Disease: Heart Disease
(Coronary Artery Disease)
What is heart disease?
The heart is like any other muscle in body and it requires adequate blood supply to provide oxygen to allow the muscle to contract and pump. Not only does the heart pump blood to the rest of the body, it also pumps blood to itself via the coronary arteries. These arteries originate from the aorta (the major blood vessel that carries oxygenated blood away from the heart) and then branch out along the surface of the heart.
Picture of a cross section of the heart.When one or more coronary arteries narrow, it may make it difficult for adequate blood to reach the heart, especially during exercise. This can cause the heart muscle to ache like any other muscle in the body. Should the arteries continue to narrow, it may take less activity to stress the heart and provoke symptoms. The classic symptoms of chest pain and shortness of breath due to atherosclerotic or coronary artery disease are called angina.
Should one of the coronary arteries become completely blocked, usually due to a blood clot that forms, blood supply to part of the heart muscle is completely lost and that piece of muscle dies. This is called a heart attack or myocardial infarction (myo=muscle + cardia=heart + infarction= tissue death).
Heart disease, for this article, will be limited to describing the spectrum of atherosclerosis or hardening of the arteries that ranges from minimal blockage that may produce no symptoms to complete obstruction that presents as a myocardial infarction. Other topics, such as myocarditis, heart valve problems, and congenital heart defects will not be covered.
What are the risk factors for heart disease?
Factors that increase the risk of developing atherosclerotic heart disease include the following:
- Smoking
- High blood pressure (hypertension)
- High cholesterol
- Diabetes
- Family history
- Obesity
Since heart disease, peripheral artery disease, and stroke share the same risk factors, a patient who is diagnosed with one of the three has increased risk of having or developing the others.
What causes heart disease?
Heart disease is the leading cause of death in the United States and can be attributed to the lifestyle factors that increase the risk of atherosclerosis or narrowing of arteries. Smoking, along with poorly controlled hypertension, and diabetes, causes inflammation and irritation of the inner lining of the coronary arteries. Over time, cholesterol in the bloodstream can collect in the inflamed areas and begin the formation of a plaque. This plaque can grow and as it does, the diameter of the artery for blood flow narrows. If the artery narrows by 40% to 50%, blood flow is compromised or decreased enough to potentially cause the symptoms of angina.
In some circumstances, the plaque can rupture or break open, leading to the formation of a blood clot in the coronary artery. This prevents oxygen-rich blood from being delivered to the heart muscle beyond that blockage and that part of the heart begins to die. This is a myocardial infarction or heart attack. If the situation is not recognized and treated, the affected muscle cannot be revived and is replaced by scar tissue. Long term, this scar tissue decreases the heart's ability to pump effectively and efficiently and may lead to ischemic cardiomyopathy (ischemic=decreased blood supply + cardio=heart + myo=muscle + pathy=disease).
Heart muscle that lacks adequate blood supply also becomes irritable and may not conduct electrical impulses normally. This can lead to abnormal electrical heart rhythms including ventricular tachycardia and ventricular fibrillation. These are the heart arrhythmias associated with sudden cardiac death.
What are the symptoms of heart disease?
The classic symptoms of angina, or pain from the heart, are described as a crushing pain or heaviness in the center of the chest with radiation of the pain to the arm (usually the left) or jaw. There can be associated shortness of breath or sweating. The symptoms tend to be brought on by activity and get better with rest. Some patients may complain of indigestion and nausea while others may have upper abdominal, shoulder, or back pain.
Unfortunately, not all pain from coronary artery disease presents in this manner. The more we learn about heart disease, the more we realize that symptoms can be markedly different in different groups of people. Women, people who have diabetes, and the elderly may have different pain perceptions and may complain of overwhelming fatigue and weakness or a change in their ability to perform routine daily activities like walking, climbing steps, or doing household chores. Some patients may have no discomfort at all.
Most often, the symptoms of heart disease become worse over time, as the narrowing of the affected coronary artery progresses over time and blood flow to that part of the heart decreases. It may take less activity to provoke symptoms and it may take longer for those symptoms to resolve with rest. This change in exercise tolerance is helpful in making the diagnosis.
Too often, however, the first presentation of heart disease may be a myocardial infarction, where a plaque ruptures causing one of the coronary arteries to occlude and prevent blood flow to the heart. This can lead to crushing chest pressure, shortness of breath, sweating, and perhaps sudden cardiac death.
How is heart disease diagnosed?
The diagnosis of heart disease begins by taking the patient's history. The health care professional needs to understand the patient's symptoms and this may be difficult. Often, health professionals ask about chest pain, but the patient may deny having pain because they describe their symptoms as pressure or heaviness. As well, words may have different meanings. The patient may describe their discomfort as sharp, meaning intense, while the health care professional may understand that term to mean stabbing. For that reason, it is important for the patient to be allowed to take the time to describe the symptoms in their own words.
The health care professional may ask questions about the quality and quantity of pain, where it is located, and where it might travel. It is important to know about the associated symptoms including shortness of breath, sweating, nausea, vomiting, and indigestion, as well as malaise and fatigue.
The circumstances surrounding the symptoms are also important. Are the symptoms brought on by activity? Do they get better with rest? Since they began, is less activity required to provoke the symptoms? Do the symptoms wake the patient? These are questions that may help decide wither the angina is stable, progressing, or becoming unstable.
- With stable angina, the activity that is required to initiate the symptoms does not fluctuate. For example, a patient may state that their symptoms are brought on by climbing up two flights of stairs or walking one mile.
- Progressive angina would find the patient stating that the symptoms are brought on by less activity than previously.
- In the case of unstable angina, symptoms may arise at rest or wake the patient from sleep.
Risk factors for heart disease will be assessed including high blood pressure, diabetes, cholesterol control, smoking history, and family history.
Physical examination may not necessarily help make the diagnosis of heart disease, but it can help decide whether other underlying medical problems may be the cause of the patient's symptoms.
After the history and physical examination are complete, your health care professional will request more testing if heart disease is considered a potential diagnosis. There are different ways to evaluate the heart anatomy and function; the type and timing of a test needs to be individualized to each patient and their situation.
Most often, the health care professional, perhaps in consultation with a cardiologist, will order the least invasive test possible to determine whether coronary artery disease is present. Although heart catheterization is the gold standard to define the anatomy of the heart and to confirm heart disease diagnosis (either with partial or complete blockage or no blockage), this is an invasive test and not necessarily indicated for many patients.
Electrocardiogram (EKG, ECG)
The heart is an electrical pump and electrodes on the skin can capture and record the impulses generated as electricity travels throughout the heart muscle. Heart muscle that has decreased blood supply conducts electricity differently than normal muscle and these changes can be seen on the EKG.
A normal EKG does not exclude coronary artery disease; it means that there may be narrowing of the coronary arteries that has yet to cause heart muscle damage. An abnormal EKG may be a “normal” variant for a patient and the result has to be interpreted based upon the patient's circumstances.
If possible, an EKG should be compared to previous tracings looking for changes in the electrical conduction patterns.
Stress tests
It would make sense that during exercise, the heart is asked to work harder and if the heart could be monitored and evaluated during that exercise, the test could uncover abnormalities in heart function. That exercise may occur by asking the patient to walk on a treadmill or ride a bicycle while at the same time, an electrocardiogram is being performed. Medications (adenosine, persantine, dobutamine) can be used to stimulate the heart, if the patient cannot exercise because of poor conditioning or because of an underlying medical condition.
Learn more about: persantine | dobutamine
Echocardiography
Ultrasound examination of the heart to evaluate the anatomy of the heart valves, the muscle, and its function may be performed by a cardiologist. This test may be ordered alone or it may be combined with a stress test to look at heart function during exercise.
Nuclear imaging
A radioactive tracer that is removed from the blood by heart muscle cells can be used to indirectly assess blow flow to the heart. Technetium or thallium can be injected into a vein while a radioactive counter can be used to map out how the blood is distributed within heart muscle cells.
Cardiac computerized tomography (CT)
Using high speed CT scan, the anatomy of the coronary arteries can be evaluated, including how much calcium is present in the artery walls and whether there is blockage or narrowing present.
Cardiac catheterization
As mentioned above, this is the gold standard for coronary artery testing. A cardiologist threads a thin tube through an artery in the groin, elbow, and wrist into the coronary arteries. Dye is injected to assess the anatomy and whether blockages are present. If so, it is possible that angioplasty may be performed, where a balloon is inflated to squash an obstructing plaque into the wall of the artery to re-establish blood flow. A stent may be placed to keep the artery from narrowing again.
What is the treatment for heart disease?
The goal is to maximize the quantity and quality of life and prevention is the key to avoid heart disease and optimize treatment. Once plaque formation has begun, it is possible to limit its progression by maintaining a healthy lifestyle with routine exercise, diet, and by controlling high blood pressure, high cholesterol, and diabetes.
A baby aspirin may be used for its antiplatelet activity, making platelets (one type of blood cells that help blood clot) less sticky and decreasing the risk of heart attack.
Learn more about: aspirin
Medications may be prescribed in patients with heart disease to maximize blood flow to the heart and increase efficiency of the pumping function of the heart.
Beta blocker medications help block the action of adrenaline on the heart, slowing the heart rate. These medications also help the heart beat more efficiently and decrease the oxygen requirements of the heart muscle during work.
Calcium channel blockers also help the heart muscle contract and pump more efficiently.
Nitrates help dilate arteries and increase blood flow to the heart muscle. They may be short-acting to treat acute angina symptoms or long-acting preparations may be prescribed.
Should there be significant stenosis or narrowing of the coronary arteries, angioplasty and/or stenting (described above) may be considered to open the blocked areas. These procedures are performed in conjunction with cardiac catheterization. Depending upon the patient's anatomy and the extent of the blockage present, coronary artery bypass graft surgery (CABG) may be required.
What are the risk factors for heart disease?
Factors that increase the risk of developing atherosclerotic heart disease include the following:
- Smoking
- High blood pressure (hypertension)
- High cholesterol
- Diabetes
- Family history
- Obesity
Since heart disease, peripheral artery disease, and stroke share the same risk factors, a patient who is diagnosed with one of the three has increased risk of having or developing the others.
What causes heart disease?
Heart disease is the leading cause of death in the United States and can be attributed to the lifestyle factors that increase the risk of atherosclerosis or narrowing of arteries. Smoking, along with poorly controlled hypertension, and diabetes, causes inflammation and irritation of the inner lining of the coronary arteries. Over time, cholesterol in the bloodstream can collect in the inflamed areas and begin the formation of a plaque. This plaque can grow and as it does, the diameter of the artery for blood flow narrows. If the artery narrows by 40% to 50%, blood flow is compromised or decreased enough to potentially cause the symptoms of angina.
In some circumstances, the plaque can rupture or break open, leading to the formation of a blood clot in the coronary artery. This prevents oxygen-rich blood from being delivered to the heart muscle beyond that blockage and that part of the heart begins to die. This is a myocardial infarction or heart attack. If the situation is not recognized and treated, the affected muscle cannot be revived and is replaced by scar tissue. Long term, this scar tissue decreases the heart's ability to pump effectively and efficiently and may lead to ischemic cardiomyopathy (ischemic=decreased blood supply + cardio=heart + myo=muscle + pathy=disease).
Heart muscle that lacks adequate blood supply also becomes irritable and may not conduct electrical impulses normally. This can lead to abnormal electrical heart rhythms including ventricular tachycardia and ventricular fibrillation. These are the heart arrhythmias associated with sudden cardiac death.
What are the symptoms of heart disease?
The classic symptoms of angina, or pain from the heart, are described as a crushing pain or heaviness in the center of the chest with radiation of the pain to the arm (usually the left) or jaw. There can be associated shortness of breath or sweating. The symptoms tend to be brought on by activity and get better with rest. Some patients may complain of indigestion and nausea while others may have upper abdominal, shoulder, or back pain.
Unfortunately, not all pain from coronary artery disease presents in this manner. The more we learn about heart disease, the more we realize that symptoms can be markedly different in different groups of people. Women, people who have diabetes, and the elderly may have different pain perceptions and may complain of overwhelming fatigue and weakness or a change in their ability to perform routine daily activities like walking, climbing steps, or doing household chores. Some patients may have no discomfort at all.
Most often, the symptoms of heart disease become worse over time, as the narrowing of the affected coronary artery progresses over time and blood flow to that part of the heart decreases. It may take less activity to provoke symptoms and it may take longer for those symptoms to resolve with rest. This change in exercise tolerance is helpful in making the diagnosis.
Too often, however, the first presentation of heart disease may be a myocardial infarction, where a plaque ruptures causing one of the coronary arteries to occlude and prevent blood flow to the heart. This can lead to crushing chest pressure, shortness of breath, sweating, and perhaps sudden cardiac death.
How is heart disease diagnosed?
The diagnosis of heart disease begins by taking the patient's history. The health care professional needs to understand the patient's symptoms and this may be difficult. Often, health professionals ask about chest pain, but the patient may deny having pain because they describe their symptoms as pressure or heaviness. As well, words may have different meanings. The patient may describe their discomfort as sharp, meaning intense, while the health care professional may understand that term to mean stabbing. For that reason, it is important for the patient to be allowed to take the time to describe the symptoms in their own words.
The health care professional may ask questions about the quality and quantity of pain, where it is located, and where it might travel. It is important to know about the associated symptoms including shortness of breath, sweating, nausea, vomiting, and indigestion, as well as malaise and fatigue.
The circumstances surrounding the symptoms are also important. Are the symptoms brought on by activity? Do they get better with rest? Since they began, is less activity required to provoke the symptoms? Do the symptoms wake the patient? These are questions that may help decide wither the angina is stable, progressing, or becoming unstable.
- With stable angina, the activity that is required to initiate the symptoms does not fluctuate. For example, a patient may state that their symptoms are brought on by climbing up two flights of stairs or walking one mile.
- Progressive angina would find the patient stating that the symptoms are brought on by less activity than previously.
- In the case of unstable angina, symptoms may arise at rest or wake the patient from sleep.
Risk factors for heart disease will be assessed including high blood pressure, diabetes, cholesterol control, smoking history, and family history.
Physical examination may not necessarily help make the diagnosis of heart disease, but it can help decide whether other underlying medical problems may be the cause of the patient's symptoms.
After the history and physical examination are complete, your health care professional will request more testing if heart disease is considered a potential diagnosis. There are different ways to evaluate the heart anatomy and function; the type and timing of a test needs to be individualized to each patient and their situation.
Most often, the health care professional, perhaps in consultation with a cardiologist, will order the least invasive test possible to determine whether coronary artery disease is present. Although heart catheterization is the gold standard to define the anatomy of the heart and to confirm heart disease diagnosis (either with partial or complete blockage or no blockage), this is an invasive test and not necessarily indicated for many patients.
Electrocardiogram (EKG, ECG)
The heart is an electrical pump and electrodes on the skin can capture and record the impulses generated as electricity travels throughout the heart muscle. Heart muscle that has decreased blood supply conducts electricity differently than normal muscle and these changes can be seen on the EKG.
A normal EKG does not exclude coronary artery disease; it means that there may be narrowing of the coronary arteries that has yet to cause heart muscle damage. An abnormal EKG may be a “normal” variant for a patient and the result has to be interpreted based upon the patient's circumstances.
If possible, an EKG should be compared to previous tracings looking for changes in the electrical conduction patterns.
Stress tests
It would make sense that during exercise, the heart is asked to work harder and if the heart could be monitored and evaluated during that exercise, the test could uncover abnormalities in heart function. That exercise may occur by asking the patient to walk on a treadmill or ride a bicycle while at the same time, an electrocardiogram is being performed. Medications (adenosine, persantine, dobutamine) can be used to stimulate the heart, if the patient cannot exercise because of poor conditioning or because of an underlying medical condition.
Learn more about: persantine | dobutamine
Echocardiography
Ultrasound examination of the heart to evaluate the anatomy of the heart valves, the muscle, and its function may be performed by a cardiologist. This test may be ordered alone or it may be combined with a stress test to look at heart function during exercise.
Nuclear imaging
A radioactive tracer that is removed from the blood by heart muscle cells can be used to indirectly assess blow flow to the heart. Technetium or thallium can be injected into a vein while a radioactive counter can be used to map out how the blood is distributed within heart muscle cells.
Cardiac computerized tomography (CT)
Using high speed CT scan, the anatomy of the coronary arteries can be evaluated, including how much calcium is present in the artery walls and whether there is blockage or narrowing present.
Cardiac catheterization
As mentioned above, this is the gold standard for coronary artery testing. A cardiologist threads a thin tube through an artery in the groin, elbow, and wrist into the coronary arteries. Dye is injected to assess the anatomy and whether blockages are present. If so, it is possible that angioplasty may be performed, where a balloon is inflated to squash an obstructing plaque into the wall of the artery to re-establish blood flow. A stent may be placed to keep the artery from narrowing again.
What is the treatment for heart disease?
The goal is to maximize the quantity and quality of life and prevention is the key to avoid heart disease and optimize treatment. Once plaque formation has begun, it is possible to limit its progression by maintaining a healthy lifestyle with routine exercise, diet, and by controlling high blood pressure, high cholesterol, and diabetes.
A baby aspirin may be used for its antiplatelet activity, making platelets (one type of blood cells that help blood clot) less sticky and decreasing the risk of heart attack.
Learn more about: aspirin
Medications may be prescribed in patients with heart disease to maximize blood flow to the heart and increase efficiency of the pumping function of the heart.
Beta blocker medications help block the action of adrenaline on the heart, slowing the heart rate. These medications also help the heart beat more efficiently and decrease the oxygen requirements of the heart muscle during work.
Calcium channel blockers also help the heart muscle contract and pump more efficiently.
Nitrates help dilate arteries and increase blood flow to the heart muscle. They may be short-acting to treat acute angina symptoms or long-acting preparations may be prescribed.
Should there be significant stenosis or narrowing of the coronary arteries, angioplasty and/or stenting (described above) may be considered to open the blocked areas. These procedures are performed in conjunction with cardiac catheterization. Depending upon the patient's anatomy and the extent of the blockage present, coronary artery bypass graft surgery (CABG) may be required.
Source: http://www.rxlist.com
In some circumstances, the plaque can rupture or break open, leading to the formation of a blood clot in the coronary artery. This prevents oxygen-rich blood from being delivered to the heart muscle beyond that blockage and that part of the heart begins to die. This is a myocardial infarction or heart attack. If the situation is not recognized and treated, the affected muscle cannot be revived and is replaced by scar tissue. Long term, this scar tissue decreases the heart's ability to pump effectively and efficiently and may lead to ischemic cardiomyopathy (ischemic=decreased blood supply + cardio=heart + myo=muscle + pathy=disease).
Heart muscle that lacks adequate blood supply also becomes irritable and may not conduct electrical impulses normally. This can lead to abnormal electrical heart rhythms including ventricular tachycardia and ventricular fibrillation. These are the heart arrhythmias associated with sudden cardiac death.
Source: http://www.rxlist.com
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