Prevalence and Risk Factors for Various Cardiac Diseases in a Hospital-Based Population of 3434 Horses (1994-2011)

Background: Risk factors for several cardiac diseases have been suspected in horses, but few have been statistically demonstrated in a large equine population.
Objectives: To describe risk factors for various cardiac diseases in a hospital-based equine population.
Animals: Files of 3434 horses admitted at the internal medicine department of the Liege Equine Teaching Hospital between 1994 and 2011were reviewed and of those, 284 were categorized as suffering from moderate to severe cardiac disease.
Methods: Observational study. After calculating prevalence for each cardiac disease, we tested whether breed (chi-square test) or gender, age, body weight (BW) and other cardiac diseases (logistic regressions) were risk factors (p<0.05 significant).
Results: Mitral regurgitation (MR, 4.4%), atrial fibrillation (AF, 2.3%), aortic regurgitation (AR, 2.1%) and tricuspid regurgitation (TR, 1.7%) were the most common cardiac abnormalities. Determinants were male gender and increasing age for AR (OR=2.03, CI=1.07-4.94), racehorses breed and middle-age for TR (OR=4.36; CI=1.10-17.24), and high BW for AF (OR=3.54; CI=1.67-7.49). MR was the major valvular disease associated with AF, pathological ventricular arrhythmia, pulmonary regurgitation (PR) and congestive heart failure (CHF). TR was also linked to AF, PR and CHF; AR was not linked to CHF.
Conclusions and clinical importance: Several previously suspected risks factors of a variety of equine cardiac diseases are statistically confirmed in the studied hospital-based population. Similar observation could be suspected in a larger randomized population and should be taken into account in health and sport’s monitoring of horses presenting predisposing factors.