Engine 73 and Ambulance 77 were dispatched this morning for cardiac arrest.  Units arrived on the scene within a minute from being dispatched. The crew from Riverdale found the patient on the floor of their home in full caridac arrest.  The crew went right to work starting CPR attaching the AED with one successful shock.  The patient was succesffully rescusitated prior to ALS arrival. The patient was quickly loaded into Ambulance 77 and transported to area hospital with the medic crew on board. Great job everyone and remember The Chain Of Survival.