Pulseless electrical activity (PEA) refers to

cardiac arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possi ...

in which the electrocardiogram shows a heart rhythm that should produce a

pulse In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the n ...

, but does not. Pulseless electrical activity is found initially in about 55% of people in cardiac arrest. Under normal circumstances, electrical activation of muscle cells precedes mechanical contraction of the heart (known as ''electromechanical coupling''). In PEA, there is electrical activity but insufficient

cardiac output In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols Q, \dot Q, or \dot Q_ , edited by Catherine E. Williamson, Phillip Bennett is the volumetric flow rate of the heart's pumping output: th ...

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 visualized by bedside ultrasound (

echocardiography An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in ...

Cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore spont ...

(CPR) is the first treatment for PEA, while potential underlying causes are identified and treated. The medication

epinephrine Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...

(aka adrenaline) may be administered. Survival is about 20% if the event occurred while the patient was already in the hospital setting.

Signs and symptoms

Pulseless electrical activity leads to a loss of cardiac output, and the blood supply to the

brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as Visual perception, vision. I ...

is interrupted. As a result, PEA is usually noticed when a person loses consciousness and stops

breathing Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cellu ...

spontaneously. This is confirmed by examining the

airway The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose t ...

for obstruction, observing the chest for respiratory movement, and feeling the

(usually at the

carotid artery Carotid artery may refer to: * Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery * External carotid artery, an artery on each side of ...

) for a period of 10 seconds.

Causes

These possible causes are remembered as the 6 Hs and the 6 Ts. See Hs and Ts * Hypovolemia * Hypoxia * Hydrogen ions (

Acidosis Acidosis is a process causing increased acidity in the blood and other body tissues (i.e., an increase in hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma. The term ''acidemia'' describe ...

) * Hyperkalemia or Hypokalemia * Hypoglycemia * Hypothermia * Tablets or Toxins * Cardiac Tamponade * Tension pneumothorax * Thrombosis (e.g.,

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...

pulmonary embolism Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream ( embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathin ...

) * Tachycardia * Trauma (e.g.,

hypovolemia Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the los ...

from blood loss) The possible mechanisms by which the above conditions can cause pulseless in PEA are the same as those recognized as producing circulatory shock states. These are (1) impairment of cardiac filling, (2) impaired pumping effectiveness of the heart, (3) circulatory obstruction and (4) pathological vasodilation causing loss of vascular resistance and excess capacitance. More than one mechanism may be involved in any given case.

Diagnosis

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 Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

(ECG/EKG). In PEA, there is organised or semi-organised electrical activity in the heart as opposed to asystole (flatline) or to the disorganised electrical activity of either

ventricular fibrillation Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and n ...

ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a fast heart rate arising from the lower chambers of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period ...

Treatment

Cardiac resuscitation guidelines (ACLS/BCLS) advise that

cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore spont ...

should be initiated promptly to maintain

until the PEA can be corrected. The approach in treatment of PEA is to treat the underlying cause, if known (e.g. relieving a tension pneumothorax). Where an underlying cause for PEA cannot be determined and/or reversed, the treatment of pulseless electrical activity is similar to that for

asystole Asystole (New Latin, from Greek privative a "not, without" + ''systolē'' "contraction") is the absence of ventricular contractions in the context of a lethal heart arrhythmia (in contrast to an induced asystole on a cooled patient on a heart-lu ...

. There is no evidence that external cardiac compression can increase cardiac output in any of the many scenarios of PEA, such as hemorrhage, in which impairment of cardiac filling is the underlying mechanism producing loss of a detectable pulse. A priority in resuscitation is placement of an intravenous or intraosseous line for administration of medications. The mainstay of drug therapy for PEA is

(adrenaline) 1 mg every 3–5 minutes. Although previously the use of

atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically given ...

was recommended in the treatment of PEA/asystole, this recommendation was withdrawn in 2010 by the

American Heart Association The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and deat ...

due to lack of evidence for therapeutic benefit. Epinephrine too has a limited evidence base, and it is recommended on the basis of its mechanism of action. Sodium bicarbonate 1meq per kilogram may be considered in this rhythm as well, although there is little evidence to support this practice. Its routine use is not recommended for patients in this context, except in special situations (e.g. preexisting metabolic acidosis, hyperkalemia,

tricyclic antidepressant overdose Tricyclic antidepressant overdose is poisoning caused by excessive medication of the tricyclic antidepressant (TCA) type. Symptoms may include elevated body temperature, blurred vision, dilated pupils, sleepiness, confusion, seizures, rapid he ...

). All of these drugs should be administered along with appropriate CPR techniques.

Defibrillator Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''coun ...

s cannot be used to correct this rhythm, as the problem lies in the response of the myocardial tissue to electrical impulses.

References

External links

{{Heart diseases Cardiac arrhythmia Diagnostic emergency medicine Medical emergencies Medical aspects of death Causes of death