(E06) Evaluation of the Audicor® Device as Diagnostic Tool in Horses with Mitral or Aortic Regurgitation

Abstract: Background -Cardiac murmurs caused by mitral (MR) or aortic regurgitation (AR) in horses often prompt further diagnostics to assess disease severity and prognosis.
Hypothesis/Objectives -This study aimed to examine the use of Audicor® Acoustic Cardiography to detect murmurs and quantify cardiac mechanical and hemodynamic function in horses with mild, moderate, or severe MR or AR.
Animals -30 horses with MR, 18 with AR, 18 healthy horses.
Methods -Prospective study. The following variables were extracted from five consecutive, subsequently averaged 10-second snapshot analyses: Heart rate (HR, min-1), electromechanical activation time (EMAT, ms), HR-corrected EMAT (EMATc, %), left ventricular systolic time (LVST, ms), HR-corrected LVST (LVSTc, %), strength of third (S3) and fourth (S4) heart sound, and systolic dysfunction index (SDI, a function of QRS duration, QT interval, EMATc, and S3). Measurements were compared between groups using one-way ANOVA.
Results -Horses with AR were 6 (2-10) years [mean difference (95% CI of the difference of means)] older than horses with MR and 7 (2-12) years older than healthy horses. The LVST was 33 (5-60) ms shorter and the EMAT/LVST ratio 0.038 (0.001-0.075) higher in horses with MR compared to AR. Body weight, HR, EMAT, EMATc, LVSTc, strength of S3 and S4, and SDI were not significantly different between groups (p > 0.05).
Conclusions and clinical importance -Acoustic cardiography can detect differences in some systolic time intervals in horses with MR vs. AR. The clinical relevance as diagnostic point-of-care device in horses with MR or AR of various severity needs to be determined.