These are three different problems. A heart attack is a circulation problem: a blocked artery cuts off blood to part of the heart muscle. A cardiac arrest is an electrical problem: the heart suddenly stops pumping. Heart failure is a pumping problem that usually builds over time: the heart cannot keep up with what the body needs.
If you or someone near you has chest pain or pressure, trouble breathing, fainting or a sudden collapse, call 911 now. Do not wait to see if it passes, and do not drive yourself.
Key takeaways
- In a heart attack the heart usually keeps beating; in a cardiac arrest it stops pumping and the person collapses.
- Heart failure means a weakened or stiff pump, not a heart that has stopped.
- Coronary artery disease sits behind many cases of all three.
- For a collapse: call 911, start chest compressions and send someone for a defibrillator.
- No article can tell you a symptom is safe to ignore; new or worsening symptoms need medical care.
The three conditions side by side
| Condition | What goes wrong | What it looks like and what to do |
|---|---|---|
| Heart attack | A blocked coronary artery starves part of the heart muscle of blood | Chest pressure or pain that may spread to the arm, jaw or back, breathlessness, cold sweat, nausea. The person is usually awake. Call 911 |
| Cardiac arrest | An electrical fault stops the heart from pumping | Sudden collapse, no response, no normal breathing. Call 911, start CPR, use a defibrillator (AED) |
| Heart failure | The heart pumps or fills too weakly to meet the body's needs | Breathlessness with effort or lying flat, swollen legs, fatigue, fast weight gain from fluid. See a clinician promptly. Call 911 for severe breathlessness |
The three are connected. Plaque in the coronary arteries can cause a heart attack. A heart attack can set off a cardiac arrest in the moment, and the muscle damage it leaves can lead to heart failure later. Our guide to how arterial plaque builds up explains where it starts.
Heart attack: a blocked artery
A heart attack happens when blood flow through a coronary artery is cut off, most often because a plaque has torn and a clot has formed on it. The muscle beyond the blockage begins to die. The sooner the artery is reopened, the more muscle is saved, which is why minutes matter.
During a heart attack the heart usually keeps beating and the person is usually conscious. Symptoms are not always dramatic. They can be mild, come and go, or feel like indigestion, and they can differ in women. See heart attack warning signs in women.
Some heart attacks are not recognized at the time at all, which we cover in silent heart disease. None of that makes chest symptoms safe to sit on. If you are unsure, treat it as an emergency.
Cardiac arrest: the heart stops pumping
In a cardiac arrest the heart's electrical system fails and the heart stops moving blood. The person collapses, does not respond and is not breathing normally. Gasping does not count as normal breathing. Without immediate help, cardiac arrest is fatal within minutes.
Coronary heart disease is the most common condition underlying sudden cardiac death, followed by heart muscle diseases, inherited rhythm disorders and valve disease.1
Cardiac arrest does not always come out of nowhere. In a study of 839 people aged 35 to 65 who had a sudden cardiac arrest, 51% had warning symptoms in the four weeks before, mainly chest pain and breathlessness. Only 19% of those with symptoms called 911 about them.
The difference in outcome was large: 32.1% of those who called 911 for their symptoms survived, compared with 6.0% of those who did not.2 Warning symptoms are a reason to call, not to wait.
What to do if someone collapses
American Heart Association guidance for bystanders comes down to recognizing the arrest, calling for emergency help, giving high-quality CPR and using an automated external defibrillator.3
- Call 911 or have someone else call, and put the phone on speaker. The dispatcher can coach you.
- Start chest compressions. Push hard and fast in the center of the chest. Do not stop to check whether it is working.
- Send someone for an AED. Switch it on and follow its spoken instructions.
What bystanders do changes the odds. A pooled analysis of 79 studies found that only 7.6% of people survived an out-of-hospital cardiac arrest to leave the hospital, and that survival was more likely when a bystander gave CPR.4 In a study of 13,769 arrests in the US and Canada, 9% survived with bystander CPR alone and 24% survived when an AED was applied before the ambulance arrived.5
Heart failure: a pump that cannot keep up
Heart failure does not mean the heart has stopped. It means the heart muscle has become too weak or too stiff to move enough blood. Fluid backs up into the lungs and legs, and ordinary activity becomes tiring.
It is usually a long-term condition that is managed over years, though it can worsen suddenly. Typical signs are breathlessness on exertion or when lying flat, swelling in the ankles and legs, fatigue and rapid weight gain from fluid. These need a prompt medical evaluation. Severe breathlessness, or breathlessness with chest pain or fainting, is a reason to call 911.
A previous heart attack is one of the main routes to heart failure, because scarred muscle cannot pump. In a community study of 2,596 people with a first heart attack and no prior heart failure, 902 developed heart failure over an average follow-up of 7.6 years.6
Your next step: know your risk before there is an emergency
Prevention is the quieter work of finding risk years earlier. Cardio Res-Q is a prevention program. It is not emergency care, it is not for symptoms you have right now, and it does not replace a cardiologist.
The Comprehensive Assessment ($775) includes a clinical evaluation and advanced blood tests. The Enhanced Assessment ($999) adds a CIMT ultrasound and a coronary calcium score. To see who should and should not book, read who Cardio Res-Q is for, or visit the Cardio Res-Q program page.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Does heart failure mean my heart is about to stop?
No. Heart failure means the heart pumps less effectively than it should. It is a serious condition that needs ongoing medical care, and people with it do have a higher risk of dangerous heart rhythms, so new or worsening symptoms should be reported quickly.
Can a young, fit person have a cardiac arrest?
Yes, although it is rare. In younger people it is more often due to an inherited heart condition than to plaque. Fainting during exercise or a family history of sudden death at a young age should be discussed with a doctor.
How do I tell a heart attack from something minor?
You often cannot, and neither can an article. Heart attack symptoms overlap with those of less serious problems, and tests are needed to tell them apart. If chest discomfort, breathlessness, sweating or nausea is new, severe or not settling, call 911.
Related reading
This article is for general education and is not medical advice. Decisions about testing and medication should be made with your clinician. If you have chest pain or other symptoms of a heart attack, call 911.
