Classification of Angina
Angina can be classified as stable, unstable, vasospastic, microvascular or refractory.
Stable Angina
Stable angina is the most common form, occurring predominately as a consequence of exertion or exercise. It is also commonly triggered by emotional stress or extremes of temperature.
Stable angina has three diagnostic features:
- Pain or constricting discomfort in the front of the chest, neck, shoulders, jaw and/or arms
- Symptoms are precipitated by physical exertion
- Symptoms are relieved by rest or glyceryl trinitrate (GTN) within 5 minutes
Patients who present with all of the above signs are described as suffering from typical angina. Those suffering with only two diagnostic features have atypical angina while those suffering from one or none of the above have non-anginal chest pain.
Typical symptoms of stable angina include:
- Central chest pain described as "constricting" or a "heaviness on the chest"
- Pain that radiates to the lower jaw or arms
- Symptoms provoked by exercise, stress or extremes of temperature
- Symptoms relieved by rest or nitrates
Atypical symptoms that may be associated with angina include nausea, gastro-intestinal discomfort or breathlessness. The pain associated with angina is relatively short-lived, typically resolving with either rest or glyceryl trinitrate within 5 minutes.
Unstable Angina
Angina is described as unstable where there is a sudden deterioration in symptoms. Deterioration of symptoms typically involves increased frequency, more prolonged or severe symptoms or symptoms provoked at lower trigger thresholds. Deterioration of symptoms is not associated with myocardial damage demonstrated by ECG changes or elevated cardiac enzymes.
The pain associated with unstable angina is typically described as more severe, persists longer and is less responsive to sublingual nitrates than stable angina. Unstable angina should be considered a medical emergency; patients describing symptoms of unstable angina should be referred urgently to their GP or A&E.
Vasospastic Angina (also known as Prinzmetal's angina)
Vasospastic angina is a rarer form of angina triggered by a spasm of the coronary artery. Vasospastic angina can present with symptoms at rest that range from minor to severe. Attacks commonly occur between midnight and the early morning.
Microvascular Angina (also known as Cardiac syndrome X)
Microvascular angina is pain or an uncomfortable feeling caused by spasms of the smaller coronary arteries. It is usually triggered by exercise, stress or anxiety. It can also occur during periods of rest. Microvascualr angina can affect both men and women but is more common in women going through the menopause or post-menopausal women.
Refractory Angina
Refractory angina is pain or discomfort that continues after treatment. This includes treatment with medication, coronary stents or coronary bypass. It has a similar mortality rate to other types of angina but patients report significantly impaired quality of life with more frequent visits to health care professionals when compared with patients with other types of angina.