What does the term 'ischemia' refer to in the context of angina pectoris?

Ischemia refers to a condition where there is a deficient supply of oxygenated blood to a particular tissue, which in the context of angina pectoris means that the heart muscle is not receiving enough oxygen. Angina pectoris is chest pain or discomfort that occurs when the heart muscle doesn't receive enough blood and, consequently, oxygen, often due to narrowed coronary arteries. This inadequate oxygen supply can lead to feelings of pressure or pain in the chest, typically triggered by physical exertion or stress when the heart demands more oxygen.

In this case, the lack of oxygen to the heart muscle directly results in the symptoms associated with angina, making it a key concept in understanding the underlying mechanisms of this condition.