Application of Acoustic Cardiography in Assessment of Cardiac Function in Horses with Atrial Fibrillation Before and After Cardioversion.

Left atrial mechanical dysfunction is common in horses following the treatment of atrial fibrillation (AF). This study aimed to evaluate the use of an acoustic cardiography monitor (Audicor) in quantifying cardiac mechanical and hemodynamic function in horses with AF before and after treatment and to correlate these findings with echocardiographic measures. Twenty-eight horses with AF and successful transvenous electrical cardioversion were included. Audicor recordings with concomitant echocardiographic examinations were performed one day before, one day after, and two to seven days after cardioversion. Key variables measured by Audicor included electromechanical activating time (EMAT), heart rate-corrected EMATc, left ventricular systolic time (LVST), heart rate-corrected LVSTc, systolic dysfunction index (SDI), and intensity and persistence of the third and fourth heart sound (S3, S4). A repeated-measures ANOVA with Tukey's test was used to compare these variables over time, and linear regression and Bland-Altman analyses were applied to assess associations with echocardiographic findings. Following conversion to sinus rhythm, there was a significant decrease in EMATc and LVSTc ( < 0.0001) and a significant increase in LVST ( = 0.0001), indicating improved ventricular systolic function, with strong agreement between Audicor snapshot and echocardiographic measures. However, S4 quantification did not show clinical value for assessing left atrial function after conversion.