ABSTRACT
In adults the commonest arrhythmia at the onset of cardiac arrest is ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). The definitive treatment of these arrhythmias-defibrillation-must be administered promptly. Survival from out-ofhospital VF falls by 7-10% for every minute after collapse. Advanced life support (ALS) is the process that attempts to deliver the definitive treatment for the underlying rhythm. Basic life support (BLS) extends the interval between the onset of the collapse and the development of irreversible organ damage and provides the opportunity for ALS to be effective.
