What to Do After Using an AED: 7 Critical Next Steps

When an AED delivers a shock, the next two minutes are the most important. Your actions right after that first jolt of electricity can mean the difference between life and death for someone in sudden cardiac arrest.

CPR1 trains thousands of people each year on exactly this scenario. If you want hands-on practice with AEDs and post-shock protocols, explore our CPR and First Aid training courses available in all 50 states.

Below, you will find the seven steps you should take after an AED delivers a shock, plus what to do if the device advises “no shock,” and how to handle the aftermath once EMS arrives.

7 Steps to Take After an AED Delivers a Shock

After the AED delivers its shock, follow this step-by-step protocol. The American Heart Association recommends resuming CPR immediately after each shock, so do not pause to check for a pulse unless you see clear signs of life.

1. Resume chest compressions immediately. Start CPR within 5 seconds of the shock. Push hard and fast at a rate of 100 to 120 compressions per minute, at least 2 inches deep on an adult. According to the American Heart Association, hands-on-chest time is the single biggest factor in cardiac arrest survival.
2. Continue CPR for 2 full minutes (5 cycles of 30:2). Give 30 compressions followed by 2 rescue breaths per cycle. Do not stop to check the patient between cycles.
3. Let the AED re-analyze the rhythm. After 2 minutes of CPR, the AED will automatically pause you and re-check the heart rhythm. Keep your hands off the patient during analysis.
4. Follow the AED prompts for additional shocks. If the device detects a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia), it will charge and instruct you to press the shock button again.
5. Repeat the CPR-analyze-shock cycle. Keep alternating between 2 minutes of CPR and AED analysis until one of three things happens: EMS arrives and takes over, the person starts breathing normally, or you become physically unable to continue.
6. Leave the AED pads attached. Do not remove the electrode pads even if the patient regains consciousness. The AED needs to keep monitoring the heart rhythm in case it becomes irregular again.
7. Prepare for the EMS handoff. When paramedics arrive, tell them how many shocks were delivered, how long CPR was performed, and whether the patient showed any signs of recovery. Hand over the AED so they can review the device data.

Research published in Circulation shows that bystander AED use before EMS arrival increases survival rates to between 50% and 70%, compared to less than 12% when defibrillation is delayed. Every second of continued care matters.

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What Happens After an AED Delivers a Shock?

An AED delivers a controlled electrical shock that interrupts the chaotic electrical activity in the heart during sudden cardiac arrest. The goal is to reset the heart so it can resume a normal rhythm on its own. During ventricular fibrillation, the heart’s muscle fibers contract randomly instead of in a coordinated pumping motion. The AED’s electrical pulse forces all the muscle fibers to stop at once, giving the heart’s natural pacemaker a chance to restart with a normal beat.

Not every shock works on the first attempt. Success depends on several factors: how quickly the AED was applied after collapse, the underlying cause of the arrest, and whether high-quality CPR was performed before the shock. After the shock, one of two things will happen:

The heart rhythm returns to normal

If the shock is successful, the patient may start breathing again or even regain consciousness. Keep the AED pads in place and monitor the person closely. Place them in the recovery position (on their side) if they are breathing but unresponsive. Stay with them until paramedics arrive, because cardiac arrest can recur within minutes.

The heart rhythm does not normalize

When a single shock does not restore normal rhythm, the AED will instruct you to resume CPR. This is expected and does not mean the AED failed. According to a study in the New England Journal of Medicine, roughly 30% to 40% of cardiac arrest patients require more than one shock. Many patients need two or three shocks combined with high-quality CPR before their heart responds. Continue the CPR-analyze-shock cycle described above without losing confidence in the process.

What to Do If the AED Says “No Shock Advised”

Not every cardiac arrest involves a shockable rhythm. The AED may detect asystole (flatline) or pulseless electrical activity (PEA), neither of which responds to defibrillation. If the AED says “no shock advised,” do the following:

• Begin or continue CPR immediately. Chest compressions keep oxygenated blood moving to the brain and vital organs.
• Leave the AED connected. It will re-analyze the rhythm every 2 minutes. A non-shockable rhythm can change to a shockable one, and you want the AED ready if that happens.
• Continue until EMS arrives or the patient shows obvious signs of life (normal breathing, movement, responsiveness).

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How to Prepare for the EMS Handoff

When paramedics arrive, a smooth handoff saves time and gives the patient the best chance of survival in the hospital. Here is what to have ready:

• Timeline of events: When the person collapsed, when CPR started, when the first shock was delivered.
• Number of shocks: Most AEDs display or announce the shock count. If you lost track, tell EMS and they will pull the data from the device.
• Patient response: Did the person regain consciousness at any point? Did they start breathing on their own?
• Medical history (if known): Any known heart conditions, medications, or allergies the patient has.

Even if someone else has already called 911, designate one person to meet the ambulance at the building entrance. This saves paramedics from searching for the right room or floor and can shave minutes off response time.

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Post-Event Follow-Up: 5 Things to Do After EMS Leaves

After the patient is transported to the hospital, the emergency is not over for your organization. These administrative steps protect you legally and ensure your AED program stays ready for the next event.

1. Complete the post-event documentation

Most states require a post-event report submitted within 1 to 3 business days. These forms capture incident details while keeping personal and medical information private. EMS agencies use the data to track community survival rates. If you work with a program management provider, they typically handle the submission, but keep a copy for your own records.

2. Download the AED event data

Many AEDs store ECG recordings, shock times, and compression data. For example, the HeartSine Samaritan PAD 350P can record up to 90 minutes of event data. Download this information and forward it to your Medical Director if required by your state’s AED regulations.

3. Refurbish the AED for future use

After use, the AED needs to be restored to a ready state. Replace the electrode pads (they are single-use), check or replace the battery, and restock the ready kit supplies. Run a self-test to confirm the device passes. If EMS took your AED with the patient, contact the hospital or EMS agency to arrange its return.

4. Debrief the responders

The AED program coordinator should meet with everyone who helped during the event. Review what went well, identify any gaps in the response, and discuss what could be improved. Equally important: offer emotional support. Witnessing a cardiac arrest is stressful, and some responders may experience anxiety or distress afterward. Many organizations provide access to counseling or an Employee Assistance Program (EAP) for this reason.

5. Review and update your AED program

A real cardiac event is the ultimate test of your AED program. Use the experience to evaluate your readiness:

• Was the AED easy to locate and access quickly?
• Did responders know how to use the AED and where to place the pads correctly?
• Are your staff CPR and AED certifications current?
• Do you have enough AEDs for your facility’s size and foot traffic?

The AHA recommends that organizations with AEDs conduct practice drills at least twice per year. Drills reveal problems that paperwork audits miss, like locked cabinets, dead batteries, or staff who have forgotten their training. Schedule a refresher drill within 30 days of any real event while the lessons are still fresh.

Need help running a response drill or refresher training? CPR1’s onsite CPR and AED certification courses bring certified instructors directly to your workplace. View available courses.

In the United States, about 356,000 out-of-hospital cardiac arrests happen each year, according to the American Heart Association. Organizations that maintain trained staff and properly serviced AEDs give their people the best chance of surviving one of these events.

Can You Use an AED on a Child or Infant?

Yes, but with modifications. For children aged 1 to 8 years, use pediatric pads or a pediatric dose attenuator if the AED has one. If pediatric pads are not available, adult pads can be used, but place one pad on the chest and one on the back to avoid overlap. For infants under 1 year, a manual defibrillator is preferred, but an AED with pediatric pads may be used if no other option is available.

The same defibrillation principles apply regardless of the patient’s age: deliver the shock, then immediately resume CPR. After the shock, follow the same 2-minute CPR cycle and let the AED re-analyze the rhythm. Pediatric cardiac arrest has different underlying causes than adult cases (respiratory failure is more common than heart rhythm problems in children), but the AED protocol remains the same.

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Frequently Asked Questions

What happens after an AED delivers a shock?

After an AED delivers a shock, the device will prompt you to immediately resume CPR for 2 minutes. It continues to monitor the heart rhythm and will re-analyze after each CPR cycle, delivering additional shocks if needed. Do not remove the pads until EMS takes over.

Should you continue CPR after an AED shock?

Yes. The American Heart Association recommends resuming CPR immediately after every AED shock. CPR keeps blood flowing to the brain and heart while the AED prepares for its next analysis. Stop only when EMS takes over, the patient starts breathing normally, or you physically cannot continue.

Can an AED deliver multiple shocks in one emergency?

Yes. An AED will analyze the heart rhythm every 2 minutes and deliver another shock each time it detects ventricular fibrillation or pulseless ventricular tachycardia. There is no limit on the number of shocks it can deliver during a single rescue.

Should you remove AED pads after a successful shock?

No. Leave the pads attached even if the patient wakes up and seems fully recovered. Cardiac arrest can recur, and the AED needs to stay connected so it can detect any new rhythm problems and deliver another shock if necessary.

Who takes over care after you use an AED?

Emergency medical services (EMS) take over when they arrive. Paramedics will use advanced equipment including cardiac monitors, IV medications, and manual defibrillators to continue treatment. Hand over the AED so the medical team can download the event data.

Do you need training to use an AED?

AEDs are designed for use by untrained bystanders. They provide voice prompts and will only deliver a shock if the heart rhythm requires it. However, formal CPR and AED training builds confidence, improves response time, and teaches high-quality CPR technique that significantly improves outcomes.

Get your team trained and certified today. Browse CPR1’s onsite and online training courses to find the right program for your organization.