Call 911 immediately, have the person sit down and stay calm, and give them a regular aspirin (300 mg) to chew. Those three actions in the first few minutes can make the difference between a full recovery and permanent heart damage. Heart muscle begins to die after roughly 20 minutes without blood flow, so every minute you spend acting matters.
Call 911 First, Not Later
The single most important thing you can do is call emergency services before anything else. Do not drive the person to the hospital yourself unless you have absolutely no other option. An ambulance crew can administer medications, shock the heart back into rhythm, and transmit heart readings to a doctor while still on the road. As one emergency physician put it, a well-trained paramedic can do nearly everything a hospital will do for you in cardiac arrest, and the ambulance essentially brings the hospital to your home.
There’s another advantage most people don’t think about. When paramedics call ahead to the hospital, the catheterization lab (where doctors reopen blocked arteries) can be prepped and waiting. That means treatment starts the moment the patient rolls through the door. If you drive to the ER yourself, that clock doesn’t start until after triage, check-in, and evaluation. The delay can easily add an hour.
Recognize the Symptoms
The classic sign is crushing chest pain or pressure, often radiating to the left arm, neck, or jaw. But not every heart attack looks like what you’ve seen in movies. Many people, especially women, experience far subtler warning signs: unusual fatigue, nausea, dizziness, shortness of breath, or pain in the upper abdomen or back. In women, chest discomfort is not always the most prominent symptom, and attacks can begin during rest or even sleep.
If someone near you suddenly looks pale, sweaty, and nauseated, or they complain of pressure in their chest that lasts more than a few minutes, treat it as a heart attack until proven otherwise. Waiting to see if it “gets better” is the most dangerous choice you can make.
Give Aspirin Right Away
After calling 911, have the person chew one full-strength aspirin (300 mg). Chewing is critical. A swallowed tablet takes much longer to enter the bloodstream, while a chewed tablet starts working within minutes. Aspirin reduces the stickiness of blood cells called platelets, making it harder for the clot blocking the artery to grow larger. This buys time for the heart muscle that’s starving for oxygen.
Don’t give aspirin if the person is allergic to it or has been told by a doctor to avoid it. Otherwise, it’s one of the simplest and most effective things a bystander can do.
If They Have Nitroglycerin
Some people with a history of chest pain carry prescribed nitroglycerin tablets. If the person has their own prescription, help them place a tablet under the tongue or between the cheek and gum. The tablet should dissolve on its own. It should not be chewed, crushed, or swallowed, because it works by absorbing through the lining of the mouth. Relief typically comes within one to five minutes. Do not give someone else’s nitroglycerin to a person who doesn’t have a prescription for it.
Why Minutes Matter
A heart attack happens when a blood clot blocks an artery feeding the heart muscle. The tissue downstream of that blockage immediately starts running out of oxygen. For the first 20 minutes or so, the damage is reversible. Cells swell and lose energy, but they can recover if blood flow is restored. After that 20-minute window, cells begin to die permanently. The longer the blockage persists, the more muscle is lost, and dead heart muscle doesn’t regenerate. This is why cardiologists use the phrase “time is muscle.”
Keep Them Calm and Still
Have the person sit down, ideally leaning back with their knees bent. Loosen any tight clothing around the chest and neck. Don’t let them walk around, get up to find their phone, or try to “shake it off.” Physical exertion forces the heart to work harder, which increases the damage when part of the heart isn’t getting blood. Keep them talking and conscious. If they’re anxious, remind them help is on the way. Anxiety raises heart rate, so a calm presence genuinely helps.
Heart Attack vs. Cardiac Arrest
These are two different emergencies that require different responses. A heart attack is a circulation problem: a blocked artery is cutting off blood supply to part of the heart. The person is typically conscious, talking, and in pain. Your job is to call 911, give aspirin, and keep them still.
Cardiac arrest is an electrical problem: the heart’s rhythm goes haywire and it stops pumping entirely. The person collapses, becomes unresponsive, and stops breathing normally. This is when CPR becomes essential.
A heart attack can trigger cardiac arrest at any moment. That’s why you need to stay with the person and watch them closely.
If They Become Unresponsive
If the person stops responding, stops breathing, or only gasps, they’ve likely gone into cardiac arrest. Start CPR immediately. Place the heel of one hand on the center of the chest, put your other hand on top, and push hard and fast. Aim for a depth of at least 2 inches and a rate of 100 to 120 compressions per minute (roughly the tempo of the song “Stayin’ Alive”). Don’t worry about rescue breaths if you’re untrained. Hands-only CPR is effective and far better than doing nothing.
If someone nearby can grab an automated external defibrillator (AED), have them do that while you keep compressing. AEDs are designed for untrained users. They give voice instructions and will only deliver a shock if the heart needs one. You cannot accidentally harm someone with an AED.
An analysis of more than 623,000 cardiac arrest cases in the United States found that people who received bystander CPR had a 28% greater chance of surviving compared to those who didn’t. They were also more likely to survive without serious brain injuries. Starting CPR before paramedics arrive is one of the strongest predictors of a good outcome.
What Not to Do
- Don’t wait to see if symptoms pass. Heart attacks sometimes start mild and escalate. Early symptoms like nausea or jaw pain can seem minor, especially in women.
- Don’t let the person eat or drink anything besides the aspirin. They may need emergency procedures, and a full stomach creates complications with anesthesia.
- Don’t give medications that aren’t theirs. Nitroglycerin, blood pressure pills, or other cardiac drugs prescribed to someone else can cause dangerous drops in blood pressure.
- Don’t leave them alone. Cardiac arrest can happen without warning during a heart attack. If no one is watching, no one can start CPR.
What Happens at the Hospital
Once paramedics take over, they’ll confirm the heart attack with a portable heart monitor and begin stabilizing the patient. At the hospital, doctors typically thread a thin tube through a blood vessel in the wrist or groin to reach the blocked artery and reopen it, often placing a small metal stent to keep it open. The faster this happens, the more heart muscle is saved. Patients treated within the first hour of symptoms often recover with minimal lasting damage. Those treated several hours later may lose significant heart function permanently.
Recovery after the procedure usually involves a hospital stay of two to four days, followed by weeks of gradually increasing activity. Most people are prescribed blood-thinning medications, cholesterol-lowering drugs, and a structured cardiac rehabilitation program that includes supervised exercise and lifestyle coaching.