Left ventricular radial and circumferential wall motion analysis in horses using strain, strain rate, and displacement by 2D speckle tracking.

The research article focuses on how non-invasive probes can be used to assess the heart function (specifically left ventricular or LV) in horses using a technique called 2D speckle tracking. The study primarily aims to demonstrate how feasible the technique is, outline the methodology, and highlight its reliability in determining the radial and circumferential wall motion of the LV in horses.

Objective and Methodology

• The main objective of this article is to prove the viability of 2D speckle tracking or 2DST for understanding the behavior of the left ventricular wall motion in horses. The technique scans and studies the circumferential and radial wall motion of the horse’s LV.
• A group of six horses, comprising three Standardbreds and three Thoroughbreds, were chosen for this observational study. These horses ranged between 8-14 years of age and had body weights between 517-606 kg.
• The researchers used repeated 2-dimensional echocardiographic studies and the collected data was later analyzed using 2DST.

Reliability Analysis and Variability Determination

• The reliability of the tests was primarily determined through an estimation of measurement variability, within-day interobserver variability, and both between-day interobserver and intraobserver variability.
• The variability was expressed through coefficient of variation (percent) and the absolute value below which the difference between two measurements will lie with 95% probability.

Findings and Conclusion

• The 2DST analyses were feasible in 16 out of the 18 echocardiographic studies conducted. They found automated tracking to be accurate during systole (contraction phase) but less reliable during diastole (relaxation phase). This resulted in diastolic measurements being considered invalid due to inaccurate tracking.
• The test showed higher reliability for radial measurements as compared to circumferential measurements. The test-retest variabilities ranged between 2.4 and 33.1% for segmental and between 4.1 and 16.1% for averaged measurements.
• The study concluded that systolic radial motion of the horse’s LV at the chordal level could be reliably characterized by 2DST. However, the clinical value of LV wall motion analysis by 2DST in horses requires further investigation.