Heart Attack (Myocardial Infarction)

What to do if you think you are having a heart attack

1. Call 911 or your local emergency number right away. Paramedics can start treatment, run an ECG and alert the hospital. Do not wait to see if it passes, and do not drive yourself.
2. Chew an aspirin (one regular 325 mg tablet, or 4 low-dose 81 mg tablets) unless you are allergic, have a bleeding problem, or the dispatcher tells you not to. Chewing works faster than swallowing it whole.
3. Sit down and rest in a comfortable position. Loosen tight clothing.
4. Take your nitroglycerin if it has been prescribed for you, as directed.
5. Leave the front door open or unlatched so responders can get in, and keep your phone nearby.
6. If the person collapses and stops breathing normally, start chest compressions: push hard and fast in the center of the chest, about 100 to 120 times a minute. Use an AED as soon as one is available.

Heart attack symptoms

Classic signs

• Chest discomfort: pressure, squeezing, tightness, heaviness or pain in the center or left of the chest lasting more than a few minutes. People often describe it as "an elephant sitting on my chest" rather than sharp pain.
• Pain spreading to one or both arms (more often the left), the shoulders, neck, jaw, back or upper stomach.
• Shortness of breath, with or without chest pain.
• Cold sweat, nausea, vomiting or lightheadedness.
• A strong sense that something is wrong.

Symptoms can start suddenly or build over hours. Some people have warning episodes of angina in the days or weeks before.

Heart attack symptoms in women

Women are as likely as men to have chest pain, but they more often also have, or only have:

• shortness of breath
• nausea or vomiting
• pain in the back, jaw, neck or upper belly
• unusual fatigue, sometimes for days beforehand
• dizziness or fainting

Because these signs are less dramatic, women tend to wait longer before calling for help. Women under 55 and those who have had preeclampsia or early menopause are also at risk of a type caused by a tear in a coronary artery (spontaneous coronary artery dissection).

Silent heart attacks

Some heart attacks cause mild or no symptoms, especially in people with diabetes, older adults and women. They may feel like indigestion, the flu or a strained muscle and are found later on an ECG or scan. They still damage the heart.

Is a swollen arm a sign of a heart attack?

Arm pain or heaviness is a common heart attack symptom, but swelling of the arm is not. A swollen arm is more often caused by a blood clot in the arm vein, an injury, an infection or lymphedema. A newly swollen, painful or discolored arm needs prompt medical assessment for a clot. Arm pain with chest discomfort, sweating or breathlessness needs a 911 call.

Heart attack vs other causes of chest pain

When in doubt, treat chest pain as a heart attack until proven otherwise.

What causes a heart attack

Most heart attacks are caused by coronary artery disease. Over decades, fatty plaques build up in the walls of the coronary arteries. When a plaque cracks, a clot forms on it and blocks the artery.

Less common causes include coronary artery spasm (sometimes triggered by cocaine or amphetamines), spontaneous coronary artery dissection, a clot traveling from elsewhere, and severe strain on the heart from blood loss, low oxygen or very fast heart rhythms.

Risk factors

• smoking or vaping nicotine
• high blood pressure
• high LDL cholesterol
• diabetes
• obesity and physical inactivity
• older age: men over 45, women over 55
• family history of early heart disease (a father or brother before 55, or a mother or sister before 65)
• chronic kidney disease, autoimmune diseases such as lupus and rheumatoid arthritis, sleep apnea
• pregnancy complications such as preeclampsia and gestational diabetes

Types of heart attack

• STEMI (ST-elevation myocardial infarction): a complete blockage that shows a typical pattern on the ECG. It needs emergency opening of the artery.
• NSTEMI (non-ST-elevation myocardial infarction): a partial or temporary blockage. The ECG pattern is different, and diagnosis rests on blood tests. Treatment is still urgent, usually within 24 to 72 hours.

Both fall under the umbrella of acute coronary syndrome, which also includes unstable angina.

How a heart attack is diagnosed

• ECG (electrocardiogram): done within 10 minutes of arriving at the ER, often already by paramedics. It shows STEMI and rhythm problems.
• Troponin blood test: a protein released from damaged heart muscle. High-sensitivity tests are repeated after 1 to 3 hours to see if levels are rising.
• Echocardiogram: an ultrasound showing which parts of the heart are not moving properly.
• Coronary angiogram: dye injected through a catheter in the wrist or groin shows the blocked artery, which can be opened in the same procedure.

Treatment

Emergency treatment

• Primary angioplasty (PCI): a balloon opens the artery and a stent holds it open. For STEMI, the target is within 90 minutes of first medical contact.
• Clot-busting medicine (thrombolysis): used when a cath lab cannot be reached quickly enough.
• Medicines: aspirin plus a second antiplatelet drug, a blood thinner, nitroglycerin, oxygen if levels are low, and pain relief.
• Coronary artery bypass surgery: for some people with several blocked arteries.

Long-term medicines

Most people take several medicines after a heart attack:

• aspirin and usually a second antiplatelet drug for up to 12 months
• a high-intensity statin to lower cholesterol and stabilize plaques
• a beta blocker
• an ACE inhibitor or ARB, especially when the heart pump is weakened
• sometimes other cholesterol-lowering or heart failure medicines

Do not stop antiplatelet medicines without talking to your cardiologist, especially after a stent.

Complications

• Abnormal heart rhythms: the most dangerous in the first hours. Ventricular fibrillation causes cardiac arrest.
• Heart failure: if a large area of muscle is damaged, the heart pumps less well.
• Cardiogenic shock, mechanical tears of the heart wall or valves, and inflammation of the heart lining (pericarditis), which are less common.
• Depression and anxiety: common in the months after, and treatable.

Recovery after a heart attack

• Hospital stay: often 2 to 5 days after a stent for an uncomplicated heart attack.
• Cardiac rehabilitation: a supervised exercise and education program over about 12 weeks. It lowers the risk of death and another heart attack, yet many people never attend. Ask for a referral.
• Driving: many people can drive after about 1 week following a successful stent, longer after larger heart attacks. Rules for commercial drivers are stricter. Check with your cardiologist and local licensing rules.
• Work: desk jobs often after 2 to 6 weeks. Physical jobs may take longer.
• Sex: usually safe once you can climb two flights of stairs without symptoms, often after 1 to 2 weeks.

Preventing a heart attack

• Stop smoking: risk falls quickly after quitting.
• Control blood pressure, cholesterol and blood sugar, with medicines if needed.
• Get at least 150 minutes of moderate activity a week.
• Eat a Mediterranean-style diet with vegetables, whole grains, fish, nuts and olive oil, and limit processed meat and salt.
• Keep a healthy weight and limit alcohol.
• Know your 10-year heart risk score and discuss it with your doctor.

Frequently asked questions

What are the first signs of a heart attack?

The first signs are usually chest pressure or discomfort lasting more than a few minutes, often spreading to the arm, jaw or back, with shortness of breath, cold sweat or nausea. Some people have warning chest discomfort on exertion in the days or weeks before.

How do heart attack symptoms differ in women?

Women often have chest discomfort too, but are more likely to have shortness of breath, nausea, vomiting, back or jaw pain, unusual fatigue and dizziness. These can occur without obvious chest pain, which leads to delays in calling for help.

How long can a heart attack last?

Symptoms can last from several minutes to hours and may come and go. Heart muscle begins to die within about 20 to 40 minutes of a complete blockage, and damage increases each hour. Any chest discomfort lasting more than 5 minutes warrants a 911 call.

Can you survive a heart attack?

Yes. Most people who reach a hospital quickly survive and return to normal activities. Survival depends heavily on speed of treatment and on avoiding cardiac arrest. Calling 911 early and getting the artery opened fast give the best chance.

What is the difference between a heart attack and cardiac arrest?

A heart attack is a blood flow problem: a blocked artery damages heart muscle while the heart usually keeps beating. Cardiac arrest is an electrical problem: the heart suddenly stops pumping, and the person collapses. A heart attack can trigger cardiac arrest.

Should I take aspirin during a heart attack?

If you have symptoms of a heart attack, call 911 first. Then chewing one regular 325 mg aspirin can help, unless you are allergic, have a bleeding disorder, or the dispatcher or your doctor has told you not to. Do not take aspirin for a suspected stroke without medical advice.