If a blood clot becomes large enough, it can completely block the flow of blood through the coronary artery. Ischemia of the heart muscle can produce chest pains and other related symptoms, as described in the following sections. If the muscle in the heart is deprived of oxygen for 30 minutes or more, it begins to die. The longer the blockage deprives the heart muscle of bloodborne oxygen, the more heart muscle dies. This complete blockage of a coronary artery leading to death of the heart muscle is called a heart attack.
Different people experience a heart attack in different ways.
The classic description of heart attack pain is an intense ache in the chest, often centered in the left side of the chest. The pain may seem to radiate outward into the neck, jaw, back, or arms . Other symptoms that can accompany a heart attack include a feeling of indigestion or nausea, shortness of breath, intense sweating, or clamminess. When any of these symptoms persist longer than approximately 30 minutes, one should assume that he or she is having a heart attack. For reasons that are unclear, about one-quarter of all heart attacks occur without producing any identifiable symptoms.