Discomfort in the chest is likely the most frequent complaint for which people seek medical attention. Chest discomfort can result from numerous things including cramping and soreness in the muscles of the rib cage, "heartburn" or other concerns associated with the upper region of the digestive tract, conditions involving the lungs such as a collapsed lung or even potentially life-threatening conditions involving the heart such as a heart-attack.

Angina, also known as angina pectoris, is a condition that can cause chest pain, ranging from mild to quite severe. Angina occurs when not enough oxygen is able to reach the heart muscle, usually due to a decrease in blood flow. Numerous conditions can affect the blood flow to the heart and thus the amount of oxygen reaching the heart muscle. These conditions include coronary artery disease, coronary artery spasm, irregular rhythms of the heart, infections, anemia and even a heart attack can cause angina to occur.

Generally, angina occurs when extra stress is placed on the heart such as during physical exercise or even at times of stress, anxiety and depression.(1) This is known as stable angina and is generally due to the presence of coronary artery disease. Unstable angina can occur at rest and at other unpredictable times such as in the middle of the night. Unstable angina can also be described as frequent and severe chest discomfort in patients that have not experienced chest discomfort previously or increased frequency, severity and worsening of angina in people diagnosed with stable angina. A rare third type of angina is referred to as variant angina, which can occur during exertion or while at rest generally resulting from a spasm in a coronary artery.(2)