Angina is also called angina pectoris. It is a type of chest pain caused by reduced blood flow to the heart. Angina is a symptom of coronary artery disease. Angina pain is often described as squeezing, pressure, heaviness, tightness or pain in the chest. It may feel like a heavy weight lying on the chest. Angina may be a new pain that needs to be checked by a health care provider, or recurring pain that goes away with treatment. Although angina is relatively common, it can still be hard to distinguish from other types of chest pain, such as the discomfort of indigestion. Still, it can be a sign of a life-threatening heart problem.  Usually, medicine and lifestyle changes can control angina. If it's more severe, you may need surgery, too. Or you may need what’s called a stent, a tiny tube that props open arteries.

The different types of angina pectoris are:

• Stable angina. Stable angina is the most common form of angina. It usually happens during activity (exertion) and goes away with rest or angina medication. For example, pain that comes on when you're walking uphill or in the cold weather may be angina.

Stable angina pain is predictable and usually similar to previous episodes of chest pain. The chest pain typically lasts a short time, perhaps five minutes or less.

• Unstable angina (a medical emergency). Unstable angina is unpredictable and occurs at rest. Or the angina pain is worsening and occurs with less physical effort. It's typically severe and lasts longer than stable angina, maybe 20 minutes or longer. The pain doesn't go away with rest or the usual angina medications. If the blood flow doesn't improve, the heart is starved of oxygen and a heart attack occurs. Unstable angina is dangerous and requires emergency treatment.
• Variant angina (Prinzmetal angina). Variant angina, also called Prinzmetal angina, isn't due to coronary artery disease. It's caused by a spasm in the heart's arteries that temporarily reduces blood flow. Severe chest pain is the main symptom of variant angina. It most often occurs in cycles, typically at rest and overnight. The pain may be relieved by angina medication.
• Refractory angina. Angina episodes are frequent despite a combination of medications and lifestyle changes

Angina symptoms include chest pain and discomfort, but it affects people differently, the discomfort also can occur in your shoulders, arms, neck, jaw, abdomen or back. Angina pain may even feel like indigestion. In addition, some people don’t feel any pain but have other symptoms like shortness of breath, fatigue, dizziness, sweating, aching, burning, feeling of fullness in your chest. Symptoms of angina in women can be different from the classic angina symptoms. These differences may lead to delays in seeking treatment. For example, chest pain is a common symptom in women with angina, but it may not be the only symptom or the most prevalent symptom for women. Women may also have symptoms like, discomfort in the neck, jaw, teeth or back, nausea, shortness of breath, stabbing pain instead of chest pressure, stomach (abdominal) pain.

Angina is caused by reduced blood flow to the heart muscle. Blood carries oxygen, which the heart muscle needs to survive. When the heart muscle isn't getting enough oxygen, it causes a condition called ischemia. The most common cause of reduced blood flow to the heart muscle is Coronary Artery Disease (CAD), an enlarged or thickened heart (hypertrophic cardiomyopathy), narrowing of a valve in the main part of your heart (aortic stenosis), swelling of the sac around your heart (pericarditis), tearing in the wall of your aorta, the largest artery in your body(aortic dissection)

Based on your symptoms and risk factors diagnosis is done by doing some of the tests like, EKG, stress test, blood tests, imaging tests, cardiac catheterization, and coronary angiography.

To know further about the journal kindly go through Angiology.