A heart attack occurs when the coronary arteries, the blood vessels that deliver blood to the heart, are suddenly blocked and cannot supply the heart with blood and oxygen. This blockage causes damage and gradual death of the heart muscle and often requires immediate treatment in order to save the person's life. Also known as a myocardial infarction, heart attacks most often occur as a result of coronary artery disease, a condition in which plaque builds up inside the arteries. Heart attacks are the leading cause of death for men and women in the United States.
Causes of a Heart Attack
A heart attack is usually caused by atherosclerosis, a buildup of cholesterol, fat and other substances within the coronary arteries. As these substances, known collectively as plaque, build up, they cause the coronary arteries to narrow making proper blood flow more difficult. This condition is known as coronary artery disease, and is the most common type of heart disease. If the plaque breaks open, a blood clot forms around the plaque. The clot may completely block oxygen-rich blood from reaching the heart muscle, causing a portion of the heart muscle to die. A heart attack may also be caused by other conditions including:
- Coronary artery dissection, a tear in the heart artery
- Coronary embolism
Another less common cause of a heart attack is a coronary artery spasm. These spasms are often caused by drug abuse, and when they occur, they suddenly cut off blood flow through the artery.
Symptoms of a Heart Attack
The initial symptoms of a heart attack may vary, but often include chest pain or discomfort. It may feel like fullness, pressure, squeezing or pain and it can come and go every few minutes. Other common heart attack symptoms include:
- Pain in the upper abdomen
- Shortness of breath
- Nausea and vomiting
- Jaw pain
- Arm, shoulder or back pain
In addition to the above symptoms, women may experience other symptoms, including:
- Abdominal pain
- Light headedness
- Clammy skin
Some people may not experience any symptoms at all. Some heart attacks may occur suddenly, but most people have warning signs and symptoms prior to the actual heart attack. The earliest warning sign is often recurrent chest pain that may occur days or weeks in advance.
Risk Factors for a Heart Attack
There are several factors that can increase the risk of a heart attack by contributing to the buildup of plaque within the coronary arteries. These factors may include:
- Advanced age
- High blood pressure
- High cholesterol
- Physical inactivity
- Illegal drug use
Individuals may be more at risk if they have a family history of heart attacks. There is also a link between certain autoimmune conditions, such as rheumatoid arthritis and lupus, and an increased risk of a heart attack.
Diagnosis of a Heart Attack
In many cases, a heart attack is diagnosed in an emergency setting and if the patient is conscious, he or she will be asked to describe the symptoms. The patient is hooked up to a heart monitor and an electrocardiogram is administered. The following diagnostic test may also be performed:
- Blood tests
- Chest X-ray
- Coronary catheterization (angiogram)
CT and MRI scans may also be performed to diagnose any heart problems and the extent of damage from a heart attack.
Treatment of a Heart Attack
A heart attack is an emergency that requires immediate treatment. Anyone experiencing symptoms of a heart attack should call 911 right away. Early treatment of a heart attack can help minimize damage to the heart muscle. Treatment for a heart attack usually includes cardiopulmonary resuscitation (CPR) to deliver oxygen to the body and brain, aspirin to prevent blood clots, thrombolytics to break up any existing clots, and nitroglycerin to treat chest pain. In some cases, surgery may be necessary to open blocked arteries, either through balloon angioplasty or a coronary artery bypass.
Preventing a Heart Attack
A heart attack can be prevented, even in individuals who have already experienced one. The risk of a heart attack may be lowered by the following:
- Not smoking
- Healthy diet
- Regular exercise
- Lowering stress levels
- Blood-thinning medications
- Controlling blood pressure and cholesterol levels
- Controlling diabetes
- Beta blockers and ACE inhibitors
Individuals who suffered from a previous heart attack can lower their risk of subsequent heart attacks through lifestyle changes, cardiac rehabilitation, and medication that helps the heart recover from any previous damage.