Aortic regurgitation (AR) may lead to left ventricular (LV) dilatation, cardiac arrhythmias and heart failure. Close follow-up of horses with AR is therefore paramount to detect onset of cardiac decompensation. The aim of this study was to examine whether two-dimensional speckle tracking (2DST) can be used to detect altered myocardial function in horses with chronic AR compared to control horses. Speckle tracking was performed on short axis and long axis images of the LV in 29 healthy Warmblood horses and 57 Warmblood horses with AR. Radial, circumferential and longitudinal strain, strain rate and displacement were measured for each segment separately and the average was calculated over all segments. Data generated from the apical segments were not included in the analysis. Radial (SR) and circumferential (SC) strain were significantly higher in horses with moderate AR (average SR 75.5 ± 24.3%, SC 19.3 ± 3.2%) but not in horses with severe AR (SR 65.5 ± 26.2%, SC 16.3 ± 3.5%), compared to control horses (SR 54.5 ± 18.0%, SC 16.8 ± 3.0%). Longitudinal strain did not show significant differences, but longitudinal displacement (DL) was larger in horses with moderate (average DL 29.5 ± 4.1 cm) and severe AR (DL 32.4 ± 6.1 cm) compared to control horses (DL 25.7 ± 4.0 cm), especially in the interventricular septum. Diastolic longitudinal strain rate was lower in early diastole in horses with severe AR (0.93 ± 0.18/s) compared to controls (1.13 ± 0.13/s). 2DST is able to detect altered myocardial motion in horses with AR, which showed significantly higher radial and circumferential strain. Further research is needed to determine whether these findings contribute to a more accurate diagnosis and prognosis in clinical cases.

中文翻译：

---

二维散斑跟踪技术评估马主动脉瓣关闭不全的左心室功能

主动脉反流（AR）可能导致左心室（LV）扩张，心律不齐和心力衰竭。因此，对具有AR的马进行密切随访对于检测心脏代偿失调的发作至关重要。这项研究的目的是检查与对照组相比，患有慢性AR的马是否可以使用二维斑点追踪（2DST）来检测心肌功能的改变。在29头健康的Warmblood马和57头带有AR的Warmblood马中，对LV的短轴和长轴图像执行了斑点跟踪。分别测量每个节段的径向，周向和纵向应变，应变率和位移，并计算所有节段的平均值。从根尖产生的数据未包括在分析中。中度AR（平均SR 75.5±24.3％，SC 19.3±3.2％）的马的径向（SR）和周向（SC）明显高，但严重AR（SR 65.5±26.2％，SC 16.3±3.5 ％），相比之下，对照马（SR 54.5±18.0％，SC 16.8±3.0％）。纵向应变没有显着差异，但与对照马匹（DL 25.7±4.0 cm）相比，中度马（平均DL 29.5±4.1 cm）和重度AR（DL 32.4±6.1 cm）的马的纵向位移（DL）更大，特别是在室间隔内。与对照组（1.13±0.13 / s）相比，患有严重AR的马的舒张早期舒张期纵向应变率较低（0.93±0.18 / s）。2DST能够检测出AR患马的心肌运动改变，从而显示出明显更高的径向和圆周应变。