Page 90 - Feline Cardiology
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88 Section C: Congenital Heart Disease
cal) procedures are not typically beneficial. Medical
therapy to control signs of right heart failure or signs
caused by arrhythmias should be considered if they are
present (see Chapter 18). Additionally, because right
atrial dilation may predispose a cat to thromboembolic
disease, preventative measures should be considered in
cats with moderate or marked right atrial dilation (see
Congenital Heart Disease Outcome and Prognosis
Chapter 20).
The prognosis for tricuspid valve dysplasia is likely
dependent on the severity of the valve malformation and
the presence of concurrent defects, and it is best deter-
mined for each individual case based on echocardiogra-
A
phy. Extent of valve dysplasia, concurrent heart defects,
arrhythmias, and congestive heart failure appear to be
negative prognostic indicators in the cat (Chetboul et al.
2004).
MITRAL VALVE MALFORMATION/DYSPLASIA
Mitral valve malformation is considered to be one of the
most common congenital malformations in the cat. As
with tricuspid valve dysplasia, this defect may be
observed as an isolated malformation or with other
defects, including tricuspid valve dysplasia.
B
Etiology, Pathophysiology, and
Figure 10.1. Radiographs from a cat with tricuspid valve mal- Gross Pathology
formation. Note the enlarged right atrium, auricle, and right ven-
tricle on the ventrodorsal view (A). A dilated and tortuous caudal Etiology
vena cava is apparent on both views (B). The etiology of this malformation is not known,
and there is no evidence of a familial etiology at this
time.
All cats in stage 1 were asymptomatic. The staging did Pathophysiology
not correspond to murmur loudness and it has not yet Mitral valve malformation results in mitral valve regur-
been studied to see whether stage of disease correlates gitation, and left atrial and left ventricular enlargement.
with progression (Chetboul et al. 2004). Elevated pressures in the left atrium can result in pul-
Tricuspid valve dysplasia has been observed to coexist
with additional congenital heart malformations; there- monary venous congestion and the development of pul-
monary edema. Pulmonary hypertension and right
fore, a thorough echocardiographic evaluation should ventricular failure can occur as well.
be performed.
Diagnosis Gross Pathology
The physical examination and electrocardiographic and Mitral valve dysplasia is characterized by an enlarged
radiographic findings can overlap with many other mitral valve annulus; short, thickened leaflets; short,
cardiac malformations and diseases, and therefore an stout chordae tendinae; and malposition of the papillary
echocardiogram is needed to confirm the diagnosis. muscles that can result in valve dysfunction, primarily
valve insufficiency (Liu 1977) (Figure 10.2).
Treatment
Because a dysplastic tricuspid valve is not generally ste- Signalment
notic in the cat, interventional (cardiac catheter, surgi- There are no known breed predispositions.