The HeartMate II™ Left Ventricular Assist System has been implanted in more than 26,000 patients and is the most widely used and studied durable mechanical circulatory support device in patients with advanced heart failure. The device is intended for use as bridge to transplantation in candidates at risk of imminent death from non-reversible left ventricular (LV) failure and for destination therapy for use in patients with end-stage LV failure. This chapter describes each component of the system, the mechanisms of the pump itself, the physiology of blood flow under different pump speeds and pressure gradients, and ways to prevent pump thrombus. In addition, the functions and interface of the System Controller and System Monitor are detailed, including the settings displayed on the monitor and the type of alarms provided, as well as their appearance on the interface. The chapter closes with a discussion of how a ramped-speed study using echocardiography and hemodynamic assessment can identify the pump speed that provides the desired level of cardiac support for each patient.
