During our lifetime the heart beat about 2100,000,000 times, once every second approximately. In a healthy individual only a few of those millions fails to propagates trough the whole heart and in all of us, sooner or latter, our life extinguish with a disorganized, often called turbulent, propagation of the last heartbeat. This talk is a review of the work done to understand how beats are missed and how turbulence arises emphasizing the nonlinear dynamics responsible for the normal and abnormal function of the heart as well as the unsolved problems.