Pericardial Effusion In Dogs & Cats

Pericardial Effusion

Radiograph of a dog with severe pericardial effusion.
The heart looks enlarged due to the fluid filling the pericardium.

Pericardial Effusion

Pericardial Effusion In Dogs

Echocardiographic image of a cat with pericardial effusion.

The heart is normally encased by a protective thin fibrous sheet of tissue called the pericardium. The pericardium functions to keep the heart in place within the chest cavity and provide lubrication and thus prevents friction between the moving heart and surrounding tissues. Pericardial effusion in dogs and cats is defined by the abnormal accumulation of excessive/abnormal fluid within the pericardial sac. This results in increased pressures within the pericardial sac that can cause compression of the chambers of the heart, known as cardiac tamponade. The right side of the heart has much lower internal pressures than the left side. Therefore, pericardial effusion usually results in the development of fluid accumulation in the abdomen as the return of blood from the body back to the right side of the heart is impeded and the vessels leak into the abdomen. However, when a sudden accumulation of fluid occurs from the spontaneous hemorrhage of a tumor; clinical signs of weakness, respiratory difficulties, and collapse can predominate due to acute changes in hemodynamic balance.

Initial management of clinically significant pericardial effusion requires removal of the fluid from the pericardial sac. This is done by inserting a catheter through the chest wall and into the pericardial sac and then aspirating the fluid that is present. There is some risk in performing this procedure, but this is minimized by utilizing ultrasound guidance and monitoring the patient's ECG. The fluid removed is frequently submitted for cytology and fluid analysis and even cultured for underlying organisms if indicated in an attempt to determine the underlying cause.

Pericardial effusion in dogs is most commonly the result of spontaneous hemorrhage from a cardiac tumor. However, it can develop from infections, secondary to heart failure, or for no known cause which is termed idiopathic pericardial effusion. The prognosis for pericardial effusion is dependent on the underlying cause and can be highly variable. The optimal noninvasive evaluation of pericardial effusion in dogs and cats is the performance of an echocardiogram by a board-certified veterinary cardiologist which allows real time evaluation for mass lesions, the hemodynamic consequences of the effusion, and therapeutic and diagnostic recommendations based on the study's findings.

Unfortunately, as many as two thirds of patients do not have an identifiable cause on initial evaluation and follow-up rechecks are required. Currently, we are actively researching the utility of certain biomarkers as an aid in the determination of the underlying cause of pericardial effusion in these situations. However, if a lesion is noted during the echocardiogram, then based on its location and appearance a strong working diagnosis can generally be made.

In cases of recurrent pericardial effusion due to an idiopathic cause or secondary to an identified heart base tumor; surgical pericardiectomy (removal of the pericardium) is recommended. By removing a portion of the pericardium it allows the fluid to accumulate within the chest cavity and prevents excessive compression of the heart, thus alleviating clinical signs. Pericardiectomy can be performed via a thoracotomy (surgical opening of chest) or via thoracoscopic guidance, and decision of which to pursue is based on individual clinical factors and is decided upon with the attending surgeon. This procedure results in a significant improvement in quality of life and long-term survival in these types of patients. Ultimately, our goal is to provide diagnostic and therapeutic plans tailored to the individual patient and carried out through open collaboration with you and your primary care veterinarian in order to optimize your pet's quality and quantity of life at home.

Cat & Dog Cardiology

CVCA - Cardiac Care for Pets • View Our Locations in Maryland and Virginia

CVCA – Cardiac Care for Pets is an established leader in veterinary cardiology. Our veterinary cardiologists specialize in evaluation and treatment of dilated cardiomyopathy, heart mumurs, pericardial effusion, and arterial thromboembolism.