I frequently see patients and family members in hospitals trying to describe a test or procedure their doctor recently briefed them on. When new patients are asked about their cardiac medical history, I often get blank responses. In this article, I will describe some of the more common cardiology tests and procedures performed today. I will limit myself to those involving the coronary arteries. In a future article, I will refer to tests and procedures involving the electrical systems, such as electrophysiological studies and pacemakers.

Medical information is one of the most helpful tools for a doctor. Some of my patients are so computer savvy that they have their medical history on a spreadsheet-type format. Whatever your method may be, I suggest the following information be available: 1) a history of current medical illnesses; 2) current medications; 3) any surgeries, plus when and where they were performed; 4) a list of all doctors with phone numbers; and finally, 5) your pharmacy’s information, including a fax number.

My favorite cardiac anatomy rendition remains the anatomy lesson given on the television episode of “Happy Days.” The heart is a four-chambered system with valves that keeps blood moving. The upper chambers are called the atria; the lower chambers are called the ventricles. Between these chambers on the right and left side are the tricuspid and mitral valves, respectively. Unoxygenated blood enters the right atrium and right ventricle. It then passes through the pulmonic valve and into the lung, where it picks up oxygen. It then travels into the left atrium through the mitral valve and finally into the left ventricle. Oxygenated blood in the left ventricle subsequently passes the aortic valve and goes into the largest artery in the body called the aorta, where blood is distributed to all parts of the body.

The first arteries off the heart are the coronary arteries. They supply oxygen to the heart muscle itself and run on the outside of the heart feeding inwardly. There are three coronary arteries, each responsible for different parts of the heart. The left main gives rise to the left anterior descending artery (LAD), which runs and supplies the front or anterior surface of the heart, as well as the septum (the area between the right and left ventricles). The circumflex coronary artery (LCx, also off the left main artery) supplies the posterior surface of the heart.

There are side branches to each of these arteries. Those off the LAD are called the diagonals, and those in the circumflex are called the obtuse marginal. Occasionally, an artery exists between the LAD and circumflex artery, called the ramus branch. The artery that supplies the bottom or inferior surface of the heart and right ventricle is called the right coronary artery (RCA). The RCA splits into two branches: the posterior descending artery (PDA) and the posterior lateral branch (PLB).

Coronary artery disease is generally considered the narrowing or stenosis of the arteries that supply the heart. The narrowing is frequently caused by a buildup of fat and cholesterol to form a plaque on the inside of the artery. Stenosed arteries reduce blood flow, which reduces the amount of oxygen delivered to the heart. When this happens, the heart cannot pump efficiently, and this could lead to chest pain and lethal arrhythmias.

One of the simplest tests to determine if you have significant coronary artery disease is the Exercise Stress Test (EST). Most stress tests today involve the addition of a radioactive isotope or tracer that is taken up by the heart. This study is called a Myocardial Perfusion Imaging Study or Nuclear Exercise Stress Test (NEST). The three most commonly used tracers are Thallium, Cardiolite and Myoview.

I have been asked about the amount of radiation involved. The camera itself is a gamma-ray-producing camera and therefore, produces no radiation. The amount of radiation in the tracer is minimal. Often these three isotopes I mentioned will be out of your body in less than three to four hours. You generally get more radiation from the Earth’s surface called “Radon” then being injected. There are rare occasions when allergic reactions to these isotopes occur.

The heart scan is a two-part test. The first part, called the rest phase, involves injecting the tracer, followed by a resting scan. In the second part, the heart is stressed either chemically or by treadmill, causing the heart arteries to dilate and therefore, increase flow. If treadmill exercise is difficult for you, we can bypass this by injecting additional drugs, such as Adenosine or Lexiscan.

Healthy arteries dilate more than non-healthy arteries. The tracer concentrates in those areas of the heart with generally better flow. In a healthy heart, there is no difference between images, but in a heart with a stenosed artery, there will be a difference in the scan between rest and stressed images called a reversible defect. A person with a previous heart attack causes a defect in that area on both stress and rest images called a fixed defect.

Prior to the test, you generally should not eat anything for 10 hours. Try to avoid certain drugs. Tell your doctor about any medications you are taking, especially those containing Theophylline or aspirin, as well as products containing caffeine.

Risks occur with these tests. Someone always tells me his or her relative died during this test. Although possible, this is extremely rare. It happens in about one in 10,000 patients. Other possible complications include allergic reactions, heart attacks, strokes and possibly death. Again, all are extremely rare. Remember, you are undergoing this test to try to avoid a big catastrophic event like a massive heart attack. Therefore, you need to weigh the risks and benefits, and in most cases, the benefits from the test far outweigh the risks.

Transthoracic Echocardiogram (TTE or 2-D Echocardiogram) is another imaging test that helps your doctor evaluate the heart. This is a completely harmless test that uses sound waves that bounce off your heart and a transducer to create an image of your heart from these sound waves. Transducers may be used to create a Doppler signal and measure the blood flow to various chambers.

The Echocardiogram can generally tell the cardiologist the following: 1) how big the heart is; 2) how thick the heart is (sometimes a measure of how blood pressure is effecting your heart, as well as how efficacious your blood pressure medication is); 3) how the heart valves are functioning, and whether they are blocked or leaking; 4) how good your heart is functioning – a term called the “ejection fraction” (normal between 50 and 75 percent); and 5) if there is any fluid around your heart – called a pericardial effusion.

We can also assess wall motion, looking at each region of the heart. Remember, each region is supplied by a specific coronary artery; therefore, if the anterior wall is not moving, the LAD is probably involved.

Transesophageal Echocardiogram (TEE) is similar to the 2-D Echocardiogram, but is more like high-definition imaging. In the transthoracic echocardiogram, the transducer probe is placed on the outside of the chest wall. The problem is that bony structures, as well as lung tissues that lie between the surface and the heart, can sometimes distort or interfere with the images, making it difficult to interpret the test.

In the Transesophageal Echocardiogram (TEE0), the transducer is sitting in the esophagus (the tube that connects your mouth with the stomach). The information obtained is the same as that from a Transthoracic Echocardiogram, plus some additional data. Valves are seen that can determine whether there are infectious vegetations on them. A fifth chamber called the left atrial appendage is a source of clots in patients with atrial fibrillations. A cardioversion can be performed safely if no clot exists.

A foramen ovale is a hole that is present at birth, but should close soon after birth. This hole allows the right atrium to communicate directly with the left atrium during pregnancy so that oxygenated blood from the mother passes directly to the fetus. Remember, the fetal lungs are not mature yet. Vocal chord damage or perforation of the esophagus (a surgical emergency) may occur in extremely rare cases.

CT Angiography is a new test that involves the use of a CAT scanner, plus dye injected from a peripheral vein. The coronary arteries can be visualized. There have been problems with this test. It involves an extremely large amount of radiation exposure to view the coronary arteries, and some lesions in the coronary arteries may not be visualized accurately. The only known complications are allergic reaction to injected contrast media and renal failure.

Cardiac Catheterization is the insertion of a flexible catheter tube up and into the coronary arteries. Angiography is described as taking an X-ray picture of blood vessels in the heart. Generally, most left-heart cardiac catheterizations are performed from a peripheral site, most commonly the right groin at the level of the common femoral artery or the radial artery in the arm.

An introducing sheath or tube is inserted into either artery. As mentioned above, sometimes the sheath is placed in the arm; however, most of them are performed from the groin. The sheath remains in place during the entire procedure. The catheter is then slid over a wire inserted in through the sheath and threaded up the aorta and finally advanced to the level of the coronary arteries. Since arteries have no pain nerves, you will not feel this. Subsequently, X-ray dye or contrast is injected through the catheter, which allows visualization of the coronary arteries. You may feel a warm flush as the dye is injected.

The camera is moved to obtain many views of the coronary arteries. A catheter may also be inserted into the left ventricle and left ventriculography performed. This is another determination of how well the left ventricle is functioning and is used to determine the ejection fraction. If an artery is blocked, an Angioplasty may be performed.

In a balloon Angioplasty, a special balloon-tip catheter is inserted at the level where the artery is blocked, and air is inserted into the balloon, which opens up the artery. Sometimes a stent is deployed at this area, also. A stent provides support for the artery. Stenting after an Angioplasty helps reduce the risk of re-stenosis (closure of the artery again). In some cases, a stent may be placed directly without balloon angioplasty being performed first. Most stents are drug-eluding stents allowing the slow release of medication over a period of time. This reduces the amount of scar tissue that forms inside the artery and helps prevent re-stenosis. The stent is in a collapsed form on a balloon. Once in place, the balloon is inflated. This pushes the plaque against the wall and opens the stent. The balloon is then deflated, which leaves the stent in place. After stenting, an Angiogram is usually taken to confirm that blood flow has improved.

Your doctor may also perform a special imaging study called an Intravascular Ultrasound Study (IVUS), in which a transducer catheter is placed directly down the coronary artery, allowing crystal clear views of the inside of the artery and how well the stent is deployed against the vessel wall. On occasion, a right-heart catheterization may also be performed, along with the left-heart catheterization. This involves advancing a balloon-tip catheter (Swan-Ganz) up and into the right side of the heart. The catheter is basically used to measure pressures inside the lung and determine whether or not pulmonary hypertension exists. As with any procedure, there may be complications. The following is a list of complications that can occur:

• - Femoral arterial damage, with possible need for surgical repair
• - Emboli/stroke, with possible need for blood thinners or thrombectomy
• - Major and minor bruising/bleeding, possibly requiring the need for blood transfusions or surgical intervention
• - Acute renal failure, with possible need for temporary or permanent dialysis
• - Anaphylactic reactions/shock, from injected contrast media with possible need for mechanical intubation or pressure support
• - Myocardial infarction
• - Cardiac perforation, with possible need for emergency pericardiocentesis
• - Possible insertion of a temporary or permanent pacemaker or intra-aortic balloon pump
• - Emergency coronary artery bypass graft surgery
• - Possible cardiac death

Currently, the complication rate for cardiac catheterization is about one in 250 patients, and for angioplasty, about one to two per 100 patients. Again, the risks of the procedure are weighed against the benefits. All of the cardiac procedures mentioned are performed with conscious sedation. No general anesthesia is required.

I hope this will help you understand some of the tests used to determine the status of the coronary arteries and the risks involved. It is important to remember to 1) try to reduce your risk factors (i.e., quit smoking, watch your cholesterol and exercise daily), 2) follow your doctor’s orders and 3) take medications as prescribed.

On a final note, at Bible study, my pastor asked me how many lives I had saved. Although flattered, I told him my usual answer: “God had a good week and saved quite a few of them. Apparently, he still has unfinished work to do.” Robert subsequently mentioned to me that God works through my hands. I can tell you this thought never leaves my mind. I will never forget or abuse this great gift God has given me. In a similar fashion, God has given all of us a gift. I hope you sincerely accept this gift, whatever it is, with humility and continue trying to help your fellow man.

Salvatore A. Barbaro III, M.D., practices general and interventional cardiology at his private practice located at 19234 Stonehue, San Antonio, Texas, 78258. For more information, please call 210-490-4600.