Two circulatory systems
Catheterization is the process where doctors use a thin, flexible tube called a catheter to look at the heart. Right heart catheterization is performed by going into a vein.
Heart catheterization, heart cath, and cardiac catheterization are three terms that all mean the same thing. In the process of catheterization, doctors use a thin, flexible tube called a catheter to look at the heart. They insert the heart catheter into a blood vessel and move it until it reaches the heart. Once the catheter is in place, they take various readings and perform diagnostic procedures.
You may not know that there are two types of cardiac catheterizations: left and right. What is the difference between left and right heart catheterization? The two procedures have some things in common but are actually quite different.
Right heart catheterization (RHC) dates back to 1929, when a young doctor named Werner Forssmann performed the procedure on himself. In 1956, Forssmann and two other doctors won the Nobel Prize for their work in cardiac catheterization. Today, heart caths are common diagnostic procedures. A right heart cath can give your doctor valuable information about how your heart and circulatory system are performing.
To understand the difference between a right heart catheterization and a left one, it helps to know a little about the circulatory system. In a sense, the body has not one circulatory system but two. One is made up of arteries and one is made up of veins. Blood arrives at the right side of the heart when it is carried there by veins after carrying oxygen and nutrients to the body. On this return trip, it is low on oxygen.
The right side of the heart then pumps the blood to the lungs to be oxygenated. The oxygenated blood then travels to the left side of the heart. The left ventricle pumps this oxygen-rich blood to the rest of the body through the arteries.
Consequently, the heart contains not one pump but two, although they combine to form one organ. A wall of muscle separates the left and right sides of the heart. This structure keeps the two kinds of blood from mixing.
Right heart catheterization vs. left
Doctors use right heart catheterizations to diagnose a variety of conditions. They can now use noninvasive methods to get some of the information that once required a heart cath, but right heart caths are still valuable in certain situations. About 10% of heart caths performed today are right heart caths.
Doctors commonly use left heart catheterizations to find blocked arteries. Often, doctors can fix some problems during this catheterization. They might insert a stent, for example. They can also use left heart caths to find problems in the left side of the heart and the aorta.
In a left heart cath, the catheter goes into an artery. In a right heart cath, it goes into a vein. Because the blood in a vein flows to the heart, doctors use a small balloon to float the catheter to the heart. That doesn't work in arteries, where blood flows away from the heart.
Reasons to have a right heart cath
Right heart catheterization is valuable in these conditions and situations:
- Pulmonary hypertension. If you have high blood pressure in the lungs, you may develop breathing problems, and your heart could fail.
- Cardiomyopathy. This is an enlargement of your heart which can lead to heart failure.
- Shock. When your body suddenly isn't getting enough blood flow and oxygen, it goes into shock. The most common causes are severe infection in the bloodstream (sepsis), massive blood loss, and sudden heart failure.
- Congenital heart disease. This term refers to birth defects that are present from birth, such as a hole in the heart.
- Heart valve disease. When a valve in your heart doesn't work correctly, your blood supply is affected.
- Heart failure. This term applies to a weakened heart that doesn't do a good job of pumping blood. It can have a variety of causes.
Also, doctors typically do a right heart catheterization before doing a heart transplant. When the new heart is in place, doctors may use RHC to check its function and ensure that the body isn't rejecting the heart.
What happens during a right heart catheterization
To perform a right heart cath, doctors can insert the catheter in three different places:
- The jugular vein in the neck
- The antecubital veins in the arm
- The femoral vein in the groin area of the leg
After traveling through a vein, the catheter enters the right atrium, the upper right chamber of the heart. It travels through the right ventricle, which is the lower chamber, and into the pulmonary artery. The pulmonary artery is the main blood vessel that takes blood from the heart to the lungs. It is called an artery because it carries blood away from the heart, even though it carries oxygen-poor blood.
During your RHC, your doctor will measure the pressure and take other readings inside the heart and the pulmonary artery. Your doctor may also take blood samples or give you medicine to see how the heart reacts.
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Diagnosis of pulmonary hypertension
One of the most important uses of right heart catheterization is to diagnose pulmonary hypertension (PH). In this condition, the arteries in the lungs are damaged. Blood no longer flows easily through them. This causes the right side of the heart to work harder and can cause right heart failure.
An echocardiogram can suggest PH, but a right heart catheterization is the gold standard for diagnosis. Some medical facilities will not treat a person for PH unless a right heart cath confirms the diagnosis.
What else to know about right heart catheterization
Doctors usually perform right heart catheterization in a special room called a cath lab. You shouldn't have to spend a night in the hospital. You'll receive a local anesthetic where the catheter goes in, but you won't be put to sleep. You may get to see images of your heart on the monitor during the procedure.
A heart cath usually lasts around 30 minutes. It can last longer, though, if you need extra tests. If your catheter is put in through a vein in your leg, you'll have to lie flat for several hours to minimize the chances of bleeding. If your doctor uses a different site, you'll be able to get up sooner.
Doctors regard heart caths as generally safe. The rate of complications is only about 1 in 100.
