Heart attack, cardiac arrest and angina: the differences and when to call 999

What is the difference between a heart attack and cardiac arrest?

The British Heart Foundation (BHF) explains that a heart attack and a cardiac arrest are different, and that both are emergencies.

A heart attack happens when the blood flow to the heart is blocked. The BHF describes a heart attack as a sudden loss of blood flow to part of the heart muscle, and the NHS says it can be life-threatening and needs emergency treatment in hospital.

In a cardiac arrest the heart stops pumping effectively. The person collapses, does not respond and is not breathing normally. The BHF says a heart attack can sometimes lead to a cardiac arrest.

If a defibrillator is nearby, the 999 call handler will say where it is and may ask someone to fetch it, and CPR should not be stopped.

A cardiac arrest usually happens suddenly and without warning.

What is angina?

Angina is chest pain or discomfort that happens when the blood supply to the heart muscle is temporarily reduced. The BHF says the discomfort of angina does not damage the heart muscle in the way a heart attack does.

Angina symptoms usually happen during exercise and pass within a few minutes, and they can be eased by resting or by using a nitrate tablet or spray.

Angina symptoms usually pass in a few minutes, but heart pain that lasts longer may be a heart attack, so call 999.

What are the symptoms of a heart attack?

The NHS lists chest pain that feels tight or squeezing. The pain can spread to the arms, jaw, neck, back or tummy.

Other signs include feeling sick, sweating, shortness of breath and light-headedness.

A key difference from angina is that heart attack symptoms are not usually relieved by a nitrate tablet or spray.

Some people with a heart attack also look pale or grey.

Women are more likely to notice symptoms such as shortness of breath, feeling sick, and back or jaw pain, and symptoms can be milder than people expect.

What are the signs of a cardiac arrest?

A person in cardiac arrest loses consciousness. They do not respond, and they are not breathing or their breathing does not look normal.

Without treatment a person in cardiac arrest may die within minutes, which is why speed matters.

When should someone call 999?

The NHS says to call 999 straight away if someone may be having a heart attack.

If someone seems to be in cardiac arrest, the NHS advises calling 999 and starting CPR, with the call handler giving instructions.

The NHS says to call 999 for the main warning signs of a heart attack, and to call NHS 111 for less severe symptoms such as a racing or irregular heartbeat. The BHF says heart attack pain is not relieved by rest or a nitrate medicine, and that a heart attack is a 999 emergency.

The NHS advises a person who may be having a heart attack to call 999 rather than drive themselves to A&E.

For less severe symptoms such as a racing or irregular heartbeat, the NHS says to call NHS 111.

How are they diagnosed and treated?

A heart attack is usually assessed with an ECG, which records the heart's electrical activity, and a blood test for troponin, a protein released when the heart muscle is damaged. The site's pages on these tests give more detail.

Treatment in hospital, with medicine or a procedure, aims to restore the blood supply to the heart.

What else do the sources say?

An NHS ECG is usually the first test, and it can show whether the heart attack needs urgent treatment to open the blocked artery.