Angina is caused by obstructive coronary artery disease (CAD) that causes decreased blood flow, lack of oxygen and ischemia to the heart muscle. Thus, the condition is also called ischemic heart disease (IHD). Atheroma is the culprit that causes obstruction of blood flow and deprives the heart muscle of blood. More attention must be paid to the prevention of atheroma, the real disease that is responsible for fatal and nonfatal heart attacks. Angina affects men aged 40–55 years more commonly than women. Angina is stable if the condition has been present for more than 2 months, or if there has been no change in the pattern of pain, particularly no change in the frequency of attacks, severity, or duration of pain. Unstable angina is recognized by a change in the pattern of pain; an increase in the frequency, severity, or duration of pain; and a lesser degree of known precipitating factors. Variant angina is a rare form of angina and is caused by coronary artery spasm, often without identifiable stimuli. The resulting myocardial ischemia in this condition also stimulates catecholamine release. During the pain, the ECG shows ST-segment elevation which resolves when pain subsides.