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What is the difference between a heart attack and an SCA?

Published on 25th February 2022

Often used interchangeably, the terms ‘heart attack’ and ‘sudden cardiac arrest’ are often misconstrued as the same thing. But medically speaking these are two completely different events – and it’s important to understand the difference, especially when discussing the use of an AED.

Both heart attacks and SCAs are serious medical emergencies – if you suspect that either may be occurring, you should ensure that the patient is provided with urgent care and medical attention.

In this article we’ll explain the key differences between a heart attack and sudden cardiac arrest, along with signs and symptoms and different methods of treatment for each.

What is a heart attack?

A heart attack (medically known as myocardial infarction) occurs when the supply of blood to the heart suddenly becomes blocked, meaning it can’t get the oxygen it needs. Blockages can occur for a number of reasons, including conditions such as arrhythmia and congestive heart failure and lifestyle-related issues including high blood pressure, high cholesterol and diabetes.

Signs and symptoms of a heart attack include:

*Discomfort in the chest area including pressure and a squeezing sensation
*Pain and/or discomfort in one or both arms, shoulder or upper back
*Pain and/or discomfort in the neck or jaw
*Shortness of breath
*Feeling light-headed
*Sweating or a ‘clammy’ feeling – breaking out in a cold sweat

Heart attack symptoms in women often differ to those in men – so it’s important to understand and notice when a heart attack might be occurring. These include:

*Stomach/abdominal pain
*Swelling in the lower leg area and ankles

It’s not usually necessary to use an AED when someone is experiencing a heart attack. Swift medical attention is key, but the most important thing to remember is keeping the patient calm, conscious and comfortable whilst you wait for professional medical assistance.

Although heart attacks are not the same as SCA, a heart attack can sometimes trigger an electrical disturbance in the heart that leads to sudden cardiac arrest.

What is Sudden Cardiac Arrest?

Compared with a heart attack which is a physical issue, SCA is an electrical issue concerning the system that provides pumping action to the heart.

When SCA occurs, the patient is unresponsive (unconscious) and their heart stops beating immediately. Because the heart is no longer pumping blood throughout the body to vital organs, including the brain, swift action is crucial in order to save the person’s life.

Common signs and symptoms of an SCA include:

*Suddenly passing out or collapsing
*No pulse
*Seizures lasting up to 10-20 seconds
*No breathing or agonal breathing – breathing which sounds like gasping, snorting, snoring or groaning

Helping someone who is having a heart attack vs helping someone having an SCA (please see our chain of survival guide for help with SCA’s)

Due to the medical difference in nature of heart attacks and SCAs, both command a different response. Both heart attacks and SCAs are serious medical incidents and should be treated as quickly as possible.

If you suspect someone is suffering a heart attack:

1/ Call the emergency services as soon as possible
2/ Encourage the person to sit or lie down and rest whilst waiting for the emergency services to arrive
3/ Continue to monitor the person and make sure they remain responsive and continue breathing
4/ Do not drive the person to hospital yourself – wait with them until an ambulance arrives
5/ Heart attacks can progress very quickly. Should the person’s condition deteriorate further (if they become unresponsive, or stop breathing) start manual CPR compressions immediately and use an AED as soon as possible if one was available.

If you suspect someone is suffering from SCA:

1/ Call the emergency services as quickly as possible
2/ If you are able to, start performing CPR straight away at 100-120 chest compressions per minute. If you aren’t confident or trained in CPR, emergency responders on the phone can support you with verbal prompts and instructions
3/ Use an AED as soon as possible if one is available. If others are present, ask someone to locate and bring the AED as you call the emergency services

Acting quickly with an AED saves lives. Whether a person is suffering from a heart attack or sudden cardiac arrest, it’s important to act quickly and appropriately in order to save the person’s life. The symptoms of heart attack and SCA vary but are generally different – but if you are unsure you should always follow instructions from emergency services and use an AED without hesitation.

Remember – if someone is having a heart attack and does not require a shock, the AED works intelligently ensuring treatment won’t be delivered if it isn’t needed. You can find more information on how AEDs work and why it’s so important to use an AED quickly and confidently here.

For expert help and support and specialist advice on AEDs, contact our friendly team today.