Angina is one of the more obvious symptoms of CHD, experienced by 3-4 per cent of adults in the UK. ‘Stable’ angina describes episodes of pain symptoms which have a trigger (eg exercise, stress, cold weather or eating a meal), and which subside within a few minutes of resting or taking medication. ‘Unstable’ angina can occur without an obvious trigger or when resting and persists despite medication.^38,39,40

Less common types of angina include:⁴⁰

• vasospastic angina, also known as coronary artery spasm or Prinzmetal’s angina, with pain arising when resting due to the coronary artery going into spasm
• microvascular angina or cardiac syndrome X which occurs when the smaller coronary arteries go into spasm, for example when exercising or when stressed or anxious.

NICE recommendations for medication to treat newly diagnosed angina start with sublingual glyceryl trinitrate (GTN) for rapid symptom relief or prior to engaging in activity likely to trigger an angina attack. If the pain does not subside within 5 minutes a second dose can be taken, but if pain continues five minutes after the second dose, a 999 call for an ambulance should be made.⁴¹

First line regular treatment is a beta-blocker or calcium channel blocker (CCB). If neither type can be tolerated or are contraindicated, then one of the following may be considered:

• a long-acting nitrate (such as isosorbide mononitrate)
• nicorandil
• ivabradine

If angina is poorly controlled on monotherapy, a beta blocker can be taken with a long-acting dihydropyridine CCB such as amlodipine, modified-release nifedipine, or modified-release felodipine. However, a beta blocker should not be combined with a rate limiting CCB such as diltiazem or verapamil, as this can cause severe bradycardia and heart failure.

For secondary prevention, antiplatelet treatment should be considered. Usually this will be aspirin 75mg unless the person is already taking clopidogrel (eg for a prior stroke) when clopidogrel should continue to be used.

People with stable angina and diabetes mellitus may be offered an angiotensin-converting enzyme (ACE) inhibitor, but this should also take into account their full cardiovascular history. A statin and antihypertensive treatments may also be considered.