A heart attack occurs when the flow of blood to the heart is blocked. The blockage is most often a buildup of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries).

Sometimes, a plaque can rupture and form a clot that blocks blood flow. The interrupted blood flow can damage or destroy part of the heart muscle.

Symptoms

• Pressure, tightness, pain, or a squeezing or aching sensation in your chest or arms that may spread to your neck, jaw or back
• Nausea, indigestion, heartburn or abdominal pain
• Shortness of breath
• Cold sweat
• Fatigue
• Lightheadedness or sudden dizziness

Heart attack symptoms vary

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. For others, the first sign may be sudden cardiac arrest. However, the more signs and symptoms you have, the greater the chance 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 might be recurrent chest pain or pressure (angina) that's triggered by activity and relieved by rest. Angina is caused by a temporary decrease in blood flow to the heart.