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

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

A couple of weeks ago I wrote about the first aid treatment for a heart attack. Often when I’m teaching though I find that people aren’t sure what is the difference between a heart attack and a cardiac arrest. In this blog I hope to explain.

The heart is a muscle

The first thing to really understand is that the heart is a muscle. It is different in some ways to any other muscle but the similarity it shares with every other muscle or cell in our body is that it needs a blood supply because it needs oxygen.

The heart cells receive oxygen from the blood the same as every other cell. However, even though the heart’s job is to pump the blood around the body it doesn’t get its own supply direct.

It has its own network of arteries to take blood to the cells and veins to take blood away. This network of arteries and veins start right from the very beginning of the aorta, the main artery leaving the heart.

What happens when someone has a heart attack?

When someone has what we call a ‘heart attack’ it’s because a clot has formed in one (or more) of these tiny arteries that feed blood to the heart cells.

The result is that the cells further along the line begin to die. You can see this is the diagram below.

It is the lack of oxygen and resultant death of these cells that affects the function of the heart and causes the pain and other symptoms associated with a heart attack.

What are the symptoms of a heart attack?

The classical symptoms of a heart attack are central or left sided chest pain that feels tight or heavy. The pain may spread to the left arm, back, neck and/or jaw. The person may feel nauseous and/or short of breath, they may look pale and/or clammy.

A heart attack is an emergency because the person may collapse and the sooner they receive treatment the better.

What do you do if you think someone is having a heart attack?

I’ve written a previous blog about the first aid treatment of a heart attack, which you can read here.

So what is a cardiac arrest?

A cardiac arrest is when someone’s heart stops beating and stops pumping blood around the body. Put simply:-

Cardiac = heart

Arrest = stopped

Cardiac arrest = heart stopped

This is why we perform CPR to pump blood around the body for them until we can get their heart beating normally again. One of the proven ways to do this is with a defibrillator.

When someone suffers a heart attack their heart is likely to continue to beat normally. Sometimes the heart attack is so severe that it causes the heart to stop and they will have a cardiac arrest as a result; but as you can see they’re not the same thing. A heart attack is a clot in one of the coronary arteries and a cardiac arrest is when the heart has stopped beating.

I hope this has helped. Please comment and ask questions if you need anything clarifying.

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