Angina pectoris is a sever pain in the chest felt due to lack of blood supply to the heart muscle. The blood flow to the heart muscle is blocked due to narrowing or blockage of  arteries that supply pure blood to the heart muscle.Angina pectoris, which is also known as angina causes chest discomfort, squeezing pain or fullness in the center of the chest. The discomfort is also felt in the neck, jaw, shoulder, back or arm.
The symptoms, cause, risk factor and treatment are explained below
Symptoms
Common presenting symptoms of angina include chest pain which usually start as mild discomfort which may progress to severe chest tightness, even described as squeezing sensation with difficulty in breathing, the pain usually may radiate to different other sides like upper part of the abdomen, jaw, upper part of the left arm, to the back between the two shoulder blades (scapula) etc from the chest. Other than pain there is increased sweating, nausea, vomiting, increased tiredness, apprehension, lightheadedness sometimes blackout may also occur.
The nature and pattern of the pain is very important as any change in them may indicate progression of previous stable angina to unstable variety, the more dangerous form of angina with increased risk of progression to heart attack. Stable angina is the most common form of angina which usually occurs with exertion both physical and mental and subsides within minutes (3 to 5 minutes) after taking rest and anti anginal drugs (nitrates).
In unstable angina the angina pain typically occurs suddenly even during resting and may last for more than 30 minutes. In many cases of unstable angina antianginal drugs are not effective.
In variant angina there severe degree of pain during resting but in contrast to unstable angina the pain is usually relieved following intake of antianginal drugs. This condition is quite uncommon affecting only 2% of the total patients of angina pectoris.
Sometimes the symptoms of angina may vary slightly in women, as there might not be any chest pain rather discomfort in the chest along with pain in the neck, upper abdomen or left arm with increased perspiration, nausea, vomiting, shortness of breath etc.
Other than limited participation in activities which might be stressful both emotionally and physically, the most dreaded complication of angina pectoris is heart attack (myocardial infarction).
Common presenting symptoms of heart attack include exaggeration of the pain both in terms of severity and nature felt during an attack of angina for prolonged duration. Heart attack requires immediate medical attention.
Causes
Like any other organ of the body heart also require oxygen to carry out normal function. The oxygenated blood is supplied to the heart muscles by the coronary arteries. Symptoms of angina occur whenever there is any imbalance between the amount of oxygen supplied and the amount of oxygen required. Usually during stressful conditions like running, during exercise, climbing stairs etc oxygen requirement in the body as a whole is increased hence heart is also required to pump increased amount of oxygenated thereby oxygen requirement of the heart itself also increases. Narrowing of the coronary arteries may compromise blood supply to the heart muscles and thus may lead to the symptoms of angina.
The most common cause of narrowing of coronary arteries is fatty deposits along the inner lining of the arteries, known as plaques (atherosclerosis).
In different varieties of angina there are different underlying reasons like in case of stable angina atherosclerosis is the main reason for poor blood supply to the cardiac muscles. In these cases usually the heart gets adequate oxygen during rest but as during stressful conditions the requirement of oxygen is increased heart muscles do not get adequate oxygen leading to symptoms of angina.
 In case of unstable angina the atherosclerotic plaques in the coronary arteries may rupture leading to clot formation and further narrowing of the already narrow coronary arteries. This change occurs suddenly hence attacks of unstable angina are usually sudden onset.
In case of variant angina contraction (spasm) may occur in some segments of coronary arteries leading to temporary inadequate oxygenation of the heart and hence the symptoms of angina.
Risk factors
Common risk factors of angina pectoris are smoking and tobacco use, diabetes, high blood pressure, abnormal lipid metabolism leading to raised cholesterol and triglyceride levels, family history of coronary artery disease, past history of coronary artery disease, advanced age, sedentary life style, increased body weight, increased amount of stress etc.
Treatment
Treatment options for angina include
1. Changes in life style like avoiding smoking, reducing body weight if obesity is there, regular exercise, consuming healthy and balanced diet containing limited amount of saturated fats etc
2. Drugs: nitrates, beta blockers, calcium channel blockers, anti platelet drugs, low dose aspirin, anticoagulants etc
3. Surgical interventions like  :
    a. Angioplasty and stent placement
    b. Coronary bypass surgery