 Beta blockers might improve patient outcomes by blunting the adverse affects of a hyperadrenergic state that occurs during a cardiac arrest and by improving the balance between myocardial oxygen supply and demand. Ditchey et al showed in an animal model that pretreatment with a beta blocker prior to cardiac arrest followed by standard epinephrine therapy results in reduced myocardial injury during CPR without compromising successful defibrillation or post resuscitation left ventricular function. 