Ischemia itself is a condition known for the restriction of blood flow to a particular part of the body. In the case of chronic ischemic heart disease, blood flow is restricted to the heart muscle.
Ischemia can cause chest pain and the same discomfort related to angina.

What is silent ischemia? Is a heart attack with no symptoms and no warning.
Reports have indicated that over three million Americans experience ischemic episodes with no symptoms. These people experience episodes without pain and as a result experience a heart attack with no warning. Most people ask what is silent ischemia and the answer is very straight forward. There is no pain or symptoms related to this condition.