Pulseless electrical activity (PEA) refers to any cardiac rhythm in which there is no palpable pulse, but the ECG shows cardiac activity. The earlier terminologies for PEA were electromechanical dissociation (EMD) and non-perfusing rhythm. It is due to the inability of the heart to generate sufficient force of contraction in response to depolarization. Severe hypoxia is probably the most common cause of PEA. The causes of PEA are remembered by the AHA (American Heart Association) mnemonic of several conditions beginning with H and T:
Hydrogen ions (acidosis)
Hyperkalemia or Hypokalemia
Thrombosis (Myocardial infarction / Pulmonary embolism)
Pulseless electrical activity is treated like a cardiac arrest with cardiopulmonary resuscitation (CPR) after a quick evaluation for the reversible causes. Bedside echocardiography is useful in confirming cardiac tamponade, which should prompt immediate pericardiocentesis. Echocardiography will also show features of right ventricular enlargement and pulmonary hypertension in pulmonary embolism. Mechanical complications of a myocardial infarction can also be sought on echocardiography.
An intercostal drain is inserted in case of tension pneumothorax. Intravenous access for correction of hypovolemia and administration of drugs is of top priority. Epinephrine, vasopressin and atropine are the important drugs which may be given. Intubation and ventilation with 100% oxygen is useful in correcting the hypoxia.