BACKGROUND The reliability of left ventricular (LV) systolic functional indices calculated from blinded echocardiographic measurements of LV size has not been tested in a large cohort of healthy children. The objective of this study was to estimate interobserver variability in standard measurements of LV size and systolic function in children with normal cardiac anatomy and qualitatively normal function. METHODS The Pediatric Heart Network Normal Echocardiogram Database collected normal echocardiograms from healthy children ≤18 years old distributed equally by age, gender, and race. A core lab used two-dimensional echocardiograms to measure LV dimensions from which a separate data coordinating center calculated LV volumes and systolic functional indices. To evaluate interobserver variability, two independent expert pediatric echocardiographic observers remeasured LV dimensions on a subset of studies, while blinded to calculated volumes and functional indices. RESULTS Of 3,215 subjects with measurable images, 552 (17%) had a calculated LV shortening fraction (SF) < 25% and/or LV ejection fraction (EF) < 50%; the subjects were significantly younger and smaller than those with normal values. When the core lab and independent observer measurements were compared, individual LV size parameter intraclass correlation coefficients were high (0.81-0.99), indicating high reproducibility. The intraclass correlation coefficients were lower for SF (0.24) and EF (0.56). Comparing reviewers, 40/56 (71%) of those with an abnormal SF and 36/104 (35%) of those with a normal SF based on core lab measurements were calculated as abnormal from at least one independent observer. In contrast, an abnormal EF was less commonly calculated from the independent observers' repeat measures; only 9/47 (19%) of those with an abnormal EF and 8/113 (7%) of those with a normal EF based on core lab measurements were calculated as abnormal by at least one independent observer. CONCLUSIONS Although blinded measurements of LV size show good reproducibility in healthy children, subsequently calculated LV functional indices reveal significant variability despite qualitatively normal systolic function. This suggests that, in clinical practice, abnormal SF/EF values may result in repeat measures of LV size to match the subjective assessment of function. Abnormal LV functional indices were more prevalent in younger, smaller children.

中文翻译：

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左心室功能参数面临的挑战：小儿心脏网络正常超声心动图数据库。

背景技术在大批健康儿童中，尚未通过盲目超声心动图测量左心室大小计算出的左心室（LV）收缩功能指标的可靠性。这项研究的目的是评估心脏解剖结构正常且定性正常的儿童左心室大小和收缩功能的标准测量中观察者间的差异。方法小儿心脏网络正常超声心动图数据库收集了年龄在18岁以下的健康儿童的正常超声心动图，按年龄，性别和种族平均分布。核心实验室使用二维超声心动图来测量左心室尺寸，然后由一个单独的数据协调中心计算左心室体积和收缩功能指数。为了评估观察者之间的差异，两名独立的儿科超声心动图专业观察员在一项研究子集上重新测量了LV尺寸，但对计算量和功能指标视而不见。结果在3,215名具有可测量图像的受试者中，有552名（17％）的左心室收缩率（SF）<25％和/或左心室射血分数（EF）<50％。受试者比具有正常值的受试者明显年轻，并且年龄较小。当比较核心实验室和独立观察者的测量值时，单个LV大小参数组内相关系数很高（0.81-0.99），表明可重复性高。SF（0.24）和EF（0.56）的类内相关系数较低。比较审稿人，根据核心实验室的测量，SF异常者中有40/56（71％）SF者中有36/104（35％）由至少一名独立观察者计算为异常。相反，从独立观察者的重复测量中计算出的异常EF较不常见。根据核心实验室的测量，至少有9/47（19％）EF异常的人和8/113（7％）EF的正常人至少由一名独立观察员计算为异常。结论尽管盲目的测量左室大小显示出健康儿童的良好重现性，但随后计算出的左室功能指数显示出明显的变异性，尽管收缩功能定性正常。这表明，在临床实践中，异常的SF / EF值可能会导致重复测量LV大小以匹配功能的主观评估。