The response of the failing heart to chronic mechanical unloading

Purpose of review: The authors present a comprehensive analysis of the evidence in support of improvements at the cellular, structural, and hemodynamic levels after left ventricular assist device support. Recent findings: The use of left ventricular assist devices as a strategy to bridge patients to cardiac transplantation and, more recently, as a form of destination therapy has provided a great opportunity to study failing myocardium at various time points. Specifically, myocardial samples can be obtained from patients at the time of left ventricular assist device implantation and again at explant, thereby allowing comparisons between paired samples of failing myocardium obtained before and after mechanical unloading. Summary: A body of knowledge has been generated that illustrates the ability of the myocardium to "heal." This information may give us better insight into cellular and molecular mechanisms of heart failure and potential new therapies for patients with end-stage heart failure.