Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
Equine Vet J. 2013 Jan;45(1):47-55. doi: 10.1111/j.2042-3306.2012.00549.x. Epub 2012 Feb 20.
The use of two-dimensional speckle tracking (2DST) for quantification of left ventricular (LV) function has recently been described in horses using long-axis images and short-axis images at chordal but not at papillary muscle level.
To compare the feasibility and reliability of 2DST for quantification of circumferential and radial LV function in short-axis images at papillary muscle and chordal level.
Repeated echocardiographic examinations were performed on 10 healthy trotter horses by 2 observers from a right parasternal short-axis view at papillary muscle and chordal level. Segmental and averaged peak values and timing of circumferential and radial strain and strain rate, radial displacement and rotation were measured in 6 LV wall segments in each imaging plane. Global peak values were calculated for circumferential strain and strain rate. The inter- and intraobserver within- and between-day variability was assessed by calculating coefficients of variation for repeated measurements.
2DST analysis was feasible in each cardiac cycle, although tracking was often inadequate during early diastole. Measurements of averaged systolic circumferential and radial strain and strain rate and radial displacement as well as global circumferential strain and strain rate could be determined with low variability. Early and late diastolic strain rate and systolic rotation showed a moderate variability. Radial segmental measurements were more reliable than circumferential measurements. The interventricular septum showed a higher circumferential and lower radial strain compared with the LV free wall. Peak timing was earlier at papillary muscle compared with chordal level.
2DST measurements of global and regional circumferential and radial LV wall motion are feasible both at papillary muscle and chordal level.
Several measurements had good reliability and should be used for evaluation of the technique in a clinical setting.
二维斑点追踪（2DST）技术最近已被用于马的左心室（LV）功能定量评估，可通过长轴图像和腱索水平的短轴图像进行，但不能通过乳头肌水平的短轴图像进行。
比较乳头肌和腱索水平短轴图像上 2DST 定量评估圆周和径向 LV 功能的可行性和可靠性。
由 2 名观察者从右胸骨旁短轴视图在乳头肌和腱索水平对 10 匹健康纯血马进行重复超声心动图检查。在每个成像平面的 6 个 LV 壁节段中测量圆周和径向应变及应变率、径向位移和旋转的节段和平均峰值及时间。计算圆周应变和应变率的整体峰值。通过计算重复测量的变异系数来评估观察者内、观察者间、日内和日间的变异性。
尽管在舒张早期跟踪往往不足，但 2DST 分析在每个心动周期都是可行的。平均收缩期圆周和径向应变及应变率和径向位移以及整体圆周应变和应变率的测量值具有较低的变异性。早期和晚期舒张期应变率和收缩期旋转的变异性中等。径向节段测量比圆周测量更可靠。室间隔的圆周应变比 LV 游离壁高，径向应变比 LV 游离壁低。与腱索水平相比，乳头肌的峰值时间更早。
乳头肌和腱索水平的 2DST 测量均可用于评估整体和节段圆周和径向 LV 壁运动。
多项测量具有良好的可靠性，应在临床环境中用于评估该技术。
