SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Valvular thickening (degenerative or inflammatory), valvulitis, prolapse, ruptured
chordae tendineae, vegetative endocarditis and stretching of the tricuspid valve
annulus with an anatomically normal valve (usually secondary to severe pulmonary
hypertension) may be detected echocardiographically in horses with TR. No
echocardiographic abnormalities, thickening of one or more of the tricuspid valve
leaflets or tricuspid valve prolapse are the most frequent echocardiographic findings in
horses with TR. Tricuspid valve prolapse is usually best imaged with 2-dimensional
echocardiography from the right cardiac window in the parasternal long axis view of the
left ventricular outflow tract, where a portion of the tricuspid valve leaflet is usually
imaged bulging into the right atrium during mid to late systole.
Primary degenerative changes of the valve leaflets, a non-infective valvulitis, bacterial
endocarditis, or dilatation of the tricuspid valve annulus secondary to chronic
pulmonary hypertension may cause thickening of the tricuspid valve leaflets.
Degenerative valve disease and endocarditis are the most common causes of tricuspid
chordal rupture in horses. The echocardiographic detection of a mobile linear echo that
moves with the valve leaflet or the subvalvular apparatus, everting into the right atrium
in systole is diagnostic of a RCT. Ruptured chordae tendineae and flail tricuspid valve
leaflets are rare in horses. While endocarditis is rare, the tricuspid valve is a common
site of bacterial endocarditis in horses with septic jugular vein thrombophlebitis. If the
horse is responding to treatment, the vegetative masses usually become smoother and
rounder. Although the regurgitation usually becomes more severe secondary to leaflet
scarring, the valvular insufficiency is much better tolerated than when the mitral valve is
involved.
Right atrial and right ventricular volume overload occur in moderate to severe TR with
the right atrium appearing larger than the left (4 chamber view) and the right ventricle
being >1/2 the size of the left ventricle. Paradoxical septal motion occurs with moderate
to severe right ventricular volume overload.
Paradoxical septal motion
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