Division of Cardiology, Terrence Donnelly Heart Centre, St Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, ON, M5B 1W8, Canada.
Department of Medical Imaging, St. Michael's Hospital and Keenan Research Centre, Li Ka Shing Knowledge Institute, University of Toronto, Toronto, Canada.
J Cardiovasc Magn Reson. 2021 Oct 21;23(1):115. doi: 10.1186/s12968-021-00806-4.
Cardiovascular magnetic resonance (CMR) is increasingly used in the evaluation of patients who are potential candidates for implantable cardioverter-defibrillator (ICD) therapy to assess left ventricular (LV) ejection fraction (LVEF), myocardial fibrosis, and etiology of cardiomyopathy. It is unclear whether CMR-derived strain measurements are predictive of appropriate shocks and death among patients who receive an ICD. We evaluated the prognostic value of LV strain parameters on feature-tracking (FT) CMR in patients who underwent subsequent ICD implant for primary or secondary prevention of sudden cardiac death.
Consecutive patients from 2 Canadian tertiary care hospitals who underwent ICD implant and had a pre-implant CMR scan were included. Using FT-CMR, a single, blinded, reader measured LV global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain. Cox proportional hazards regression was performed to assess the associations between strain measurements and the primary composite endpoint of all-cause death or appropriate ICD shock that was independently ascertained.
Of 364 patients (mean 61 years, mean LVEF 32%), 64(17.6%) died and 118(32.4%) reached the primary endpoint over a median follow-up of 62 months. Univariate analyses showed significant associations between GLS, GCS, and GRS and appropriate ICD shocks or death (all p < 0.01). In multivariable Cox models incorporating LVEF, GLS remained an independent predictor of both the primary endpoint (HR 1.05 per 1% higher GLS, 95% CI 1.01-1.09, p = 0.010) and death alone (HR 1.06 per 1% higher GLS, 95% CI 1.02-1.11, p = 0.003). There was no significant interaction between GLS and indication for ICD implant, presence of ischemic heart disease or late gadolinium enhancement (all p > 0.30).
GLS by FT-CMR is an independent predictor of appropriate shocks or mortality in ICD patients, beyond conventional prognosticators including LVEF. Further study is needed to elucidate the role of LV strain analysis to refine risk stratification in routine assessment of ICD treatment benefit.
心血管磁共振（CMR）越来越多地用于评估可能接受植入式心脏复律除颤器（ICD）治疗的患者，以评估左心室（LV）射血分数（LVEF）、心肌纤维化和心肌病病因。目前尚不清楚 CMR 衍生的应变测量值是否可预测接受 ICD 治疗的患者的适当电击和死亡。我们评估了特征追踪（FT）CMR 中 LV 应变参数在因原发性或继发性预防心脏性猝死而接受随后 ICD 植入的患者中的预后价值。
连续纳入来自加拿大 2 家三级保健医院并接受 ICD 植入且植入前 CMR 扫描的患者。使用 FT-CMR，一位单独的、盲目的读者测量了 LV 整体纵向应变（GLS）、圆周应变（GCS）和径向应变（GRS）。Cox 比例风险回归用于评估应变测量值与全因死亡或经独立确定的适当 ICD 电击的主要复合终点之间的关联。
在 364 例患者（平均年龄 61 岁，平均 LVEF 为 32%）中，中位随访 62 个月时，64 例（17.6%）死亡，118 例（32.4%）达到主要终点。单变量分析显示 GLS、GCS 和 GRS 与适当 ICD 电击或死亡之间存在显著关联（均 p<0.01）。在包含 LVEF 的多变量 Cox 模型中，GLS 仍然是主要终点的独立预测因素（HR 为每增加 1% GLS 增加 1.05，95%CI 为 1.01-1.09，p=0.010）和单独死亡（HR 为每增加 1% GLS 增加 1.06，95%CI 为 1.02-1.11，p=0.003）。GLS 与 ICD 植入指征、缺血性心脏病或晚期钆增强之间无显著交互作用（均 p>0.30）。
FT-CMR 的 GLS 是 ICD 患者适当电击或死亡率的独立预测因素，超过了包括 LVEF 在内的传统预后因素。需要进一步研究以阐明 LV 应变分析在常规评估 ICD 治疗获益中的风险分层中的作用。
