What Do You Do If Someone Has a Heart Attack?

Calling emergency services immediately is the single most important thing you can do when someone is having a heart attack. While you wait for paramedics, keep the person still and calm, help them chew an aspirin if one is available and they are not allergic, and be ready to start CPR if they lose consciousness and stop breathing normally. Those steps sound simple, but each one involves judgment calls that trip people up in the moment, and the difference between a heart attack and a cardiac arrest changes what you should do next.

Heart Attack Versus Cardiac Arrest

About half of the general public knows that a heart attack and a cardiac arrest are not the same thing, but most struggle to explain the difference clearly.¹ That confusion matters because the two conditions demand different responses from a bystander. A heart attack is a circulation problem: a blocked artery cuts off blood flow to part of the heart muscle, which starts to die. The person is typically conscious, talking, and in pain. A cardiac arrest is an electrical problem: the heart suddenly stops pumping effectively, the person collapses, and they stop breathing normally within seconds. A heart attack can trigger a cardiac arrest, which is why you need to stay with the person and watch for sudden collapse, but the two events are not interchangeable.

If the person is conscious and talking, you are dealing with a heart attack. Your job is to get professional help coming and keep them comfortable. If they go unresponsive, you may be dealing with a cardiac arrest, and you need to start chest compressions right away. Keeping that distinction in mind shapes everything that follows.

Recognizing Heart Attack Symptoms

The classic image is someone clutching their chest with crushing pain, and chest pain or pressure is indeed the most common symptom. But heart attacks often announce themselves with a cluster of less dramatic signs: discomfort in one or both arms, the jaw, the neck, or the back; cold sweats; nausea; lightheadedness; or shortness of breath that seems to come out of nowhere. The tricky part is that many people experience only some of these, and some experience none of the “classic” ones at all.

Women in particular tend to present differently. In one hospital-based study, roughly 85% of women having a heart attack showed up with what clinicians call atypical symptoms, including dizziness, sweating, shortness of breath, vomiting, palpitations, fainting, back pain, and fatigue, compared with about 70% of men.² Women also tend to experience more warning signs in the days leading up to the event, particularly unusual fatigue, and they generally wait longer before going to the hospital after symptoms start.³ That delay is dangerous because the longer heart muscle goes without blood flow, the more damage accumulates.

The practical takeaway: if someone, especially a woman over 50, complains of sudden unexplained fatigue, nausea, jaw pain, or shortness of breath and looks unwell, take it seriously even if they are not clutching their chest. Waiting for the “Hollywood heart attack” to appear costs time that the heart muscle cannot spare.

Call Emergency Services Before Anything Else

Your instinct might be to throw the person in the car and drive to the nearest emergency room. Research shows that self-transport does get patients to the ER door a few minutes faster on average than an ambulance, but that comparison misses the point. What matters is when treatment begins, not when the car pulls up to the building. Patients who called 911 received their first care within about six minutes of making the call, while self-transporting patients waited a median of 32 minutes, until they walked through the ER doors, before anyone could help them.⁴ Among patients who needed clot-busting medication, those brought by paramedics received it roughly 17 minutes sooner from the moment they decided to seek help.

Paramedics also carry equipment that a private car does not. They can run an electrocardiogram on the way, transmit it to the hospital, and have a cardiac team assembled before the ambulance even arrives. That relay shaves additional minutes off the time to definitive treatment. There is also a safety argument: among patients with cardiac symptoms serious enough to need hospital admission, cardiac arrest during transport was far more common in the EMS group than among self-transporters, but that difference reflects the fact that sicker patients tend to call 911.⁵ If the person having chest pain is one of those sicker patients, collapsing in the back seat of your car on the highway is a far worse outcome than collapsing in front of paramedics who can defibrillate on the spot.

The one scenario where driving makes sense is when you are so remote that EMS response times are extremely long and a hospital is close by. Short of that, call emergency services and let them come to you.

Aspirin While You Wait

Once you have called for help, the next thing to consider is aspirin. During a heart attack, a blood clot is blocking an artery. Aspirin interferes with the clotting process and can slow the blockage from getting worse. Getting aspirin into the bloodstream early is considered beneficial even when weighed against the small bleeding risk in people whose chest pain turns out not to be a heart attack.⁶

If the person is conscious, not allergic to aspirin, and has not been told by a doctor to avoid it, give them a regular-strength aspirin (325 mg) or up to four low-dose (81 mg) aspirin and have them chew the tablet rather than swallow it whole. Chewing exposes more surface area and gets the drug into the blood faster. A study comparing a chewed tablet to a liquid aspirin solution found that even a chewed tablet produced measurable blood levels within three minutes, though the liquid form was absorbed even faster.⁷ Most people do not carry liquid aspirin, so chewing is the practical choice.

One critical exception: if the person takes a medication for erectile dysfunction, such as sildenafil, and also uses any form of nitrate medication (nitroglycerin pills or patches, isosorbide), the combination of nitrates and those drugs carries a significantly higher risk of dangerous blood pressure drops and worse cardiac outcomes.⁸ Aspirin itself is not the problem here, but if the person reaches for their own nitroglycerin and has recently used an erectile dysfunction drug, warn them not to take it and tell the 911 dispatcher. That interaction is the dispatcher’s business, not yours to manage medically, but flagging it can save crucial minutes.

Keeping the Person Comfortable

While you wait for paramedics, your role is essentially to monitor and reassure. Have the person sit down or lie in whatever position feels most comfortable for them. Many people prefer sitting slightly upright, which can ease breathing. Loosen any tight clothing around the neck or chest. Do not give them food or water beyond a sip to wash down the aspirin, because they may need procedures under sedation once they reach the hospital, and a full stomach complicates that.

Keep talking to them. Anxiety spikes heart rate and blood pressure, both of which increase the heart’s demand for oxygen at the worst possible time. A calm, steady presence helps more than you might expect. Ask simple questions to track their mental state. If they start slurring words, become confused, or lose consciousness, tell the dispatcher immediately, because the situation may be escalating toward cardiac arrest.

If They Collapse and Stop Breathing Normally

This is where the response shifts dramatically. If the person becomes unresponsive and is not breathing or is only gasping, you are likely dealing with a cardiac arrest, and CPR needs to start immediately. Do not wait to be sure. Those irregular gasps, sometimes called agonal breathing, are present in up to 40% of out-of-hospital cardiac arrests and are commonly mistaken for normal breathing, leading bystanders to hold off on CPR.⁹ Agonal breaths are slow, labored, and may sound like snoring, gurgling, or snorting. They are not real breathing. If someone is unresponsive and making those sounds, treat it as cardiac arrest.

Place the person flat on their back on a firm surface. Put the heel of one hand on the center of their chest, between the nipples, and your other hand on top. Push hard and fast, at least two inches deep, aiming for a rate of about 100 to 120 compressions per minute. If you have never been trained in CPR or are uncomfortable giving rescue breaths, chest compressions alone are effective. A pooled analysis of studies found that compression-only CPR was associated with better survival to hospital discharge than traditional CPR with breaths among bystanders in out-of-hospital cardiac arrest.¹⁰ The likely reason is that untrained rescuers who attempt mouth-to-mouth often pause compressions for too long, and uninterrupted compressions keep blood flowing to the brain.

There is some evidence that when dispatchers walk bystanders through CPR over the phone, conventional CPR with both compressions and breaths may produce slightly better neurological outcomes than compressions alone.¹¹ So if the dispatcher is coaching you and you feel able to give breaths, follow their instructions. If you are on your own or uncomfortable, just push. Pushing without breaths is vastly better than doing nothing.

Using an Automated External Defibrillator

If someone nearby can grab an AED while you are doing compressions, use it. These devices are increasingly common in airports, gyms, shopping centers, and office buildings. They are designed to be used by people with no medical training: you open the case, turn it on, stick the adhesive pads to the person’s bare chest where the diagrams show, and follow the voice prompts. The machine analyzes the heart rhythm and will only deliver a shock if it detects one of the specific rhythms that respond to defibrillation. You cannot accidentally shock someone who does not need it.

Timing matters enormously. Survival is highest when the AED is applied within three to five minutes of a witnessed collapse, and community programs that equip first responders with AEDs consistently show better cardiac arrest survival than waiting for paramedics to arrive and defibrillate.¹² After the shock, or if the machine advises no shock, resume chest compressions immediately and keep going until paramedics take over or the person starts moving and breathing normally.

One frustrating reality is that even though AEDs are widely available, they are used in only a small fraction of all out-of-hospital cardiac arrests. People walk past them without knowing what they are, or panic and forget to look for one. If you work or spend time in a building with an AED, take a moment to note where it is. That five seconds of awareness could save a life someday.

Common Mistakes Bystanders Make

Several well-meaning actions can actually make things worse or waste precious time:

Checking for a pulse: Untrained people are notoriously bad at finding a pulse, and the time spent searching is time not spent on compressions. If the person is unresponsive and not breathing normally, skip the pulse check and start CPR.
Giving water or food: A conscious heart attack patient does not need hydration. Fluids or food can cause problems if they vomit or need emergency sedation.
Having them lie flat if they are conscious: A conscious person having a heart attack often breathes more easily sitting up. Let them find a comfortable position rather than forcing them onto their back.
Driving to the hospital: As discussed earlier, self-transport delays the start of medical care and removes the person from the reach of equipped paramedics.
Giving ibuprofen or acetaminophen instead of aspirin: Only aspirin has the rapid antiplatelet effect that helps during a heart attack. Other over-the-counter pain relievers do not work the same way.

Fear of Doing Harm

One of the biggest barriers to bystander action is the fear of making things worse or facing legal consequences. Research in places without strong legal protections for rescuers found that fear of litigation is a real deterrent to performing CPR, even among people who have had first-aid training.¹³ In the United States, all 50 states have some form of Good Samaritan law that protects bystanders who provide reasonable emergency assistance in good faith. Most other Western countries have similar protections.

The reality is that if someone is in cardiac arrest, they are already clinically dead. You are not going to make them worse by trying. Broken ribs from compressions, which do happen, heal. Brain death from lack of oxygen does not. If you are ever in doubt about whether to act, act. The legal system, the medical system, and the person’s family will all be on your side.

What Happens When Paramedics Arrive

When the ambulance arrives, step back but stay nearby. Paramedics will want to know what happened: when symptoms started, what the person complained of, whether they took aspirin, whether they lost consciousness and for how long, and whether you performed CPR. Give this information quickly and clearly. Every detail helps the hospital team make faster decisions.

For a heart attack, the hospital’s goal is to reopen the blocked artery as fast as possible, typically through a procedure where a catheter is threaded into the artery and a small balloon is inflated to clear the blockage. The clock on that procedure starts the moment the patient arrives at the hospital, and cardiac teams can assemble remarkably fast. In one analysis of the chain of events during these emergency procedures, the longest delay was actually the interventional team arriving at the hospital after being paged, averaging about 18 minutes.¹⁴ That is why everything you do before the ambulance arrives, recognizing symptoms, calling quickly, giving aspirin, performing CPR if needed, matters so much. You are buying the heart muscle time that the hospital team then uses to save it.

Emerging Technology and Bystander Response

Researchers are exploring whether wearable technology can close the gap between cardiac arrest and the call for help. A proof-of-concept study tested whether a smartwatch could automatically detect when a person’s heart stopped pumping and immediately alert emergency services without the wearer (or a bystander) doing anything. The system correctly identified cardiac arrest in about 90% of cases and sent a virtual alert to dispatchers instantly.¹⁵ The technology is still early-stage, tested in a controlled medical setting rather than in the wild, but it points toward a future where the device on your wrist calls for help before anyone nearby even realizes something is wrong. For people who live alone or have known heart disease, that kind of automated detection could eventually eliminate the most dangerous delay in the chain: the minutes that pass before anyone realizes what is happening.