Pulseless Electrical Activity

What is pulseless electrical activity?

Pulseless electrical activity (PEA) is a condition where your heart stops because the electrical activity in your heart is too weak to make your heart beat. When your heart stops, you go into cardiac arrest, and you don’t have a pulse.

PEA is a “nonshockable” heart rhythm, meaning a defibrillator won’t correct it. If not treated quickly, PEA causes sudden cardiac death within minutes.

How does pulseless electrical activity work?

At the beginning of every heartbeat, a cluster of cells (the sinoatrial node) near the top of your heart creates an electrical current, which then spreads to other areas of your heart. As the current passes through the heart muscle, the muscle reacts by flexing. That causes your heart to squeeze and pump blood.

That electrical current is detectable with a diagnostic test called an electrocardiogram (ECG or EKG). With PEA, your heart does have a detectable electrical current, but your heart isn’t strong enough to pump blood to the body.

PEA can take two different forms:

• Pseudo-PEA: This is a type of PEA where the electrical activity in your heart does cause your heart muscle to squeeze very weakly. That squeezing does move some blood, but it isn’t a proper heartbeat and it isn’t strong enough to pump blood effectively, so you still don’t have a pulse.
• True PEA: This is PEA where your heart has electrical activity, but your heart muscle isn’t reacting to it. That means blood isn’t moving at all and you don’t have a pulse.

PEA is a common irregular heart rhythm (arrhythmia) that happens in connection to cardiac arrest. When you go into cardiac arrest, you are “clinically dead.”

Stages of death

When your heart stops, there are still some treatments that may be able to save your life. That’s why modern medicine distinguishes the types of death. The types are:

• Clinical death. This is when your heart stops, you aren’t breathing and your heart isn’t pumping blood. Once you go into cardiac arrest, you are clinically dead for up to five minutes (on average).
• Brain death. When your heart stops, you pass out within seconds. That happens because your brain has an incredibly high oxygen demand compared to the rest of your body. If your brain goes without blood flow for more than five minutes or so, your brain cells start to die. Once your brain cells die, it’s not possible to revive you. In rare cases, a person with brain death does remain "alive" because of life support machines. That usually happens because a loved one with the authority to make medical decisions chooses to keep that person on life support. However, the person on life support can't survive without it. In most places, the law considers a person with brain death legally dead, even if life support keeps their body going.

Because there’s about five minutes after your heart stops before your brain cells begin to die, that window means there’s a small chance that life-saving measures like CPR can revive you. For that reason, time is critical to help someone who goes into cardiac arrest. Unfortunately, even with measures like CPR, most people don’t survive cardiac arrest if it happens outside of a hospital setting.

Pulseless electrical activity vs. asystole: What’s the difference?

PEA and asystole (also known as “flat-lining”) can lead to cardiac arrest. The difference is that with PEA, your heart still has some detectable electrical activity. With asystole, there’s no electrical activity to detect.

What are the most common causes of pulseless electrical activity?

The causes of PEA fall into two distinct categories.

Primary PEA

This happens because of a problem with your heart itself. It usually has a connection with cardiac arrest, or cardiac arrest causes it directly.

Secondary PEA

This is PEA from a distinct outside cause rather than from a problem with your heart itself. The most likely causes of secondary PEA are:

• Blood loss or low blood pressure.
• Low oxygen levels.
• Dehydration or other electrolyte problems.
• Heart attack.
• Pulmonary embolism.
• Irregular heart rhythms (arrhythmias), especially ventricular fibrillation and ventricular tachycardia.
• Hypothermia (low body temperature).
• Trauma (either directly to the heart or to the chest overall).
• Air, blood or fluid filling areas inside your chest, putting so much pressure on your heart that it can’t beat correctly.
• Toxic effects. Drugs (prescription or recreational) and other toxic substances can affect your heart, causing PEA.

How common is PEA?

PEA occurs in about 20% of sudden heart-related deaths outside of hospitals. Inside hospitals, it accounts for about 10% of heart-related deaths.

How is this problem treated?

The only way to know if a stopped heart involves PEA is with an electrocardiogram, which isn’t always available outside of a hospital setting. Fortunately, the treatment for cardiac arrest is always the same, regardless of whether or not PEA is involved.

Immediate, effective CPR should always be the top priority when cardiac arrest happens, especially outside of a hospital setting. CPR should continue until emergency services or first responders arrive.

If PEA happens inside a hospital, the following treatments are likely:

• CPR. This is always a key part of treatment inside and outside the hospital environment.
• Epinephrine. This medication, also known as adrenaline, can help restore your heart to a normal rhythm.
• Treating the cause of PEA. Secondary PEA means it has a specific cause such as blood loss, electrolyte problems, etc. Treating the specific cause can help return your heart to a normal rhythm.

Is PEA a shockable rhythm?

Certain malfunctions in your heart’s electrical system that create arrhythmias are “shockable.” That means defibrillation (an electric shock) can stop those rhythms by restoring your heart to a normal rhythm.

The two shockable rhythms are ventricular fibrillation and pulseless ventricular tachycardia. Both of those can turn into PEA, but PEA itself isn’t shockable. However, CPR for pulseless electrical activity can sometimes get your heart to switch to a shockable rhythm. If that happens, then defibrillation can happen, which has a chance of restoring your heart to a normal rhythm.

Can you avoid developing PEA?

PEA doesn’t happen predictably, and it’s a common part of the normal dying process. That means it’s not preventable. While it might be possible to revive someone who has PEA, this isn’t always the case.

When should this symptom be treated by a doctor or healthcare provider?

Cardiac arrest is always a medical emergency that needs immediate care. You should always call 911 (or the local emergency services number in your area) and start CPR. If you don’t know CPR, 911 operators can often instruct you over the phone on how to give CPR.

The main symptoms of cardiac arrest are:

• Fainting or passing out unexpectedly.
• Fighting to breathe or not breathing at all.
• If you can’t feel a pulse on the person’s neck or wrist.

A note from Cleveland Clinic

Pulseless electrical activity usually happens along with cardiac arrest, a very dangerous condition. Fortunately, modern medicine’s understanding of PEA and similar conditions has grown tremendously over the past few decades. However, the first few moments are especially critical, especially when cardiac arrest happens outside of a hospital. That means effective CPR and quick medical attention can make a big difference and improve the chances of survival.