Angina - or angina pectoris (Latin for squeezing of the chest) - is chest pain, discomfort, or tightness that occurs when an area of the heart muscle is receiving decreased blood oxygen supply. It is not a disease itself, but rather a symptom of coronary artery disease, the most common type of heart disease.
The lack of oxygen rich blood to the heart is usually a result of narrower coronary arteries due to plaque buildup, a condition called atherosclerosis. Narrow arteries increase the risk of pain, coronary artery disease, heart attack, and death.
Angina may manifest itself in the form of an angina attack, pain or discomfort in the chest that typically lasts from 1 to 15 minutes. The condition is classified by the pattern of attacks into stable, unstable, and variant angina.
- Stable (or chronic) angina is brought on when the heart is working harder than usual, such as during exercise. It has a regular pattern and can be predicted to happen over months or even years. Symptoms are relieved by rest or medication.
- Unstable angina does not follow a regular pattern. It can occur when at rest and is considered less common and more serious as it is not relieved by rest or medicine. This version can signal a future heart attack within a short time - hours or weeks.
- Variant (Prinzmetal's) angina and microvascular (smallest vessels) angina are rare and can occur at rest without any underlying coronary artery disease. This angina is usually due to abnormal narrowing or relaxation (spasm) of the blood vessels, reducing blood flow to the heart. It is relieved by medicine.
Angina risk factors
Those at an increased risk of coronary artery disease are also at an increased risk of angina. Risk factors include:
- Unhealthy cholesterol levels
- Hypertension (high blood pressure)
- Tobacco smoking
- Being overweight or obese
- Metabolic syndrome
- Sedentary lifestyle
- Being over 45 for men and over 55 for women
- Family history of early heart disease.
Causes of angina
Atherosclerosis - a buildup of plaque around the artery wall - is the most common cause of angina.
Angina is most frequently the result of underlying coronary artery disease. The coronary arteries supply the heart with oxygen rich blood. When cholesterol aggregates on the artery wall and hard plaques form, the artery narrows.
It is increasingly difficult for oxygen rich blood to reach the heart muscle as these arteries become too narrow. In addition, damage to the arteries from other factors (such as smoking and high levels of fat or sugar in the blood) can cause plaque to build up where the arteries are damaged. These plaques narrow the arteries or may break off and form blood clots that block the arteries.
The actual angina attacks are the result of this reduced oxygen supply to the heart. Physical exertion is a common trigger for stable angina, as the heart demands more oxygen than it receives in order to work harder. In addition, severe emotional stress, a heavy meal, exposure to extreme temperatures, and smoking may trigger angina attacks.
Unstable angina is often caused by blood clots that partially or totally block an artery. Larger blockages may lead to heart attacks. As blood clots form, dissolve, and form again, angina can occur with each blockage.
Variant angina occurs when an artery experiences a spasm that causes it to tighten and narrow, disrupting blood supply to the heart. This can be triggered by exposure to cold, stress, medicines, smoking, or cocaine use.
Symptoms of angina
Angina is usually felt as a squeezing, pressure, heaviness, tightening, squeezing, burning or aching across the chest, usually starting behind the breastbone. This pain often spreads to the neck, jaw, arms, shoulders, throat, back, or even the teeth.
Stable angina usually is unsurprising, lasts a short period of time, and may feel like gas or indigestion. Unstable angina occurs at rest, is surprising, last longer, and may worsen over time. Variant angina occurs at rest and is usually severe.
On the next page we look at how angina is diagnosed, the available treatments for the condition and how angina can be prevented.