The 2015 American Heart Association (AHA) guidelines update for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) presents modifications based on new science and ongoing controversies since the previous 2010 guidelines. Key changes include a new focus on 'systems of care and continuous quality improvement' and a transition to a continuously updated web-based format for the guidelines. The update outlines 315 classified recommendations, emphasizes high-quality CPR, and aims to double bystander CPR rates and cardiac arrest survival by 2020.