When the discomfort is in the hands, it is often felt as a numbness. In all cases, however, angina pectoris results either from decreased blood supply to the heart, or an increase in blood demand by the heart that exceeds the supply available to it. Angina pectoris, in its early stages, begins with exertion or strong emotion and ends when the exertion or strong emotion cease. It can also be relieved by nitroglycerin tablets or other medications that can improve blood supply to the heart. In this phenomenon, the anginal discomfort disappears even though the exercise or emotion continue.
Unstable angina is a medical emergency.
Usually the blockages, or stenoses, develop slowly. There are two basic ways that this happens. In either case, the blood flow through the affected artery is reduced suddenly. New-onset angina is unstable when it occurs in patients who have never had anginal symptoms before. In patients who have had stable angina, the discomfort is more intense, more frequent, brought on by less effort, or different in character from the previously stable angina.