目的：研究肥厚型心肌病（hypertrophic cardiomyopathy, HCM）患者左心室舒张功能的心脏磁共振（cardiac magnetic resonance, CMR）心肌应变率参数与心源性猝死风险间的关系。方法：纳入160例HCM患者和50名健康志愿者的CMR扫描数据,收集应变率（strain rate, SR）参数,包括左心室舒张期峰值径向应变率（radial strain rate, RSR）、圆周应变率（circumferential strain rate, CSR）和长轴应变率（longitudinal strain rate, LSR）。根据2014版欧洲心脏病学会（European Society of Cardiology, ESC）指南和2020版美国心脏病学会/美国心脏病协会（American College of Cardiology/American Heart Association, ACC/AHA）指南分别对患者进行心源性猝死（sudden cardiac death, SCD）风险分级,使用独立样本t检验比较同一指南定义下高风险与低风险2组间的舒张功能差异,用单因素方差分析比较2种指南定义下不同风险亚组间的舒张功能差异,对指南中的主要风险因素与舒张功能CMR应变率参数间的相关性进行线性回归分析。结果：HCM患者左心室舒张期SR绝对值较对照组显著降低（RSR,-1.27±0.60比-2.40±0.59;CSR,0.71±0.24比1.22±0.25;LSR,0.52±0.24比0.89±0.20,P均<0.05）。根据2014版ESC指南分层,SCD高风险患者（27例）的舒张期RSR绝对值较低风险患者显著降低（P<0.05）,而两者间的CSR及LSR无差异;根据2020版ACC/AHA指南,SCD高风险患者（92例）舒张期的3个心肌SR指标绝对值均较低风险患者显著降低（P均<0.05）。对在2014 ESC中为低风险而在2020版ACC/AHA指南中为高风险的患者（65例）,其舒张期SR绝对值与2种指南均为高风险的患者相仿,但显著低于2种指南中均为低风险的患者。在主要SCD危险因素中,舒张期心肌SR绝对值在左室壁最大厚度≥30 mm和延迟强化/左室心肌质量比值≥15%时绝对值显著降低,左室舒张功能受损严重,左室壁最大厚度、延迟强化/左室心肌质量比值与舒张期心肌SR均有显著相关性（相关系数r为RSR: 0.48/0.35, CSR: -0.42/-0.31, LSR: -0.37/-0.16, P均<0.05）。结论：CMR左心室心肌SR在SCD高风险患者中显著降低,且与部分危险因素具有相关性,可作为辅助评估SCD风险的潜在生物学标志物。

Objective: To investigate the relationship between cardiac magnetic resonance(CMR) myocardial strain rate (SR) parameters of left ventricular diastolic function and the risk of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). Methods: A total of 160 HCM patients and 50 healthy control subjects who underwent CMR were enrolled. Radial strain rate (RSR), circumferential strain rate (CSR) and longitudinal strain rate(LSR) of left ventricle (LV) by CMR were measured. Risk stratification of SCD by 2014 European Society of Cardiology(ESC) and the 2020 American College of Cardiology/American Heart Association (ACC/AHA) guidelines were performed in patients respectively. Differences in diastolic function between high-risk and low-risk groups under the same guideline were compared with t test and one-way ANOVA was used to compare diastolic function between subgroups based on two guidelines. Linear regression analysis was performed to analyze the association of commonly risk factors in guidelines and diastolic function. Results: The absolute value of diastolic SR of LV in HCM was significantly decreased when compared with those of control subjects (RSR: -1.27 ± 0.60 vs -2.40 ± 0.59, CSR: 0.71 ± 0.24 vs 1.22 ± 0.25, LSR: 0.52 ± 0.24 vs 0.89 ± 0.20, all P<0.05). There were significant differences in diastolic RSR and CSR among HCM different phenotypes (all P<0.05). Patients with high SCD risk (n=27) according to the 2014 ESC guidelines had significantly lower diastolic RSR(P<0.05) than those with low SCD risk,while had no difference in CSR and LSR. Patients with high SCD risk (n=92) according to the 2020 ACC/AHA guidelines had significantly lower diastolic SR(RSR, CSR and LSR) (all P<0.05) than those with low SCD risk. The diastolic SR in patients with low SCD risk by 2014 ESC but high SCD risk by ACC/AHA were similar with patients at high risk based on both guidelines, and were significantly lower than that of patients at low risk in both guidelines. Among the four major risk factors, the absolute value of diastolic myocardial SR were significantly decreased in the group which had higher maximum left ventricular wall thickness (≥30 mm) and late gadolinium enhancement/left ventricle mass (≥15%), and LV diastolic function was severely impaired. Maximum left ventricular wall thickness and late gadolinium enhancement/left ventricle mass both had significant association with diastolic myocardial SR (correlation coefficient r were 0.48/0.35 in RSR, -0.42/-0.31 in CSR, -0.37/-0.16 in LSR, all P<0.05). Conclusions: SR of LV myocardial by CMR is significantly reduced in patients at high risk of SCD, and is correlated with some risk factors, which may serve as a new biomarker to assist the stratification of SCD risk.