Background:Cardiac remodeling, after a myocardial insult, often causes progression to heart failure. The relationship between alterations in left ventricular blood flow, including kinetic energy (KE), and remodeling is uncertain. We hypothesized that increasing derangements in left ventricular blood flow would relate to (1) conventional cardiac remodeling markers, (2) increased levels of biochemical remodeling markers, (3) altered cardiac energetics, and (4) worsening patient symptoms and functional capacity.MethodsThirty-four dilated cardiomyopathy patients, 30 ischemic cardiomyopathy patients, and 36 controls underwent magnetic resonance including 4-dimensional flow, BNP (brain-type natriuretic peptide) measurement, functional capacity assessment (6-minute walk test), and symptom quantification. A subgroup of dilated cardiomyopathy and control subjects underwent cardiac energetic assessment. Left ventricular flow was separated into 4 components: direct flow, retained inflow, delayed ejection flow, and residual volume. Average KE throughout the cardiac cycle was calculated.Results:Patients had reduced direct flow proportion and direct-flow average KE compared with controls (P<0.0001). The residual volume proportion and residual volume average KE were increased in patients (P<0.0001). Importantly, in a multiple linear regression model to predict the patient’s 6-minute walk test, the independent predictors were age (β=−0.3015; P=0.019) and direct-flow average KE (β=0.280, P=0.035; R² model, 0.466, P=0.002). In contrast, neither ejection fraction nor left ventricular volumes were independently predictive.Conclusions:This study demonstrates an independent predictive relationship between the direct-flow average KE and a prognostic measure of functional capacity. Intracardiac 4-dimensional flow parameters are novel biomarkers in heart failure and may provide additive value in monitoring new therapies and predicting prognosis.

中文翻译：

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左心室血流分析

背景：心肌损伤后的心脏重塑通常会导致进展为心力衰竭。左心室血流变化（包括动能 (KE)）与重塑之间的关系尚不确定。我们假设左心室血流紊乱增加与（1）常规心脏重塑标志物，（2）生化重塑标志物水平增加，（3）心脏能量改变，以及（4）患者症状和功能能力恶化有关。方法三十-4 名扩张型心肌病患者、30 名缺血性心肌病患者和 36 名对照接受了磁共振，包括 4 维流动、BNP（脑型利钠肽）测量、功能能力评估（6 分钟步行测试）和症状量化。扩张型心肌病亚组和对照组受试者接受了心脏能量评估。左心室血流分为 4 个部分：直接流量、保留流入、延迟射血流量和残余容量。计算整个心动周期的平均 KE。P <0.0001)。患者残余体积比例和残余体积平均KE增加（P <0.0001）。重要的是，在预测患者 6 分钟步行测试的多元线性回归模型中，独立预测因子是年龄（β=-0.3015；P =0.019）和直流平均 KE（β=0.280，P =0.035；R ²模型，0.466，P=0.002)。相比之下，射血分数和左心室容积都不能独立预测。结论：本研究表明直流平均 KE 与功能能力的预后测量之间存在独立的预测关系。心内 4 维血流参数是心力衰竭的新型生物标志物，可在监测新疗法和预测预后方面提供附加价值。