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What is Pericardial Effusion?

The pericardium is a thin membrane that surrounds the heart similar to how a fetus is protected by the amniotic sac. It holds about 5 milliliters of fluid for lubrication and to protect the heart. Pericardial effusion is when the sac fills up with more fluid from various sources and compresses the heart and lungs. This can stop the heart ventricles from filling completely, which affects the heart’s ability to beat effectively. Although all breeds, sexes, and ages of dogs are susceptible, it is more common in Golden Retrievers and males about seven to nine years old.

Pericardial effusion is a life-threatening condition in dogs from a buildup of blood, pus, or another bodily fluid in the pericardial sac. This dangerous problem causes a huge pressure on the heart and slows its ability to pump blood through the body. It also puts pressure on the lungs, making breathing more difficult.  There are many causes of pericardial effusion such as cancer, infections, metabolic disorders, toxins, trauma, and cardiovascular disease.


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Symptoms of Pericardial Effusion in Dogs

The signs of pericardial effusion can vary greatly depending on the underlying cause of the condition. Some of the most often reported include:


  • Weakness
  • Coughing
  • Exercise intolerance


  • Collapsing or fainting
  • Loss of weight
  • Fatigue
  • Pale gums


  • Respiratory distress
  • Rapid breathing
  • Increased heart rate


  • Coughing
  • Wheezing
  • Extreme lethargy
  • Collapse
  • Death


  • Appetite loss
  • Abdominal distention
  • Weakness
  • Lack of interest in exercise
  • Weight loss


  • Vomiting
  • Diarrhea (sometimes bloody)
  • Fever
  • Difficulty breathing


  • Weight loss
  • Vomiting
  • Exercise intolerance
  • No appetite
  • Weak heartbeat


  • Sudden coughing
  • Frothing at the mouth
  • Collapse
  • Death


  • Congenital
  • Cancerous
  • Traumatic (injury)
  • Inflammatory
  • Infectious
  • Toxic
  • Metabolic
  • Cardiovascular
  • Idiopathic (unknown)

Causes of Pericardial Effusion in Dogs

Sometimes, the cause of pericardial effusion is unknown, but there are also many causes that can include:

  • Idiopathic- No known cause
  • Congenital - Peritoneopericardial hernia, mitral valve dysplasia, congenital pericardial cysts, tricuspid dysplasia
  • Inflammatory – Endocarditis, pericarditis, myocarditis
  • Cardiovascular – Congestive heart failure, mitral valve disease
  • Toxic – Pesticides, radiation therapy, toxic plants
  • Metabolic – Kidney failure, liver failure, hypothyroidism
  • Infectious – Bacteria, parasites, fungi, tuberculosis
  • Neoplastic pericardial effusion – Malignant tumor, pericardial lipoma, hemangiosarcoma
  • Injury – Surgical complication, accident

Diagnosis of Pericardial Effusion in Dogs

The first thing your veterinarian will want is your dog’s health history and immunization records if you have them. After that, a complete physical examination will be performed, which will likely include vital signs with special concentration on the heart. Auscultation, pulse, heart rate, breath sounds, and capillary refill time are all essential tests to evaluate the health of the heart. A simple blood test can detect a cardiac peptide in the blood that can detect heart failure and determine the severity as well. In addition, complete blood count (CBC), biochemical analysis, and blood cultures will be done to detect underlying conditions that may be the cause of the pericardial effusion. An echocardiogram (ECHO) shows the function and structure of the heart. Also, an electrocardiogram (ECG) is usually used to check the heart’s electrical function. Thoracic radiographs (x-rays) will show the size and shape of your dog’s heart.

Treatment of Pericardial Effusion in Dogs

The treatment for pericardial effusion depends on the cause of the condition. However, the first thing the veterinarian will want to do is stabilize your dog. Once that is done, the veterinarian can treat the fluid build up.


To stabilize your dog, the veterinarian will need to remove the extra fluid from the pericardium. The fastest and least invasive way to do this is by performing a pericardiocentesis. The veterinarian will sedate your dog and use a catheter to slowly extract the fluid while watching the heart with echocardiography (ultrasound of the heart) to see what is going on. An electrocardiograph will also be used to watch for arrhythmia. The fluid will be sent to the laboratory for analysis. Your dog will be kept overnight for continuous cardiac monitoring due to the risk of arrhythmia and shock.

  • Congenital - If the problem is congenital, it may require surgery to repair a defect or medication to treat an ongoing issue
  • Cancerous - The veterinarian will most likely refer you to a veterinary oncologist for treatment due to the seriousness of the illness
  • Traumatic (injury) - A traumatic injury needs to be treated right away, usually with surgery
  • Inflammatory - Some of the inflammatory causes require medication such as diuretics and possibly antibiotics but it depends on the specific cause  
  • Infectious - Infections require medication such as antibiotics, antifungals, or antiparasitics
  • Toxic - Toxins require special treatment depending on the type of toxin and how long it has been since consumption. Usual treatments include prompting emesis, gastric lavage, fluid therapy, and medication
  • Metabolic - A metabolic disease or disorder is usually treated with medication
  • Cardiovascular - Cardiovascular conditions often require surgical repair and possible medication

Recovery of Pericardial Effusion in Dogs

The prognosis depends on the cause of the pericardial effusion and how severe the problem is. In many cases, with immediate treatment, your dog could have a complete recovery. However, there are some causes of pericardial effusion that cannot be fixed and supportive treatment is all that can be given. If the condition is severe and unresponsive to treatment, euthanasia may be the only choice.