Mono-dimensional, two-dimensional and Doppler echocardiographic measurements in healthy Standardbred neonatal foals in the first 5 days of life.
Authors: D'el Rey Dantas Fernanda Timbó, Forni Giulia, Hallowell Gayle, Castagnetti Carolina, Menchetti Laura, Romito Giovanni, Lanci Aliai, Mariella Jole, Freccero Francesca
Journal: Equine veterinary journal
Summary
# Editorial Summary Echocardiographic assessment of neonatal foals remains challenging because measurements vary significantly with age, bodyweight and breed, yet baseline reference values for Standardbred foals in their first week of life have been lacking. This prospective observational study evaluated 56 healthy Standardbred neonates with serial transthoracic echocardiography at three intervals during the first five days post-partum, performing 114 examinations and rigorously assessing both intra- and inter-observer reproducibility using intraclass correlation coefficients. Key findings demonstrated progressive enlargement of left-sided cardiac structures over the study period—left ventricular internal diameter increased from 5.3 cm to 5.6 cm and left atrial diameter from 5.8 cm to 6.0 cm—alongside a reciprocal decrease in pulmonary artery dimensions (sinus diameter declining from 2.8 cm to 2.5 cm), reflecting the normal transition from foetal to neonatal circulation and increasing left-to-right shunting as pulmonary vascular resistance falls. These breed-specific reference ranges are immediately applicable for practitioners evaluating Standardbred neonates, helping distinguish physiological maturation from pathological cardiac changes during a critical window when early identification of congenital defects or functional abnormalities can significantly impact treatment outcomes and prognosis.
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Practical Takeaways
- •Establishes reference echocardiographic values for healthy Standardbred neonatal foals in the first 5 days of life, enabling clinicians to distinguish physiological changes from pathological abnormalities
- •Demonstrates that pulmonary artery diameter gradually decreases while left-sided cardiac chambers enlarge during early neonatal adaptation—these are expected physiological responses to transition from fetal to extrauterine circulation
- •Intra-observer reliability is good but inter-observer agreement is variable; standardization and experience are important when using echocardiography to assess neonatal foals clinically
Key Findings
- •Left ventricular internal diameter increased from 5.3±0.6 cm at T1 to 5.6±0.8 cm at T3 (p<0.01)
- •Left atrial diameter increased from 5.8±0.6 cm at T1 to 6.0±0.6 cm at T3 (p=0.01)
- •Pulmonary artery diameter decreased from 2.8±0.3 cm to 2.5±0.3 cm at the sinus level over the 5-day period (p<0.01)
- •Intra-observer echocardiographic agreement was excellent for most variables; inter-observer agreement was excellent for approximately 50% of variables