Increasing in frequency, and claiming more than 250,000 lives per year, heart failure represents a major public health problem. In spite of newer medical therapies, a significant proportion of patients progress to irreversible end-stage heart disease, for which cardiac transplantation remains the only long term hope. The inability to meet the demand for donor organs has led to the development of left ventricular assist devices as a temporizing measure while awaiting a transplantation. The "bridging to transplantation" experience has firmly established the efficacy of these devices as short-term and medium-term mechanical assistance and has provided valuable lessons applicable to long-term support. Mechanical cardiac assistance technology has dramatically improved and can provide reliable univentricular support with minimal thromboembolic and infectious complications. Although major obstacles remain, the potential benefits are great enough and the morbidity and mortality of end-stage heart disease high enough to warrant the evaluation of wearable left ventricular assist devices for long-term mechanical assistance.