BACKGROUND While left ventricular ejection fraction (LVEF) has been shown to have prognostic value in ischemic cardiomyopathy (ICMX) patients, right ventricular ejection fraction (RVEF) has not been systematically evaluated in either ICMX or non-ischemic cardiomyopathy (NICMX) patients. Moreover, an accurate estimation of RVEF is problematic due to the geometry of the right ventricle (RV). Over the years, there have been improvements in the resolution, image acquisition and post-processing software for cardiac magnetic resonance imaging (CMR), such that CMR has become the "gold standard" for measuring RV volumetrics and RVEF. We hypothesize that CMR defines RVEF more so than LVEF and might have prognostic capabilities in ischemic and non-ischemic cardiomyopathy patients (ICMX and NICMX). METHODS Patients that underwent CMR at our institution between January 2005 and October 2012 were retrospectively selected if three-dimensional (3D) LVEF < 35%. Patients were further divided into ICMX and NICMX groups. The electronic medical record (EMR) database inquiry determined all-cause mortality and major adverse cardiovascular events (MACE). Additionally, a Social Security Death Index (SSI) database inquiry was performed to determine all-cause mortality in patients who were lost to follow-up. Patients were further sub-grouped on the basis of 3D RVEF ≥ 20%. Separately, patients were sub-grouped by LVEF ≥ 20% in both ICMX and NICMX cases. A cut-off of ≥20% was chosen for the RVEF based on the results of prior studies showing significance based on Kaplan⁻Meier (KM) survival curves. Cumulative event rates were estimated for each subgroup using the KM analysis and were compared using the log-rank test. The 3D RV/LVEFs were compared to all-cause mortality and MACE. ICMX patients were defined using the World Health Organization (WHO) criteria. RESULTS From a 7000-patient CMR database, 753 heart failure patients were selected. Eighty-seven patients met WHO definition of ICMX and NICMX (43 ICMX and 44 NICMX). The study patients were followed for a median of 3 years (Interquartile range or IQR 1.5⁻6.5 years). The mean age of patients was 58 ± 13 years; 79% were male. In ICMX, mean 3D LVEF was 21% ± 6% and mean 3D RVEF was 38% ± 14%, while for NICMX, mean 3D LVEF was 16% ± 6% and mean 3D RVEF was 30% ± 14% (p < 0.005 for intra- and inter-group comparison). It should be noted that LVEF < RVEF in both groups and the ejection fraction (EF) in NICMX was less than the corresponding EF in ICMX. Overall mortality was higher in ICMX than NICMX (12/40, 30% vs. 7/43, 16%; p < 0.05). Patients were stratified based on both RVEF and LVEF with a threshold of EF ≥ 20% separately. RVEF but not LVEF was a significant predictor of death for NICMX (χ² = 8; p < 0.005), while LVEF did not predict death in ICMX (χ² = 2, p = not significant). Similarly, time to MACE was predicted by RVEF for NICMX (χ² = 9; p < 0.005) but not by LVEF in ICMX (χ² = 1; p = NS). Importantly, RVEF, while predictive of NICMX MACE, did not emerge as a predictor of survival or MACE in ICMX. CONCLUSIONS Via 3D CMR in non-ischemic CMX patients, RVEF has important value in predicting death and time to first MACE while 3D LVEF is far less predictive.

中文翻译：

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非缺血性心肌病患者可以使用3D RVEF进行预后吗？心血管MRI研究。

背景技术虽然已显示左心室射血分数（LVEF）在缺血性心肌病（ICMX）患者中具有预后价值，但尚未对ICMX或非缺血性心肌病（NICMX）患者系统评价右室射血分数（RVEF）。此外，由于右心室（RV）的几何形状，RVEF的准确估算存在问题。多年来，用于心脏磁共振成像（CMR）的分辨率，图像采集和后处理软件得到了改进，因此CMR已成为测量RV体积和RVEF的“黄金标准”。我们假设CMR对RVEF的定义比对LVEF的定义更多，并且可能在缺血性和非缺血性心肌病（ICMX和NICMX）患者中具有预后能力。方法回顾性分析2005年1月至2012年10月在我院接受CMR检查的患者，如果三维（3D）LVEF <35％。将患者进一步分为ICMX和NICMX组。电子病历（EMR）数据库查询确定了全因死亡率和主要不良心血管事件（MACE）。此外，还进行了社会保障死亡指数（SSI）数据库查询，以确定失访的患者的全因死亡率。根据3D RVEF≥20％将患者进一步分组。在ICMX和NICMX病例中，患者分别按LVEF≥20％分组。根据先前研究的结果，根据Kaplan⁻Meier（KM）生存曲线显示出显着性，选择RVEF的临界值≥20％。使用KM分析估算每个亚组的累积事件发生率，并使用对数秩检验进行比较。将3D RV / LVEF与全因死亡率和MACE进行比较。ICMX患者是根据世界卫生组织（WHO）的标准定义的。结果从7000名患者的CMR数据库中，选择了753名心力衰竭患者。87名患者达到了WHO对ICMX和NICMX的定义（43 ICMX和44 NICMX）。研究患者的中位随访时间为3年（四分位间距或IQR1.5⁻6.5年）。患者的平均年龄为58±13岁。79％是男性。在ICMX中，平均3D LVEF为21％±6％，平均3D RVEF为38％±14％，而对于NICMX，平均3D LVEF为16％±6％，平均3D RVEF为30％±14％（p <0.005）用于组内和组间比较）。应该注意的是，LVEF < 两组的RVEF和NICMX中的射血分数（EF）均小于ICMX中的相应EF。ICMX的总死亡率高于NICMX（12/40，30％vs. 7/43，16％; p <0.05）。根据RVEF和LVEF对患者进行分层，分别将EF≥20％作为阈值。RVEF而非LVEF是NICMX死亡的重要预测因子（χ2 = 8； p <0.005），而LVEF并未预测ICMX死亡（χ2 = 2，p =不显着）。同样，NICMX的RVEF可以预测到MACE的时间（χ2 = 9； p <0.005），而ICMX的LVEF不能预测MACE的时间（χ2 = 1； p = NS）。重要的是，RVEF虽然可以预测NICMX MACE，但并未成为ICMX生存或MACE的预测指标。结论在非缺血性CMX患者中，通过3D CMR，RVEF在预测死亡和首次发生MACE的时间方面具有重要价值，而3D LVEF的预测性低得多。