Cardiac catheterization is a diagnostic procedure that involves the insertion of a catheter (a long, thin, flexible tube) into the heart. The catheter is introduced into the body through a vein or artery, usually in the leg, and guided by the doctor toward the heart. The doctor uses special x-ray equipment to monitor the progress of the catheter as he maneuvers it through the vein or artery toward the heart.
Once the catheter is inside the heart, the doctor is able to position it and inject dye into the chambers and vessels of the heart. When viewed with the special x-ray equipment, this dye allows the doctor to see the pumping action of the heart, the function of the heart valves, and the blood flow in the coronary arteries, which supply oxygen-rich blood to the heart muscle.
Other terms may be used to describe cardiac catheterization. These terms include coronary angiography, angiogram, and cardiac (or heart) cath.
Cardiac catheterization allows the doctor to see the heart as it pumps blood. He is able to view the expansion and contraction of the chambers of the heart; the opening and closing of the heart valves; and the flow of blood through the coronary arteries.
As compared to other diagnostic tests, cardiac catheterization provides more accurate and detailed information. This is especially important when visualization of the coronary arteries is required. This test provides the doctor with a picture of the arteries of the heart and allows him the assess the presence, location, and degree of severity of blockages in the coronary arteries. This information will allow the cardiologist to chose the best treatment for you.
Cardiac catheterization enables doctors to diagnose a number of common heart conditions.
The inside walls of arteries are normally smooth and flexible, allowing blood to flow through them easily. With time, fatty deposits may accumulate on the inside of an artery’s wall, causing it to become plugged.
As the build up of fatty deposits on the interior of the arteries continues, the opening of the arteries narrows with the result being a reduction in the flow of blood. When blockages occur in the coronary arteries, symptoms of angina (chest pain or discomfort) may result. Severe blockages may even cause a heart attack.
If your doctor suspects you have coronary artery disease, a cardiac catheterization is often recommended. During the heart catheterization, the x-ray dye is injected into the coronary arteries. Pictures taken show the flow of blood through the coronary arteries. Actual blockages will appear as areas where the vessel is pinched, resulting in a dramatic reduction of blood flow. The x-ray pictures allow the doctor to identify the points where blockage of the coronary vessels is present and evaluate the severity of the blockage.
The heart valves keep the flow of blood moving through the heart in one direction by opening and closing in sequence with the contraction of the heart muscle. When valve disease is present, one or more of the heart valves do not work properly. The valve may be "narrowed," which limits the ability of the chamber of the heart to fill completely, or the valve may "leak," which allows some blood to back up against the normal direction of flow.
Most valve defects are mild and have little effect on the pumping function of the heart. However, some defects become progressively worse and may cause weakening of the heart.
Heart catheterization allows the cardiologist to see the operation of the heart vales and monitor the flow of blood through the heart. This allows the doctor to confirm the diagnosis of heart valve disease and measure the severity of a valve’s narrowing or leakage.
A congenital heart defect is a deformity of the heart that is present at birth. Common examples of congenital heart defects include an abnormal hole between heart chambers, or a narrowed valve.
When congenital heart defects are severe, the pumping action of the heart may be compromised, limiting its efficiency in delivering oxygen-rich blood to the body. Some congenital heart defects make the heart work harder to compensate for the deformity, which, with the passage of time, causes the heart to weaken and decrease in efficiency.
Cardiac catheterization is often used to confirm the diagnosis of congenital heart defects and to assess the extent of the problem.
In some instances, the decision to perform a heart catheterization may be made while you are hospitalized. In other cases, you may go to the hospital specifically for the heart catheterization procedure, generally arriving at the hospital in the morning on the day of the procedure. In those instances where you know in advance that you are going to undergo a heart catheterization, there are a number of things you can do to prepare for the procedure:
Several routine tests will be performed before the procedure, including an ECG and blood tests. For your convenience, these tests may be done one or two days prior to the heart catheterization.
In preparation for the procedure, the area where the catheter will be inserted is cleaned and shaved. This makes it easier for the cardiologist to insert the catheter and minimizes the risk of infection. Usually, the preferred site for placing the catheter is the groin; however, in some cases, the crease of the arm is used.
Empty your bladder as completely as possible before the test starts. (A bedpan or urinal will be available during the procedure). Generally, you’ll be allowed to wear your dentures, hearing aids, and eyeglasses during the procedure. A small intravenous needle ("IV line") is inserted into a vein in your arm so that medications may be injected directly into the vein, if needed. A sedative will be given to help you relax.
Cardiac catheterization is performed in a specially equipped x-ray room, called a cardiac catheterization laboratory, or simply "cath lab". Since you will be mildly sedated, you will be taken to the cath lab on a movable bed. Once in the cath lab, you will be transferred to a special x-ray table and draped with sterile sheets. The cath lab has a large x-ray camera above the table, several television screens showing views from the x-ray camera, heart monitors, and other special equipment.
The cath lab team generally includes a cardiologist, an assistant, a nurse, and one or two technicians. It is important to the cath lab team that you be comfortable throughout the procedure, so be sure to let them know of any concerns you may have. You will need to keep your legs and arms as still as possible during the procedure.
The area where the catheter will be inserted is cleansed thoroughly. A tiny needle is used to inject a local anesthetic into the skin at the site where the catheter will be inserted. This numbs area to minimize discomfort during the procedure. The injection may cause a mild stinging sensation.
Once the area is numb, a small incision is made in the skin. A needle is inserted in the blood vessel into which a sheath (a small tube) will be inserted. The cardiologist will place the various catheters through this small tube during the procedure.
After insertion into the blood vessel, the catheter is carefully guided toward the heart. The television screen connected to the x-ray camera allows the doctor and staff to follow the progress of the catheter.
Once the catheter is in place inside the heart, the cardiologist is able to assess the function of the heart in several ways. The pressures inside the heart can be measured and x-ray dye injected into the heart chambers and coronary arteries.
Pressure readings taken inside the heart allows the doctor to assess the heart’s pumping function and estimate the severity of valve defects. Monitor screens in the cath lab display the pressure readings. These readings may also be recorded on special tracing paper.
Pictures taken of the blood flow through the coronary arteries are called coronary angiograms. Specially shaped catheters are placed into the heart, one after the other. The special shape of these catheters allows the x-ray dye to be directed toward the openings of the coronary arteries. Once in position, the x-ray dye is injected through the catheter into each coronary artery. The x-ray camera takes pictures. These pictures reveal blockages in the coronary arteries and show their impact upon blood flow.
When the doctor takes pictures of the heart’s main pumping chamber (the left ventricle), the procedure is called a left ventriculogram. A special catheter is maneuvered into the left ventricle. Then, x-ray dye is injected under pressure into the left ventricle. A series of pictures are taken to view the left ventricle during its pumping action.
When a leaky valve or a hole in the heart is present, the x-ray dye inside the heart shows abnormal flow of dye going in the "wrong" direction.
During the heart catheterization, the x-ray camera is tilted at various angles to obtain the best views of the coronary arteries and heart chambers.
Although you will be mildly sedated, you will be awake during the procedure. Cardiac catheterization usually is not painful; however, you will experience some unusual sensations.
You will feel a stinging or burning sensation when the groin area is anesthetized. Some pressure may also be felt in the area when the sheath is placed. You will not feel the catheters moving through the blood vessels and into your heart. When x-ray dye is injected into the coronary arteries, you may feel some tingling or discomfort; however, this sensation subsides in seconds. The injection of dye into the left ventricle causes a warm sensation ("hot flash") over your body, lasting for 10-20 seconds.
A complete cardiac catheterization study generally lasts about one hour. Lying still on the x-ray table for this period of time may be uncomfortable. The staff will do their best to help you stay comfortable throughout the procedure.
Once the procedure is completed and the catheters are removed, firm pressure is applied over the insertion site for 10-20 minutes. This is to stop the bleeding from the arterial site.
You will be taken back to your room or the recovery area. A pressure device will be applied to the insertion site. For a period of time, usually four to six hours, you will lie flat in bed, to allow the puncture in the artery to form a seal. During that time, do not bend or lift the extremity where the catheters were inserted. To relieve stiffness, you may move your foot or wiggle your toes. You may bend the other leg at the knee to relieve stress on your back.
The nurse will check your pulse and blood pressure frequently, and will also keep checking the site where the catheters were inserted. If you feel sudden pain at the site, or if you notice a warm, sticky sensation of fluid, notify the nurse immediately.
You will be able to eat shortly after returning to your room. You will be given fluid through an I.V. or asked to drink plenty of liquids to "flush" the x-ray dye out of the body.
The doctor who performed the study may be able to discuss with you some of the results soon after the test. A complete, detailed analysis of all the findings will take more time.
Cardiac catheterization is an "invasive" procedure that requires the insertion of a catheter into the body. Therefore, the procedure has a small level of risk. Thanks to modern equipment and techniques, heart catheterization is considered a relatively safe procedure.
Most complications associated with cardiac catheterization are minor and of no long-term consequence. These include nausea and vomiting, allergic skin rash (hives), and heartbeat irregularity. Some patients may bleed at the insertion site. If blood collects under the skin, swelling and/or a "bruise" may develop.
Less frequently, catheterization may be associated with more serious complications. These include damage to blood vessels, formation of blood clots, infection, abnormal heart rhythms, a heart attack, or a stroke. Fatalities are extremely rare.
Most patients who undergo catheterization do not experience complications. Nonetheless, you should be aware of the risks of the procedure. Be sure to ask you doctor about any special risks that apply to you.
In most cases, the benefits of cardiac catheterization far outweigh the risks. Catheterization provides important information about the heart’s pumping function and the condition of the coronary arteries and heart valves. This information often cannot be obtained by any other means. It allows the doctor to make an accurate diagnosis and begin treatment before irreversible damage to the heart occurs.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.