Pulseless electrical activity
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Pulseless Electrical Activity (also known by the older term Electromechanical Dissociation or Non-Perfusing Rhythm) is a condition where the heart generates and conducts the electrical impulses required to stimulate itself but fails to produce mechanical contraction or an output. On electrocardiography (ECG) this may appear as any rhythm, whether slow, fast or regular.
The normal condition when electrical activation of muscle cells precedes mechanical contraction is known as Electromechanical Coupling.
Pulseless electrical activity will generally occur secondary to:
1- Severe shock (severe blood loss or marked volume depletion)
2- Severe trauma such as electrocution, cold water drowning and adverse drug reactions.
3- Myocardial infarction.
4- Cardiac arrest.
5- End-stage heart disease.
6- Cardiac tamponade (fluid surrounding the heart).
7- Cardiac rupture.
The approach in treatment of PEA is to treat the underlying cause. These possible causes are remembered as the 5 H's and the 5 P's.
Where an underlying systemic cause is unable to be determined in sufficient time pulseless electrical activity should receive treatment methods as if the patient were in asystole. Treatment is intravenous delivery Epinephrine 1 mg every 3-5 minutes, and, if the underlying rhythm is bradycardia, Atropine 1 mg IV up to .04 mg/kg (varies with regional protocols). Both these drugs should be administered along with appropriate CPR techniques. Defibrillators are not used for this rhythm, as the problem lies in the response of the myocardial tissue to electrical impulses. Resuscitation protocols (such as ALS), contain instructions on how to systemically consider the causes for PEA. These include hypoxia, acidosis, tension pneumothorax and various others.
