Understanding the different causes of these two manifestations of Coronary Heart Disease.

In recent years, cardiologists have developed a new understanding of the causes of heart attack and angina. It is now commonly accepted that they are caused by different types of arterial plaque:

• Angina, which is characterized by temporary chest pain, pressure or discomfort, is caused by hard, relatively stable plaque that visibly blocks or narrows one or more arteries.
• Heart Attack (myocardial infarction) is caused — in up to 85% of events — by vulnerable plaque. This is plaque with a high likelihood of forming clots (thrombosis) and progressing rapidly. The most common type of vulnerable plaque is a soft plaque hidden within the arterial wall that is "vulnerable" to sudden rupture.

When it ruptures, the plaque's contents are released into the blood stream. They quickly coagulate to form a blood clot that can block blood flow to the heart and cause an attack.