What Is a Heart Attack?
A heart attack occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery. Often, this blockage leads to arrhythmias (irregular heartbeat or rhythm) that cause a severe decrease in the pumping function of the heart and may bring about sudden death. If the blockage is not treated within a few hours, the affected heart muscle will die and be replaced by scar tissue.
A heart attack is a life-threatening event. Everyone should know the warning signs of a heart attack and how to get emergency help. Many people suffer permanent damage to their hearts or die because they do not get help immediately.
Each year, more than a million persons in the U.S. have a heart attack and about half (515,000) of them die. About one-half of those who die do so within 1 hour of the start of symptoms and before reaching the hospital.
Emergency personnel can often stop arrhythmias with emergency CPR (cardiopulmonary resuscitation), defibrillation (electrical shock), and prompt advanced cardiac life support procedures. If care is sought soon enough, blood flow in the blocked artery can be restored in time to prevent permanent damage to the heart. Yet, most people do not seek medical care for 2 hours or more after symptoms begin. Many people wait 12 hours or longer.
A heart attack is an emergency. Call the emergency services if you think you (or someone else) may be having a heart attack. Prompt treatment of a heart attack can help prevent or limit lasting damage to the heart and can prevent sudden death.
Other Names for Heart Attack
What Causes a Heart Attack?
Most heart attacks are caused by a blood clot that blocks one of the coronary arteries (the blood vessels that bring blood and oxygen to the heart muscle). When blood cannot reach part of your heart, that area starves for oxygen. If the blockage continues long enough, cells in the affected area die.
Coronary Artery Disease (CAD) is the most common underlying cause of a heart attack. CAD is the hardening and narrowing of the coronary arteries by the buildup of plaque in the inside walls (atherosclerosis). Over time, plaque buildup in the coronary arteries can:
- Narrow the arteries so that less blood flows to the heart muscle
- Completely block the arteries and the flow of blood
- Cause blood clots to form and block the arteries.
- Taking certain drugs, such as cocaine
- Emotional stress
- Exposure to cold
- Cigarette smoking.
Certain factors make it more likely that you will develop CAD and have a heart attack. These are called risk factors. Risk factors you cannot change include:
- Your age
- Men: over age 45
- Women: over age 55
- Having a family history of early heart disease
- Heart disease diagnosed in father or brother before age 55
- Heart disease diagnosed in mother or sister before age 65
- Having a personal history of CAD
- Angina
- A previous heart attack
- A surgical procedure (angioplasty, heart bypass) to increase blood flow to your heart.
- Smoking
- High blood pressure
- High blood cholesterol
- Obesity
- Being physically inactive
- Diabetes (high blood sugar) .
The warning signs and symptoms of a heart attack can include:
- Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes, or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. Heart attack pain can sometimes feel like indigestion or heartburn.
- Discomfort in other areas of the upper body. Can include pain, discomfort, or numbness in one or both arms, the back, neck, jaw, or stomach.
- Shortness of breath. Often comes along with chest discomfort. But it also can occur before chest discomfort.
- Other symptoms. May include breaking out in a cold sweat, having nausea and vomiting, or feeling light-headed or dizzy.
The symptoms of angina can be similar to those of a heart attack. If you have angina and notice a change or a worsening of your symptoms, talk with your doctor right away.
Know the warning signs of a heart attack so you can act fast to get treatment. Many heart attack victims wait 2 hours or more after their symptoms begin before they seek medical help. This delay can result in death or lasting heart damage.
If you think you may be having a heart attack, or if your angina pain does not go away as usual when you take your angina medicine as directed, call for help. You can begin to receive life-saving treatment in the ambulance on the way to an emergency room.
How is a Heart Attack Diagnosed?
Diagnosis (and treatment) of a heart attack can begin when emergency medical personnel arrive after you call the emergency services. Don't put off calling because you are not sure that you are having a heart attack.
At the hospital emergency room, doctors will work fast to find out if you are having or have had a heart attack. They will consider your symptoms, medical and family history, and test results. Initial tests will be quickly followed by treatment if you are having a heart attack.
Tests used include:
- Electrocardiogram (ECG). This test is used to measure the rate and regularity of your heartbeat. A 12-lead ECG is used in diagnosing a heart attack.
- Blood tests. When cells in the heart die, they release enzymes into the blood. They are called markers or biomarkers. Measuring the amount of these markers in the blood can show how much damage was done to your heart. These tests are often repeated at intervals to check for changes. The specific blood tests are:
- Troponin test. This test checks the troponin levels in the blood. It is considered the most accurate blood test to see if a heart attack has occurred and how much damage was done to the heart.
- CK or CK-MB test. These tests check for the amount of the different forms of creatine kinase in the blood.
- Myoglobin test. This test checks for the presence of myoglobin in the blood. Myoglobin is released when the heart or other muscle is injured.
- Nuclear heart scan. This test uses radioactive tracers (technetium or thallium) to outline heart chambers and major blood vessels leading to and from the heart. A nuclear heart scan shows any damage to your heart muscle.
- Cardiac catheterisation. A thin flexible tube (catheter) is passed through an artery in the groin or arm to reach the coronary arteries. Your doctor can determine pressure and blood flow in the heart's chambers, collect blood samples from the heart, and examine the arteries of the heart by x-ray.
- Coronary angiography. This test is usually performed along with cardiac catheterisation. A dye that can be seen using x-ray is injected through the catheter into the coronary arteries. Your doctor can see the flow of blood through the heart and see where there are blockages.
A heart attack is a medical emergency. Delaying treatment can mean lasting damage to your heart or even death. The sooner treatment begins, the better your chances of recovering. Your treatment may begin in the ambulance or in the emergency room and continue in a special area called a coronary care unit or CCU.
In the Hospital
If you are having a heart attack, doctors will:
- Work quickly to restore blood flow to the heart
- Continuously monitor your vital signs to detect and treat complications
- Thrombolytic drugs ("clot-busters") are used to dissolve blood clots that are blocking blood flow to the heart. When given soon after a heart attack begins, these drugs can limit or prevent permanent damage to the heart. To be most effective, they need to be given within 1 hour after of the start of heart attack symptoms.
- Angioplasty procedures are used to open blocked or narrowed coronary arteries. A stent, which is a tiny metal mesh tube, may be placed in the artery to help keep it open.
- Coronary artery bypass surgery uses arteries or veins from other areas in your body to bypass your blocked coronary arteries.
- EKG, which detects any heart rhythm (arrhythmia) or functional problems
- Blood pressure
- Pulse oximetry, which measures the amount of oxygen in the blood and provides an early warning sign of a low level of oxygen in the blood.
- Beta blockers to decrease the workload on your heart by slowing your heart rate. This makes your heart beat with less force and lowers your blood pressure. Some beta blockers are also used to relieve angina (chest pain) and in heart attack patients to help prevent additional heart attacks. They are also used to correct irregular heartbeat.
- Angiotensin-converting enzyme (ACE) inhibitors to lower blood pressure and reduce the strain on your heart. They are used in some patients after a heart attack to increase survival rate and help slow down further weakening of the heart.
- Nitrates, such as nitroglycerin, to relax blood vessels and stop chest pain.
- Anticoagulants to thin the blood and prevent clots from forming in your arteries.
- Antiplatelet medications (such as aspirin and clopidigrel) to stop platelets from clumping together to form clots. These medications are given to people who have had a heart attack, have angina, or who experience angina after angioplasty.
- Glycoprotein IIb-IIIa inhibitors, which are potent antiplatelet medicines given intravenously to prevent clots from forming in your arteries.
- Medicines to relieve pain and anxiety.
- Medicines to treat arrhythmias (irregular heart rhythms), which often occur during a heart attack.
- Oxygen therapy.
While you are still in the hospital or after you go home after your heart attack, your doctor may order other tests, such as:
- Echocardiogram. In this test, ultrasound is used to make an image of your heart that can be seen on a video monitor. It shows how well the heart is filling with blood and pumping it to the rest of the body.
- Exercise stress test. This test shows how well your heart pumps at higher workloads when it needs more oxygen. EKG and blood pressure readings are taken before, during, and after exercise to see how your heart responds to exercise. The first EKG and blood pressure reading are done to get a baseline. Readings are then taken while you walk on an exercise treadmill or pedal a stationary bicycle. The test continues until you reach a heart rate set by your doctor. The exercise part is stopped if chest pain or a very sharp rise in blood pressure occurs. Monitoring continues for 10 to 15 minutes after exercise or until your heart rate returns to baseline.
Your doctor may prescribe cardiac rehabilitation (rehab) to help you recover from a heart attack and help prevent another heart attack. Almost everyone who has survived a heart attack can benefit from rehab.
The cardiac rehab team may include:
- Doctors
- Your family doctor
- A heart specialist
- A surgeon
- Nurses
- Exercise specialists
- Physical therapists and occupational therapists
- Dietitians
- Psychologists or other behaviour therapists.
- Exercise training to help you learn how to exercise safely, strengthen your muscles, and improve your stamina. Your exercise plan will be based on your individual ability, needs, and interests.
- Education, counselling, and training to help you understand your heart condition and find ways to reduce your risk of future heart problems. The cardiac rehab team will help you learn how to cope with the stress of adjusting to a new lifestyle and to deal with your fears about the future.
After a heart attack, your treatment may include cardiac rehab in the first weeks or months, checkups and tests, lifestyle changes, and medications. You will need to see your doctor for checkups and tests to see how your heart is doing. Your doctor will most likely recommend lifestyle changes, such as quitting smoking, losing weight, changing your diet, or increasing your physical activity.
After a heart attack, most people take daily medications. These may include:
- Aspirin
- Medicines that lower your cholesterol or your blood pressure
- Other medicines to help reduce your heart's workload.
How Can I Prevent a Heart Attack?
Most heart attacks are caused by coronary artery disease (CAD). You can help prevent a heart attack by knowing about your risk factors for CAD and heart attack and taking action to lower your risks.
You can lower your risk of having a heart attack, even if you have already had a heart attack or are told that your chances of having a heart attack are high.
To prevent a heart attack, you will most likely need to make lifestyle changes. You may also need to get treatment for conditions that raise your risk.
Make Lifestyle Changes
You can lower your risk for CAD and a heart attack by making healthy lifestyle choices:
- Eat a healthy diet to prevent or reduce high blood pressure and high blood cholesterol, and maintain a healthy weight
- If you smoke, quit
- Exercise as directed by your doctor
- Lose weight if you are overweight or obese
In addition to making lifestyle changes, you can help prevent heart attacks by treating conditions you have that make a heart attack more likely:
- High blood cholesterol. If you have high cholesterol, follow your doctor's advice about lowering your cholesterol. Take medications to lower your cholesterol as directed.
- High blood pressure. If you have high blood pressure, follow your doctor's advice about keeping your blood pressure under control. Take blood pressure medications as directed.
- High blood sugar (diabetes). If you have diabetes, follow your doctor's advice about keeping your blood sugar levels under control. Take medications as directed.
If you have already had a heart attack, it is very important to follow your doctor's advice to prevent a second heart attack:
- Make lifestyle changes as directed
- Take your medications as directed
- Follow any other treatment recommended by your doctor, such as cardiac rehabilitation.
Make sure that you have an emergency action plan in case you have signs of a second heart attack. Talk to your doctor about making your plan, and talk with your family about it. The plan should include:
- The signs and symptoms of a heart attack
- Instructions for the prompt use of aspirin and nitroglycerin
- How to access emergency medical services in your community (most people dial the emergency services)
- The location of the nearest hospital that offers 24-hour emergency heart care.
Life after a Heart Attack
There are millions of people who have survived a heart attack. Many recover fully and are able to lead normal lives.
If you have already had a heart attack, your goals are to:
- Recover and resume normal activities as much as possible
- Prevent another heart attack
- Prevent complications, such as heart failure or cardiac arrest.
- Lifestyle changes, such as quitting smoking, changing your diet, or increasing your physical activity
- Medications such as aspirin, nitroglycerin tablets for angina, medicines to lower your cholesterol or blood pressure, and medicines to help reduce your heart's workload
- That you participate in a cardiac rehabilitation programme.
Returning to Usual Activities
After a heart attack, most people are able to return to their normal activities. Ask your doctor when you should go back to:
- Driving
- Physical activity
- Work
- Sexual activity
- Strenuous activities (running, heavy lifting, etc.)
- Air travel.
Driving can usually begin within a week for most patients without chest pain or other complications if allowed by state law. Each state has rules for driving a motor vehicle following a serious illness. Patients with complications or chest pain should not drive until their symptoms have been stable for a few weeks.
Your doctor will tell you when you should return to each of these activities.
Anxiety and Depression After a Heart Attack
After a heart attack, many people worry about having another heart attack. They often feel depressed and may have trouble adjusting to a new lifestyle. You should discuss your feelings of anxiety or depression with your doctor. Your doctor can give you medicine for anxiety or depression, if needed. Spend time with family, friends, and even pets. Affection can make you feel better and less lonely. Most people do not continue to feel depressed after they have fully recovered.
Know How and When to Seek Medical Attention
Having a heart attack increases your chances of having another one. Therefore, it is very important that you and your family know how and when to seek medical attention. Talk to your doctor about making an emergency action plan, and talk with your family about it. The plan should include:
- The signs and symptoms of a heart attack
- Instructions for the prompt use of aspirin and nitroglycerin
- How to access emergency medical services in your community
- The location of the nearest hospital that offers 24-hour emergency heart care.
Unfortunately, most heart attack victims wait 2 hours or more after their symptoms begin before they seek medical help. This delay can result in death or lasting heart damage.
Summary
- A heart attack occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a blood clot. This may cause the heart to stop beating and pumping blood effectively (arrhythmia) and lead to death or permanent damage to the heart.
- Each year, over a million people in the U.S. have a heart attack and about half of them die. About one-half of those who die do so within 1 hour of the start of symptoms and before reaching the hospital. Most of these sudden deaths (within 1 hour) are due to arrhythmias that cause a severe decrease in the pumping function of the heart.
- Signs of a heart attack include chest pain that may also spread to the back, shoulders, arms, neck, or jaw. You may have other symptoms such as shortness of breath, nausea, sweating, or dizziness. Symptoms vary, and some people have no symptoms. Know the signs of a heart attack so you can act fast to get treatment.
- Unfortunately, many heart attack victims wait 2 hours or more after their symptoms begin before they seek medical help. This delay can result in death or lasting heart damage.
- The amount of damage from a heart attack depends on how much of the heart is affected, how soon treatment begins, and other factors.
- Both men and women have heart attacks.
- Risk factors for heart disease and heart attack include those that you cannot change, such as your age and a family history of early heart disease. But there are also many things you can do to lower your risk, such as not smoking, eating a diet low in fat and cholesterol, and exercising regularly. It is also important to keep your weight, cholesterol levels, and blood pressure under control.
- Diagnosis and treatment of a heart attack can begin when emergency medical personnel arrive after you call the emergency services. At the hospital emergency room, doctors will work fast to find out if you are having or have had a heart attack and give you treatment.
- If you are having a heart attack, doctors will work quickly to restore blood flow to the heart and continuously monitor vital signs to detect and treat complications.
- Long-term treatment after a heart attack may include cardiac rehabilitation, checkups and tests, lifestyle changes, and medications.
- After a heart attack, most people are able to return to their normal activities. Ask your doctor when you should go back to driving, physical activity, work, sexual activity, strenuous activities, and air travel.
- If you have had a heart attack, it is very important to have an emergency action plan in case of another heart attack. Talk to your doctor about your plan and make sure that your family members understand it.
- Remember, a heart attack is an emergency. Call the emergency services if you think you (or someone else) may be having a heart attack. Don't delay!
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