Heart Attack Diagnosis

  • Diagnosis

    A heart attack, clinically known as a myocardial infarction, occurs when an artery supplying the heart with blood carrying oxygen and nutrients suddenly becomes blocked, causing part of the heart muscle to die Figure 01. Because your heart is a muscle, it needs oxygen to function, just like any other tissue. The special blood vessels that feed the heart are called coronary arteries. Coronary artery disease is a process of narrowing that occurs over time in these important vessels and can lead to a heart attack. The narrowing is caused by the build-up of fats and plaques in arteries, and can exist and grow without any symptoms.

    When the artery becomes blocked, your heart does not receive the blood and oxygen it needs to survive. A heart attack can leave your heart much weaker and less able to pump blood around to the rest of your body, as a portion of the muscle has died and is no longer functioning as well.

    Click to enlarge: What happens during a heart attack

    Figure 01. What happens during a heart attack

    Heart attacks are the most common cause of cardiovascular death. Worldwide, about 20% to 30% of patients suffering from a heart attack die from it, one-third within the first few hours.

    Most heart attacks occur because the walls of an artery have a built up a fatty material called cholesterol plaque. The plaque ruptures, exposing a new, rough surface and releases a substance that causes the blood to clot. The clot forms on the plaque and blocks the artery Figure 02. The buildup of fatty material (cholesterol plaque) in the arteries is called artherosclerosis. It is the underlying cause of most heart attacks. The plaque buildup causes the arteries to harden and narrow, which makes may reduce blood delivery to the heart during exercise or stress. This can cause momentary chest pain that comes on when the heart is stressed (a condition known as angina). The plaque eventually ruptures, and its rough surface attracts the type of blood cells that cause clotting. Once the clot forms, no more blood reaches the heart, and part of the muscle usually dies as a result.

    Click to enlarge: Healthy artery vs. an artery with plaque buildup

    Figure 02. Healthy artery vs. an artery with plaque buildup

    High blood pressure (hypertension), as well as smoking cigarettes, pipes, or cigars, may contribute to plaque buildup. Your heart also has to work harder when pushing against a “high-pressure” system. This increased workload makes your heart larger and more inefficient. High blood pressure also can lead to congestive heart failure, kidney damage or kidney failure, dementia, and blindness.

    Occasionally, inflammatory diseases or cocaine abuse can also cause a heart attack.

    Stress, anger, or physical exertion may trigger a heart attack if your arteries are clogged and you have heart disease. Doctors do not understand why a heart attack often follows physical or emotional stress. One reason may be that during a stressful episode, your heart’s need for oxygen increases but the body is unable to increase the blood flow through the diseased heart (ischemia). Stress hormones also make arteries narrow, which may cause a break in the fatty material built up in the blood vessel. Researchers have noticed that number of heart attacks increases during earthquakes and other natural disasters.

    Severe chest pain is the most frequent symptom of a heart attack, although it is possible to be having a heart attack and not have chest pain at all. Another common symptom is a sensation of heavy pressure on the chest Figure 03. Signs of a heart attack can be subtle or very obvious, and they vary from person to person. Chest pain from a heart attack, if it is present, can be strong and constant and usually lasts for 30 minutes or more. Many people describe the pain as crushing, while others say it is like squeezing, or burning. The pain often radiates down the left arm, but can also spread to your neck, back, right arm, jaw or upper chest. Some people feel little pain, while others describe the sensation as similar to heartburn, or a tight feeling in the chest. If you have more than one heart attack in your lifetime, the second attack may feel different from the first, so it’s a good idea to be familiar with the possible symptoms.

    Click to enlarge: Areas of pain with heart attack

    Figure 03. Areas of pain with heart attack

    You are likely to feel anxious, restless and nauseous, and look pale, gray, and sweaty.

    You may feel faint, weak or short of breath, and have a sense of impending doom. You may even vomit.

    The pain from a condition called angina (medical term for chest pain due to coronary heart disease) is similar to what you may feel during a heart attack. If you have angina, and the pain does not go away within a few minutes after resting or medication, you may be having a heart attack. Angina is a symptom of a condition myocardial ischemia (insufficient blood supply to the heart). This occurs when the heart muscle (myocardium) doesn't get as much blood (hence as much oxygen) as it needs for a given level of work. Angina attacks may be brought on by exercise, stress, or excitement, but can even happen when you are at rest. Angina is almost always an indication that you are at risk for a heart attack sometime in the future. Attacks usually only last a few minutes, and the pain can be eased with medication called nitroglycerin. The nitroglycerin pills are placed under the tongue and work almost immediately to control the pain, as they dissolve quickly and enter the bloodstream right away. If you take your medication and rest, but the pain does not go away, it may be due to a heart attack. If pain is not relieved after three nitroglycerin pills, you should seek immediate medical attention, usually by calling 911.

    Being over the age of 50, being male, and having heart disease in your family all put you at greater risk for heart attack. Older adults are more likely to suffer from coronary artery disease than younger people. Eighty percent of people who die from the disease are 65 or older. Men are at greater risk of heart attack than women. A man’s risk begins around the age of 35 or 40, although even younger men have been known to have heart attacks. Women become at risk for coronary artery disease by the time they are in their late fifties or early sixties. Once a woman has been postmenopausal for 10 years, her risk is equal to that of a man.

    Estrogen is believed to protect the heart from the disease, which is why more heart attacks are seen in post-menopausal women. After a woman stops menstruating (menopause), which usually occurs in the mid to late forties, the amount of estrogen she produces drops significantly. It is not a coincidence that more heart attacks are seen in post-menopausal women.

    Children of people with coronary heart disease are more prone to the condition.

    If you smoke cigarettes, cigars, and pipes, your risk of heart attack is doubled. Smoking increases the rate fatty material builds up in the arteries. In addition, secondhand smoke can up the odds for nonsmokers who are exposed to it.

    Having high blood pressure and high blood cholesterol makes you more likely to have a heart attack. The buildup of fatty material, called plaque, can be caused by consuming too much of certain types of fats. High blood pressure (hypertension) exaggerates this process.

    Having a diet that contains high levels of bad cholesterol puts you at greater risk for developing high blood pressure and coronary artery disease. Cholesterol is a type of soft, fat-like substance (lipid) critical to good health in moderate quantities. It is a part of cell membranes, is found in all body tissues, and can be converted into various hormones. Cholesterol comes from two sources: your own liver produces it, and it is also found in food you eat (especially animal products such as meat, poultry, seafood, dairy products, and eggs).

    Risk factors like smoking tobacco, not getting enough exercise, and being overweight or obese can be controlled. Having high blood pressure, high cholesterol, and high fat levels in the blood are also risk factors that you can manage. Medications, if necessary, can be used to control cholesterol and high blood pressure, and are usually very effective, as is diet and exercise.

    If you have diabetes mellitus, you are at greater risk of heart attack than nondiabetics. Even if you maintain good control of your blood sugar levels, about 66% of those with diabetes die of a heart or blood vessel condition.

    Your chances of developing coronary artery disease increase with each risk factor you have. If you are an obese smoker with high blood pressure, high cholesterol, and a family history of heart disease, you have a greater chance of developing heart disease than someone who has only one of these conditions. The level of severity in each risk factor also increases the possibility of getting heart disease.

    Increased homocysteine (a naturally occurring amino acid) levels are also a risk factor. Homocysteine is a naturally occurring amino acid. A high blood level of homocysteine (known as hyperhomocysteinemia) is thought to be a risk factor because it can irritate your arteries, making them rigid and rough, which can lead to plaque buildup. Doctors are still looking into the connection between homocysteine and heart disease, but many believe taking folic acid and vitamins B6 and B12 may help lower your homocysteine levels and thus your risk of developing coronary heart disease.

    Stress plays a part as well. Stress hormones may make fatty material built up in the artery more likely to break, because they cause the arteries to constrict. Stress management may help you to better cope with situations that make you mad. Whether this reduces the likelihood of a heart attack is not known at present.

    Your doctor may perform several tests to determine if you are having a heart attack. If you are having chest pains, your doctor will perform an electrocardiogram (ECG). This test keeps track of the electrical activity in your heartbeat, and will alert your doctor of specific changes that occur only when you experience a heart attack. You health professional may also do a blood test that measures certain cardiac enzymes (released by dying heart cells) that are detectable a few hours after a heart attack occurs. The levels of these enzymes (known as cardiac markers) can help your doctor determine if a heart attack is present (if the ECG did not already do this). Your doctor may order other tests, such as an ultrasound to examine the heart (echocardiogram) or nuclear imaging, if the results of an ECG and other tests do not clearly show whether or not you are having a heart attack. If you have had a heart attack, you may have low blood pressure or an increased heart rate, so your doctor will also listen to your heart and lungs to check for any complications.

    Forming good habits early in life is the best way to prevent a heart attack. Control your weight and adopt healthy eating habits. Plaque buildup usually begins in the late teens, meaning all adults have a certain amount of it. It takes a long time for the buildup to develop, which means you have many years to form the kinds of healthy lifestyle habits that will prevent the buildup from becoming heavy.

    Avoid red meat, fried foods, high-fat dairy products and high-fat processed foods. Avoid the skin of chicken, and eat eggs only occasionally, as they are both high in cholesterol. Learn to substitute other types of snacks on the run, such as low-fat yogurt and fruit, for greasy fast food. The earlier you adopt good habits, the easier it will be to reach for something healthy when you need a quick bite, as opposed to stopping for a hotdog or a hamburger at lunch when you are in a hurry.

    The diet and exercise habits that you form over the long term will have the greatest effect on lowering your risk for heart attack. Your health care professional can help to provide you with a sensible eating and exercise plan

    Changing your diet to include more fruits, vegetables, and fish, developing an exercise program, and quitting smoking can decrease your risk of a heart attack. Try to eat two to three servings of fruit and three to five servings of vegetables a day. Eating fish twice a week is also recommended. Losing even 10 to 20 pounds can help cut heart risks if you are overweight. Regular, vigorous exercise can help prevent coronary artery disease, but even moderate routines are helpful and can lower cholesterol, blood pressure, weight and blood sugar levels. If you are a smoker, you can dramatically and quickly lower your risk of suffering from a heart attack by stopping today.

    While drinking moderate amounts of alcohol (one drink per day for women and two for men) may lower your coronary heart disease risk, doctors do not recommend that you start drinking or increase the amount of alcohol you normally consume. Studies have shown that people who drink moderate amounts of alcohol have a lower risk of heart disease than nondrinkers; however, too much alcohol can increase blood pressure and cause other problems.

    Have your blood pressure and cholesterol levels checked. An easy blood pressure check can alert you to potential problems, and your doctor can order a simple blood test to check your cholesterol levels. If your blood pressure or cholesterol levels are high, you and your doctor can decide on a plan to bring the numbers down to within normal range. Your doctor will want to see blood pressure readings below 135/85 mm Hg. Your levels of “good” cholesterol (HDL) and your levels of “bad” cholesterol (LDL) are important to consider, in addition to your total cholesterol level, which doctors recommend to be less than 200 mg/DL.

  • Prevention and Screening

    Forming good habits early in life is the best way to prevent a heart attack. Control your weight and adopt healthy eating habits. Plaque buildup usually begins in the late teens, meaning all adults have a certain amount of it. It takes a long time for the buildup to develop, which means you have many years to form the kinds of healthy lifestyle habits that will prevent the buildup from becoming heavy.

    Avoid red meat, fried foods, high-fat dairy products and high-fat processed foods. Avoid the skin of chicken, and eat eggs only occasionally, as they are both high in cholesterol. Learn to substitute other types of snacks on the run, such as low-fat yogurt and fruit, for greasy fast food. The earlier you adopt good habits, the easier it will be to reach for something healthy when you need a quick bite, as opposed to stopping for a hotdog or a hamburger at lunch when you are in a hurry.

    The diet and exercise habits that you form over the long term will have the greatest effect on lowering your risk for heart attack. Your health care professional can help to provide you with a sensible eating and exercise plan

    Changing your diet to include more fruits, vegetables, and fish, developing an exercise program, and quitting smoking can decrease your risk of a heart attack. Try to eat two to three servings of fruit and three to five servings of vegetables a day. Eating fish twice a week is also recommended. Losing even 10 to 20 pounds can help cut heart risks if you are overweight. Regular, vigorous exercise can help prevent coronary artery disease, but even moderate routines are helpful and can lower cholesterol, blood pressure, weight and blood sugar levels. If you are a smoker, you can dramatically and quickly lower your risk of suffering from a heart attack by stopping today.

    While drinking moderate amounts of alcohol (one drink per day for women and two for men) may lower your coronary heart disease risk, doctors do not recommend that you start drinking or increase the amount of alcohol you normally consume. Studies have shown that people who drink moderate amounts of alcohol have a lower risk of heart disease than nondrinkers; however, too much alcohol can increase blood pressure and cause other problems.

    Have your blood pressure and cholesterol levels checked. An easy blood pressure check can alert you to potential problems, and your doctor can order a simple blood test to check your cholesterol levels. If your blood pressure or cholesterol levels are high, you and your doctor can decide on a plan to bring the numbers down to within normal range. Your doctor will want to see blood pressure readings below 135/85 mm Hg. Your levels of “good” cholesterol (HDL) and your levels of “bad” cholesterol (LDL) are important to consider, in addition to your total cholesterol level, which doctors recommend to be less than 200 mg/DL.

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