The physiologic basis for the management of ventricular assist devices.

Mechanical ventricular assist devices are now approved as destination therapy for terminal heart failure. It is the purpose of this review to discuss the physiology of this technology that is considered in outpatient care. The currently available pulsatile devices are solely dependent of preload volume and, when placed in the automatic mode, can maintain physiologic cardiac outputs with exercise. However, because of their dependence on preload volume, there are unique physiologic consequences; device bradycardia represents volume depletion, device tachycardia reflects volume overload. The differential diagnosis of left ventricular assist device dysfunction includes native right ventricular failure, native left ventricular recovery, or other technical considerations. The management of biventricular mechanical support as well as arrhythmia management and the role of echocardiographic assessment in this unique patient population will be discussed. Expertise in outpatient management of such devices is now a requisite for subspecialists in heart failure, In the future, technical innovations may simplify management for professionals, patients, and their families.