FIGURE 9.1 Pathophysiologic pathways from etiologies to cardiac arrest Arrhythmia management is a relatively infrequent problem in pediatric life support The absence of atherosclerotic vascular disease makes the child’s myocardium less susceptible to arrhythmias, and a minority of arrested children present with a shockable rhythm As a result, antiarrhythmic medications and defibrillation are infrequently used The most common cardiac rhythms to be recognized and managed in pediatric arrest are sinus bradycardia, pulseless electrical activity (PEA), and asystole The exceptions to this are those children with congenital heart disease and those who have sustained direct myocardial trauma (see Chapter 86 Cardiac Emergencies ) These children may have unusual and difficult arrhythmias that require subspecialist expertise to achieve a successful outcome Finally, there is still much to be learned about caring for children requiring resuscitation The creation of research networks and CPR registries has greatly expanded the possibility for prospective, large, multicenter trials Exemption from informed consent is an evolving concept in studies of children with a life-