The heart has a sac around it called the pericardium. The purpose of this sac is to protect the heart from the structures that surround it. Inside the sac there is normally a small amount of fluid evenly spread in a thin layer around the whole heart. This fluid around the heart is known as pericardial fluid and basically acts as a lubricant to allow the heart to pump and turn with minimal friction. I’ll use the terms fluid around the heart and pericardial effusion interchangeably throughout this article so you become familiar with the terms.
How does Excess Fluid Around the Heart Develop?
There is normally a small amount of fluid around the heart (small pericardial effusion). This is produced by the sac around the heart and is an important part of normal heart functioning. Excess fluid around the heart is known as a pericardial effusion. But where does this excess fluid come from? Often, when the heart experiences inflammation (known as pericarditis) extra fluid releases and collects within the sac. It is also possible for blood to fill the sac during or after trauma, surgery, or complications of other heart procedures. Blood around the heart is known as hemopericardium. The fluid around the heart is usually continually produced and drained, so the level stays constant. Sometimes in patients with heart failure, high pressures within the heart cause the fluid not to drain properly. The body, however, continues to produce pericardial fluid, leading to excess fluid around the heart (chylous pericardial effusion).
Causes of Pericardial Effusion
The most common cause of pericardial effusion is inflammation of the lining around the heart. In most cases, the exact caused is never found. In other cases an autoimmune reaction – where the body attacks its own cells – is the culprit. This is primarily seen in conditions like lupus and rheumatoid. Some drugs have also been associated with the development of pericardial effusion . Another caused of excess fluid around the heart is kidney disease (uremic pericardial effusion). Finally, it is relatively common to see small amounts of excess pericardial fluid during pregnancy.
A bloody pericardial effusion is typically a more urgent issue and is seen as a result of blood leaking from inside the heart, or from the large vessels that leave the heart. Causes may include heart muscle tearing during a heart attack or a tearing of the great vessels leaving the heart (an aortic dissection). More rarely, a bloody pericardial effusion can result from the presence of cancer cells in the lining around the heart. In these cases, cancer typically originates elsewhere in the body and invades the heart.
When Does Fluid Around the Heart become a Problem? – Cardiac Tamponade
Imagine the sac around the heart (pericardium) to be like a hot water bottle that’s the shape of a heart that allows for a small amount of fluid to be there acting like a lubricant. If there’s a sudden, significant increase in fluid around the heart, the sac doesn’t expand. Instead, the fluid compresses the heart, as the pressure inside the sac are greater than the pressure inside the heart. This renders the heart incapable of filling with blood, essentially causing a shortage of oxygenated blood. This process is known as cardiac tamponade and can be life threatening.
Cardiac tamponade only occurs if there is a sudden and significant increase in pericardial fluid or if there is a very large amount of fluid collected over time. Interestingly, it can be more dangerous for just 50cc of fluid to collect rapidly, than for 1 liter of fluid to collect over time. Why is this? When there is a slower accumulation of pericardial fluid over time, the sac around the heart slowly enlarges to accommodate the fluid – something it cannot do if there is a sudden increase. Effusions involving blood are often emergencies, because the blood may leak into the sac at high pressure.
When I drain these effusions, sometimes patients are surprised that such a small amount of fluid could cause such a big problem. Other patients are amazed such a large amount of fluid (often liters) wasn’t causing noticeable problems.
Detecting Fluid Around the Heart – Diagnostic Testing for a Pericardial Effusion
The main way to assess a pericardial effusion is an ultrasound scan of the heart known as an echocardiogram. The echo helps quantify the amount of fluid around the heart, tells us how the heart is handling the excess fluid, and determines what action must be taken. Sometimes features on the echocardiogram help us determine the fluid type, i.e. blood vs. other. Pericardial effusions are also commonly picked up on CT scans. CT scans are useful for determining the amount of fluid around the heart; however, echocardiograms are more effective for understanding how the pericardial effusion is affecting the heart.
I have fluid around my heart, what should I do? – Management of a pericardial effusion
Treatment & Management
The treatment for pericardial effusion depends upon the amount of fluid surrounding the heart. Generally, patients with pericardial effusion are broken into three groups; mild, moderate, or large (cardiac tamponade).
Mild Pericardial Effusion
Unless it has occurred rapidly and led to unstable symptoms, mild pericardial effusion is usually found by chance on scans performed for other purposes. Typically a mild effusion will require no specific treatment for the effusion itself. Instead, the underlying cause is treated. The presence of an effusion may alert the physician to perform various tests to identify a cause and rule out more serious causes. For example, if the effusion is attributed to lupus, the effusion will probably resolve with treatment of lupus. The same may apply to any cause. Typically a follow-up scan is performed to ensure the effusion has resolved. Sometimes the fluid is drained and sent for analysis.
Moderate Pericardial Effusion
The management of a moderate pericardial effusion depends on the individual case, its effect on heart function, and the presence of symptoms. In some cases, especially when the underlying cause is known and there is no significant effect on the heart function, the effusion may just be monitored over time with echocardiograms. If the effusion persists, grows larger over time, or causes symptoms it may need to be drained. The cardiologist in charge of the case will typically make this decision.
Large Pericardial Effusion or Cardiac Tamponade
Large effusions will typically be drained. After the excess fluid around the heart has been drained, a drain may be temporarily left in place to ensure further fluid does not accumulate. In some cases, particularly when effusions recur, a hole is made in the sac to allow continuous drainage.
By its self, the presence of fluid around the heart doesn’t cause symptoms. Instead, symptoms occur when excess pressure in the heart sac prevents proper functioning of the heart. In severe cases, this can cause a state of shock. Usually, symptoms only occur if the accumulation of fluid is rapid or if the amount is very large. Symptoms of a significant effusion may include:
- Light headaches
- Shortness of breath
- Passing out or fainting
Effusions themselves don’t cause chest pain; however, effusions associated with pericarditis – inflammation of the sac around the heart – may be associated with chest pain.
Draining Fluid Around the Heart: Pericardiocentesis, Pericardial Drain, Pericardial Window
When do we drain the fluid around the heart?
In general there are two indications to drain pericardial effusions. First, doctors remove the fluid if it is affecting heart function. Second, doctors will drain fluid around the heart to test the pericardial fluid in a lab and determine the effusions’s cause.
How do we drain fluid around the heart?
There are 2 main ways to do drain pericardial fluid. The first is a minimally invasive procedure – known as a pericardiocentesis – that involves passing a small tube through the skin into the lining around the heart. The fluid is drained through the tube, and a drain can be left in if required. The second is a surgical procedure that involves making a small incision underneath the breastbone. As in a pericardiocentesis, a tube is used to access the pericardial fluid, often making a small hole in the lining of the pericardial sac known as a pericardial window. The window will generally stay open over time, allowing constant drainage of the fluid to prevent accumulation.
The less invasive pericardiocentesis procedure is usually tried first. Often the drain is left for up to a few days to see if the fluid builds back up. If the fluid continues to accumulate, a pericardial window procedure can be considered. Sometimes an immediate surgical approach is required, particularly in emergencies when a bloody effusion is caused by a rupture of the heart or the great vessels itself.
What questions should I ask my doctor?
Once someone is found to have a pericardial effusion, they will be referred to a cardiologist who will evaluate them and make treatment decisions. Questions to ask include:
- How big is the effusion and is it affecting the function of the heart?
- What is the cause of the effusion?
- If the effusion is felt large or significant enough to be drained, what is the way in which this will be done, and what is the plan if it should come back?
- Finally, what is the long-term treatment plan?