Pulseless electrical activity
| Pulseless electrical activity | |
|---|---|
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| A drawing of what a rhythm strip showing PEA would look like | |
| Classification and external resources | |
| Specialty | cardiology |
| ICD-10 | I46.9 |
| ICD-9-CM | 427.9 |
| DiseasesDB | 4166 |
| eMedicine | med/2963 |
Pulseless electrical activity (PEA), also known by as electromechanical dissociation, refers to cardiac arrest in which a heart rhythm is observed on the electrocardiogram that should be producing a pulse, but is 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 the heart either does not contract or there are other reasons this results in an insufficient cardiac output to generate a pulse and supply blood to the organs. 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.
Cardiopulmonary resuscitation (CPR) is the first treatment for PEA, while potential underlying causes are identified and treated. The medication epinephrine may be administered. Survival is about 20%.
Pulseless electrical activity leads to a loss of cardiac output, and the blood supply to the brain is interrupted. As a result, PEA is usually noticed when a person loses consciousness and stops breathing spontaneously. This is 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.
These possible causes are remembered as the 6 Hs and the 6 Ts. See Hs and Ts
This list is not fully comprehensive. Most notably, it does not include anaphylaxis. Pressure effects associated with artificial ventilation may also contribute to significant reduction in cardiac output, resulting in a clinical diagnosis of PEA.
The possible mechanisms by which the above conditions can cause pulseless in PEA or 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.
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