2018 ACVIM Forum Research Abstract Program: Seattle, Washington, June 14 - 15, 2018

Warmblood horses with atrial fibrillation, successful TVEC and continued normal sinus rhythm for at least one month thereafter were included in this study. Echocardiography was performed 24h, 72h and 1mt after TVEC. Maximum LA area (LAA max ) and LA diameter (LAD max ) as well as active and passive LA fractional area change (FAC) were measured using 2DE on a right-parasternal 4-chamber view focusing on the left atrium. LA dimensions were measured at endsystole and allometrically scaled to a body weight of 500 kg. Global longitudinal peak strain (S L ) and strain rate (SR L ) during active booster pump function were measured on the same recordings using 2DST analyses. Measurements were judged in relation to previously established reference intervals. Friedman one-way ANOVA with Dunn';s multiple comparison test was performed to detect differences between timepoints. Linear regression analysis was performed to describe associations of S L and SR L with conventional 2DE measurements of LA size and function, considering for repeated measurements within horses. P < 0.05 was considered significant.