Page 187 - Feline Cardiology

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Arrhythmogenic Right Ventricular

Cardiomyopathy

Key Points

• Arrhythmogenic right ventricular cardiomyopathy is an adult onset, uncommon myocardial disease in the cat.
• Radiographic and echocardiographic findings consist of right atrial and ventricular enlargement; pleural effusion may be
present.
• Congenital tricuspid valve dysplasia is an important differential diagnosis.

INTRODUCTION referral hospital in New York (Fox 1999). A recent study
that screened apparently healthy cats for the presence of
Arrhythmogenic right ventricular cardiomyopathy is an heart disease identified ARVC in 1 out of 103 cats (1%)
adult onset primary myocardial disease characterized by (Paige et al. 2009).
fibrofatty infiltration of the right ventricular myocar-
dium. It is observed in cats, dogs, and human beings, Pathophysiology
although the disease does have some species differences The disease is characterized by right ventricular enlarge-
(Fox et al. 2000; Basso et al. 2004; Harvey et al. 2005). ment with thinning of the ventricular free wall and right
Arrhythmogenic right ventricular cardiomyopathy is atrial enlargement. Right heart failure may be observed
thought of as predominantly a right sided heart disease, (Fox et al. 2000).
but in some cases the disease includes the left ventricle
and interventricular septum as well. In dogs and human Pathology
beings the disease may ultimately lead to left ventricular A diagnosis of feline ARVC is confirmed by pathologic
dysfunction as well, but this has not been well described evaluation. Right atrial and ventricular dilation are
in the cat (Basso et al. 2004). observed as well as focal or diffuse thinning of the
wall. Aneurismal bulges may be observed in the apical,
ETIOLOGY, PATHOPHYSIOLOGY, AND GROSS subtricuspid, or infundibular regions. Key histopatho-
PATHOLOGY
logic findings include right ventricular myocardial
Etiology atrophy and fibrous or fibrofatty replacement. Although
the findings are most commonly observed in the right
Although the disease is noted to be familial in human
beings and dogs, the etiology in the cat is unknown ventricle, they can also be observed in the other cham-
(Basso et al. 2004). bers as well. Lymphocytic infiltrates are also commonly
Arrhythmogenic right ventricular cardiomyopathy is observed.
an uncommon disease that is increasing in clinical rec- SIGNALMENT
ognition. The prevalence is unknown, but one report
estimated that it represented 2–4% of feline myocardial This is an adult onset form of cardiomyopathy with
diseases diagnosed at the Animal Medical Center, a large an age at diagnosis ranging from 1–20 years of age (Fox

Feline Cardiology, First Edition. Etienne Côté, Kristin A. MacDonald, Kathryn M. Meurs, Meg M. Sleeper.
© 2011 John Wiley & Sons, Inc. Published 2011 by John Wiley & Sons, Inc.

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