Sudden Cardiac Arrest: Causes, Symptoms & Survival Guide

So, does one know a cardiac arrest is coming, and how does that feel?

Noticing the above signs in anyone requires you or anyone around them to perform cardiac arrest first aid to prevent complete cardiopulmonary arrest.

Follow these steps to respond to cardiac arrest:

1. Seek immediate medical attention for the affected person by calling 911 (or the local emergency services line in your country).

2. Position the person correctly, so they are lying on their back on a flat surface.

3. Assess the person for signs of breathing or pulse and start cardiopulmonary resuscitation (CPR). That means pushing hard and fast on the chest center to make 100-120 compressions per minute and 2 rescue breaths every 30 minutes. Ensure the chest rises completely after every compression.

This video has the details on how to perform CPR for cardiac arrest, even if you are not trained.

4. Use an automated External Defibrillator (AED) to send an electrical shock to the heart and hopefully restore normal heart activity. Most public places, including airports, shopping malls, schools, gyms, and workplaces, have an AED available. Anyone can use the device by following the voice prompts, and it performs the shock if recommended.

Here’s a quick demonstration of how to use an AED.

5. If an AED is not available, or if recommended by the AED prompts after a shock is delivered, continue CPR until medical help arrives. This often draws the line between life and death.

Not all the signs mentioned earlier mean sudden cardiac arrest is imminent. But, because it can be fatal in minutes or cause permanent brain damage, it is better to see a doctor if any of the signs preceding a cardiac arrest are noticed.

So, seek medical advice if you notice these cardiac arrest signs: 

• Unexplained pains in the chest.
• Shortness of breath.
• Unexplained wheezing.
• Fainting, or near-fainting experiences.
• Irregular heartbeats or palpitations.
• Dizziness or lightheadedness.

It’s crucial to see a doctor if you have the above signs, especially if:

• Your family has a history of sudden cardiac death.
• You’ve had an SCA episode before.
• You have a diagnosed heart condition, including a heart rhythm disorder or arrhythmia.

The ultimate cardiac arrest cause is ventricular fibrillation, or the irregular heart rhythm that causes the heart ventricles (lower chambers) to vibrate without pumping blood.

However, an irregular heartbeat can be triggered by other heart conditions and risk factors.

• Coronary heart disease (CAD): Causes reduced blood flow that weakens the heart muscle.
• Congenital heart disease: Structural heart abnormalities that are already present at birth.
• Cardiomyopathy: Abnormally large or thick heart muscle.
• Brugada syndrome: Causes abnormal and life-threatening heart rhythm.
• Long QT syndrome (LQTS): An inherited or drug-triggered condition that causes a chaotic heart rhythm.
• Serious electrolyte imbalance: Due to low magnesium and potassium. 
• Respiratory arrest: Cessation of breathing from drowning, trauma, or other causes.
• Heart attack: Due to a blood flow blockage to the heart.

• Diabetes.
• Obesity and inactivity (a sedentary lifestyle).
• History of arrhythmia, heart attack, or coronary artery disease.
• High blood pressure and cholesterol.
• Smoking, alcohol, and recreational drugs.
• Ageing and being male.
• Obstructive sleep apnea.
• Chronic kidney disease.
• Extreme physical activity, as in the case of sudden cardiac arrest in athletes.
• Extreme loss of blood.

If heart activity is not restored soon, the brain and other body organs are deprived of blood for the duration of the cardiac arrest. This can come with complications, such as:

• Extensive brain damage.
• Death.

If the person does survive the cardiac arrest, they may still experience the following complications: 

• Cognitive issues, like problems with speech, remembering, and concentration.
• Episodes of fatigue.
• Organ failure, following damage to the liver, kidneys, and lungs.
• Mental health issues, including post-traumatic stress disorder (PTSD), mood disorders, anxiety, and depression. 
• Possible recurrence of cardiac arrest.

Timely and consistent rehabilitation is often required for recovery, which is usually partial and slow in coming. As such, preventing sudden cardiac arrest can go a long way.

Prevention is the best approach when it comes to sudden cardiac arrest and can be done with the following strategies:

• Take care of your heart health by keeping healthy blood pressure, cholesterol, and sugar levels.
• Follow a heart-friendly, healthy diet consisting of vegetables, fruits, lean proteins, and whole grains in the recommended amounts.

• Exercise regularly, targeting at least 150 minutes of moderate activity every week.
• Avoid excessive alcohol and smoking. Quitting is even better with smoking.
• Be vigilant, and seek medical attention should you experience any of the signs of sudden cardiac arrest, such as pressure in the chest, heart palpitations, and fainting.
• Work with your doctor and talk to your healthcare provider about preventative measures, such as an Implantable Cardioverter Defibrillator (ICD) and buying an AED if you are confirmed to be at a high risk of arrhythmia. 

Heart health experts consider sudden cardiac arrest a public health crisis. That’s not just because it affects around a thousand people daily in the US only, but also because around 90% of the cases are fatal. The remaining 10% experience adverse health effects due to brain damage consequences if they survive.

Initiating CPR immediately a person collapses and is unconscious can save their life while awaiting emergency medical response. Using an AED when available to cause shock to the heart and restore heart activity is equally crucial.

Most importantly, prevent sudden cardiac arrest by living a healthy life.

• Sudden Cardiac Arrest Foundation: About Sudden Cardiac Arrest.
• Martin, S.S. et al. (2025), on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Committee. 2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association. AHA Journals, 151 (6), e41-e660. 
• Mayo Clinic: Sudden Cardiac Arrest.
• Cleveland Clinic: Cardiac Arrest.
• National Heart, Lung, and Blood Institute: What Is an Arrhythmia?
• Yow AG, Rajasurya V, Ahmed I, et al. Sudden Cardiac Death. [Updated 2024 Mar 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. 
• WHO: Healthy Diet.