Pulseless Electrical Activity (PEA): Causes, Signs, Diagnosis, and Treatment

Understand the causes, risk factors, symptoms, and lifesaving response for Pulseless Electrical Activity (PEA) in cardiac emergencies.

By Medha deb

Created on Sep 25, 2025

Understand the causes, risk factors, symptoms, and lifesaving response for Pulseless Electrical Activity (PEA) in cardiac emergencies.

Pulseless Electrical Activity (PEA) is a critically serious cardiac emergency characterized by electrical activity in the heart without a detectable pulse. Unlike other cardiac arrhythmias, PEA does not result in effective heart contractions, leading rapidly to collapse and requiring immediate medical response. Understanding PEA, including its types, causes, symptoms, and emergency treatment, is essential for both healthcare professionals and the general public.

What is Pulseless Electrical Activity (PEA)?

PEA is a form of cardiac arrest in which the heart’s electrical conduction system continues to function weakly or abnormally, but the muscular contractions are insufficient to produce a palpable pulse or circulate blood. This means the heart may show organized electrical activity on an electrocardiogram (EKG or ECG), yet there is no effective heartbeat or circulatory output. Without prompt intervention, PEA is fatal.

Pulseless: No detectable pulse despite electrical activity.
Electrical Activity: Some form of organized heart rhythm detectable by EKG.
Cardiac Arrest: The absence of effective blood circulation.

PEA used to be known as “electromechanical dissociation,” reflecting the mismatch between electrical rhythm and mechanical heart function.

Types of Pulseless Electrical Activity

Pseudo-PEA: The heart still manages some mechanical movement and tiny blood output, but not enough for a detectable pulse. Only EKG monitoring or special ultrasound imaging can detect its faint activity.
True PEA: The heart’s electrical system is sending minimal signals, but there are no muscular contractions and thus no heartbeat. This is classic PEA, carrying a particularly poor prognosis without quick treatment.

What are the Primary Causes of PEA?

The underlying mechanisms of PEA generally stem from conditions that severely compromise the heart’s ability to contract, even while electrical signals persist. PEA does not arise randomly, but almost always has a direct underlying cause.

Common Causes:

Cardiac ischemia (heart attack/blockage)
Severe oxygen deprivation (hypoxia)
Electrolyte imbalances (especially potassium: hypokalemia/hyperkalemia)
Severe acidosis (excess acid in blood)
Volume loss (hypovolemia, eg. bleeding or dehydration)
Hypothermia (body temperature under 35°C or 95°F)
Thrombosis (clots in lungs or heart arteries)
Cardiac tamponade (fluid compressing the heart in the pericardial sac)
Tension pneumothorax (air leakage causing lung collapse and chest pressure)
Major trauma or drug/toxin exposure

The “5 Hs and 5 Ts” Mnemonic

Clinicians use the “5 Hs and 5 Ts” to help remember the most important reversible causes of PEA:

5 Hs	5 Ts
Hypovolemia	Tension pneumothorax
Hypoxia	Trauma
Hydrogen ion (acidosis)	Cardiac tamponade
Hypo-/Hyperkalemia	Thrombosis (coronary)
Hypothermia	Thrombosis (pulmonary)

Rapidly identifying and treating these causes is vital to successful resuscitation.

Who is at Risk for Developing PEA?

Anyone can develop PEA under critical physiological stress, but certain people are at higher risk due to medical history, age, or exposure to specific conditions.

Adults older than 70, especially females, have an increased risk.
People with a history of significant heart disease, especially prior heart attacks or heart failure.
Individuals with chronic kidney disease or electrolyte imbalances.
Trauma patients or those experiencing acute severe blood loss.
Patients exposed to hypothermia or extreme metabolic disturbances.
Certain medications (like beta-blockers or calcium channel blockers) may increase susceptibility.

Symptoms of PEA

PEA does not have traditional “warning signs” because it causes sudden cardiac arrest. Its hallmark is the sudden absence of a pulse despite the presence of an electrical heart rhythm. Key findings may include:

No detectable pulse despite organized electrical activity on EKG
Unconsciousness and sudden collapse
Absence of breathing or gasping respirations
Pale or cyanotic (bluish) skin
Possible signs related to the underlying cause, such as chest trauma, tracheal deviation, cool extremities, or abnormal heart sounds

Diagnosing Pulseless Electrical Activity

Diagnosis must be rapid. When a patient collapses, the following are evaluated:

Electrocardiogram (EKG/ECG): Shows organized rhythm, but no corresponding pulse.
Physical examination: Confirms lack of a pulse and attempts to identify potential causes (such as trauma or abnormal breath sounds).
Bedside ultrasound: Can help distinguish pseudo-PEA (weak heart movement) from true PEA (no heart movement at all).
Medical history and recent events: Helps search for clues—recent heart disease, trauma, drug overdose, or severe infection.

PEA must be differentiated from other cardiac arrest rhythms: ventricular fibrillation, pulseless ventricular tachycardia, and asystole. Only PEA presents with an organized electrical rhythm but no pulse.

Treatment and Emergency Response

PEA is a medical emergency. Rapid intervention is required, as every minute reduces the chances of survival. Since PEA is not a shockable rhythm (unlike ventricular fibrillation), defibrillator shocks do not help until the underlying cause is resolved. The focus is on high-quality CPR (cardiopulmonary resuscitation) and immediate treatment of reversible causes.

Immediate Steps in Treating PEA

Call for emergency medical help if you suspect cardiac arrest.
Start high-quality chest compressions immediately. Aim for a rate of 100–120 compressions per minute, going 2 inches deep in the center of the chest on adults.
Continue CPR without interruption until advanced help arrives.
Advanced providers will:
- Insert advanced airways and provide oxygen.
- Establish intravenous (IV) access.
- Administer epinephrine every 3–5 minutes during resuscitation.
- Search for and correct reversible causes (“5 Hs/5 Ts”).
- Monitor vitals and cardiac rhythms closely to detect any change.

Is Defibrillation Used for PEA?

Defibrillation is not routinely used in PEA, as the underlying issue is not usually an electrical conduction problem, but the lack of mechanical heart response. However, if the rhythm shifts to a shockable form (ventricular fibrillation or pulseless ventricular tachycardia), defibrillation may become necessary.

Prognosis and Outcomes

The prognosis for PEA is generally poor, particularly if the underlying cause is not rapidly identified or is irreversible. Survival rates vary based on patient factors and how quickly effective CPR and targeted therapy begin. Early intervention to address correctable causes (like hypoxia, hypovolemia, tension pneumothorax, etc.) is essential for improving outcomes.

Can PEA Be Prevented?

Because PEA is a result of underlying severe medical conditions, prevention focuses on identifying and managing those risk factors before cardiac arrest occurs.

Managing chronic diseases like heart disease, kidney dysfunction, and diabetes.
Ensuring correction of electrolyte disturbances in hospitals.
Preventing trauma and treating severe injuries promptly.
Monitoring medications that could influence heart rhythm or contractility.

Additional Facts and Epidemiology

PEA is responsible for about 20% of out-of-hospital sudden cardiac deaths.
A significant portion of in-hospital cardiac arrests are initially documented as PEA, especially in older patient populations.
Women and older adults are somewhat more predisposed to PEA events, according to clinical studies.

Frequently Asked Questions (FAQs)

What are the main differences between pseudo-PEA and true PEA?

Pseudo-PEA: Some minimal heart muscle movement exists, possibly detected by ultrasound, but no effective circulation.
True PEA: No effective heart action and no pulse, though electrical activity is present on EKG.

Can PEA be treated with a defibrillator?

No, PEA is not a shockable rhythm. Treatment focuses on high-quality CPR and identifying and correcting the root cause.

What rhythm is seen on ECG in PEA?

There is often an organized electrical rhythm — such as a normal sinus, bradycardia, or heart block — but there is no pulse.

What is the survival chance after PEA cardiac arrest?

Survival varies depending on rapidity and effectiveness of emergency response and if reversible causes are found. Prognosis is poor without intervention.

What steps can be taken to prevent PEA?

Managing chronic illnesses, correcting metabolic issues and electrolyte problems in hospital care, and immediate management of trauma or acute illnesses are the best strategies.

Summary Table: Key Points of PEA

Aspect	Description
Definition	Cardiac electrical activity without a detectable pulse
Main Causes	Hypoxia, hypovolemia, acidosis, cardiac tamponade, trauma, thrombosis, electrolyte imbalance
Diagnosis	Organized rhythm on EKG, no pulse, physical findings and bedside imaging help
Emergency Response	CPR, epinephrine, correcting underlying causes
Prognosis	Poor without rapid intervention; improves if reversible causes are promptly addressed

Conclusion

Pulseless Electrical Activity is an acute, life-threatening condition that requires immediate recognition and intervention. Understanding the causes and focusing resuscitation on correcting reversible underlying factors, in tandem with effective CPR, remains the best chance for patient survival. Continued awareness and prompt action are key to saving lives in PEA emergencies.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

Read full bio of medha deb