Transvenous electrical cardioversion of atrial fibrillation in horses: Horse and procedural factors correlated with success and recurrence

Abstract

Background: Transvenous electrical cardioversion (TVEC) is 1 of the main treatment options for atrial fibrillation (AF) in horses. Large-scale studies on factors affecting success and prognosis have primarily been performed in Standardbred populations. Hypothesis/Objectives: To determine factors affecting cardioversion success, cardioversion difficulty and recurrence in a predominant Warmblood study sample. Animals: TVEC records of 199 horses. Methods: Retrospective study of TVEC procedures of horses admitted for AF without severe echocardiographic abnormalities. Horse and procedural factors for success and cumulative amount of energy (≤ 600 J vs > 600 J) were determined using multivariable logistic regression. A survival analysis was performed to determine risk factors for recurrence. Results: Two hundred and thirty-one TVEC procedures were included, with a 94.4% success rate and 31.9% recurrence rate (51/160). Mitral regurgitation (OR 0.151, 95% CI 0.032-0.715, P =.02) and AF cycle length (OR 1.05, 95% CI 1.01-1.09, P =.02) were independent determinants for success. Catheter type (OR 0.154, 95% CI 0.074-0.322, P