This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Spontaneous coronary artery dissection (SCAD) is a condition in which blood accumulates between the layers of tissue that make up the wall of the coronary artery (the vessel that supplies blood to the heart). The trapped blood then creates a blockage which interferes with blood flow to the heart. Depending on the degree of blockage, symptoms can range from chest pain to heart attack or cardiac arrest.  For some, the first symptom is a heart attack. If the blockage is partial, symptoms may include shortness of breath, a rapid heartbeat, sweating, nausea, and fatigue (tiredness).  Though SCAD can occur at any age, most cases occur in otherwise healthy people between the ages of 30 and 50. It is more common in women.  SCAD is an urgent situation and requires immediate attention.  Though the exact cause of SCAD is not fully understood, risk factors include pregnancy, recently giving birth, very high blood pressure, and extreme exercise.  Certain conditions such as connective tissue disorders or fibromuscular dysplasia (FMD) may also increase a person’s risk of developing SCAD.  Treatment depends on the signs and severity of the disease but may include allowing the dissection to heal on its own, medications to reduce the risk of clots, or percutaneous coronary intervention. Some cases require surgery.  People who have survived SCAD may be at risk for another dissection. 
For more information, visit GARD.