Cardiac arrest or heart attack: what's the difference and what to do

"He had a heart attack" and "he went into cardiac arrest" sound like the same thing, and people often use them interchangeably. They aren't the same, and the difference changes what you should do. The short answer: in a heart attack the heart is still beating; in cardiac arrest it has stopped.

A heart attack: a "plumbing" problem

In a heart attack, an artery that feeds the heart gets blocked, usually by a clot. The heart keeps beating, but part of it stops getting blood and oxygen and starts to suffer. The person is usually awake: chest pain (tightness, heaviness or pressure, often spreading to the left arm, the neck or the back), sweating, shortness of breath, sometimes nausea. It's an emergency, but they are talking and breathing.

Full symptoms and first aid for a heart attack: Acute Myocardial Infarction.

Cardiac arrest: an "electrical" problem

In cardiac arrest, the electrical rhythm that keeps the heart beating stops. The heart no longer pumps blood to the body, and within seconds the person collapses. They don't respond when you talk to them or shake them, and they aren't breathing normally — or they take a few noisy, gasping breaths that are easy to mistake for breathing. Without help, cardiac arrest kills within minutes.

How to tell them apart in seconds

One question separates them: are they responsive and breathing?

• Awake, talking, or complaining of pain — think heart attack (or another emergency).
• Collapsed, unresponsive, not breathing normally — this is cardiac arrest, and every second counts.

How they're connected

One can lead to the other. A severe heart attack can disrupt the heart's electrical rhythm and trigger cardiac arrest. That's why you never wait for a heart attack to "pass on its own".

What to do in each case

If you suspect a heart attack (awake, chest pain):

• Call 112 (or 166 for the Greek ambulance service) right away.
• Have them sit or lie down comfortably and keep them calm. No physical effort.
• Stay with them until the ambulance arrives, ready to act if they lose consciousness.

If it's cardiac arrest (unresponsive, not breathing):

• Call 112 and put it on speaker so your hands are free.
• Start CPR immediately: hard, fast compressions in the centre of the chest, without stopping.
• Ask someone to bring an AED and use it as soon as it arrives; the device talks you through it. Where to find the nearest one: The open defibrillator map.

Remember one thing

Heart attack: awake, in pain. Cardiac arrest: collapsed, not breathing. In the second case you don't wait — 112, CPR, AED. Those few minutes until the ambulance arrives are held by the person standing next to them, and they can be the difference for a life.

This article is for information only and does not replace hands-on training.