The frequency of shockable heart rhythms (ventricular fibrillation or pulseless ventricular tachycardia) as the initial recorded rhythm is lower among patients with witnessed cardiac arrests in the home than among those with witnessed arrests in a public setting, according to a study by the Research Outcomes Consortium recently published in the New England Journal of Medicine.
The frequency of shockable arrhythmias was higher for bystander-witnessed cardiac arrests in a public location (60%), particularly those in which an AED was applied by a bystander in a public location (79%). Therefore, as might be expected, the rate of survival to hospital discharge was significantly higher when an AED was applied by a bystander after a cardiac arrest in a public location (34%, vs. 12% for arrests at home; adjusted model P=0.04).
Study results strengthen the argument for putting AEDs in public locations, according to the authors. Although the role of AEDs in cardiac arrests that occur in the home will probably continue to evolve, the relatively low incidence of shockable arrhythmias in this setting suggests that a treatment strategy that emphasizes prompt, bystander-delivered CPR of high quality (e.g., with the assistance of a dispatcher) should be as effective in saving lives as the widespread deployment of AEDs in homes.
In an editorial questioning interpretation of study results, Gust H. Bardy, MD, states "The dismissal of home AEDs is premature and other than personal expense, there is no known downside to such a purchase." Moreover, he says, "It is time to reassess the value of CPR, not dismiss definitive therapy with defibrillation."