ME; Sanatani, S; Balaji, S; Young, M-L; Siddiqui, S; Schwartz, PJ; Shivkumar, K; Ackerman, MJ
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