Department of Radiology, Leiden University Medical Center, P.O. Box 9600, postal zone C2-S, 2300 RC, Leiden, The Netherlands.
Department of Cardiology, Leiden University Medical Center, P.O. Box 9600, postal zone C2-S, 2300 RC, Leiden, The Netherlands.
J Cardiovasc Magn Reson. 2019 May 16;21(1):28. doi: 10.1186/s12968-019-0536-5.
Impaired left ventricular (LV) contraction and relaxation may further promote adverse remodeling and may increase the risk of ventricular arrhythmia (VA) in ischemic cardiomyopathy. We aimed to examine the association of cardiovascular magnetic resonance (CMR)-derived circumferential strain parameters for LV regional systolic function, LV diastolic function and mechanical dispersion with the risk of VA in patients with prior myocardial infarction and primary prevention implantable cardioverter defibrillator (ICD).
Patients with an ischemic cardiomyopathy who underwent CMR prior to primary prevention ICD implantation, were retrospectively identified. LV segmental circumferential strain curves were extracted from short-axis cine CMR. For LV regional strain analysis, the extent of moderately and severely impaired strain (percentage of LV segments with strain between - 10% and - 5% and > - 5%, respectively) were calculated. LV diastolic function was quantified by the early and late diastolic strain rate. Mechanical dispersion was defined as the standard deviation in delay time between each strain curve and the patient-specific reference curve. Cox proportional hazard ratios (HR) (95%CI) were calculated to assess the association between LV strain parameters and appropriate ICD therapy.
A total of 121 patients (63 ± 11 years, 84% men, LV ejection fraction (LVEF) 27 ± 9%) were included. During a median (interquartile range) follow-up of 47 (27;69) months, 30 (25%) patients received appropriate ICD therapy. The late diastolic strain rate (HR 1.1 (1.0;1.2) per - 0.25 1/s, P = 0.043) and the extent of moderately impaired strain (HR 1.5 (1.0;2.2) per + 10%, P = 0.048) but not the extent of severely impaired strain (HR 0.9 (0.6;1.4) per + 10%, P = 0.685) were associated with appropriate ICD therapy, independent of LVEF, late gadolinium enhancement (LGE) scar border size and acute revascularization. Mechanical dispersion was not related to appropriate ICD therapy (HR 1.1 (0.8;1.6) per + 25 ms, P = 0.464).
In an ischemic cardiomyopathy population referred for primary prevention ICD implantation, the extent of moderately impaired strain and late diastolic strain rate were associated with the risk of appropriate ICD therapy, independent of LVEF, scar border size and acute revascularization. These findings suggest that disturbed LV contraction and relaxation may contribute to an increased risk of VA after myocardial infarction.
左心室（LV）收缩和舒张功能障碍可能进一步促进不良重构，并增加缺血性心肌病患者室性心律失常（VA）的风险。我们旨在研究心血管磁共振（CMR）衍生的 LV 局部收缩功能、LV 舒张功能和机械离散的圆周应变参数与先前心肌梗死和原发性预防植入式心脏复律除颤器（ICD）患者的 VA 风险之间的关联。
回顾性确定了在原发性预防 ICD 植入前接受 CMR 的缺血性心肌病患者。从短轴电影 CMR 中提取 LV 节段圆周应变曲线。对于 LV 节段应变分析，计算中度和重度应变受损的程度（应变介于-10%和-5%之间和> -5%的 LV 节段百分比）。通过早期和晚期舒张应变率来量化 LV 舒张功能。机械离散度定义为每个应变曲线与患者特定参考曲线之间延迟时间的标准偏差。计算 Cox 比例风险比（HR）（95%CI）以评估 LV 应变参数与适当 ICD 治疗之间的关联。
共纳入 121 例患者（63±11 岁，84%为男性，LV 射血分数（LVEF）为 27±9%）。在中位数（四分位距）47（27；69）个月的随访期间，30 例（25%）患者接受了适当的 ICD 治疗。晚期舒张应变率（每-0.25 1/s HR 1.1（1.0；1.2），P=0.043）和中度应变受损程度（每+10% HR 1.5（1.0；2.2），P=0.048）与适当的 ICD 治疗相关，但重度应变受损程度（每+10% HR 0.9（0.6；1.4），P=0.685）无关，独立于 LVEF、晚期钆增强（LGE）瘢痕边界大小和急性血运重建。机械离散度与适当的 ICD 治疗无关（每+25 ms HR 1.1（0.8；1.6），P=0.464）。
在因缺血性心肌病而接受原发性预防 ICD 植入的患者中，中度应变受损程度和晚期舒张应变率与适当 ICD 治疗的风险相关，独立于 LVEF、瘢痕边界大小和急性血运重建。这些发现表明，LV 收缩和舒张功能障碍可能导致心肌梗死后 VA 风险增加。
