Articles on Medical Diseases and Conditions

Category: Guide to Preventing and Treating Heart Disease

Essential Information You and Your Family Need to Know about Having a Healthy Heart

  • Nuclear Imaging

    Nuclear imaging, or scanning, techniques produce highly accurate pic- tures of your heart and its function by introducing a small, safe amount

    of radiation into your body. Trace amounts of radioactive material, called radionuclides, are injected into your bloodstream. The radionuclides tag your red blood cells and circulate with them into your heart and heart muscle. A specialized gamma camera, which reacts to the radiation by emitting light, constructs an image that is displayed on a monitor. Your doctor can study both your heart muscle and blood ?ow. Nuclear imaging techniques are often done in combination with a stress test and an injection of thallium. The nuclear isotope ?ows in the blood and may not appear on areas of the heart where there is a decreased blood supply; this is called a cold spot, or a perfusion (?ow) defect.

    Thallium Stress Test

    A thallium stress test shows how well blood is ?owing to the heart mus- cle during exercise. It can show any decreased blood ?ow to speci?c parts of the heart due to blockage of a coronary artery, the aftereffects of a heart attack, the effectiveness of procedures done to open coronary arteries, and other causes of chest pain. This test is also called a perfu- sion scan (perfusion is the ?ow of blood through a speci?c organ or tis- sue) or an isotope stress test (thallium and technetium are the two most common isotopes, or radioactive substances, used for these tests).
    As with other nuclear scanning techniques, thallium or another trac- ing substance injected into your bloodstream travels to your heart and enters heart muscle cells. The images produced by the scan show how much blood is getting to different parts of your heart. If the supply appears reduced to a certain area, it indicates a coronary artery block- age. If no blood is getting to some tissue, it is probably dead (scar) tis- sue from a previous heart attack. The ?ow is compared at rest and after medication-induced stress. The test should not be performed during pregnancy.

    What to Expect

    You prepare for a thallium stress test like any other stress test. Do not eat or drink anything for 3 or 4 hours before the procedure, and wear clothing and shoes that will be comfortable during a treadmill exercise test—for example, athletic shoes or running shoes. Ask your doctor about whether you should take your usual medications before the test, particularly if you have diabetes and are taking insulin. For people who cannot exercise, this test can also be performed after medication is injected to simulate the effects of exercise. Ask how long the test will take; it may take several hours.
    At the time of the test, a technician will apply electrodes to your chest and back that are attached to an ECG (electrocardiography) machine. Your heart rate and blood pressure will be measured, and then you will get on a treadmill. You will continue on the treadmill at a grad- ually increasing pace, until you are at or near your maximum level of exercise. You will be injected with the thallium (or other tracing mate- rial). Your heart rhythm is monitored continuously, and your blood pressure is checked periodically. You will then lie down on a table with a gamma camera over it, and the technician will take images of your heart while it is still working hard. You may need to hold a position for several minutes with your arm raised over your head.
    After the exercise portion of the test is over, you can leave the of?ce or laboratory for 3 or 4 hours. You may get something to eat and drink, as long as it does not contain caffeine or chocolate. When you return, you will lie down on the table under the gamma camera for images of your heart at rest. The thallium has moved through your body and can now be seen. It is important to lie still during this part of the test, which may last from 10 to 20 minutes. Some people ?nd it challenging to lie in one position on a hard table, but there is no actual pain. When the test is complete, you can return to your usual activities and eat or drink anything you like.
    Some laboratories choose to do the resting scan ?rst and then the exercise scan. This test should not be performed during pregnancy.

    What the Results Mean

    You will probably get the full results in a few days. Generally, the results of a thallium stress test are as follows:
    • If your results are normal during both exercise and rest, the blood flow through your coronary arteries to your heart muscle is adequate.
    • If the blood ?ow is normal during rest but not during exercise (which your doctor may call a perfusion defect), then your heart is not getting enough blood when it is working harder. An artery is probably blocked.
    • If your blood ?ow is reduced during rest and worsens during exer- cise, a portion of your heart is undersupplied at all times.
    • If no thallium is present at all in some of your heart muscle both during and after exercise (the so-called ?xed effect), you have prob- ably had a heart attack and some tissue is dead; it is now scar tissue.

  • Echocardiography

    Echocardiography uses high-frequency sound waves (also called ultra- sound) to produce a moving image of your heart. The sound waves are introduced into your body through a handheld device called a trans- ducer. They bounce off the structures and ?uids in the heart and return as echoes through the transducer. The echoes are converted into images on a monitor.

    Echocardiogram

    Using different types of echocardiography, your doctor can see the size, shape, and contraction of the heart muscle; watch the heart valves work- ing; and see how blood is ?owing through your heart and arteries. Dur- ing one test, a two-dimensional mode looks at the heart’s structures and function to see a larger picture, including a cross section; and a form called Doppler echocardiography to assess blood ?ow within the heart and to identify abnormal ?ow patterns.
    In conjunction with a stress test, the echocardiogram may show that the wall of the heart does not move as well after exercise, suggesting that part of the heart may not get suf?cient

    blood flow during exercise. That lack of blood can impair the heart muscle’s ability to contract.

    What to Expect

    You can have an echocardiogram in a doctor’s of?ce or a hospital. You do not need to pre- pare in any special way. You will be asked to remove your clothes, and electrodes will be attached to your chest and back, as in the pro- cedure for an ECG (page 122). The techni- cian will spread a gel over your chest to help with transmission. He or she will move the transducer over your heart and chest, pressing ?rmly, and will ask you to lie in several differ- ent positions and breathe slowly, or hold your breath to improve the image. The entire pro- cedure will take 45 minutes to an hour.

    What the Results Mean

    You may have to wait several days for the full results of the echocardiogram. If the test doesn’t reveal anything unexpected, you may get the results by phone. The test will indicate to your doctor how the chambers or walls of your heart have been altered by conditions such as heart attack, high blood pressure, previous heart damage, or heart failure. If you have had echocardio- grams before, the doctor can compare the results of the tests to assess how effective treatment has been.
    The test also allows the doctor to analyze the strength and nature of your heart’s pumping action, which he or she may describe in terms of the “ejection fraction.” A normal ejection fraction is about 55 to 65 per- cent, meaning that more than half of the blood in your left ventricle (the main pumping chamber) is squeezed out in a single heartbeat. If the percentage is signi?cantly lower, the echocardiogram can show where the pumping action is weakened—for example, it may reveal an area of the heart weakened by a heart attack. The test may be especially meaningful for genetic conditions that can pose the risk of sudden death—for example, hypertrophic cardiomyopathy, which is an abnor- mal thickness of a heart muscle segment commonly observed in young athletes who die suddenly.
    The echocardiogram also reveals the condition of each of the four heart valves and how well they are working. The use of the Doppler mode shows in real time how blood passes through the valves, which can indicate the nature of a valve problem; for example, backward ?ow may indicate a leaky valve. The echocardiogram also gives information about the volume of circulating blood, which might be affected by treatments such as diuretics. The echocardiogram answers questions about how several factors are interacting on your heart, how treatment can be tailored to address a speci?c type of malfunction, and how best to maintain the heart’s ability to pump blood.

    Transesophageal Echocardiography

    Your doctor may order a transesophageal echocardiogram (TEE), a form of echocardiography that overcomes some of the limitations of a regular echocardiogram. As the name implies, a transesophageal echocardiogram involves threading a small probe (less than half an inch wide) down your esophagus (the tube from your throat to your stom- ach). Instead of viewing your heart through your chest wall, the trans- esophageal echocardiogram transmits images from within your esophagus, which is much closer to the heart. It may be necessary if your weight, body shape, or other considerations make conventional echocardiographic techniques less useful.
    You should not eat after midnight on the day of the test. However, if the test needs to be done urgently, it is best not to have eaten for 4 hours so that you are less likely to feel nauseous or vomit. Discuss with your doctor any medications you are taking, and whether you should take them before the test.
    The test will probably be done in a hospital. Because you will be given a sedative, you should make arrangements to get a ride home. First you will lie on a table and an intravenous (IV) line will be inserted into your arm to deliver a sedative. The technician will place electrodes on your chest
    that will be hooked up to an electrocardiographic machine to monitor your heart rhythms through- out the test.
    After numbing your throat with an anesthetic spray, the technician will gently insert a probe with the transducer at the end into your throat and down your esophagus. This part of the procedure is the most uncomfortable, and you may feel like gagging. Once the transducer is in place, you will not feel any pain. You will be partially awake for the pro- cedure, because you may be asked to hold your breath or strain as if you were having a bowel movement, which puts your heart under some pressure and may help reveal problems.
    When the test is over, the transducer and IV will be removed and you will be disconnected from the electrocardiographic equipment. You may feel sleepy from the sedative, and the doctor will want to make sure that your heart rate and blood pressure are normal, so you may remain in the hospital for a few hours. Most often you will be advised to wait at least 2 hours before you eat or drink anything, because your throat may still be numb. After the anesthetic wears off, your throat may be sore for a day or two. It’s best not to drive for 24 hours, to be sure that the anes- thetic is entirely out of your system, so arrange for a ride home from the test.

  • Blood Tests

    Beyond routine blood tests that are done to assess a variety of condi- tions, some blood tests are speci?c to the diagnosis of cardiovascular disease. Blood tests can indicate the levels of lipids (cholesterol and triglycerides), cardiac enzymes (markers of cardiac damage), the oxygen content, and the amount of time it takes for your blood to clot (pro- thrombin time). Some newer blood tests detect injury to the heart muscle in a person who has had a symptom such as chest pain, shortness of breath, or light-headedness. These tests can be done quickly in an emergency setting for immediate detection of a heart attack.
    For some types of blood tests, such as the lipid pro?le, you will be asked to fast overnight. For many heart-related blood tests, blood will be drawn from a vein or sometimes from an artery, rather than from a ?ngertip.

    Lipid ProfileMeasuring the cholesterol circulating in your blood is a common, rou- tine test . Called a lipoprotein pro?le, or sometimes a lipid panel, the test measures the levels of your total cholesterol, low-density lipoproteins (LDL, the “bad” cholesterol), high-density lipoproteins (HDL, the “good” cholesterol), and triglycerides (the most common form of fat in the blood). This is to determine whether you need treat- ment or to check if a treatment is working.
    If these measurements are not precise enough, a more sophisticated test, called a nuclear magnetic resonance lipid test, can be done to more precisely measure and classify subparticles of HDL and LDL. Other new tests, which may help to further assess risk, include measuring apoprotein levels such as apoprotein B, a component of LDL, and apoprotein A-1, a component of HDL. The usefulness of these tests is uncertain; currently, they are used mainly to decide if people with bor- derline high LDL and HDL levels need drug treatment.

    Cardiac Enzymes

    Testing your blood for certain cardiac enzymes (proteins), which are sometimes called cardiac markers because they indicate heart muscle injury, can be a way to detect damage to your heart from a heart attack very early in the course of the attack. If you are having chest pains, your doctor may order these tests to see if damage is being done to your heart. If you go to an emergency room because of warning signs of a heart attack , the doctor will probably do this analysis.
    Small amounts of cardiac enzymes are found in the blood of healthy people. However, the heart muscle is rich in these enzymes, and they can leak into your blood in larger amounts if your heart is damaged by a heart attack. They may enter your bloodstream very early in an attack, before you realize you are having one, or before much heart tissue has been damaged.
    One enzyme commonly measured to con?rm the existence of heart muscle damage is creatine kinase (CK). Different types of CK are found in heart muscles and in the skeleton. The enzyme type that most accu- rately con?rms heart damage is the form of CK known as CK-MB. The level of CK-MB found in the blood increases about 6 hours after the start of a heart attack and reaches its peak in about 18 hours. If you have had a symptom such as pain, testing for these markers can con?rm whether a heart attack has occurred.
    Other cardiac markers called troponins (including troponin I and troponin T) have a role in heart muscle contraction and are very sensitive indicators of heart muscle damage. Their presence in your blood can indicate very mild damage to your heart that tests for creatine kinase don’t detect. Troponins increase in as little as 4 hours after the beginning of an attack and can remain elevated in your blood for 2 weeks.
    Myoglobin is still another marker used to detect heart damage. It is a less speci?c marker of cardiac damage than one type of CK but has the advantage of being the very ?rst of the cardiac markers to rise after a heart attack, as early as a couple of hours after the heart damage occurs. This makes a blood test for myoglobin useful in determining whether someone who is having chest pain is having a heart attack.

    Homocysteine

    Homocysteine is an amino acid in your blood. Doctors have studied homocysteine closely because high levels of it appear to place you at higher risk of cardiovascular disease, regardless of your age or other risk factors. Some evidence suggests that homocysteine might damage the lining of your arteries and promote blood clots, but no direct cause- and-effect relationship has been established. Although homocysteine levels were at first strongly linked to heart disease, more recently researchers have found that link not as strong as they ?rst thought. The level of homocysteine in your blood may be partly hereditary, but it is also related to your diet. In some cases, an elevated level of homocys- teine results from a vitamin B12 de?ciency, so it is important that your doctor measure your level of vitamin B12 through a blood test.
    Your doctor may test your homocysteine levels if you have a strong history of heart disease but you don’t have the obvious risk factors such as high cholesterol, high blood pressure, diabetes, and others. Eating a diet rich in folic acid and B vitamins helps reduce homocys- teine. Many doctors routinely recommend that those at risk for heart disease take folic acid and vitamin B complex. Other doctors rec- ommend the supplements only if homocysteine levels are elevated; however, recent research suggests folate supplements may block the action of naturally occurring folates and vitamin B that you eat in your diet.

    Creactive Protein

    Although high cholesterol is most often considered the major risk fac- tor for heart attack because of its role in the accumulation of plaque in the arteries, not all people who have heart attacks have arteries that are blocked in this way. Doctors have been studying the role of in?amma- tion within the arteries as a separate process that may contribute to the development of coronary artery disease. In?ammation may also explain why in some people, an artery recloses after a balloon angioplasty has been performed to open it.
    In?ammation anywhere in your body causes swelling. If it occurs in your arteries, this swelling can reduce the blood ?ow to your heart. When in?ammation occurs, your body produces a substance called C-reactive protein. The level of C-reactive protein in your blood (detected by a blood test) is a strong predictor of heart disease, espe- cially in people who have had prior heart attacks.
    No one is sure yet what causes the in?ammation in the arteries. It may be a bacterial agent such as Helicobacter pylori (which also causes stomach ulcers) or a viral agent such as the herpes simplex virus. Chlamydia pneumoniae, another type of bacteria, has been studied as a possible predictor of heart disease but with no clear evidence that the bacteria is involved. Some research suggests that in?ammation may damage the arterial wall in a speci?c way that increases the chance of blood clots that block the artery. Obesity and diabetes may also cause an increase in C-reactive protein levels. In fact, visceral or belly fat is the best predictor of an individual’s high level of C-reactive protein. If you are at a moderate or high risk for cardiovascular disease, measur- ing your C-reactive protein may help guide your treatment. You can lower your C-reactive protein with a heart-healthy diet and exercise to lose the belly fat, and also by quitting smoking.

  • Chest X-ray

    Even though far more sophisticated imaging techniques have been developed, the basic chest X-ray can occasionally be a useful tool to assess your cardiovascular system. The X-ray technique works by pass- ing a small, relatively safe amount of radiation through your body and onto a piece of ?lm. The chest X-ray gives your doctor an image of your heart and lungs that reveals the size and shape of your heart, the pres- ence of calcium deposits within your heart, and the presence of congestion in your lungs. If your heart is enlarged, the shape of the enlargement may offer clues to the cause. For example, a narrowed

    heart valve causes a different shape than the enlargement due to conges- tive heart failure.
    Calcium, which shows clearly on an X-ray, sometimes builds up in diseased or injured tissue. In the heart, calcium deposits may accumu- late on a valve, an artery, or the heart muscle itself. The presence of these deposits will direct further testing.
    X-rays also make a picture of your lungs and help your doctor deter- mine whether your symptoms are caused by heart disease or lung dis- ease. The presence of ?uid in lung tissue (a sign called pulmonary edema) means that a weakened heart may have caused ?uid to back up, thereby congesting the lungs (congestive heart failure).
    Having an X-ray done is easy and painless. You will be asked to remove your clothes above your waist and to take off any jewelry that might interfere with the image. You will stand against the X-ray machine, hold your arms out, and hold your breath while the X-ray is being taken (to make your heart and lungs show up more clearly, and to help you hold still).

  • Exercise Echocardiography

    As with other stress tests, an exercise echocardiogram shows how your heart functions when it is working harder. It is most often done to con- ?rm or rule out coronary artery disease. The moving image enables your doctor to see where blockages are occurring.
    A stress echocardiogram may be done in a doctor’s of?ce or a hospi- tal. The test has two parts. First, the technician does a resting echocar- diogram (ultrasound of the heart) while you lie on a table. Then you get on a treadmill or a stationary bicycle and exercise until your heart is working to maximum. A second echocardiogram is done while your heart rate is still high. The test will show if there are any exer- cise-induced changes in your heart in the results of the echocardiogram. For example, in areas of the heart where the blood supply is limited because of obstructions of the blood vessels to the heart muscle, that area may not contract as well as it should. In another example, an exercise- induced abnormality not present when the heart is at rest suggests reversible blood ?ow abnormalities and the need for treatment to prevent a heart attack.

    Chemical Stress Testing

    If a disability (for example, arthritis, back trouble, or a stroke) prevents you from exercising for a stress test, your doctor can use intravenous medication to increase your heart rate combined with an imaging tech- nique such as echocardiography to see how your heart functions when it’s working harder. This method is called chemical or pharmacologic stress testing. The medications most commonly used are dobutamine, dipyridamole, or adenosine.
    The drugs are administered so that your heart rate increases gradu- ally. If you are able to do some exercise, you may be asked to walk on a treadmill for a minute or so after the drug is injected. Trained medical assistants will monitor you throughout the test, and you should report any unusual symptoms. Dobutamine may cause a marked increase in blood pressure or an arrhythmia. Adenosine may cause a brief, passing slowing of the heart rate. Both adenosine and dipyridamole can cause wheezing and should be used cautiously, if at all, in people with asthma or chronic obstructive pulmonary disease. The drugs can be stopped at any time.
    Preparation for a chemical stress test is similar to regular stress test- ing. You will be asked not to eat or drink anything for at least 3 hours before the test, in order to avoid nausea. If you take medications, be sure to talk to your doctor about what to do; you may need to stop tak- ing them for an interval before the test. If you have diabetes and take insulin, you will need speci?c instructions. If you have any history of asthma, bronchitis, or emphysema, tell your doctor, because some stress-inducing medications may be harmful to you.

  • Electrocardiography

    Electrocardiography is a technique to study your heart’s electrical activ- ity by recording the path of an electrical impulse from its origin in the sinoatrial node through your heart as it causes the heart to contract (see page 11). The printout of this activity, an electrocardiogram, is a graph of the electrical activity of each heartbeat over time and the rhythm of successive beats.

    Electrocardiogram

    The electrocardiogram (ECG) is a safe, inexpensive way to get a wealth of information: it tells your doctor about your heart rate and heart rhythm. The ECG may also suggest whether a heart attack has occurred and whether there are potential problems with blood supply to the heart. It is a routine, painless test.

    What to Expect

    You do not have to prepare in any special way to have an ECG, except perhaps to wear clothes that you can take off easily. The ECG may be done in your doctor’s of?ce or in a hospital. For the test, you may be asked to change into a hospital gown and sit or lie on an examina- tion table. In order to conduct the electrical impulse, electrodes will be attached to various parts of your body: your chest, back, wrists, and ankles. To ensure a good connection between your skin and each elec- trode, which is mounted on a sticky patch, the technician will clean these areas, perhaps shave areas of the chest on a man, and apply a conducting gel. Then he or she will hook up the electrodes and enter

    some data into the electrocardiograph machine. You will not feel anything during the testing, which usually lasts a minute or less. There is no electrical energy being passed into your body, and there is no danger of electrical shock. The ECG simply records your heart’s activity.

    What the Results Mean

    In a healthy person, the electrical impulse during a heartbeat follows a regular, sequential path. The electrodes over different parts of your heart follow the path of the impulse and record it on the ECG. The most basic piece of information it gives is your heart rate, which is usu- ally measured by your pulse, but the ECG can give a more accurate rate if your pulse is unusually irregular or hard to feel. Normal heart rates range between 60 and 100 beats per minute.
    The ECG also indicates your heart rhythm, which should be regu- lar. The test may reveal either an abnormally fast beat (tachycardia) or an abnormally slow one (bradycardia). It can also demonstrate an elec- trical blockage in the heart that alters the rhythm and causes an irregu- lar ECG tracing. Each type of arrhythmia causes a distinctive type of tracing pattern.
    In addition, the ECG may tell whether you have had a heart attack, because damaged muscle or scar tissue doesn’t transmit the electrical impulse the same way as healthy tissue would. It can indicate approxi- mately where the damage is in the heart ventricle. Often the ECG reveals evidence of a past heart attack that you didn’t even know occurred. It can also indicate if you are having an attack during the test.
    A component of the wave on the ECG can be affected by an inade- quate supply of blood or oxygen to your heart, particularly if the test is obtained during chest pain symptoms. Further tests may be necessary to determine why this is happening and under what circumstances.
    The ECG can provide information about structural abnormalities, the effects of medications on the heart rhythm and electrical conduc- tion, hypertension, kidney problems, or hormonal problems that affect the wave pattern in speci?c ways. Although a normal ECG does not always exclude heart disease, it still is a reassuring ?nding. Also, if there is a heart problem, the ECG may give clues that indicate what type of testing is needed to further isolate and identify the problem.

    Holter Monitoring

    Because a conventional ECG records only a brief period (6 seconds) of your heart activity, a continual recording over a period of 24 hours or longer may be useful to identify changes in your heart’s rate or rhythm. To accomplish this form of ambulatory ECG, you will wear a battery-powered recording device called a Holter monitor. About the size of a small paperback book, the Holter monitor is portable enough to wear around your waist or on your belt. The monitor connects to electrodes placed on your chest via wires (leads) that pass under your clothes.
    Being ?tted for a Holter monitor is a painless procedure. It is a good idea to bathe or shower before you go to your doctor’s of?ce, because you cannot get the monitor wet once you are wearing it. The technician will prepare your skin just as for an of?ce ECG. At least one electrode and lead may be taped down to secure it as you move around. You will wear the device usually for 24 hours, including while you sleep. You will also be asked to keep a log as you go about your usual day: what you were doing and whether you experienced any symptoms, and at what times. Every heartbeat will be recorded and analyzed for information.
    After the designated monitoring period, you will return to your doc- tor’s of?ce to turn in the device. Having the electrodes removed might be uncomfortable, like tearing off a bandage. The tracings for the mon- itoring period will be analyzed, and correlations will be made between the Holter recording and the times of unusual symptoms or events in your log.

    Event Monitoring

    If you are having symptoms that are unpredictable or infrequent, you may have to use another ECG device called an event monitor or transtelephonic monitor, which records your heart rhythm. You are usu- ally asked to use this monitor for one month. You can take it off to bathe, or for other brief periods, but it’s best to wear it as often as possible. A small recorder is attached to a bracelet or ?nger clip. If you experience a symptom, such as light-headedness, you attach the recorder (if you are not wearing it) and push a button on the monitor that triggers a memory of what was recorded for several minutes before and after you pushed the button. This data can be transmitted over the telephone, or you can bring the monitor to the of?ce. This helps identify any rhythm disturbances that occur while you have symptoms. If a dangerous rhythm problem is identi?ed, you may be instructed to seek medical attention urgently.
    Another type of event monitor, this one implantable, has been devel- oped to capture your heart’s activity during infrequent symptoms that occur only a few times a year. Called an implantable loop recorder, it is inserted in your chest, and you wear it for as long as 18 months.

    Exercise Stress Testing

    An exercise stress test is a continuous ECG that shows how your heart performs during exercise, when the body is demanding more blood and oxygen. It shows the adequacy of the blood sup- ply to the coronary arteries and how well the heart muscle functions. You also might hear it called a treadmill test, an exercise tolerance test, or an exercise ECG. It is a common diagnostic tool for detecting coronary artery disease and the origin of symptoms such as chest pain, because it shows whether the blood supply in the coronary arteries is reduced. It can identify a safe level of exercise for any heart patient, checks the effectiveness of medications, helps predict the risk of heart attack, and checks the effectiveness of procedures done to improve circulation in a person with coronary artery disease.
    The test is designed to place stress on your heart—about as much as a fast walk or a jog up a hill in a carefully controlled environment with trained staff close at hand. During the test, the technician will carefully monitor your heart rate, breathing, blood pressure, heart rhythm, and how tired you feel.

    Having an exercise stress test
    An exercise stress test is a type of ECG that shows how the heart performs when you exercise. Usually the test is done while you walk on a treadmill, and then the speed or slope are gradually increased to make your heart work harder. The test is like a carefully supervised workout, with a warm-up, a gradual increase in the level of exercise, and a cool-down period. A doctor or technician will watch you closely throughout the test.

    The most typical stress test is done by having you walk on a treadmill or ride a stationary bicycle. If the test shows that your heart doesn’t function normally during exercise, you may need to repeat the treadmill test combined with echocardiography  or nuclear tech- nology  to better identify the problem. Often these tests are done with the initial exercise stress test to improve the accuracy of diagnosis, especially in women. If you are unable to exercise because of illness, you may undergo a chemical stress test (see page 128), for which you will be given a drug that mimics some of the effects of exercise on your heart rate while ECG tracings or nuclear images are made.

    What to Expect

    You will be asked not to eat for 12 hours before the test, because a meal can make you uncomfortable or nauseous. You can drink a small amount of liquid such as water, but no beverage such as coffee, tea, soda, or chocolate that contains caffeine. Be sure to ask your doctor about any medications you take and whether you should stop taking them before the test. If you have diabetes, you will be given speci?c instructions about taking insulin.
    A technician will prepare your skin for the placement of electrodes, similar to the preparation for a regular ECG. You will also be ?tted with a blood pressure cuff. A resting ECG will be taken before you start exercising, and then you will get on a treadmill or a bicycle. The ?rst 2 or 3 minutes you will exercise at a slow, warm-up pace. Then every 2 or 3 minutes, the speed or slope will be increased gradually to simulate going uphill. The doctor will probably encourage you to continue until you are too tired to go on, or until you have a symptom such as pain, dizziness, or shortness of breath. After this pro- cedure, you lie down or sit quietly for about 10 minutes. Your doctor or technician will monitor your heart and blood pressure throughout this period. He or she will ask you questions about how tired or out of breath you feel. If the ECG reveals any potential problems, the doctor or technician will ask you to stop exercising. After the test is complete, you can return to your normal day.

    What the Results Mean

    The doctor reading the ECG may be able to tell you preliminary results immediately, but a complete analysis will probably take several days. If the test shows that your heart functions normally during exer- cise, the results can be used to help you plan a ?tness program. If the results indicate that your heart functions abnormally during exercise, you may need to have more tests, such as an echocardiographic stress test  or a nuclear stress test, to determine more precisely where the blood supply is being blocked. On occasion, you may go straight to having an angiography . If you already have coronary artery disease, the test can reveal a new blockage or one that is worsening.
    The choice of stress testing will depend in part on your medical history and your doctor’s preferences. Exercise stress testing is less specific—and therefore, less helpful—than thallium or echocardio- graphic stress testing; however, exercise stress testing is much less expensive and thus is often used as a ?rst step in screening for heart dis- ease. Those who already have heart conditions that may in?uence the ECG result may need nuclear stress testing. Echocardiographic stress testing may be better for women because women, especially young women, are prone to false positives on ECGs.

  • Evaluating a Heart Problem

    If you experience any symptoms that might be indicators of a heart problem—such as chest pain, shortness of breath, or a pounding heart—see your doctor immediately. He or she will interview you thoroughly about your medical history and symptoms and then do a physical examination to try to detect what might be causing the symptoms. Depending on what the examination reveals, he or she may order further testing to diagnose the problem. If you know what to expect, you will probably feel more relaxed about the exam, and you can be better prepared to answer questions. It will be very helpful if you can bring in notes with speci?c details about when you experienced a symptom, how often it recurred, and how long it lasted.

    Medical History

    If you are seeing a doctor for the ?rst time, he or she will ask some gen- eral questions about your medical history. If you are reporting a speci?c event, the questions will focus on that event. Here is a general outline of what to expect:
    • Questions about your chief complaint. Your doctor will want to know what brought you into the of?ce. He or she will ask speci?c questions such as how it felt, when it occurred, what you were doing when it occurred, or what seemed to relieve it. Be as thor- ough and speci?c as you can be. Do not hesitate to volunteer information beyond the questions.
    • Questions about your medical history. Information about other medical conditions you have or have had can help indicate possi- ble causes for your symptoms and rule out unnecessary tests or inappropriate treatments. Again, written notes may help you remember illnesses, tests, or surgery that you have had. If you are seeing a specialist, your other doctor or doctors may be able to send medical records and test results in advance of your appoint- ment. If you are referred to a spe- cialist, ask the referring doctor for pertinent test results to take with you to the appointment.
    • Medications. Your doctor will want to review all the medications you are taking; bring a list that includes dosages to the appointment. It is important to include herbal prepa- rations and nonprescription med- ications, because they may interact with other drugs. Also, know and remember your drug allergies.
    • Family history. Be prepared to answer questions about the medical history of your parents, siblings, and children. This information gives the doctor clues about hereditary aspects of some conditions and your overall risk.
    • Lifestyle. Information about habits such as smoking or drinking, diet, and exercise are important. Some of these factors may help explain a symptom; for instance, caffeine can cause an irregular heartbeat in some people. Do not worry about looking bad or being embarrassed by your habits. This information can help a great deal with diagnosis and treatment. You may also be asked questions about your workplace and about stress.
    • Other organ systems. Your doctor may systematically review other body systems to make sure nothing is overlooked.

    A Physical Examination in Detail

    A cardiovascular physical examination will include taking your blood pressure (see page 43), measuring your heart rate and rhythm by check- ing your pulses, inspecting the veins in your neck, checking your body for swellings, and listening to the sounds of your breath, heart, and

    blood vessels. You will probably be asked to change out of your clothes into a hospital gown and sit or lie on an examining table.
    • Measuring your heart rate and rhythm. Your doctor will check the pulse at your wrist, in the carotid arteries in your neck, or in the femoral arteries in your groin. The pulses enable him or her to measure your heart rate and to determine if your heart- beat is regular, skips beats, or has extra beats. An absent or reduced pulse at one of the sites may indicate a blockage in a blood vessel.
    • Veins in your neck. The doctor will look at (not feel) the jugular vein in your neck to observe the pulse. The location and size of the pulse indicates the pressure on the right side of the heart and the possible presence of excess ?uid in your system.
    • Swelling. Swellings in parts of your body such as your legs and ankles can indicate excess ?uid or a blockage in a vein.
    • Listening to your breath. Listening to your breath sounds by placing a stethoscope on your chest can reveal ?uid building up in your lungs (which makes a crackling sound) or scarred tissue in your lungs. Thumping on your chest can help locate where the ?uid is; a ?uid-?lled area sounds dull instead of hollow.
    • Listening to your heart. Putting the stethoscope on four distinct sites over your heart, your doctor can listen to blood ?owing through your heart and heart valves. A heart murmur is the sound of turbulence caused by a problem with a valve or another heart structure. You may be asked to stand up, squat, or lie back, because murmurs change when you are in different positions. Extra sounds, called gallops, or other types of sounds may indicate vari- ous types of heart problems. Some unusual sounds are completely harmless.
    • Listening to blood vessels. Your doctor can evaluate blood ?ow in large blood vessels by listening at different points in your neck, abdomen, and groin. Turbulence in these vessels makes a sound called a bruit, which may indicate blockage.
    Depending on what the doctor learns from this basic examination, or “cardiac workup,” he or she may order blood tests, imaging procedures, or other tests of cardiac function in order to diagnose more speci?cally and plan treatment.

    After a physical examination including listening to your heart and lungs with a stethoscope—your doctor will need more detailed infor- mation about your heart. The doctor will ask questions about diseases you have been diagnosed with, any persistent symptoms you have noticed, and your family medical history. A variety of tests are available to examine the structure of your heart, how well it functions, whether it is damaged or diseased, and the nature or extent of the disease.
    Which tests you take depend on your symptoms, your medical history, your general cardiac condition, and your doctor’s assessment. Usually you will have some simple tests ?rst, such as an ECG (an electrocardiogram, which records your heart’s electrical activity), and then additional tests as needed to assess your particular problem. In addition to electrocardiography, other means of testing include blood tests; echocardiography (which uses sound waves to examine the heart valves and chambers); different types of stress tests (to study the heart while it is working harder); nuclear imaging (using safe amounts of radioactive materials to study heart function); other imaging tech- niques; and in some cases, more invasive tests that are done in a hospi- tal setting.
    The tests can reveal useful information speci?c to your heart symp- tom or problem that will help guide your treatment. Many of the tests are noninvasive, meaning that they do not involve a needle stick or the introduction of any catheters (tubes) into your body. Knowing how and why a test is performed will help you feel more comfortable, and under- standing something about the possible results will help you learn about your heart along with your doctor. Don’t hesitate to ask questions before or after any test. Many tests require your permission or informed consent, and your doctor should fully explain beforehand any risks from the tests.

  • Physical Examinations and Diagnostic Tests

    The best way to monitor your health is to see your doctor and work together as a team for your health. Many of the major risk factors (such as blood pressure and cholesterol) are apparent only with a med- ical examination. The earlier you can identify a problem area and start to work on it, the more likely you will be able to prevent the develop- ment of more serious disease. For instance, an evaluation of prehyper- tension (see page 43) or prediabetes (see page 106) gives you a head start on these risk factors. As you work on one risk factor (for instance, exer- cising more to lower cholesterol) you will very likely be improving oth- ers as well. Know all your risk factors from your medical history—not only high blood pressure, diabetes, and smoking, but also risks from
    menopause, aging, and lifestyle choices regarding food and exercise.

  • Stress

    In addition to the major risk factors for heart disease (high cholesterol, high blood pressure, physical inactivity, smoking, and diabetes), stress can be a contributing factor. The effects of stress on your heart health are dif?cult to study and quantify in part because people not only expe- rience different levels of stress, but they also respond differently. Researchers have identi?ed several ways that stress may adversely affect some people’s hearts:
    • Under stress, your body releases extra hormones (epinephrine and norepinephrine) that raise your blood pressure, which may over time injure the lining of your arteries. As the arteries repair them- selves, they may thicken, which promotes the buildup of plaque.
    • A stressful situation tends to raise your heart rate and blood pres- sure, so your heart requires more oxygen. In someone who already has heart disease, this oxygen shortage can bring on chest pain (angina).
    • Stress increases the clotting factors in your blood, which increases the chances that a blood clot will form and block an artery, espe- cially one already partially closed by plaque.
    Then, of course, there are the ways that many people may choose to deal with stress—overeating, smoking, drinking excessively—that are damaging to the cardiovascular system.

    The fact is that everyone is under stress of some kind at least intermittently and perhaps much of the time. You can usually recognize symptoms of your own stress in the form of aches and pains, dif?culty ?ghting off mild infections like colds, sleeplessness, or feelings of anxiety or irritability. You also probably know when some of your less healthy coping mecha- nisms are escalating—as, for example, when you put on weight during a tough time, or start smoking more.
    Learning to manage stress makes good sense for your overall health. But more research is needed before experts can reliably recommend specific methods of stress reduction as treatments for cardio- vascular diseases. Generally, if you or your doctor believes that stress is having a harmful effect on your health, you can work on several strategies to manage its impact:

    • Communicate with family and friends about the things that trou- ble you. Their support and love will help reduce your response to stressful situations.
    • If you feel a sense of urgency because of competing demands on your time, consider time management techniques that will help you prioritize and set realistic expectations. Your workplace, library, or the Internet may offer speci?c methods. Also, be cau- tious about agreeing to take on new projects.
    • Choose a relaxation technique, such as yoga, meditation, or biofeedback, and make time to master it and practice it regularly. Although there is no conclusive medical proof these techniques can lower blood pressure, there are some promising studies point- ing in that direction.
    • When you know that a speci?c problem is causing you anxiety, talk to your doctor or other health-care provider about a support group that focuses on that problem. These resources may be avail- able through a community center, hospital, religious organization, or YMCA.
    • Professional counseling or psychotherapy may help you through certain dif?cult periods. Your doctor can help refer you to an     appropriate professional. If medications such as antidepressants are appropriate, your doctor or a psychiatrist can prescribe them and help you get essential counseling as well.
    • Use commonsense therapy: eat a healthy diet, exercise regularly (see the box on page 80), limit alcohol and caffeine, and do not smoke.
    Managing stress, or preventing stress in the ?rst place, is especially important to people who have already had a heart attack or a stroke. Preventing another heart attack or stroke called secondary prevention by doctors is a key goal for the doctor-patient team. As noted repeat- edly in this book, lifestyle changes are crucial to prevention or second- ary prevention, and stress management should be a key focus of lifestyle changes that also include controlling your cholesterol level, controlling your blood pressure, losing weight if needed, exercising regularly, and stopping smoking.
    Depression may be related to stress but is a disorder that needs treat- ment. It is natural to a certain degree to feel “blue” or be upset after a heart attack or a stroke. However, if you have persistent depression, it is important to note that it is treatable—that is, not just “something to live with” (see also “Depression after a Stroke,” page 232). Depression symptoms include prolonged periods of feeling sad or unable to cope, strong feelings of guilt, strong feelings of pessimism or loss of hope, a loss of interest in normal pleasures (including sex), unusual weight changes (unintentional losses or gains), and dif?culty relating to loved ones or coworkers. If you or a loved one has depression, seek treatment from your primary care doctor; he or she will make treatment sugges- tions, possibly including medications or talking therapy, or refer you to a psychiatrist or other mental health professional.

  • Peripheral Artery Disease

    Peripheral artery disease (PAD) occurs when the blood vessels in the leg are narrowed or plugged by the buildup of plaque. Atherosclerosis, the process that causes PAD, tends to start earlier in life and progress more rapidly in people with diabetes. In most people, PAD is symptomless in its early stages. If the disease progresses to a severe stage, however, the most common symptom is pain in the leg muscles—not the joints— when you exert yourself. This symptom, called intermittent claudica- tion, means that the muscles in your legs and feet are not getting enough blood and oxygen when they are working. The pain of intermit- tent claudication comes on with activities such as walking and is relieved by rest or stopping the activity. Without treatment, PAD can progress to the point where the blood supply is so poor that it can lead to dam- age of skin and muscle tissue deprived of blood in your lower legs and feet. Surgery on the blood vessels or even amputation may be necessary in severe cases. A large number of amputations of toes, feet, or legs occurs in people with diabetes and PAD.
    As many as one in three people with diabetes has peripheral artery disease, but they may not realize it if they have not experienced any signs. Your risk of having PAD is higher if you smoke, have high blood pressure, have high cholesterol, are overweight, are physically inactive, are over 50 years old, have a family history of cardiovascular disease, or have already had a heart attack or a stroke.
    If you notice that your calves hurt when you exercise but stop hurting when you rest; if you often sense numbness, tingling, or cold- ness in your legs or feet; or if you have sores or infections on your feet or legs that don’t heal, see your doctor right away to be tested for PAD.
    If you have experienced neuropathy, a common diabetic symptom that is a burning sensation in the feet or thighs, you might easily con- fuse the two types of pain. Describe the pain as speci?cally as possible to your doctor. He or she may want to test for the condition even if you are not experiencing symptoms, especially if you have some of the risk factors in addition to your diabetes.
    The most common test for PAD is checking the pulses in your ankles and feet. If you have PAD, your treatment will begin with lifestyle changes, including quitting smoking, controlling your diabetes, control- ling your blood pressure, being more physically active, beginning an exercise program to improve blood ?ow, and eating a low-fat diet to control your cholesterol. Your doctor may also prescribe medications, such as drugs that treat your leg pain so that you can walk farther; antiplatelet agents, which help prevent blood clots; or statins, which help lower your blood cholesterol.