Acute coronary syndrome: what it is, symptoms and emergency treatment

Acute coronary syndrome (ACS) is not a single illness but a group of conditions with the same underlying problem: the blood supply to the heart muscle is suddenly reduced or blocked. NICE guideline NG185 divides management into STEMI and into NSTEMI and unstable angina.

The BHF says that most heart attacks are caused by coronary heart disease, in which the coronary arteries become narrowed by a gradual build-up of fatty deposits called atheroma. If a piece of atheroma breaks off, a blood clot forms around it and can block the artery, starving the heart muscle of blood and oxygen.

The NHS lists the symptoms of a heart attack below. The BHF adds that pain can spread to either arm, the neck, jaw, upper back or stomach, that less common symptoms include suddenly feeling anxious like a panic attack, severe tummy pain, or lots of coughing or wheezing, and that symptoms are different for different people.

The BHF says women and men generally experience the same heart attack symptoms, but women tend not to recognise them as quickly.

• Chest pain that may feel crushing or squeezing, and may spread to the arm, neck and jaw.

• Feeling short of breath.

• Feeling sick or being sick.

• Feeling like you have indigestion, with a burning feeling and feeling full or bloated.

• Sweating.

• Pale, blue or grey skin, which on brown or black skin may be easier to see on the palms of the hands.

The NHS says call 999 if you have chest pain that feels tight or like squeezing on your chest, chest pain that is spreading to your arms, neck or jaw, severe difficulty breathing, pale, blue or grey lips or skin, or if someone has passed out and is not responding normally. Do not drive yourself to A&E.

The BHF says not to worry about wasting anyone's time, because a heart attack is a medical emergency and delay can mean serious heart damage.

• Sit and rest on the floor in a comfortable position, with your knees bent and back supported (NHS).

• Take 300 mg aspirin if you have it and are not allergic to it (NHS, BHF).

• If you have angina and have a glyceryl trinitrate (GTN) spray, use it (NHS).

• Keep checking the person is responding and breathing, and start CPR if they stop responding and stop breathing (NHS).

The NHS says you will need tests including an electrocardiogram (ECG) and blood tests to find out if you are having a heart attack. If these show a heart attack, you may have an echocardiogram to see if the heart has been damaged, and a coronary angiogram, which finds exactly where the blood flow is blocked, and the blockage may be treated at the same time.

NICE says a formal risk assessment for NSTEMI and unstable angina should include a full clinical history, a physical examination, a resting 12-lead ECG, and blood tests such as troponin I or T, creatinine, glucose and haemoglobin. The BHF says paramedics do an ECG, so you should not try to take yourself to hospital.

The NHS says you will need treatment in hospital and that it depends on how severe the heart attack is. NICE says people with STEMI should be assessed immediately for coronary reperfusion therapy, either primary percutaneous coronary intervention (PCI) or fibrinolysis, delivered as quickly as possible, and offered a single loading dose of 300 mg aspirin unless allergic. For NSTEMI and unstable angina NICE says to offer aspirin as soon as possible and continue it indefinitely unless contraindicated.

The NHS says you will be given medicines to take long-term after a heart attack to treat the causes and reduce the risk of another. These may include antiplatelets, statins, and other medicines to lower blood pressure such as ACE inhibitors and beta-blockers.

The NHS says for some people it may take several weeks to recover, with little impact on their life, while for others recovery can take months or years. You will usually need to rest, including time off work, and be referred to cardiac rehabilitation, in person or remotely by video calls or apps. It says to talk to your GP if you feel anxious or have low mood.

The NHS says you are more likely to have a heart attack if you smoke, have high blood pressure, have high cholesterol, have a close relative who has had a heart attack, have diabetes, or are living with overweight or obesity. It says you cannot always prevent a heart attack, but you can stop smoking, keep your cholesterol and blood pressure at healthy levels, eat a healthy balanced diet, cut down on salt and saturated fat, maintain a healthy weight, exercise regularly and cut down on alcohol.

Acute coronary syndrome is treated as an emergency through 999, ambulance and NHS hospital services, often with direct transfer to a heart attack centre for primary PCI. Private cardiology is relevant mainly for ongoing risk assessment and follow-up, and should be coordinated with your NHS cardiac team and GP.