Österberg Anna Wålinder, Min Sandar, Helle Emmi, Bulic Anica, Mital Seema
Crown Princess Victoria Children's Hospital, Linköping University Hospital, Linköping University, Linköping, Sweden; Division of Paediatrics, Department of Biomedical and Clinical Sciences, Medical Faculty, Linköping University, Linköping, Sweden (Present Address); Division of Cardiology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
Heart Rhythm. 2025 Jun 3. doi: 10.1016/j.hrthm.2025.05.059.
The clinical significance of QT prolongation in pediatric hypertrophic cardiomyopathy is unclear.
This study aimed to determine the prevalence, risk factors, and outcomes of QT prolongation in pediatric patients with hypertrophic cardiomyopathy.
Phenotype-positive, pediatric patients with primary hypertrophic cardiomyopathy (P-HCM) (n = 212) and RASopathy hypertrophic cardiomyopathy (n = 55) were included. Corrected JT (JTc) interval as a measure of QT prolongation was calculated at baseline and last follow-up. Factors associated with JTc duration were analyzed using a generalized estimating equation model. Association of JTc prolongation (JTc of > 370 ms) with risk of sudden cardiac death (SCD) events was analyzed. SCD events were defined as a composite of SCD, resuscitated SCD event, or appropriate shock from a primary prevention implantable cardioverter-defibrillator.
Notably, 24% of patients with P-HCM and 44% of patients with RASopathy hypertrophic cardiomyopathy had prolonged JTc (P = .004). JTc had only a modest correlation with the severity of left ventricular hypertrophy. In P-HCM, JTc prolongation was associated with SCD events on multivariable analysis (hazard ratio 2.9 [1.2-6.8], P = .016); 5-year SCD event-free survival from baseline evaluation was 86% in P-HCM. Including JTc as a risk factor improved the c-statistic for 5-year SCD risk prediction to 0.85 compared with 0.73 when using Precision Medicine in Cardiomyopathy risk scores alone and to 0.73 compared from 0.70 when using hypertrophic cardiomyopathy Risk-Kids scores alone.
JTc prolongation was independently associated with the risk of SCD events. Including JTc prolongation with SCD risk scores improved 5-year SCD risk prediction for P-HCM. This has implications for closer SCD risk monitoring in patients with P-HCM with JTc prolongation.
小儿肥厚型心肌病中QT间期延长的临床意义尚不清楚。
本研究旨在确定小儿肥厚型心肌病患者QT间期延长的患病率、危险因素及预后情况。
纳入表型阳性的原发性肥厚型心肌病（P-HCM）小儿患者（n = 212）和RAS病相关性肥厚型心肌病小儿患者（n = 55）。在基线和末次随访时计算校正JT（JTc）间期作为QT间期延长的指标。使用广义估计方程模型分析与JTc时长相关的因素。分析JTc延长（JTc>370 ms）与心源性猝死（SCD）事件风险的相关性。SCD事件定义为SCD、复苏的SCD事件或一级预防植入式心律转复除颤器的适当电击的复合事件。
值得注意的是，24%的P-HCM患者和44%的RAS病相关性肥厚型心肌病患者存在JTc延长（P = .004）。JTc与左心室肥厚的严重程度仅有适度相关性。在P-HCM中，多变量分析显示JTc延长与SCD事件相关（风险比2.9 [1.2 - 6.8]，P = .016）；从基线评估开始的5年无SCD事件生存率在P-HCM中为86%。将JTc作为危险因素纳入后，5年SCD风险预测的c统计量提高到0.85，而单独使用心肌病精准医学风险评分时为0.73，单独使用肥厚型心肌病Risk-Kids评分时为0.70，相比之下提高到0.73。
JTc延长与SCD事件风险独立相关。将JTc延长纳入SCD风险评分可改善P-HCM的5年SCD风险预测。这对于密切监测JTc延长的P-HCM患者的SCD风险具有重要意义。
