Auscultatory findings and left atrial function as indicators of mitral valve regurgitation severity in horses.

Echocardiography remains essential for MR severity assessment; murmur grade and LA fractional area change offer supportive information.

This retrospective cohort study evaluated auscultatory findings and left atrial functional parameters as potential indicators of mitral valve regurgitation (MR) severity in horses. A total of 151 horses were included: 50 controls (no/trivial MR) and 101 horses with MR classified as mild (n=58), moderate (n=36), or severe (n=7), all in sinus rhythm. Systolic murmur intensity and duration both demonstrated significant positive associations with MR severity (P<0.001), and murmur duration correlated with the longest regurgitant jet duration on color-flow Doppler (P<0.001). Left atrial fractional area change (LA FAC) decreased progressively with increasing MR severity (P<0.001), suggesting impaired left atrial reservoir or conduit function as regurgitation worsens. However, tissue Doppler-derived myocardial velocities of the left atrial and left ventricular free walls during atrial contraction did not differ significantly between MR severity groups after Bonferroni correction (P≥0.073), limiting their diagnostic utility. Study limitations include the lack of a validated gold standard for equine MR grading and a small number of severe MR cases, which may have reduced statistical power. The authors conclude that while auscultation provides a clinically accessible approximation of MR severity, echocardiography remains essential for accurate diagnosis and jet characterization. Among left atrial functional variables, only LA FAC showed meaningful association with MR severity, whereas tissue Doppler indices were not reliably discriminatory in this equine population.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.