The use of rotary blood pumps for assistance of advanced heart failure continues to increase with the growing prevalence of the disease itself and the availability of small and clinically applicable devices. These devices are used either as cardiac support prior to transplantation or to assist the recovery of the heart. As rotary blood pumps produce a non-pulsatile flow, several questions concerning the physiology of pulseless circulation are remaining. This book gives an introduction on cardiac support with blood pumps and covers the physiology of low-pulse and pulseless circulation under rotary assist device support according to the literature.