Real-time three-dimensional echocardiography for left atrial volume assessment in Thoroughbred racehorses: Observer variability and comparison with two-dimensional echocardiography.
Authors: Worsman Francesca C F, Miller Zack J, Shaw Darren J, Blissitt Karen J, Keen John A
Journal: Equine veterinary journal
Summary
# Left atrial volume assessment in racehorses: evaluating 3D echocardiography reliability Left atrial enlargement predicts serious cardiac outcomes in humans and dogs, making reliable measurement techniques crucial for equine cardiac screening. Worsman and colleagues assessed whether real-time three-dimensional echocardiography (3DE) could reliably quantify left atrial volume in 22 Thoroughbreds, comparing measurements made by two independent observers using both semi-automatic and manual analysis methods against conventional two-dimensional echocardiography (2DE). Intraobserver repeatability was good for 3DE—with intraclass correlation coefficients of 76–85% for maximum and minimum atrial volumes—but interobserver agreement was considerably weaker (58% and 50% respectively), indicating that different operators produced systematically different measurements despite using the same imaging dataset. Measurements between 3DE and 2DE showed virtually no correlation (14% for maximum volume, ~0% for minimum), suggesting these methods are not interchangeable. For practitioners using 3DE to monitor individual horses longitudinally, the strong intraobserver reliability is reassuring; however, the substantial interobserver variability means clinicians should establish baseline measurements with a single experienced operator and maintain consistency when tracking atrial dimensions over time, whilst recognising that absolute values may differ meaningfully between practitioners.
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Practical Takeaways
- •3DE can reliably track changes in left atrial size within the same observer over time, useful for monitoring individual cases longitudinally
- •Be aware that LAV measurements will differ between veterinarians using 3DE; establish baseline measurements with your preferred operator for meaningful comparison
- •2DE and 3DE measurements are not interchangeable—choose one method and remain consistent rather than switching between techniques for follow-up assessments
Key Findings
- •3DE assessment of left atrial volume showed good intraobserver reliability with ICC 76-85% for both maximum and minimum volumes
- •Interobserver agreement was poor (ICC 58% for LAVmax, 50% for LAVmin), indicating consistent measurement differences between observers
- •2DE and 3DE methods showed minimal agreement (ICC 14% for LAVmax, ~0% for LAVmin), suggesting they measure different parameters
- •3DE was deemed suitable for longitudinal clinical case evaluation despite observer variability