Left ventricular radial and circumferential wall motion analysis in horses using strain, strain rate, and displacement by 2D speckle tracking.
Authors: Schwarzwald C C, Schober K E, Berli A-S J, Bonagura J D
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: 2D Speckle Tracking for Equine Left Ventricular Function Assessment Two-dimensional speckle tracking echocardiography offers a non-invasive method to quantify left ventricular wall motion in horses, yet its clinical reliability remained largely undocumented prior to this 2009 investigation. Schwarzwald and colleagues performed repeated echocardiographic examinations on six horses (three Standardbreds, three Thoroughbreds, aged 8–14 years) analysed by two independent observers using 2D speckle tracking to generate strain, strain rate, displacement, and rotational data, with variability assessed across measurement repeatability, within-day and between-day observer comparisons, and intra-observer consistency. The technique proved feasible in 89% of studies, with radial measurements demonstrating substantially better reliability than circumferential ones; radial systolic indices (strain, strain rate, and displacement) showed test-retest variability ranging from 2.4–33.1% for individual segments and 4.1–16.1% when data were averaged, whilst diastolic tracking proved inaccurate due to loss of speckle coherence during the relaxation phase. For equine practitioners seeking objective quantification of ventricular contractility—particularly in performance horses or those with suspected cardiac dysfunction—2D speckle tracking offers a feasible tool for systolic radial wall motion at the chordal level, though clinicians should recognise the wider variability of segmental versus global measurements and recognise that diastolic function assessment remains unreliable with this methodology.
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Practical Takeaways
- •2D speckle tracking can be used clinically to assess left ventricular radial wall motion and systolic function in horses during routine echocardiography
- •Radial measurements are more reliable than circumferential measurements; clinicians should focus on radial strain analysis for consistent results
- •Diastolic measurements should not be used for clinical interpretation with this technique as tracking accuracy is poor during diastole
Key Findings
- •2D speckle tracking was feasible in 16 of 18 echocardiographic studies (89%) in horses
- •Radial strain measurements showed test-retest variability of 2.4-33.1% for segmental and 4.1-16.1% for averaged measurements
- •Radial systolic motion was reliably characterized but circumferential measurements were less reliable
- •Automated tracking was accurate during systole but inaccurate during diastole, making diastolic measurements invalid