In ECPR, where CPR times often range from 30 to 120 minutes, only patients with good circulation during CPR survive, while non-survivors commonly suffer from anoxic brain injury. The selection process during CPR is challenging causing a general survival rate of just 2 out of 10, and the urgent need for better selection criteria has been emphasized. It it crucial to keep cardiac arrest times as short as possible, pre primed-ECMO can facilitate this. The ECMO treatment and the long CPR times of ECPR can also affect the measurements of the neurologic prognostication guidelines after cardiac arrest, making its validity uncertain in this specific cohort. Further, the long-term neuropsychological follow-up is limited to a few patients, making it uncertain if ECPR gives the survivors good long-term life satisfaction or just a prolonged life. Our overall aim is to optimize and improve the care pathway for ECPR patients by refining patient selection, assessing pre-primed ECMO, validating neurological prognostication guidelines, and understanding long-term outcomes and challenges faced by survivors. Specific Aim 1: Evaluating predictors for good neurological outcomes in ECPR and to develop and validate (internally and externally) an evidence-based selection tool for ECPR. Specific aim 2: To assess the sterility and function of pre-primed ECMO. Specific aim 3: To evaluate the applicability of current guidelines for neurological prognostication after cardiac arrest in ECPR patients, and to assess the predictive value of individual and combined neurological tests in this specific patient population. Specific aim 4: To determine the long-term neuropsychological outcomes, identify the problems survivors experience in daily life, and assess life satisfaction - by comprehensive follow-up visits with validated questionnaires and neuropsychology testing up to 10 years after the ECMO-treated cardiac arrest