What Is a Heart Attack?

Plain English

A heart attack, also called a myocardial infarction, happens when part of the heart muscle does not get enough oxygen-rich blood. This usually happens when a coronary artery becomes blocked by a blood clot, often after plaque inside the artery ruptures. The longer the blockage lasts, the greater the chance of permanent heart damage.

Why it matters

A heart attack can damage the heart muscle and may lead to complications such as abnormal heart rhythms, heart failure, cardiac arrest, repeat heart attack, or reduced pumping function. Quick treatment can limit damage and improve survival.

Tests and numbers

Common tests include EKG, troponin and other cardiac blood tests, blood pressure and heart rate, echocardiogram, ejection fraction, stress test, coronary angiogram, LDL cholesterol, and A1C or glucose. No single number tells the whole story.

Symptoms and warning signs

Common warning signs include chest pain or pressure, pain in the arm, shoulder, jaw, neck, back, or upper abdomen, shortness of breath, cold sweat, nausea, lightheadedness, fainting, and unusual fatigue. Some people — including women, older adults, and people with diabetes — may have more subtle symptoms.

How it can happen

Risk factors build over time, plaque forms in coronary arteries, blood flow becomes limited, plaque can rupture and trigger a clot, and heart muscle injury occurs if blood flow stays blocked. Some heart attacks involve spasm, small vessel disease, or dissection rather than typical blockage.

Outlook

The outlook depends on how quickly treatment happens, how much heart muscle was damaged, ejection fraction, age, kidney function, diabetes, blood pressure, cholesterol, and rhythm problems. Many people recover and lower future risk with medications, lifestyle changes, follow-up testing, and cardiac rehabilitation when recommended.

How diet and exercise help

Reducing saturated and trans fats, eating more fiber, choosing heart-healthy fats, limiting ultra-processed foods, reducing sodium and added sugars, and consistent safe activity can support cholesterol, blood pressure, and overall heart risk. After a heart attack, ask your provider when it is safe to resume activity.

Metrics to monitor

Home metrics include blood pressure, heart rate, chest symptoms, shortness of breath, activity tolerance, weight, glucose, medication adherence, smoking status, and diet. Report-based metrics include troponin, EKG findings, LDL, HDL, triglycerides, total and non-HDL cholesterol, ApoB, Lp(a), A1C, blood pressure trends, kidney function, potassium and sodium, coronary angiogram findings, stent or bypass notes, echocardiogram findings, ejection fraction, wall motion abnormalities, stress test findings, and cardiac rehab notes.

Common questions

What is a heart attack?

A heart attack happens when blood flow to part of the heart muscle is blocked or severely reduced. Without quick treatment, the heart muscle can become damaged.

Is a heart attack the same as cardiac arrest?

No. A heart attack is a circulation problem caused by blocked blood flow to the heart muscle. Cardiac arrest is an electrical problem where the heart suddenly stops pumping effectively. A heart attack can sometimes lead to cardiac arrest.

What are the most common symptoms of a heart attack?

Common symptoms include chest pain or pressure, discomfort in the arm, shoulder, jaw, neck, back, or upper abdomen, shortness of breath, cold sweat, nausea, lightheadedness, fainting, or unusual fatigue.

Can a heart attack happen without chest pain?

Yes. Some people have shortness of breath, fatigue, nausea, back pain, jaw pain, or other symptoms without major chest pain. This can be more common in women, older adults, and people with diabetes.