Equine Valvular Disease Study Guide

Overview and Clinical Importance

Valvular heart disease is one of the most commonly encountered cardiac abnormalities in horses. Unlike small animals where stenotic lesions are common, equine valvular disease is almost exclusively regurgitant in nature. The majority of valvular disease in horses is acquired rather than congenital, with degenerative changes being the most frequent etiology. Understanding the pathophysiology, clinical presentation, diagnostic approach, and management of valvular disease is essential for NAVLE success and clinical practice.

Approximately one-third of all horses develop a heart murmur during their lifetime. The most commonly affected valves are the mitral valve and aortic valve. While many horses with valvular regurgitation remain asymptomatic and can continue athletic careers, severe disease can lead to congestive heart failure, arrhythmias, and sudden death.

Cardiac Valve Anatomy Review

The equine heart contains four valves that ensure unidirectional blood flow. The atrioventricular (AV) valves (mitral and tricuspid) separate the atria from the ventricles, while the semilunar valves (aortic and pulmonic) guard the ventricular outflow tracts.