What is a heart attack?
A heart attack, or myocardial infarction, happens when the heart tissue does not receive enough oxygen. This lack of oxygen causes serious damage (infarction) to the heart muscle (myocardium) and its ability to function effectively. Coronary artery disease, more commonly referred to as atherosclerotic heart disease, is the most common cause of heart attack and the leading cause of death for both men and women in the United States. A heart attack occurs every 40 seconds in the U.S.—half of all first-time heart attacks are fatal?
The most common symptom of heart attack—chest pain—is a direct result of the heart muscle not getting enough oxygen-rich blood. The heart is a muscle that requires a steady supply of oxygen in order for it to pump blood effectively to the rest of the body. Oxygen is supplied to the heart by blood that flows through the coronary arteries. Coronary artery disease can seriously reduce blood flow through those arteries. It is due to the buildup of plaque on the coronary artery walls (atherosclerosis).
There are no symptoms of coronary artery disease until the arteries are narrow enough to restrict blood flow or a blood clot blocks blood flow to the heart. Angina is a type of chest pain that occurs when the heart muscle is not getting enough oxygen-rich blood. Having angina may mean that you are at increased risk for a future heart attack or that a heart attack may occur soon.
The area of the heart that is damaged in a heart attack and the severity of a heart attack vary depending on which coronary artery is blocked, how long the blockage lasts, and other factors. Damage to the heart can become permanent within minutes and result in the death of the affected heart tissue (myocardial necrosis or infarction). The more damage there is, the less able the heart is to pump blood to the rest of the body. A heart attack will be fatal if the heart stops beating (cardiac arrest) and treatment is not available within minutes. Treatment includes cardiopulmonary resuscitation (CPR) and other lifesaving procedures.
Immediate heart attack treatment to restore blood flow to the heart and prevent cardiac arrest minimizes the risk of death and other serious heart attack complications, such as heart failure and disability.
Seek immediate medical care (call 911) if you, or someone you are with, have heart attack symptoms, such as chest pain and difficulty breathing, which may be combined with dizziness, sweating, fainting and anxiety.
What are the symptoms of a heart attack?
The most common symptom of heart attack is chest pain or discomfort that lasts for more than a few minutes. Although chest pain is the key warning sign of a heart attack, it can sometimes be confused with indigestion, pneumonia, or other disorders.
Common symptoms of heart attack
Symptoms of heart attack can differ depending on the area or areas of the heart affected and individual factors. Common symptoms include:
- Chest pain, which people tend to describe as crushing, squeezing, tightness, pressure or fullness in the chest
- Back, shoulder, neck, jaw or arm pain (you may notice your chest pain radiates, or moves to these areas)
- Dizziness or lightheadedness
- Feeling of indigestion
Not all people who have a heart attack experience chest pain. In some cases, people may not have any symptoms. In other cases, symptoms may be mild or vague and include weakness, fatigue, dizziness, backache, or a burning feeling in the upper abdomen. It is important to understand that women who experience myocardial infarction more often report nausea rather than chest pain.
Silent heart attacks
Of the 805,000 heart attacks in the United States every year (CDC, 2019), about 1 in 5 heart attacks is silent, meaning the person did not experience noticeable symptoms. But a silent heart attack can still damage the heart muscle and cause cardiovascular complications.
Serious symptoms that might indicate a life-threatening condition
Heart attack is a life-threatening condition. Seek immediate medical care (call 911) if you, or someone you are with, have any of these symptoms:
- Bluish coloration of the lips or fingernails combined with pale skin
- Change in level of consciousness or alertness, such as passing out or unresponsiveness
- Fatigue with chest pain
- Loss of pulse
- Nausea and vomiting associated with chest pain
- Pain in the shoulders, back, neck, jaw or arms that radiates from the chest or occurs by itself
- Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, or wheezing
- Sudden, unexplained anxiety and restlessness
What causes a heart attack?
Heart attacks are caused by a buildup of plaque and inflammation in the coronary arteries. This is atherosclerosis. Plaque buildup and inflammation occur over many years and the process itself does not cause symptoms. But with time, plaque narrows the coronary arteries, reducing the amount of oxygen-rich blood that reaches the heart muscle. When the heart is not receiving enough oxygen-rich blood, you may experience angina, a type of serious chest pain. Angina is an important warning sign that the heart may be starved of oxygen.
Arteries narrowed by atherosclerosis are more likely to develop blood clots that completely block blood flow to the heart muscle, resulting in a heart attack. If the blood and oxygen supply is cut off severely or for a long period of time, the affected section of the heart muscle dies. The result is loss of function to the heart muscle in the area affected by the lack of oxygen. The sooner heart attack diagnosis and treatment occur, the more heart muscle you can save.
What are the risk factors for heart attack?
A heart attack can happen to anyone, but some people are at greater risk than others. Heart attack risk factors increase your chances of having a myocardial infarction. They include:
- African American, Hispanic American, or American Indian ancestry
- Age older than 45 years (heart attack risk increases with age)
- Diabetes, type 2
- High cholesterol (dyslipidemia); low levels of HDL, or “good,” cholesterol; high levels of LDL, or “bad,” cholesterol; and high triglycerides carry the greater risk of heart attack
- Excessive alcohol consumption
- Family history of heart attack at an early age
- Long-term stress
- Male biological sex, although females are equally at risk after menopause
- Sedentary lifestyle
Having high levels of certain substances in the body, which can be seen on blood tests, is associated with increased risk for heart attack. These include:
- High cholesterol, which can lead to atherosclerosis
- High C-reactive protein (CRP) level, which reflects inflammation
- High homocysteine level, which may damage artery walls and increase the risk of developing clots that can lead to heart attack and stroke
How do you prevent a heart attack?
As atherosclerosis and coronary artery disease is the leading underlying cause of heart attack, prevention is the same for both. You can reduce your risk of heart disease and heart attack by:
- Eating a diet that is low in saturated fat and high in fiber, whole grains, and fruits and vegetables
- Limiting alcohol consumption to no more than one drink per day for women and two drinks per day for men
- Maintaining a healthy weight
- Not smoking
- Participating in a regular exercise program, even if you are a healthy weight
- Reducing excessive stress
- Seeking regular medical care and following your treatment plan for such conditions as high cholesterol, hypertension, and type 2 diabetes
How do doctors diagnose heart attack?
If you or a loved one thinks you are having a heart attack, call 911. Your care provider will perform an electrocardiogram (ECG) in the emergency department or in the ambulance. An ECG is an analysis of your heart rate and rhythm. If the ECG detects a heart attack, immediate intervention is necessary.
Other tests doctors may use during heart attack diagnosis include:
- Blood tests to detect markers of heart attack, such as troponin
- Chest X-ray to help rule out other possible causes of chest pain, such as pneumonia
- Coronary angiography to determine where blood flow is compromised (angiography may be performed during heart attack treatment)
- Echocardiogram to evaluate the size and structure of your heart as it is pumping
What are the treatments for heart attack?
The goal of treatment for heart attack is to relieve pain, restore blood flow to the heart to preserve heart muscle, and prevent death. If diagnosed early, some heart attacks can be successfully treated before the development of permanent heart damage and complications, such as heart failure and cardiac arrest.
Heart attack treatment plans are individualized to the type and severity of your heart attack; your risk factors, lifestyle, and medical history; and other diseases and conditions you may have.
Interventional procedures for heart attack
Percutaneous coronary intervention (PCI), such as coronary balloon angioplasty, is the standard of care when there is a complete blockage of one or more coronary arteries, and it has been less than two hours (120 minutes) since diagnosis. (Percutaneous means through the skin.) The cardiologist usually places a stent after angioplasty to hold the space open. Angioplasty restores blood flow to the heart muscle. The doctor repeats the procedure if there are other blockages.
General treatments for heart attack
In addition to PCI, general care of someone with heart attack may include:
- Intensive monitoring and stabilization of heart rhythm and vital signs, which in some cases may require cardiopulmonary resuscitation (CPR) and advanced life support measures, such as intubation and mechanical ventilation to support breathing
- Monitoring your heart rate and rhythm with a continuous electrocardiogram (known as an EKG or ECG) and blood tests to determine the presence or extent of heart damage
- Regular follow-up care after discharge from the hospital, which is very important to help monitor your treatment and progress, and to promptly address any problems or complications
- Supplemental oxygen to increase the amount of oxygen that is delivered to the heart tissue and the rest of the body
- Treatment of abnormal heart rhythms (cardiac arrhythmias) with medications and possibly cardioversion or electrical defibrillation
Medications used to treat a heart attack
Doctors prescribe a variety of medications to treat heart attack including:
- ACE inhibitors (ramipril, lisinopril, enalapril or captopril) to lower blood pressure and help prevent heart failure
- Aspirin to help prevent new blood clots
- Beta blockers (metoprolol, atenolol and propranolol) to lower blood pressure and help reduce strain on the heart
- Heparin or another anticoagulant to help prevent new blood clots
- Morphine to reduce pain and anxiety and lower the amount of oxygen the heart needs
- Nitroglycerine to help widen narrow coronary arteries
- Thrombolytic (clot-dissolving) drugs to break up and dissolve the clot that is causing the heart attack. Thrombolytic drugs are most effective if given within three hours of the onset of chest pain.
Surgical treatments for a heart attack
In some cases, a surgical procedure may be necessary for heart attack, such as:
- Coronary artery bypass. In this surgery, new graft arteries are placed to bypass the blocked coronary artery or arteries. Blood flow is then redirected through healthy new graft arteries to the affected heart tissues.
- Implantation of defibrillator/pacemaker device to monitor and restore a normal heartbeat.
Other treatments for a heart attack
Other treatments and therapies that may be recommended as part of a complete treatment program for a heart attack include:
- Cardiac rehabilitation and physical therapy to help strengthen your body, reduce complications, increase alertness, reduce fatigue, improve your overall health, and enhance your ability to function in everyday activities
- Complementary or alternative treatments, such as acupuncture, massage therapy, and yoga, to help reduce stress, increase flexibility, and improve well-being. Complementary treatments are not meant to substitute for full medical care. Be sure to notify your doctor if you are consuming nutritional supplements or homeopathic (nonprescription) remedies as they may interact with the prescribed medical therapy.
- Palliative care to improve the overall quality of life for families and patients with serious diseases
What are the potential complications of heart attack?
Complications of a heart attack are life-threatening. When the heart is damaged by a heart attack, it becomes weak and is unable to pump blood effectively throughout the body. This is called heart failure.
Damage to the heart caused by a heart attack can also trigger life-threatening abnormalities in heart rhythm (cardiac arrhythmias). Certain cardiac arrhythmias, such as ventricular tachycardia and ventricular fibrillation, can make the heart completely ineffective at pumping blood. These cardiac arrhythmias can lead to cardiac arrest (when the heart stops beating) and death within minutes.
Heart attack can also lead to the development of clots that lodge in other areas of the body, which can cause a stroke. Heart attack can also result in serious, permanent disability.
You can help minimize the risk of serious complications of a heart attack by following the treatment plan you and your healthcare professional design specifically for you.
Complications of a heart attack include:
- Blood clots that cause stroke and pulmonary embolism (blood clots in the lungs)
- Cardiac arrest
- Cardiogenic shock
- Fatal cardiac arrhythmias
- Heart failure
- Heart valve damage