Vitals signs on presentation to receiving facility including blood pressure, heart rate, respiratory rate, weight, height Witnessed or unwitnessed arrest Presence or absence of bystander CPR Resuscitation attempted by trained emergency personnel prior arrival at initial facility (receiving or transferring) Initial Rhythm prior to ROSC (for a pulseless arrest, the initial rhythm when the AED is placed) Therapies applied during resuscitation including CPR, defibrillation, medications, intubation Estimated time from initial arrest to initial ROSC Initial electrocardiogram characteristics including presence or absence of ST elevation, rhythm, corrected QT interval, QRS width Initial perfusing rhythm following resuscitation Time from arrival of medical personnel at scene of arrest to arrival at receiving facility. If the patient is brought to the receiving facility by someone other than medical personnel, then time is set to 0. Time to arrival to referral center from receiving facility. If referral center is also the receiving facility, then the time is set to 0. Time to arrival from receiving facility to intensive care unit or cath lab if the cath lab precedes the ICU Time to arrival to cath lab from the receiving facility Presence or absence of significance obstructive lesions and list of involved vessels if patient undergoes coronary angiography during hospitalization PCI performed and vessels treated if patient undergoes PCI during hospitalization Presence of absence of any ST elevation on an electrocardiogram within 24 hours of admission to referral facility Any use of mechanical support within 24 hours of admission to referral facility Any use of therapeutic cooling within 24 hours of admission to referral facility Any use of vasopressor agents within 24 hours of admission to referral facility Admission hemoglobin, creatine, and cardiac troponin, bicarbonate, pH, pO2 Glasgow Coma Score Presence or absence of cardiogenic shock within 24 hours of admission to referral facility Left Ventricular Ejection Fraction determined during the hospitalization and Closest to the time of death or discharge