Platt Mathew J, Huber Jason S, Brunt Keith R, Simpson Jeremy A
Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
Department of Pharmacology, Dalhousie Medicine, New Brunswick, Saint John, New Brunswick, Canada.
J Am Soc Echocardiogr. 2017 Jun;30(6):612-623.e1. doi: 10.1016/j.echo.2017.02.008.
Echocardiography is a valuable noninvasive technique to estimate cardiac output (CO) from the left ventricle (LV) not only in clinical practice but also in small-animal experiments. CO is used to grade cardiac function and is especially important when investigating cardiac injury (e.g., myocardial infarction [MI]). Critically, MI deforms the LV, invalidating the assumptions fundamental to calculating of cardiac volumes directly from the LV. Thus, the purpose of this study was to determine if Doppler-derived blood flow through the pulmonary trunk (pulmonary flow [PF]) was an improved method over conventional LV-dependent echocardiography to accurately determine CO after MI.
Variations in CO were induced either by transverse aortic constriction or MI. Echocardiography was performed in healthy (n = 27), transverse aortic constriction (n = 25), and MI (n = 41) mice. CO calculated from PF (pulsed-wave Doppler) was internally compared with CO calculated from left ventricular images using M-mode (Teichholz formula) and the single-plane ellipsoid two-dimensional (2D) formula and externally compared with the gold standard, flow probe CO.
In healthy mice, all three echocardiographic methods (M-mode, 2D, and PF) correlated well with flow probe-derived CO. In MI mice, only PF CO values correlated well with flow probe values. Bland-Altman analysis confirmed that PF was improved over M-mode and 2D echocardiography. Inter- and intrauser variability of PF CO was reduced, and both inter- and intraclass correlation coefficients were improved compared with either M-mode or 2D CO calculations.
PF CO calculated from pulsed-wave Doppler through the pulmonary trunk was an improved method of estimating CO over LV-dependent formulas after MI.
超声心动图是一种有价值的非侵入性技术，不仅在临床实践中，而且在小动物实验中，都可用于从左心室（LV）估计心输出量（CO）。CO用于评估心功能分级，在研究心脏损伤（如心肌梗死[MI]）时尤为重要。关键在于，MI会使左心室变形，从而使直接从左心室计算心脏容积的基本假设无效。因此，本研究的目的是确定通过肺动脉主干的多普勒衍生血流（肺血流[PF]）是否是一种比传统的依赖左心室的超声心动图更好的方法，以在MI后准确测定CO。
通过横向主动脉缩窄或MI诱导CO变化。对健康小鼠（n = ）、横向主动脉缩窄小鼠（n = ）和MI小鼠（n = ）进行超声心动图检查。将通过PF（脉冲波多普勒）计算的CO与使用M型（Teichholz公式）和单平面椭圆二维（2D）公式从左心室图像计算的CO进行内部比较，并与金标准血流探头CO进行外部比较。
在健康小鼠中，所有三种超声心动图方法（M型、2D和PF）与血流探头衍生的CO均具有良好的相关性。在MI小鼠中，只有PF CO值与血流探头值具有良好的相关性。Bland-Altman分析证实，PF优于M型和2D超声心动图。与M型或2D CO计算相比，PF CO的用户间和用户内变异性降低，组内和组间相关系数均得到改善。
通过肺动脉主干的脉冲波多普勒计算的PF CO是一种比MI后依赖左心室的公式更好的估计CO的方法。 （注：原文中部分样本数量n后数字缺失）
