The treatment options for a heart attack depend on whether you've had an ST segment elevation myocardial infarction (STEMI), or another type of acute coronary syndrome (NSTEMI or unstable angina).

An ST segment elevation myocardial infarction (STEMI) requires emergency assessment and treatment. It's important you're treated quickly, to minimise damage to your heart after a STEMI.

If you have symptoms of a heart attack and an electrocardiogram (ECG) shows you have a STEMI, you'll be assessed for treatment to unblock your coronary arteries.

The treatment used will depend on when your symptoms started and how soon you can access treatment.

• If your symptoms started within the past 12 hours – you'll usually be offered a coronary angiography and primary percutaneous coronary intervention (primary PCI).
• If your symptoms started within the past 12 hours but you cannot access percutaneous coronary intervention (PCI) quickly – you'll be offered medicine to break down blood clots.
• If your symptoms started more than 12 hours ago – you may be offered a different procedure, depending on your symptoms. The best course of treatment will be decided after an angiogram and may include medicine, PCI or bypass surgery.
• If a PCI isn't suitable for you – you may be offered a combination of medicines to prevent blood clots, called antiplatelet medicines.

Primary percutaneous coronary intervention (primary PCI)

Primary percutaneous coronary intervention (primary PCI) is an emergency treatment of a STEMI. It's a procedure to widen any blocked coronary arteries. It's sometimes called coronary angioplasty.

Coronary angiography is done first, to assess your suitability for percutaneous coronary intervention (PCI).

You may also be given blood-thinning medicines to prevent further clots from forming, such as low-dose aspirin.

You may need to continue taking medicines for some time after PCI.

PCI or coronary angioplasty is a potentially complex procedure that requires specialist staff and equipment, and not all hospitals have the facilities.

This means you'll need to be taken urgently, by ambulance, to one of the specialist centres (Heart Attack Centres) that now serve most of the UK's regions.

During coronary angioplasty, a thin tube with a sausage-shape balloon at the end (called a catheter) is put into a blood vessel in your groin or arm. The catheter is passed through your blood vessels and up to your heart, over a fine guidewire, using X-rays to guide it.

Once the catheter is in the narrowed section of your coronary artery, the balloon is inflated to open it. Flexible metal mesh (a stent) is usually inserted into the artery to help keep it open afterwards.

Medicines to break down blood clots

If you cannot be treated urgently with PCI, you'll offered medicines to break down blood clots, known as thrombolytics or fibrinolytics. These are usually given by injection.

Thrombolytics, or fibrinolytics, target and destroy a substance called fibrin. Fibrin is a tough protein that blocks blood from going through the coronary artery.

You may still need coronary angiography and PCI once your condition is stable or if thrombolysis does not work.

Medicines to prevent blood clots

If PCI is not suitable for you, you may be treated with 2 types of antiplatelet medicines (usually aspirin and 1 other medicine).

These medicines make blood flow through your veins more easily. This means your blood will be less likely to form a clot.

Both antiplatelet medicines usually need to be taken for up to 12 months.

Coronary artery bypass graft

A coronary angioplasty or PCI may not be technically possible if the anatomy of your arteries is different from normal. This may be the case if there are too many narrow sections in your arteries or if there are lots of branches coming off your arteries that are also blocked.

In such circumstances, an alternative operation, known as a coronary artery bypass graft (CABG), may be considered.

A CABG involves taking a blood vessel from another part of your body (usually your chest, leg or arm) and attaching it to your coronary artery above and below the narrowed area or blockage. This new blood vessel is known as a graft.

The graft diverts blood around narrowed or clogged parts of your major arteries to improve blood flow and oxygen supply to your heart.

If an ECG shows you have an NSTEMI or unstable angina, medicines to prevent blood clots, including aspirin and other medicines, are usually recommended.

In some cases, further treatment with coronary angioplasty or coronary artery bypass graft (CABG) may be recommended, after initial treatment with these medicines.

Medicines to thin the blood may need to be taken for up to 12 months.