A heart attack is the death of a segment of heart muscle caused by a loss of blood supply. The blood is usually cut off when an artery supplying the heart muscle is blocked by a blood clot. There are clear symptoms of a heart attack that require immediate medical attention. A feeling of pressure, tightness, pain, squeezing, or aching in the chest or arms that spreads to the neck, jaw, or back can be a sign that a person is having a heart attack. A heart attack happens when there is a sudden loss of blood flow to a part of your heart muscle. Most heart attacks are caused by coronary heart disease.
A heart attack is life-threatening. If you think you or anyone else is having a heart attack, call 999 for an ambulance immediately. If you’re not sure, it’s still important to seek medical attention to be on the safe side. A heart attack occurs when the flow of blood to the heart is blocked, most often by a build-up of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries). The interrupted blood flow can damage or destroy part of the heart muscle. A heart attack, also called a myocardial infarction, can be fatal, but treatment has improved dramatically over the years. Not all people who have heart attacks have the same symptoms or have the same severity of symptoms. Some people have mild pain; others have more severe pain. Some people have no symptoms, while for others; the first sign may be sudden cardiac arrest. However, the more signs and symptoms you have, the greater the likelihood you're having a heart attack. Some heart attacks strike suddenly, but many people have warning signs and symptoms hours, days or weeks in advance.
The earliest warning may be recurrent chest pain (angina) that's triggered by exertion and relieved by rest. Angina is caused by a temporary decrease in blood flow to the heart. A heart attack differs from a condition in which your heart suddenly stops (sudden cardiac arrest, which occurs when an electrical disturbance disrupts your heart's pumping action and causes blood to stop flowing to the rest of your body). A heart attack can cause cardiac arrest, but it's not the only cause.