Bhandari S, et al. - In this work, researchers described rhythm profiles (patterns of rhythm transitions during two-minute CPR cycles) following attempted defibrillation and assessed their relationship to survival. they observed the common occurrence of rhythm transitions after attempted defibrillation. Transient organized rhythm during the preceding two-minute CPR cycle was associated with favorable survival among patients with ventricular fibrillation at the subsequent two-minute check. This suggested distinct physiologies that could serve as the basis for different treatment strategies.