Cardiac catheterization is a technique doctors use to perform many tests and procedures on the heart and blood vessels. Catheterization is an invasive procedure in which a catheter (a long, thin tube) is inserted into your body. For cardiac catheterization, a small puncture is made, usually in your groin, to access directly the underlying vein or artery. The catheter is guided through a blood vessel into your heart. A num- ber of tests and some treatments can be accomplished by injecting sub- stances (such as dyes) or guiding instruments into the catheter.
Typically, cardiac catheterization is the method by which iodine- based dye is introduced for a coronary angiogram (imaging of the inside of your blood vessels, such as your coronary arter- ies; ); a ventriculogram (imaging of the interior of your ventricles, done for some types of heart valve diseases or diseases of the heart muscle); or electrophysiology studies (an assessment of your heart’s electrical activity). Specialized types of angiograms can be done via catheterization to get information about your peripheral blood ves- sels and the arteries in your lungs (pulmonary angiography). Cardiac catheterization can also be done to study congenital heart defects and to assess the pressures of the blood within the heart.
Less invasive and less expensive tests (such as echocardiography or nuclear scanning) can provide a great deal of information, but only cardiac catheterization can detect some types of problems such as blockage in the artery. Cardiac catheteriza- tion may be done after other tests, in order to con?rm or build on those results. Doctors can also do a biopsy (obtaining a sample of tissue) of heart muscle via a cardiac catheter, to detect in?ammation or to check for tissue rejection after a heart transplant .

Elective Cardiac Catheterization

If you are having cardiac catheterization done for a diagnostic test such as an angiogram or other nonurgent reason, you will probably go to a hospital, but often it is an outpatient procedure. Cardiac catheterization is a relatively common procedure, but because it is invasive it does carry some risk. Your doctor may still recommend it because he or she thinks that the bene?t from the information the test can provide is greater than the risk. Talk to your doctor beforehand and ask any ques- tions that concern you. Some people experience problems such as bruis- ing, temporary numbness, or bleeding at the site of the catheter insertion, but these reactions are infrequent. Some people have allergic reactions to the iodine-based dye that is used as a contrast medium .
More serious complications such as inducing a heart attack, stroke, or an arrhythmia are even rarer and usually occur only in people who are already seriously ill. Remember that you will be carefully monitored and sterile procedures will be followed throughout the test.

What to Expect

Before having cardiac catheterization, talk to your doctor about any med- ications you are taking, because he or she may want you to stop taking them—especially blood thinners or anticoagulants—for several days before the procedure. It’s a good idea to make a written list of your med- ications, including dosages, and bring it with you to the procedure, so that any doctors and technicians present know exactly what you are taking.
You will be told not to eat or drink anything after midnight before having cardiac catheterization. If you have diabetes, talk to your doctor beforehand about your food and insulin intake. If you are allergic to iodine dye, you will receive steroids the day before the test and another medication just before the test (see also the box on page 139.)
On the day of the cardiac catheterization, you can expect that the preparations and the procedure together will take 2 to 3 hours, with several more hours spent in a recovery room. You will probably have blood tests, an ECG (see page 122), and a chest X-ray done ?rst. The procedure itself will be done in a catheterization laboratory, or cath lab. You will be attached to an ECG machine and will wear a blood pressure cuff. An IV will be inserted into your arm, and you will receive a mild sedative to relax you throughout the procedure.
The doctor or nurse will prepare the area of your groin where the catheter will be inserted by cleansing it and shaving it if necessary. He or she will inject your groin area with a local anesthetic so that you will not have any pain, but you will be awake so that your doctor can tell you what is happening and what he or she will do next throughout the procedure. Then the doctor will puncture the skin to enter the artery or vein into which the catheter will be inserted, using a specialized needle, and he or she will thread the catheter into the blood vessel toward your heart. You should not feel any pain during this process.
The doctor will thread the catheter through your artery and up into your heart. Then whatever test or procedure you are having will be per- formed via the catheter. The doctor may guide more than one catheter into different areas of your heart. A variety of instruments can be inserted to guide the tip of the catheter, draw blood samples, inject dye, take pressure readings in the chambers of the heart, and perform other

testing procedures. Depending on what you are having done, you may feel sensations such as ?ushing, brief nausea, or your heart skipping a beat. These feelings are normal, so don’t worry if they occur. Ask your doctor beforehand what you might expect. If you feel any chest pain, tell your doctor right away.
When the procedure is complete, the catheter and the IV will be removed. To stop any bleeding, the doctor or nurse will press very ?rmly on the insertion site, which may be uncomfortable, and then will put on a bandage.
You will be moved to a recovery room, and pressure will be applied on the insertion site for another 15 minutes or so. In some people, stitches or a closure device like a plug are needed to close the artery. You should try to lie still and keep your leg straight for several hours. A nurse will continue to monitor your heart rate and blood pressure. You will be free to leave when the sedative has worn off and any bleeding is controlled.
Someone else should drive you home. At home, plan on resting with your leg (or arm, if that was the insertion site) still for 6 to 8 hours. You should not strain or lift heavy objects for 48 to 72 hours, but you can probably resume normal activities after that. You may be told to take plenty of ?uids to ?ush out the dye. Most people can walk in about 6 hours or so.

What the Results Mean

Cardiac catheterization can be used both as a diagnostic tool and for treatment. The most common diagnostic use is to help show clearly the anatomy of your heart and in particular the blood vessels of your heart. Through imaging during cardiac catheterization, doctors can detect if there are blockages in your blood vessels and also the sizes and locations of the blockages. Treatment options include management with medica- tions and a healthy lifestyle, surgery, or treatment done during catheter- ization. For example, your doctor may perform balloon angioplasty (see page 176) as part of the cardiac catheterization if he or she sees plaque inside the arteries that needs to be compressed against the walls of the blood vessels to allow for improved circulation of blood. In addi- tion, the doctor might place a stent to improve blood ?ow through a blocked artery. If after catheterization it appears that your blood vessels will need surgical repair, the doctor will discuss with you the possibility of a cardiac artery bypass graft . The information from the pictures taken during the catheterization helps the surgeon in plan- ning the procedure. See also “Considering Your Options,”.

Angiography

Angiography is an X-ray examination in which a contrast dye outlines the heart or blood vessels. To perform an angiogram, your doctor will insert a cardiac catheter (see page 143), positioning the tip of the catheter either into your left ventricle or at the opening of each of the coronary arteries. Then an iodine-based contrast agent (dye) will be injected so your doctor can watch the blood ?ow through these struc- tures. Some people are allergic to the iodine-based dye (see the box on page 139 for information on what to do if you are allergic). When the dye is in your ventricle, you may feel warm.
The angiogram shows how well the heart is pumping, its shape and internal parts, and whether there is any faulty valve action that causes leakage or backflow. If the dye is in your coronary arteries, the angiogram shows whether any narrowing or blockages are restricting or cutting off blood supply.

The diagnostic catheterization and angiogram will probably take about 1 hour, but you should allow most or all of the day for the entire procedure. After the test, you will rest until the sedative has worn off. You can drink lots of liquids to help rid your body of the contrast agent.

Electrophysiology Studies

For some people with problems related to their heart’s electrical activ- ity, such as arrhythmias (irregular heartbeats), an ECG or other tests do not give enough information. Electrophysiology studies are tests that require cardiac catheterization to enable doctors to send controlled electrical impulses into the heart to determine where the problem is and how it might be corrected.
To perform electrophysiology studies, the doctor inserts a cardiac catheter  and then passes a type of electrode into the chambers of your heart. This electrode catheter will relay impulses into your heart to make it beat at different speeds. Your doctor can follow the impulses and map your heart’s electrical conduction system and its reaction to the impulses. You might be given a medication through the catheter to cause an arrhythmia, or you might be given medications designed to stop the arrhythmia in order to see which ones work best in you.
Tilt-table testing is another type of electrophysiology test. You will not feel pain, but you will feel your heart changing speeds, and this feel- ing might be uncomfortable or even alarming. In the course of the studies, the table you are lying on may be tilted to bring you into an upright position, because your heart rhythm or blood pressure might change when you are upright. Straps around your chest will hold you securely. This test is usually done on people who have unexplained light-headedness. Because the studies may involve both diagnosing your condition and testing some drugs, the procedure may be lengthy. Depending on what is being done, the studies may take 1 to 4 hours.
After the studies are done, your recovery period will be similar to that for any cardiac catheterization . The risks involved in electrophysiology studies include the risks of any catheterization proce- dure. In addition, even though the electrical stimulation of your heart is very carefully controlled, there is some risk of severely abnormal heart rhythms occurring. The laboratory in which the studies are done is equipped with a de?brillator (a machine that stops abnormal heart rhythms with electric shock). If such an emergency occurs, you may lose consciousness and the doctors will use the de?brillator and resuscitate you if necessary. If you do remain conscious, you will be given a fast- acting anesthetic before the de?brillator is used.

The Testing Process

Very probably, your doctor will need to do several tests to gather enough information to diagnose your condition and decide on the right course of treatment. The series of tests your doctor recommends for you will not necessarily be the same as for someone else with a similar problem. The results of one test might yield information that requires more testing to fully understand your unique situation. You also might need to have the same test several times to determine how your heart is responding to any medications, surgical procedures, or other treat- ments. Your personal medical history is also a factor in determining which tests are appropriate.
Don’t hesitate to ask your doctor why a speci?c test is required at this time and what information he or she hopes to derive. Ask the doc- tor directly about the pros and cons of any procedure, and discuss thoroughly how you feel about any risks versus bene?ts of having the procedure.
You can also ask what different results might indicate about the next steps in your treatment. If you have any questions or concerns, you always have the option of seeking a second opinion. Remember that you are in charge of your own health and should make sure you have enough information to make an informed decision about any test or treatment.
If you decide to get another opinion, either to con?rm a diagnosis or to get more information about your options, tell your doctor that you plan to do so. Your primary-care physician or local medical society can help you ?nd another quali?ed doctor. Never feel guilty about getting a second opinion or think this will hurt your doctor’s feelings.
When you go to see a doctor for a second opinion, bring a complete set of your records and copies of any tests that have been done. If you get a different recommendation from a second doctor, it doesn’t neces- sarily mean that one is right and the other is wrong. There is room for legitimate differences of opinion, especially concerning a complicated problem or major treatment decisions.
You are the most important decision maker. Your con?dence in the choices made and your priorities about how treatments for your heart condition affect your life are extremely important factors to consider. Your overall treatment will be most successful if you and your doctor or doctors are working together to make decisions that positively affect your life.