Cardiac Catheterization (Cath) is a specialized study of the heart during which a catheter, or thin hollow flexible tube, is inserted into the artery of the groin or arm. Under x-ray visualization, the tip of the catheter is guided to the heart. Pressures are measured and an x-ray Angiogram (Angio) movie of the heart and blood vessels are obtained while injecting an iodinated colorless "dye" or contrast material through the catheter. The dye can show whether a substance called plaque has narrowed or blocked any of your coronary arteries. Plaque is made up of fat, cholesterol, calcium, and other substances found in your blood. Plaque narrows the inside of the arteries and, in time, may restrict blood flow to your heart. When plaque builds up in the coronary arteries, the condition is called coronary heart disease or coronary artery disease (CAD).
If catheters are introduced through the femoral or groin artery, the procedure is known as "left heart" catheterization, because the catheter goes from the femoral artery to the aorta, coronary arteries, and the Left Ventricle (LV). This accounts for the majority of procedures. Left heart cath can also be performed by using the artery in the arm. If a catheter is also placed in the right femoral vein to measure pressures within the right side of the heart, the procedure is called "right heart" catheterization. This is used in patients with congenital heart disease, diseases of the heart valve, or certain conditions involving the pericardium, or sac, of the heart. This may also be used in certain diseases of the heart muscle, heart failure, shock, or when measurements of heart output or lung pressures are needed. Right and left heart catheterization is a combination of both.
There are three major arteries that run on the surface of the LV. This is the most important pumping chamber of the heart and supplies oxygenated blood to the body. The aorta arises from the LV and gives out a series of branches as it makes its way from the heart to the lower portion of the abdomen. The coronary arteries are the very first branches that arise from the aorta. There are two major coronary branches that come off the aorta. The one that arises from the left is known as the Left Main Coronary Artery. This immediately divides into the Left Anterior Descending (LAD) and the Circumflex (Circ).
The LAD supplies blood to the front portion (anterior wall) of the LV and the septum (partition wall that separates the LV from the Right Ventricle (RV). The Circ wraps around the heart and supplies blood to the back or posterior wall of the LV. The Right Coronary Artery (RCA) arises from the right side of the aorta and supplies blood to the bottom or inferior wall of the LV. It also supplies branches to the RV. The coronary arteries are vital because they supply oxygen and nutrients to the heart muscle. Without blood flow, the muscle would sustain permanent damage in the form of a heart attack or myocardial infarction.
What Happens During a Cardiac Cath?
You will be given a hospital gown to wear for a cardiac cath. An intravenous (IV) line will be started in your arm so that medications and fluids can be administered through your vein during the procedure.
The cardiac cath room is cool and dimly lit. You will lie on a special table. If you look above, you will see a large camera and several TV monitors. You can watch the pictures of your cardiac cath on the monitors.
A staff member will shave and clean the site where the catheter will be inserted (arm or groin). Sterile drapes are used to cover the site and help prevent infection. It is important that you keep your arms and hands down at your sides and not disturb the drapes.
Electrodes (small, flat, sticky patches) will be placed on your chest. The electrodes are attached to an
that charts your heart's electrical activity.
You will be given a mild sedative to help you relax, but you will be awake and conscious during the entire procedure. The doctor will use a local anesthetic to numb the catheter insertion site.
If the catheter is to be inserted at the groin (called the "femoral" approach), a local anesthetic will be injected to numb the area. A small incision will be made over the blood vessel through which the catheter and introducer sheath will be inserted. The catheter will be inserted through the sheath and threaded to the arteries of your heart. If you feel pain, tell your health care providers. If the catheter is to be inserted into your arm (at the bend of the elbow, called the "brachial" approach), a local anesthetic will be injected into the skin in your arm to numb the area. A small incision will be made over the blood vessel through which the catheter introducer sheath (a tube through which the catheter is passed) and catheter will be inserted. The catheter will be inserted through the sheath and threaded to the arteries of your heart.
Again, you may feel pressure as the incision is made or when the sheath and catheter are inserted, you should not feel pain; tell your health care providers if you do.
When the catheter is in place, the lights will be dimmed and a small amount of dye (or "contrast material") will be injected through the catheters into your arteries and heart chambers. The contrast material outlines the vessels, valves, and chambers.
When the contrast material is injected into your heart, you may feel hot or flushed for several seconds. This is normal and will go away in a few seconds. Please tell the doctor or nurses if you feel itching or tightness in the throat, nausea, chest discomfort, or any other symptoms.
The X-ray camera will be used to take photographs of the arteries and heart chambers. Your doctor may ask you to take a deep breath, hold your breath, or to cough during the procedure You will be asked to hold your breath while the X-rays are taken. When all the photos have been taken, the catheter will be removed and the lights will be turned on.
What Happens After the Cardiac Cath?
If the catheter was inserted in your groin, the introducer sheath will be removed and the incision will be closed with stitches, a collagen seal, or applied pressure. In some situations, the introducer sheath may be stitched into place and removed after the bleeding stops. A collagen seal is a protein material that works with your body's natural healing processes to form a clot in the artery.
If the catheter was inserted in your arm, the catheter and sheath are removed. The incision will be closed with stitches or applied pressure. You will need to keep your arm straight for at least an hour. You will be able to walk around. You will be observed for a few hours to make sure you are feeling well after the procedure. You may receive medication to relieve discomfort in your arm after the anesthetic wears off. You will be given instructions regarding how to care for your arm when you return home. Tell your nurse if you think you are bleeding or feel any numbness or tingling in your fingers.
A sterile dressing will be placed on the groin area to prevent infection. You will need to lay flat and keep the leg straight for two to six hours to prevent bleeding. Your head can not be raised more than two pillows high (about 30 degrees). Do not raise your head off the pillows, as this can cause strain in your abdomen and groin. Do not try to sit or stand. The nurse will check your bandage regularly, but tell your nurse if you think you are bleeding (have a wet, warm sensation) or if your toes begin to tingle or feel numb. You may receive medication to relieve discomfort in the groin area after the anesthetic wears off. Your nurse will help you out of bed when you are allowed to get up.
Your doctor's orders will determine when you will be allowed out of bed to go to the bathroom. You will need assistance getting out of bed, so ask for help. The nurse will help you sit up and dangle your legs on the side of the bed.
You will need to drink plenty of liquids to clear the contrast material from your body.
You may feel the need to urinate more frequently. This is normal. If a urinary catheter was not placed during the procedure, you will need to use a bedpan or urinal until you are able to get out of bed.
Your doctor will tell you if you are able to return home or will need to stay overnight. In either case, you will be monitored for several hours after the procedure.
Treatment, including medications, dietary changes, and future procedures will be discussed with you prior to going home. Care of the wound site, activity, and follow-up care will also be discussed.
Please ask your doctor if you have any questions about cardiac cath.