Sudden cardiac arrest (SCA) is a medical emergency that occurs when the heart suddenly stops beating effectively. This usually happens due to an electrical malfunction in the heart that causes an irregular heartbeat (arrhythmia). As a result, the heart can’t pump blood to the rest of the body, including the brain, lungs, and other vital organs.

SCA can be fatal if not treated immediately. It requires prompt intervention with cardiopulmonary resuscitation (CPR) and, ideally, defibrillation to restore a normal heart rhythm. Automated external defibrillators (AEDs) are often used in public places and by trained individuals to deliver a shock to the heart, which can help restore a normal rhythm.

Several factors can increase the risk of sudden cardiac arrest, including:

1. Coronary artery disease: Narrowing or blockage of the coronary arteries, which supply blood to the heart muscle, can lead to SCA.
2. Previous heart attack: Scarring from a previous heart attack can disrupt the heart’s electrical system, increasing the risk of arrhythmias.
3. Heart failure: A weakened heart muscle can disrupt the heart’s electrical activity, leading to arrhythmias.
4. Arrhythmias: Certain arrhythmias, such as ventricular fibrillation, can trigger SCA.
5. Family history: Having a family history of SCA or sudden death at a young age may increase the risk.
6. Certain medications or substances: Some medications and recreational drugs can increase the risk of arrhythmias and SCA.

It’s important to recognize the signs of sudden cardiac arrest, which can include sudden loss of responsiveness, no normal breathing, and no pulse. Immediate action with CPR and defibrillation can greatly improve the chances of survival.