Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 153
Fig. 2-127 A 2-year-old male German Shepherd dog with exercise
intolerance. A grade 2/6 systolic murmur was present and
the jugular veins were distended. A right parasternal short-axis
view of the heart base revealed dilation of the right atrium (ra)
and right ventricle (rv) as well as prolapse of the tricuspid valve
leaflets (arrows). Also identified are the aorta (ao) and pulmonary
artery (pa). Diagnosis: Tricuspid valve dysplasia with
prolapse.
Fig. 2-128 A 2-year-old female
Labrador Retriever with anorexia,
hydrothorax, and hydroperitoneum.
A right lateral four-chamber view
reveals severe dilation of the right
atrium (RA). The tricuspid valve is
severely deformed, with tethering
and thickening of the septal leaflet
(single arrow) and a severely elongated
parietal leaflet (double arrow).
Diagnosis: Tricuspid valve dysplasia.
The radiographic signs depend upon the site and severity of the lesion and are a result of
valvular insufficiency. Left ventricular and left atrial enlargement are observed with mitral
valve insufficiency (see Fig. 2-89). The degree of chamber enlargement and the change with
time useful in determining the severity and in monitoring progression of the mitral insufficiency.
Chronic, severe mitral regurgitation may result in endocardial damage, atrial wall
perforation, and pericardial hemorrhage. 376 Radiographic changes may range from normal
cardiac size and shape to left-sided cardiomegaly. Cardiomegaly may be accompanied by
pulmonary venous congestion or pulmonary edema. Animals with mitral endocardiosis
also may have tricuspid valve endocardiosis. They may have tricuspid insufficiency and
radiographic evidence of right ventricular and right atrial enlargement.