ImportanceThe ability to predict sudden cardiac death (SCD) in children and adolescents with hypertrophic cardiomyopathy (HCM) is currently inadequate. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) imaging is associated with SCD events in adults with HCM.ObjectiveTo examine the prognostic significance of LGE in patients with HCM who are younger than 21 years.Design, Setting, and ParticipantsThis multicenter, retrospective cohort study was conducted from April 8, 2015, to September 12, 2022, in patients with HCM who were younger than 21 years and had undergone CMR imaging across multiple sites in the US, Europe, and South America. Observers of CMR studies were masked toward outcomes and demographic characteristics.ExposureNatural history of HCM.Main Outcome and MeasuresThe primary outcome was SCD and surrogate events, including resuscitated cardiac arrest and appropriate discharges from an implantable defibrillator. Continuous and categorical data are expressed as mean (SD), median (IQR), or number (percentage), respectively. Survivor curves comparing patients with and without LGE were constructed by the Kaplan-Meier method, and likelihood of subsequent clinical events was further evaluated using univariate and multivariable Cox proportional hazards models.ResultsAmong 700 patients from 37 international centers, median (IQR) age was 14.8 (11.9-17.4) years, and 518 participants (74.0%) were male. During a median (IQR) [range] follow-up period of 1.9 (0.5-4.1) [0.1-14.8] years, 35 patients (5.0%) experienced SCD or equivalent events. LGE was present in 230 patients (32.9%), which constituted an mean (SD) burden of 5.9% (7.3%) of left ventricular myocardium. The LGE amount was higher in older patients and those with greater left ventricular mass and maximal wall thickness; patients with LGE had lower left ventricular ejection fractions and larger left atrial diameters. The presence and burden of LGE was associated with SCD, even after correcting for existing risk stratification tools. Patients with 10% or more LGE, relative to total myocardium, had a higher risk of SCD (unadjusted hazard ratio [HR], 2.19; 95% CI, 1.59-3.02; P < .001). Furthermore, the addition of LGE burden improved the performance of the HCM Risk-Kids score (before LGE addition: 0.66; 95% CI, 0.58-0.75; after LGE addition: 0.73; 95% CI, 0.66-0.81) and Precision Medicine in Cardiomyopathy score (before LGE addition: 0.68; 95% CI, 0.49-0.77; after LGE addition: 0.73; 95% CI, 0.64-0.82) SCD predictive models.Conclusions and RelevanceIn this retrospective cohort study, quantitative LGE was a risk factor for SCD in patients younger than 21 years with HCM and improved risk stratification.

中文翻译：

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年轻肥厚型心肌病患者的心肌瘢痕形成和心源性猝死


重要性目前预测肥厚型心肌病 （HCM） 儿童和青少年心源性猝死 （SCD） 的能力不足。心血管磁共振 （CMR） 成像的晚期钆增强 （LGE） 与成人 HCM 的 SCD 事件相关。目的探讨 LGE 对 21 岁以下 HCM 患者的预后意义。设计、设置和参与者这项多中心回顾性队列研究于 2015 年 4 月 8 日至 2022 年 9 月 12 日进行，对象是 21 岁以下且在美国、欧洲和南美洲的多个地点接受过 CMR 成像的 HCM 患者。CMR 研究的观察者对结果和人口统计学特征不知情。暴露HCM 的自然病程。主要结局和测量主要结局是 SCD 和替代事件，包括复苏的心脏骤停和植入式除颤器的适当放电。连续数据和分类数据分别表示为平均值 （SD）、中位数 （IQR） 或数字 （百分比）。通过 Kaplan-Meier 方法构建比较有和没有 LGE 患者的幸存者曲线，并使用单变量和多变量 Cox 比例风险模型进一步评估后续临床事件的可能性。结果来自37个国际中心的700例患者中，中位年龄（IQR）为14.8 （11.9-17.4）岁，其中男性518例（74.0%）。在 1.9 （0.5-4.1） [0.1-14.8] 年的中位 （IQR） [范围] 随访期间，35 名患者 （5.0%） 经历了 SCD 或等效事件。230 例患者 （32.9%） 存在 LGE，占左心室心肌的平均 （SD） 负担为 5.9% （7.3%）。 老年患者、左心室质量较大且壁厚最大的患者 LGE 量较高;LGE 患者的左心室射血分数较低，左心房直径较大。LGE 的存在和负担与 SCD 相关，即使在纠正了现有的风险分层工具之后也是如此。相对于总心肌，LGE 为 10% 或更高的患者发生 SCD 的风险更高（未调整的风险比 [HR]，2.19;95% CI，1.59-3.02;P < .001）。此外，增加 LGE 负担改善了 HCM Risk-Kids 评分（增加 LGE 前：0.66;95% CI，0.58-0.75;增加 LGE 后：0.73;95% CI，0.66-0.81）和心肌病精准医学评分（增加 LGE 前：0.68;95% CI，0.49-0.77;增加 LGE 后：0.73;95% CI，0.64-0.82）SCD 预测模型的性能。结论和相关性在这项回顾性队列研究中，定量 LGE 是 21 岁以下 HCM 患者发生 SCD 的危险因素，并改善了风险分层。