Treating Sudden Cardiac Arrest (SCA)
The only definitive treatment to terminate ventricular fibrillation is defibrillation, the application of an electric shock to the heart using a defibrillator. Successful termination of ventricular fibrillation by defibrillation enables the heart to resume a coordinated normal rhythm. If applied quickly after the onset of SCA, defibrillation can be highly effective. Although cardiopulmonary resuscitation (CPR) can be performed in the event of SCA, it does not terminate ventricular fibrillation and is only useful to sustain life for several minutes until defibrillation can be administered.
Time to Therapy
Timely defibrillation is the single most important factor in saving the SCA victim's life. The sooner defibrillation therapy can be performed, the higher the likelihood of survival. In hospital environments, external defibrillation is frequently successful because the patient is continuously monitored and trained hospital personnel are readily available to apply the shock. Otherwise, successful defibrillation depends on the SCA victim being observed and on the arrival of emergency medical personnel. Since most SCA events are not witnessed and response times average greater than ten minutes outside the hospital, the survival rate of SCA victims is typically less than 10%. For every minute that passes between the occurrence of sudden cardiac arrest and use of a defibrillator, on average, the chances of surviving diminish by 10 percent.