Defibrillation and cardioversion are used for rapid termination of a tachyarrhythmia (a fast abnormal rhythm originating either in the atrium or ventricle) that is unresponsive to baseline treatment or is causing the patient to have cardiovascular compromise (inadequate systemic perfusion). Baseline treatment consists of correcting metabolic problems, use of vagal maneuvers (bag of ice water over the eyes and face of the infant without obstructing the airway, pressure on closed eyelids), use of medications (adenosine, digoxin, propranolol, verapamil, amiodarone, procainamide, lidocaine, or magnesium sulfate), or transesophageal pacing. It is best to try these maneuvers or medical therapy if intravenous access is available. Neonatal arrhythmias are rare, and the majority of them can be treated with these initial measures.
Current defibrillators are capable of delivering 2 modes of shock: synchronized and unsynchronized. Synchronized shocks are lower dose and used for cardioversion. Unsynchronized shocks are higher dose and used for defibrillation. Pediatric cardiology consultation is recommended for all infants with a tachyarrhythmia.