Build-up of cholesterol inside the coronary arteries (atherosclerosis) is the main cause of heart attacks. Rare causes include spasm, aneurysm, dissection or tearing, and birth defects of a coronary artery. Atherosclerosis and spasm are discussed elsewhere in this section.
Coronary Dissection and Tearing
Blood flow through a coronary artery can decrease if the wall of the artery is damaged. Two causes of damage include aneurysm and dissection. An aneurysm is an outward ballooning of a coronary artery wall. Blood flow may become abnormal and the artery can burst or rupture; a life-threatening complication. In a dissection, a tear occurs in the wall of the artery. Blood may leak out or a blockage may result. These can also be life-threatening.
The cause of an aneurysm and dissection is often hard to diagnose. In some cases it is due to an abnormal structure of the coronary wall. This condition can be passed down from our parents and grandparents. Alternatively, an abnormality in the aorta can extend into the coronary arteries. The aorta is the large artery leading from the left side of the heart to the rest of the body. Finally, trauma to the coronary arteries can cause dissections. The trauma can come from outside the body as in a car accident where the steering wheel hits the chest. It can also be due to local trauma when a cardiologist attempts a balloon and stent procedure. Any damage to a coronary artery is life-threatening and usually requires emergency surgery to correct the problem.
Birth/Inherited/Congenital Defects
In very rare cases the coronary arteries take an unusual path to the heart muscle. This path may be between or through other structures. In such cases, a heart attack could occur. These abnormalities are sometimes not diagnosed until much later in life. The treatment usually involves surgery to correct the abnormality.