Many people use the two terms interchangeably, but a cardiac arrest and a heart attack aren’t the same thing, though a heart attack can lead to cardiac arrest.
What is a heart attack?
A heart attack is a serious medical emergency and you should dial 999 if you suspect you, or someone else is, suffering a heart attack. A heart attack occurs when there is a sudden loss of blood flow to part of the heart muscle. Most heart attacks are caused by coronary heart disease, and happen when one of the coronary arteries is blocked.
Heart attacks are life-threatening, and can lead to cardiac arrest. However, whilst a heart attack is taking place, the heart is still pumping and the patient is still responsive. If the patient becomes unresponsive and stops breathing normally, then you should begin treating them for cardiac arrest immediately.
What is a cardiac arrest?
Cardiac arrest is when the heart has stopped pumping blood around the body, leading to immediate loss of consciousness. The casualty will either stop breathing or be breathing highly irregularly. Cardiac arrest is usually caused by an issue with the electrical signals in the heart, with the most common cause being an abnormal heart rhythm called ventricular fibrillation. Due to abnormal electrical activity in the heart, rather than pumping blood, it quivers, or fibrillates. This is one of two ‘shockable’ kinds of cardiac arrest, meaning it can be treated using defibrillation.
Over 30,000 out-of-hospital cardiac arrests occur each year in the UK, and the survival rate is less than 10%. Part of the problem is that there is just a short period of up to six minutes to intervene before the casualty suffers severe tissue death or brain damage. The Department of Health requires ambulance crews to reach the most seriously ill patients in an average time of seven minutes. Even when this happens, it’s often too late.
So what can you do to help?
The chances of survival can be significantly increased by immediate intervention from bystanders, through CPR (cardiopulmonary resuscitation), and where possible, defibrillation. Unfortunately, a report by the Resuscitation Council found that only 30-40% of bystanders intervene when they witness someone collapse. What’s more, a survey conducted for St John Ambulance found 61% of people don’t know how to respond to a cardiac arrest. Although 81% of people know what a defibrillator does, 70% would not feel confident using one and 62% wrongly believe it could cause harm if used incorrectly.
For every minute without treatment, the chance of survival decreases by around 14%. Without any intervention from bystanders, the chances of survival are almost zero. However, CPR can treble the chances of survival and defibrillation before emergency services arrive can raise it to more than 50%. In short, rapid first aid by either trained first aiders or untrained bystanders is absolutely essential for saving a life when cardiac arrest happens outside of hospital.