Chest pain. Is it a Heart Attack?
Updated: Jul 31, 2019
Chest pain is one of the most common presentations to the ambulance service. Every call is taken extremely seriously, as it's the most common symptom of a heart attack, which can rapidly lead to cardiac arrest and death.
There are other (less sinister) causes of chest pain, but a cardiac cause must always be ruled out first.
The term 'cardiovascular disease' describes all diseases of the heart and circulation. It is a leading cause of death in the UK, killing 150,000 people each year, or 1 death every 3 minutes. 42,000 of these deaths are in people who are under 75 years old.
The risk factors for cardiovascular disease are well known and often interlinked.
High blood pressure
Modifiable Lifestyle Factors:
Obesity or being over-weight
Poor diet and lack of exercise
Causes of chest pain
The heart is a large muscle that sits in the centre of the chest, usually just off to the left. It supplies itself with blood through a network of blood vessels that cover the surface of the heart - the coronary arteries. It is through these vessels that oxygen and sugar are supplied to allow the muscle to continue to pump blood around the body.
As a result of developing cardiovasular disease, fatty deposits (sometimes called plaques or atheromas) begin to build up in the walls of the arteries, which also become stiff and brittle. When the blood flow to the muscle is interrupted by the narrowed arteries, the patient will usually experience 'chest pain'.
As a plaque begins to grow, it reduces the internal size of the blood vessel, which in turn reduces the individual's tolerance to exercise. The heart isn't receiving sufficient blood to service the increased demand, and when this happens, the person experiences chest pain as a result. If the individual rests, the chest pain will resolve after a few minutes. This is known as stable angina, and is a warning sign that something is wrong.
People who are diagnosed as having angina will usually be prescribed a small red bottle of GTN (glyceryl tri-nitrate) to spray under their tongue, although sometimes it's given in tablet form. GTN is very good at opening up blood vessels, which allows more blood flow through the narrowed arteries and helps to resolve the chest pain more quickly and minimise any permanent damage. The person is likely to be used to taking their GTN when they experience chest pain.
The narrowing of the coronary arteries speeds up the blood flowing through it, which then slows down again on the other side and becomes turbulent, like the eddies in a river. This action can aggravate the internal wall of the vessel which can cause the plaque to rupture followed by the formation of a blood clot. This is called a heart attack.
This clot may form at the site of the plaque, or it may become detached, travelling further along the artery until it is too big to big to fit in to smaller arteries. Where the clot has become mobile, the original aggravated site may continue to produce more clots.
Wherever the blood clot ends up, the piece of heart muscle fed by that artery will be starved of oxygenated blood and begin to die. If the clot is higher up the arterial tree (in a larger vessel) then it can cause an extremely serious, if not fatal, heart attack. If the clot is relatively small and forms in one of the smaller vessels, only a very small amount of muscle will be involved and the person may not even know that it has happened.
If a significant piece of the heart muscle is affected by angina or a heart attack, it is very likely that the person will experience 'chest pain'.
Cardiac chest pain is often described as crushing or squeezing in nature, sometimes also going down someone's left arm, up in to their neck and jaw, or through to their back. However, people experience chest pain in many different ways and may describe it's location and nature in a variety of ways.
It is possible to have a heart attack without chest pain, but it's relatively rare. This 'silent heart attack' usually occurs in particular groups of patients, such as diabetics, who have sustained significant nerve damage as a result of poor blood sugar control over a prolonged period.
In angina, the chest pain will come on with exercise and will be relieved by rest. However, in a heart attack, the pain may come on at rest, and will not be relieved by rest, as the blood clot is still causing a problem.
If the angina attack or heart attack is severe, because the problem is higher up in the arterial tree, the person may also be showing signs of shock. These include:
Pale, cold, clammy skin
Fast breathing rate
Complaining of nausea or even vomiting
Fast pulse rate
The treatment of any chest pain by a first aider or responder is relatively simple, but critical. Call 999 for an ambulance and use the words 'chest pain'. The call handler will talk you through what to do, which is likely to include the following.
Make the person comfortable, lying them down if they are showing signs of shock.
Next, if it is available and the person can usually take it, give them 300mg of aspirin. This should be chewed to get the drug in to the system as quickly as possible. If it's dispersible, dissolve it in water and ask the person to drink it as usual.
Aspirin interrupts the clotting process and should stop any more clots being formed. It won't do anything about the clots that already exist though, as it's not a 'clot-buster'.
If the person has already been diagnosed with angina, they may well have been taking their GTN to try to resolve the pain. However, if this is not the case and they have it with them, it is worth encouraging them to take it. This will help to relax the cardiac arteries and may allow oxygenated blood to pass the clot, or allow it to travel further down the arterial tree, minimising the amount of muscle affected.
Around 80% of out-of-hospital cardiac arrests in the UK are the result of a heart attack. If there's a defibrillator nearby, send someone to go and get it and prepare to do CPR. If the person becomes unconscious and stops breathing, then they are in cardiac arrest.
Start CPR and use the defibrillator. You can read more about what to do if someone is in cardiac arrest in a previous post.
Remember, anyone with chest pain must be treated as potentially having a heart attack until proven otherwise. Call 999 straight away and follow their instructions.