Stefadouros M A, Canedo M I
Br Heart J. 1977 Apr;39(4):390-8. doi: 10.1136/hrt.39.4.390.
Although echocardiography is ideally suited for repetitive use on a patient for evaluation of left ventricular function, the value of this application is minimised by the uncertainty as to whether changes in left ventricular dimensions observed on a patient at different times or by different observers are real or result from the ultrasonic beam penetrating the left ventricle at different angles. Accordingly, an instrument was designed and constructed in our laboratory to improve the reproducibility of echocardiographic measurements of left ventricular dimensions. The instrument represents an orthogonal reference frame by means of which the spatial orientation of the ultrasonic beam relative to the chest is determined and reproduced in subsequent studies, while the point of entrance of the beam is marked on the chest wall. Using this instrument, left ventricular echograms were initially recorded on a group (I) of 23 subjects with or without heart disease and the study was repeated 8 hours to 49 (mean 7) days later by the same observer and also, in 16 cases, by an independent observer. The average values from 2 to 6 (mean 4) heart cycles were used for the left ventricular end-diastolic dimension (Dd), end-systolic (Ds) dimension, and their difference (delta D). Differences in all three variables between studies were random and statistically insignificant, never exceeding 3-5 mm for Dd or Ds, and 4 mm for deltaD. For comparison, left ventricular internal dimensions were also obtained in a seprate group (II) of 14 subjects by the standard method of using the mitral valve as an internal landmark, without the benefit of this instrument. All 14 subjects had the initial study repeated within 8 hours to 11 (mean 3-8) days later by the same and also by an independent observer. Though in the group as a whole there was no significant difference in left ventricular dimensions between studies, individual variations reached 11 mm for Dd, 9 mm for Ds, and 9 mm for deltaD, and the degree of scatter was significantly larger than in group I. This initial experience indicates that the use of this instrument improves the reproducibility and enhances the reliability of estimates of echocardiographic left ventricular dimensions and function on a patient examined at different times by the same or independent observers.
虽然超声心动图非常适合对患者反复使用以评估左心室功能，但由于不同时间或不同观察者在患者身上观察到的左心室尺寸变化是真实的还是由超声束以不同角度穿透左心室所致存在不确定性，使得这种应用的价值大打折扣。因此，我们实验室设计并制造了一种仪器，以提高超声心动图测量左心室尺寸的可重复性。该仪器代表一个正交参考框架，通过它可以确定超声束相对于胸部的空间方向，并在后续研究中重现，同时超声束的入射点会标记在胸壁上。使用该仪器，首先对一组（I组）23名有或无心脏病的受试者记录左心室超声心动图，8小时至49天（平均7天）后由同一名观察者重复该研究，在16例中也由一名独立观察者重复。左心室舒张末期内径（Dd）、收缩末期内径（Ds）及其差值（ΔD）采用2至6个（平均4个）心动周期的平均值。不同研究之间这三个变量的差异是随机的且无统计学意义，Dd或Ds的差异从未超过3 - 5毫米，ΔD的差异从未超过4毫米。作为对比，在另一组（II组）14名受试者中，采用以二尖瓣作为内部标志的标准方法获取左心室内径，而未使用该仪器。所有14名受试者在8小时至11天（平均3.8天）后由同一名观察者和一名独立观察者重复初始研究。虽然总体而言该组不同研究之间左心室尺寸无显著差异，但个体差异Dd达到11毫米，Ds达到9毫米，ΔD达到9毫米，且离散程度明显大于I组。这一初步经验表明，使用该仪器可提高可重复性，并增强同一或独立观察者在不同时间对患者进行超声心动图左心室尺寸和功能评估的可靠性。
