Heart disease is a general term for a wide variety of diseases and conditions that affect the function of the heart.
What is going on in the body?
The main job of the heart is to pump blood to the rest of the body. The primary concern with most heart conditions is how much they affect the heart's ability to pump blood. When people use the term heart disease, they are most often referring to atherosclerosis, or clogged arteries.
Clogged heart arteries cause coronary artery disease, or CAD. In turn, coronary artery disease can lead to:
chest pain in the form of stable angina or unstable angina
congestive heart failure, in which the heart fails to pump enough blood to supply body tissues
- irregular heartbeats, or arrhythmias
Heart disease, however, can also refer to many other conditions. This is important for people to remember when they see or hear the term heart disease. Heart disease is the leading cause of death in the United States and in many other countries.
What are the causes and risks of the disease?
There are many causes of heart disease. Atherosclerosis, or clogging of the arteries, is partly or fully responsible for many diseases that affect the heart, including:
congestive heart failure, a condition in which a weakened heart is unable to pump enough blood throughout the body
heart attacks, also called myocardial infarctions
irregular heartbeats, or arrhythmias, such as ventricular tachycardia
- stable angina or unstable angina, conditions in which chest pain occurs when the heart fails to receive enough oxygen
Factors that increase a person's risk of developing atherosclerosis include:
- excess weight and obesity
- family history of atherosclerosis or coronary artery disease
- high blood pressure
- high cholesterol levels
- increasing age
- lack of exercise
- male gender
High blood pressure can cause heart disease even when arteries are not clogged. The increased blood pressure can cause heart enlargement, called hypertrophy, and congestive heart failure. It also increases the risk of clogged arteries, which can further damage the heart.
Congenital heart disease, which means heart disease that is present at birth, can result in a heart that has an abnormal structure or function. For example, a baby with Down syndrome may have an atrial septal defect and/or ventricular septal defect. Heart valve conditions, such as pulmonary stenosis, may be present at birth as well.
Other causes of heart disease include:
- autoimmune disorders, in which the body is attacked by its own immune system
- heart valve infections, known as endocarditis, which can damage the valves and cause conditions such as aortic regurgitation or mitral stenosis
- infections of the heart muscle, known as myocarditis
- infection of the lining around the heart, a condition called bacterial pericarditis
- kidney failure, which can cause pericarditis, an inflammation of the lining around the heart. Kidney failure may also cause an abnormal collection of fluid around the heart, called pericardial effusion.
- toxins, such as alcohol and some chemotherapy medicines used to treat cancer. Both of these can cause a condition called cardiomyopathy,a disease of the heart muscle.
Many other conditions can also affect the heart.
What can be done to prevent the disease?
Prevention of heart disease is related to its cause. Heart disease caused by atherosclerosis can be prevented by not smoking and by controlling high blood pressure, diabetes, and cholesterol. Avoidance of alcohol could prevent cases due to this cause. Maintaining a healthy body weight, including physical activity in everyday life, and eating a diet designed to minimize heart disease can help decrease heart disease risk.
The American Heart Association recently issued recommendations about hormone replacement therapy (HRT) in women. For women who have already had a heart attack or have heart disease, it appears that HRT does not protect against having another heart attack or dying from heart disease. The studies that support this information were done with women over 65 years of age. It is unclear if this information also holds true for younger postmenopausal women who take HRT.
For women who have not already had a heart attack or who do not have heart disease, HRT should not be started for the sole purpose of preventing heart disease. The research is not strong enough to support doing that at this time. Also, it is not necessary for a woman to stop HRT if she is doing well on it.
Overall, the decision to use HRT should be based upon the proven benefits and risks of HRT. Women should discuss the benefits and risks with their healthcare professionals. Together, they can choose the most appropriate course of action.
How is the disease diagnosed?
Heart disease is often suspected after a medical history is taken and a physical exam is performed. Further tests may be done to determine the type, severity, and cause of the heart condition. These may include:
blood and urine tests
cardiac catheterization, a special X-ray done with a contrast agent to look at the heart and its blood supply
echocardiogram, which uses sound waves to view the beating heart
electrocardiogram (ECG), which shows the electrical activity of the heart
- stress ECG tests, in which the person either walks on a treadmill or receives a medicine while the effects on the heart are examined with an ECG or imaging test
Long Term Effects
What are the long-term effects of the disease?
Long-term effects depend on the type, severity, and cause of heart disease. Heart attacks
and congestive heart failure
are common causes of death in the United States. Heart infections may go away completely after treatment and have no long-term effects. In other cases, they may cause permanent damage to the heart or even death.
What are the risks to others?
Heart disease is not contagious. Some inherited causes of heart disease can be passed on to one's children. If the underlying cause is an infection, the infection may be contagious.
What are the treatments for the disease?
There are many possible treatments for heart disease. Medicines are commonly used to:
act as diuretics, or water pills, such as furosemide (i.e., Lasix) and hydrochlorothiazide (i.e., Microzide)
control high blood pressure, such as atenolol (i.e., Tenormin), hydrochlorothiazide (i.e., Microzide), amlodipine (i.e., Norvasc), or enalapril (i.e., Vasotec)
control high cholesterol, such as pravastatin (i.e., Pravachol), simvastatin (i.e., Zocor), and lovastatin (i.e., Altoprev, Mevacor)
help the heart pump better, such as digoxin (i.e., Lanoxin) or dobutamine
help the heart relax and rebuild itself, such as carvedilol (i.e., Coreg) and captopril (i.e., Capoten)
prevent blood clots in the heart, such as warfarin (i.e., Coumadin)
- stop or control irregular heartbeats, such as amiodarone (i.e., Cordarone, Pacerone) or procainamide (i.e., Procanbid, Pronestyl)
Surgery or other procedures may also be used to treat heart disease. These procedures include:
- angioplasty, in which a special tool is used to open up clogged arteries during cardiac catheterization
- heart bypass surgery. This is a form of open heart surgery that uses blood vessels from another part of the body to go around, or bypass, blockages in the heart arteries.
- heart valve replacement, a form of open heart surgery to replace damaged heart valves
- heart transplantation
- open heart surgery to repair birth defects in the heart
Many other medicines and surgery techniques are used to treat heart disease. Cardiac rehabilitation and other forms of exercise can also help to improve the person's ability to function.
What are the side effects of the treatments?
All medicines and surgeries have possible side effects. Medicines may cause allergic reactions or stomach upset. Surgery can be complicated by bleeding, infection, or reactions to anesthesia.
What happens after treatment for the disease?
Most individuals with coronary artery disease are encouraged to begin a regular exercise program. A person with CAD should make every effort to reduce coronary risk factors. This may include smoking cessation, control of other diseases such as diabetes
and high blood pressure,
and eating a healthy diet for prevention of heart disease.
Many people with heart disease need lifelong treatment and monitoring. Death may occur, even with the best treatment.
How is the disease monitored?
A person with heart disease needs to make regular visits to the healthcare professional, to report any new or worsening symptoms and to be monitored with periodic ECGs and blood tests.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.