Adaptations to pulsatile versus nonpulsatile ventricular assist device support.

The refinement of mechanical cardiac assist devices over the past 50 years largely has been driven by the clinical imperatives to provide reliable circulatory support to patients waiting for cardiac allografts (bridge to transplant) or longterm support for patients with very advanced heart failure (destination therapy). In the course of increasing success with these applications, investigators from numerous centers also have demonstrated that circulatory support with a ventricular assist device (VAD) provides a unique window into the plasticity of the failing human heart. Indeed, since Levin et al1 first described reverse remodeling of VAD-supported hearts in 1995, there have been scores of original publications documenting the rather striking impact of VAD support on the phenotype of the failing heart. As highlighted in several recent reviews,2–6 VAD support promotes regression of pathological cardiac hypertrophy at the organ, tissue, and cellular level, including improvements in many of the signature pathological abnormalities characteristic of failing human hearts.