Wiktor Wise
Pulseless electrical activity (PEA) is a poorly understood phenomenon in resuscitation research and practice. It is a form of cardiac arrest where the electrocardiogram shows a heart rhythm that should produce a pulse but does not. PEA is characterised by the absence of a palpable pulse in an unconscious patient with organised electrical activity other than ventricular tachyarrhythmia on ECG. The condition has a poor prognosis and low survival rates, partly because little is known about its underlying causes.
Characteristics and Values of Pulseless Electrical Activity (PEA)
| Characteristics | Values |
|---|---|
| Definition | A syndrome characterised by the absence of a palpable pulse in an unconscious patient with organised electrical activity other than ventricular tachyarrhythmia on ECG/EKG. |
| Diagnosis | Confirmed by the absence of a pulse and electrocardiography (ECG/EKG) showing organised or semi-organised electrical activity in the heart. |
| Symptoms | Loss of consciousness and spontaneous breathing. |
| Treatment | Cardiopulmonary resuscitation (CPR) is the first treatment, while potential underlying causes are identified and treated. Defibrillators are not used. |
| Prognosis | Poor, with a 6% survival rate to hospital discharge. |
| Causes | Can be primary (cardiac) or secondary (non-cardiac). Non-cardiac causes include hypovolemia, hypoglycemia, hypothermia, and tension pneumothorax. |
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What You'll Learn
Pulseless electrical activity (PEA) is a form of cardiac arrest
PEA is typically confirmed by examining the airway for obstruction, observing the chest for respiratory movement, and feeling the pulse, usually at the carotid artery, for a period of 10 seconds. It can be distinguished from other causes of cardiac arrest with a device capable of electrocardiography (ECG/EKG), which shows a heart rhythm that should produce a pulse but does not. While PEA is classified as a form of cardiac arrest, significant cardiac output may still be present, which can be determined and visualised by bedside ultrasound (echocardiography).
The treatment for PEA focuses on addressing the underlying cause, if known. For instance, relieving a tension pneumothorax. Cardiopulmonary resuscitation (CPR) is the first treatment for PEA to maintain cardiac output until the issue can be corrected. However, defibrillators cannot be used to correct the rhythm as the problem lies in the response of the myocardial tissue to electrical impulses. The survival rate for PEA of a cardiac cause is only 6%.
PEA has many potential causes, including primary (cardiac) and secondary (non-cardiac) factors. Cardiac tamponade, dynamic lung hyperinflation, tension pneumothorax, and coronary artery graft occlusion or dehiscence are common causes. Hypovolemia and hypoxemia are the two most common and easily reversible causes of PEA. In some cases, PEA occurs when the myocardium has sustained a severe and generalised injury, such as extensive myocardial infarction, resulting in insufficient functional ventricular muscle to respond adequately to the electrical signal.
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PEA is characterised by the absence of a pulse
Pulseless electrical activity (PEA), also known as electromechanical dissociation, is a clinical condition characterised by the absence of a pulse. It is a form of cardiac arrest in which the electrocardiogram (ECG) shows a heart rhythm that should produce a pulse, but does not. In other words, there is electrical activity but insufficient cardiac output to generate a pulse and supply blood to the organs. This can occur when the heart itself is failing to contract or for other reasons.
PEA is always caused by a profound cardiovascular, respiratory, or metabolic insult. This initial insult weakens cardiac contraction, and this situation is exacerbated by worsening acidosis, hypoxia, and increasing vagal tone. Further compromise of the inotropic state of the cardiac muscle leads to inadequate mechanical activity, despite the presence of electrical activity. This creates a vicious cycle, causing degeneration of the rhythm and subsequent death of the patient.
The absence of a pulse confirms a clinical diagnosis of cardiac arrest, but PEA can only be distinguished from other causes of cardiac arrest with a device capable of electrocardiography (ECG/EKG). In PEA, there is organised or semi-organised electrical activity in the heart as opposed to asystole (flatline) or the disorganised electrical activity of either ventricular fibrillation or ventricular tachycardia.
True PEA is a more severe pathophysiology in which there is a complete absence of mechanical contractions—a true uncoupling of cardiac mechanical activity from the cardiac rhythm. It is characterised by the absence of any aortic pulse pressures and profoundly slow rhythms with wide QRS complexes. In contrast, pseudo-PEA is a state of cardiogenic shock in which there are still cardiac electrical activity and myocardial contractions, but they are not adequate to produce a palpable pulse.
Cardiopulmonary resuscitation (CPR) is the first treatment for PEA, while potential underlying causes are identified and treated. The overall prognosis for patients with PEA is poor unless a rapidly reversible cause is identified and corrected.
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PEA is usually noticed when a person loses consciousness
Pulseless electrical activity (PEA) is a poorly understood phenomenon in resuscitation research and practice. It is a phase in the dying process of humans and animals, and it is characterised by the absence of a palpable pulse in an unconscious patient with organised electrical activity other than ventricular tachyarrhythmia on an electrocardiogram (ECG/EKG).
In PEA, there is electrical activity but insufficient cardiac output to generate a pulse and supply blood to the organs, whether the heart itself is failing to contract or otherwise. While PEA is classified as a form of cardiac arrest, significant cardiac output may still be present, which may be determined and best visualised by bedside ultrasound (echocardiography).
Cardiopulmonary resuscitation (CPR) is the first treatment for PEA, while potential underlying causes are identified and treated. The approach to treating PEA is to address the underlying cause, if known, such as relieving a tension pneumothorax. Where an underlying cause for PEA cannot be determined and/or reversed, the treatment of PEA is similar to that for asystole.
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PEA can have primary (cardiac) or secondary (noncardiac) causes
Pulseless electrical activity (PEA) is a poorly understood phenomenon in resuscitation research and practice. It is a phase in the dying process of humans and animals, and it is characterised by the presence of electrical activity in the heart without palpable pulses or myocardial contractions. This results in a loss of cardiac output and the blood supply to the brain is interrupted. Consequently, PEA is usually observed when a person loses consciousness and stops breathing spontaneously.
The noncardiac causes of PEA include hypovolemia, hypoglycemia, hypothermia, and tension pneumothorax. Hypovolemia and hypoxemia are the two most common and easily reversible causes of PEA.
Cardiac resuscitation guidelines (ACLS/BCLS) recommend promptly initiating cardiopulmonary resuscitation (CPR) to maintain cardiac output until the underlying cause of PEA can be treated. However, the survival rate for PEA of a cardiac cause is low at 6%.
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Treatment for PEA depends on addressing the underlying cause
Pulseless electrical activity (PEA) is a type of cardiac arrest where there is electrical activity in the heart but insufficient cardiac output to generate a pulse. This leads to a loss of cardiac output and the blood supply to the brain is interrupted, resulting in a loss of consciousness and spontaneous breathing.
If the underlying cause of PEA is hypovolemia, it should be treated aggressively, especially in patients with active bleeding. Hypoxia should be treated with oxygen therapy. Tension pneumothorax is another potential underlying cause of PEA that can be treated. In refractory cases, if the patient has suffered chest trauma, a thoracotomy may be performed, provided adequate expertise is available. Pericardiocentesis and emergent cardiac surgery may also be lifesaving procedures in appropriate patients with PEA.
In addition to treating the underlying cause, resuscitative pharmacology can be used, including epinephrine and atropine. Epinephrine should be administered in 1-mg doses intravenously/intraosseously (IV/IO) every 3-5 minutes during PEA. Higher doses of epinephrine have not been shown to improve survival or neurological outcomes in most patients. However, special populations, such as those who have overdosed on beta-blockers or calcium channel blockers, may benefit from higher-dose epinephrine.
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Frequently asked questions
Pulseless electrical activity is a form of cardiac arrest where there is electrical activity in the heart but insufficient cardiac output to generate a pulse and supply blood to the organs. This can be caused by the heart failing to contract or other reasons.
PEA is usually noticed when a person loses consciousness and stops breathing spontaneously.
Cardiopulmonary resuscitation (CPR) is the first treatment for PEA while potential underlying causes are identified and treated. The only treatment for PEA of a cardiac cause is CPR, which has a survival rate to hospital discharge of only 6%.
