PURPOSE OF REVIEW: Large pulsatile left ventricular assist devices have been used as bridge-to-transplant therapy for the past 20 years. Over the past 2 years, a number of smaller rotary pumps have been introduced into clinical trials in the United States, Europe, and Australia. These devices offer the potential for smaller operations, greater resistance to infection, and new opportunities for bridge-to-recovery therapy. RECENT FINDINGS: Ongoing trials with axial flow devices support greater durability and less device-related infection than the HeartMate XVE (Thoratec Corporation, Pleasanton, California, USA). A greater tendency for pump thrombus and a higher anticoagulation requirement, however, are disadvantages compared with the HeartMate device. SUMMARY: Large pulsatile left ventricular assist devices have been the mainstay of mechanical support. The combination of durability and smaller pump size has become a focus of mechanical circulatory support in the current era. Ongoing clinical trials in the United States with three rotary pumps in both bridge-to-transplant and destination trials will likely result in a major increase in options for circulatory support. At least five other small, durable devices have recently entered non-US trials and are poised for clinical studies in the US. The National Institutes of Health-sponsored Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) will facilitate the introduction of new technology and study patient and device outcomes. © 2006 Lippincott Williams & Wilkins.