Unstable angina affects the heart and is a medical emergency. An ambulance should be called using 999.
Symptoms of unstable angina
Angina is a condition in which the blood supplied to heart muscles is restricted due to hardening and narrowing of the arteries connected to the heart and restricting the amount of oxygen.
An angina attack usually begins with chest pain that may then affect the left arm, neck, jaw or back. The attack may begin after physical exertion or stress, but can develop without obvious triggers.
With unstable angina, the symptoms begin rapidly and can last for up to half an hour.
Unstable angina may be experienced by a person who has previously had symptoms of stable angina, which is more predictable.
Unstable angina increases the risk of a person having a stroke or heart attack.
Causes of unstable angina
The hardening and narrowing of the arteries which may lead to unstable angina is called atherosclerosis. The risk of atherosclerosis increases with age, being a smoker, being obese, eating a diet high in bad fats and having high blood pressure.
Other risk factors include drinking too much alcohol, having diabetes, not doing enough exercise and a family history of angina or heart problems.
Diagnosis of unstable angina
A person who has suffered an unstable angina attack will be tested when they get to hospital with an electrocardiogram (ECG) to check their heart rhythm.
A coronary angiography will be arranged to check for narrowing of the arteries and any blockages.
Blood tests will be taken to check for enzyme levels that signal heart damage.
After a diagnosis of unstable angina, a person's risk of further attacks will be worked out using the Global Registry of Acute Cardiac Events or GRACE.
Treatment for unstable angina
One typical angina treatment, glyceryl trinitrate, may not always be effective for unstable angina.
The NHS advises people suffering an angina attack to chew an aspirin while waiting for an ambulance. Aspirin helps prevent blood clots, stroke and heart attacks. People with an allergy to aspirin should not take aspirin in this situation.
Medication may be prescribed to make the blood thinner and less likely to clot, such as aspirin, clopidogrel, fondaparinux or heparin.
Depending on the results of a coronary angiography, a procedure may be recommended to remove any blockage or to widen arteries. Coronary angioplasty, also known as PCI or PTCA, uses stents to relieve blockages and narrowing of the arteries.