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Pericardial Effusion and Other Disorders of

the Pericardium

Key points

• Pericardial disease is uncommon in the cat.
• The most common congenital pericardial disease is peritoneopericardial diaphragmatic hernia (PPDH); the most common
acquired pericardial abnormality is pericardial effusion.
• Cardiac tamponade secondary to pericardial effusion is rare in cats.
• Congestive heart failure is the most common cause of feline pericardial effusion.

INTRODUCTION between the pericardial and peritoneal cavity. The defect
allows cranial displacement of abdominal organs into
The pericardium is the membrane, composed of two the pericardial sac. Because there is normally no direct
layers, which surrounds the heart. The outer layer is the communication between these two spaces, a PPDH is
fibrous “parietal” pericardium; the inner serous “vis- never an acquired, traumatic defect. However, traumatic
ceral” pericardium is invaginated by the heart during events can cause abdominal organs to move into the
embryogenesis and forms the epicardium. The pericar- pericardial sac through a congenital PPDH. In one ret-
dial cavity exists between these two layers and normally rospective study evaluating feline PPDH cases, domestic
contains a small volume of serous fluid, which is an longhair cats and Himalayans were over represented,
ultrafiltrate of serum. The pericardium functions to and domestic shorthair cats were underrepresented
prevent cardiac overdilation, lubricate the myocardial (Reimer et al. 2004).
surface, protect the heart from infections or adhesions, Clinical signs depend on the degree of herniation.
stabilize the heart within the chest, and regulate stroke Most affected cats show no clinical signs, and the defect
volume between the ventricles (Miller 1994). Pericardial is noted incidentally when thoracic radiographs are
diseases make up approximately one percent of canine taken for other reasons. In a subset of affected cats,
cardiac disease with pericardial effusion being most major organ herniation is present and clinical signs
common (Miller 1994). Pericardial diseases are even are noted by the owner, such as vomiting, diarrhea,
more rare in the cat. anorexia, cough, dyspnea, or lethargy. The liver and
gallbladder are the most often herniated organs
CONGENITAL PERICARDIAL DISEASES
followed by the small intestine, spleen, stomach, and
Peritoneopericardial diaphragmatic hernia (PPDH) is omentum (Reed 1988). Therefore, the most common
the most frequently recognized congenital pericardial clinical signs are usually referable to the gastrointestinal
defect in the cat. There are several proposed theories or respiratory systems. On physical examination, a
regarding the embryologic mechanism (Frye and Taylor decreased or displaced cardiac apex beat may be noted
1968); the end result is a persistent communication and heart sounds are often muffled, particularly when

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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