在非缺血性心肌病中，细胞外容积分数比左心室射血分数与左心室局部速度改变的相关性更强。
Extracellular volume fraction is more closely associated with altered regional left ventricular velocities than left ventricular ejection fraction in nonischemic cardiomyopathy.
作者信息
Collins Jeremy, Sommerville Cort, Magrath Patrick, Spottiswoode Bruce, Freed Benjamin H, Benzuly Keith H, Gordon Robert, Vidula Himabindu, Lee Dan C, Yancy Clyde, Carr James, Markl Michael
机构信息
From the Departments of Radiology (J. Collins, C.S., J. Carr, M.M.) and Biomedical Engineering (P.M., M.M.) and Division of Cardiology, Department of Medicine (B.H.F., K.H.B., R.G., H.V., D.C.L., C.Y.), Feinberg School of Medicine, Northwestern University, Chicago, IL; and Siemens Medical Solutions USA, Chicago, IL (B.S.).
出版信息
Circ Cardiovasc Imaging. 2014 Dec 31;8(1). doi: 10.1161/CIRCIMAGING.114.001998. Print 2015 Jan.
BACKGROUND
Nonischemic cardiomyopathy is a common cause of left ventricular (LV) dysfunction and myocardial fibrosis. The purpose of this study was to noninvasively evaluate changes in segmental LV extracellular volume (ECV) fraction, LV velocities, myocardial scar, and wall motion in nonischemic cardiomyopathy patients.
METHODS AND RESULTS
Cardiac MRI including pre- and postcontrast myocardial T1 mapping and velocity quantification (tissue phase mapping) of the LV (basal, midventricular, and apical short axis) was applied in 31 patients with nonischemic cardiomyopathy (50±18 years). Analysis based on the 16-segment American Heart Association model was used to evaluate the segmental distribution of ECV, peak systolic and diastolic myocardial velocities, scar determined by late gadolinium enhancement, and wall motion abnormalities. LV segments with scar or impaired wall motion were significantly associated with elevated ECV (rs =0.26; P<0.001) and reduced peak systolic radial velocities (r=-0.43; P<0.001). Regional myocardial velocities and ECV were similar for patients with reduced (n=12; ECV=0.28±0.06) and preserved left ventricular ejection fraction (n=19; ECV=0.30±0.09). Patients with preserved left ventricular ejection fraction showed significant relationships between increasing ECV and reduced systolic (r=-0.19; r=-0.30) and diastolic (r=0.34; r=0.26) radial and long-axis peak velocities (P<0.001). Even after excluding myocardial segments with late gadolinium enhancement, significant relationships between ECV and segmental LV velocities were maintained indicating the potential of elevated ECV to identify regional diffuse fibrosis not visible by late gadolinium enhancement, which was associated with impaired regional LV function.
CONCLUSIONS
Regionally elevated ECV negatively affected myocardial velocities. The association of elevated regional ECV with reduced myocardial velocities independent of left ventricular ejection fraction suggests a structure-function relationship between altered ECV and segmental myocardial function in nonischemic cardiomyopathy.
背景
非缺血性心肌病是左心室（LV）功能障碍和心肌纤维化的常见原因。本研究的目的是无创评估非缺血性心肌病患者节段性左心室细胞外容积（ECV）分数、左心室速度、心肌瘢痕和壁运动的变化。
方法与结果
对31例非缺血性心肌病患者（50±18岁）进行了心脏磁共振成像，包括对比剂增强前后的心肌T1映射和左心室（基底、心室中部和心尖短轴）的速度量化（组织相位映射）。基于16节段美国心脏协会模型的分析用于评估ECV、收缩期和舒张期心肌峰值速度、延迟钆增强确定的瘢痕以及壁运动异常的节段分布。有瘢痕或壁运动受损的左心室节段与ECV升高（rs = 0.26；P<0.001）和收缩期峰值径向速度降低（r = -0.43；P<0.001）显著相关。左心室射血分数降低（n = 12；ECV = 0.28±0.06）和保留（n = 19；ECV = 0.30±0.09）的患者区域心肌速度和ECV相似。左心室射血分数保留的患者显示，ECV增加与收缩期（r = -0.19；r = -0.30）和舒张期（r = 0.34；r = 0.26）径向和长轴峰值速度降低之间存在显著关系（P<0.001）。即使排除延迟钆增强的心肌节段后，ECV与节段性左心室速度之间仍保持显著关系，表明ECV升高有可能识别延迟钆增强不可见的区域弥漫性纤维化，这与局部左心室功能受损有关。
结论
局部ECV升高对心肌速度有负面影响。区域ECV升高与心肌速度降低之间的关联独立于左心室射血分数，提示在非缺血性心肌病中，ECV改变与节段性心肌功能之间存在结构-功能关系。
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