Mitral valvular insufficiency associated with ruptured chordae tendineae in three foals.

Mitral valvular insufficiency associated with ruptured chordae tendineae was diagnosed in 3 foals with signs of congestive heart failure, which were believed to be secondary to the development of pulmonary hypertension associated with the valvular insufficiency. The septal leaflet of the mitral valve was affected in all 3 foals, and foal 2 also had ruptured chordae tendineae associated with the caudal mitral valve leaflet. Bacterial endocarditis and myocardial necrosis were associated with the ruptured chordae tendineae in foals 3 and 2, respectively. Idiopathic rupture was considered in foal 1. Two-dimensional echocardiography demonstrated a flail mitral valve leaflet in foals 2 and 3 and a ruptured chorda tendineae in foal 3. The ruptured chorda tendineae in foal 1 was not visualized with M-mode echocardiography.