When the heart works harder, for example, during exercise or on emotional stress or excitement, it requires an increased blood flow. However, ischaemia prevents increased blood flow and the result being a condition known as ANGINA PECTORIS.

Symptoms of angina may include chest pain ranging from a mild tightness or pressure to more severe pain under the breast bone. It may be felt up towards the throat or down the left arm. It may also be exacerbated by cold weather or a heavy meal. When angina occurs, it may be necessary to rest, thereby reducing the extra workload on the heart and the symptoms should then dissipate.

Sometimes, angina can be so severe that it occurs even at rest. This is known as UNSTABLE ANGINA. There are treatments available for angina.