Association Between Atrial Fibrillation and Right-sided Manifestations of Congestive Heart Failure in Dogs with Degenerative Mitral Valve Disease or Dilated Cardiomyopathy

Introduction: To determine whether dogs with atrial fibrillation (AF) are more likely to develop right-sided manifestations of congestive heart failure (R-CHF) than dogs without AF.

Animals: Two hundred twenty dogs diagnosed with congestive heart failure (CHF) secondary to degenerative mitral valve disease (DMVD, n = 155) or dilated cardiomyopathy (DCM, n = 65) at a referral institution.

Methods: Medical records were reviewed to extract relevant clinical and echocardiographic data.

Results: Fifty dogs had AF at the time of CHF diagnosis, including 17/155 (11.0%) dogs with DMVD and 33/65 (50.8%) dogs with DCM. Sixty dogs had R-CHF evidenced by cavitary effusions. Among DMVD dogs, R-CHF occurred in 13/17 (76.5%) dogs with AF compared with 10/138 (7.2%) dogs without AF; among DCM dogs, R-CHF occurred in 24/33 (72.7%) dogs with AF compared with 13/32 (40.6%) dogs without AF. Dogs with AF were more likely to manifest R-CHF signs than dogs without AF (p < 0.0001 for DMVD; p = 0.0125 for DCM). The presence of AF, diagnosis of DCM, and moderate to severe tricuspid regurgitation were associated with R-CHF in multivariate analysis. AF was the strongest predictor of R-CHF (odds ratio, 14.44; 95% confidence interval, 5.75-36.26).

Conclusions: Dogs with AF are more likely to manifest R-CHF than dogs without AF. Cavitary effusions are an expected finding in approximately three-quarters of dogs with AF and CHF secondary to either DCM or DMVD.