Ventricular arrhythmia in hypertrophic cardiomyopathy (HCM) relates to adverse structural change and genetic status. Cardiovascular magnetic resonance (CMR)–guided electrocardiographic imaging (ECGI) noninvasively maps cardiac structural and electrophysiological (EP) properties. The purpose of this study was to establish whether in subclinical HCM (genotype [G]+ left ventricular hypertrophy [LVH]−), ECGI detects early EP abnormality, and in overt HCM, whether the EP substrate relates to genetic status (G+/G−LVH+) and structural phenotype. This was a prospective 211-participant CMR-ECGI multicenter study of 70 G+LVH−, 104 LVH+ (51 G+/53 G−), and 37 healthy volunteers (HVs). Local activation time (AT), corrected repolarization time, corrected activation-recovery interval, spatial gradients (G/G), and signal fractionation were derived from 1,000 epicardial sites per participant. Maximal wall thickness and scar burden were derived from CMR. A support vector machine was built to discriminate G+LVH− from HV and low-risk HCM from those with intermediate/high-risk score or nonsustained ventricular tachycardia. Compared with HV, subclinical HCM showed mean AT prolongation ( 0.008) even with normal 12-lead electrocardiograms (ECGs) ( 0.009), and repolarization was more spatially heterogenous (G: = 0.005) (23% had normal ECGs). Corrected activation-recovery interval was prolonged in overt vs subclinical HCM ( 0.001). Mean AT was associated with maximal wall thickness; spatial conduction heterogeneity (G) and fractionation were associated with scar (all 0.05), and G+LVH+ had more fractionation than G−LVH+ ( 0.002). The support vector machine discriminated subclinical HCM from HV (10-fold cross-validation accuracy 80% [95% CI: 73%-85%]) and identified patients at higher risk of sudden cardiac death (accuracy 82% [95% CI: 78%-86%]). In the absence of LVH or 12-lead ECG abnormalities, HCM sarcomere gene mutation carriers express an aberrant EP phenotype detected by ECGI. In overt HCM, abnormalities occur more severely with adverse structural change and positive genetic status.

中文翻译：

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磁共振成像引导心电图对亚临床和明显肥厚型心肌病的电生理特征

肥厚型心肌病（HCM）中的室性心律失常与不良结构变化和遗传状态有关。心血管磁共振（CMR）引导心电图成像（ECGI）无创地绘制心脏结构和电生理（EP）特性。本研究的目的是确定在亚临床 HCM（基因型 [G]+ 左心室肥厚 [LVH]−）中，ECGI 是否可以检测到早期 EP 异常，而在明显的 HCM 中，EP 底物是否与基因状态相关（G+/G −LVH+) 和结构表型。这是一项 211 名参与者的前瞻性 CMR-ECGI 多中心研究，其中包括 70 名 G+LVH−、104 名 LVH+（51 G+/53 G−）和 37 名健康志愿者 (HV)。局部激活时间 (AT)、校正复极时间、校正激活恢复间隔、空间梯度 (G/G) 和信号分割源自每个参与者的 1,000 个心外膜部位。最大壁厚和疤痕负荷源自 CMR。建立支持向量机来区分 G+LVH− 和 HV，以及区分低风险 HCM 和中/高风险评分或非持续性室性心动过速。与 HV 相比，即使 12 导联心电图 (ECG) 正常 (0.009)，亚临床 HCM 也显示平均 AT 延长 (0.008)，并且复极在空间上更加异质 (G: = 0.005)（23% 的心电图正常）。与亚临床 HCM 相比，纠正的激活-恢复间隔延长 (0.001)。平均 AT 与最大壁厚相关；空间传导异质性（G）和分割与疤痕相关（均为 0.05），且 G+LVH+ 的分割程度高于 G−LVH+（0.002）。支持向量机区分亚临床 HCM 和 HV（10 倍交叉验证准确度 80% [95% CI: 73%-85%]），并识别出心源性猝死风险较高的患者（准确度 82% [95% CI: 78%-86%]）。在没有 LVH 或 12 导联心电图异常的情况下，HCM 肌节基因突变携带者表达 ECGI 检测到的异常 EP 表型。在明显的 HCM 中，由于不良的结构变化和阳性的遗传状态，异常发生得更严重。