Sorry, gethigh, your understanding of physiology is a little off: epi works to increase heart rate, and to increase peripheral vascular resistance. Its primary use in CPR is to increase heart rate. Epi is given when no pulse is present. Atropine is given first to counter bradycardia (the first part of cardiac arrest in people). Lidocaine is given last to counteract ventricular fibrillation (end-stage cardiac arrest).