Classification of Angina
Angina can be classified as stable, unstable, atypical, or Prinzmetal's (variant) angina.
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.
Prinzmetal's angina
Prinzmetal's or variant angina is a rarer form of angina triggered by a spasm of the coronary artery. Prinzmetal's angina can present with symptoms at rest that range from minor to severe. Attacks commonly occur between midnight and the early morning.