Pulseless electrical activity

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The diagnosis of pulseless electrical activity (PEA), also known as electromechanical dissociation (EMD), refers to the presence during cardiac arrest of electrical activity of the heart, in the absence of a ventricular tachyarrhythmia, but no measurable cardiac output . PEA is one of the non-shockable rhythms, the other being asystole.

Clinical presentation

Pulseless electrical activity is one of the possible states found in an unconscious patient who has had a cardiac arrest. It is characterized by the presence of cardiac electrical activity, which may be organized or disorganized, in the absence of a ventricular tachyarrhythmia (i.e. ventricular tachycardia/fibrillation), but no measurable cardiac output. Lack of output may be recognized by the absence of any arterial pulse or systolic blood pressure .

Pathology

Etiology

Classically the etiologies have been described as the 4 Hs and 4 Ts :

A recent large retrospective Swiss study reviewing 1,866 out-of-hospital cardiac arrests (over a 10-year-period) demonstrated that the most frequent cause of pulseless electrical activity was hypoxia, accounting for almost 25% of all cases. Acute coronary syndrome was cited as the primary cause in 12.5% cases. Other cardiac dysrhythmias, such as long QT syndrome, were also common etiologies. Most interestingly was the discovery that intracranial hemorrhage, in 80% of cases subarachnoid hemorrhage, was the underlying precipitant of PEA in almost 7% of all cases .

See also