Healing the heart with ventricular assist device therapy: mechanisms of cardiac recovery.

As experience has grown with the use of mechanical circulatory support systems in patients with cardiogenic shock, many anecdotes have been noted where myocardial recovery occurred and devices could be removed with reasonable residual cardiovascular performance and resolution of the shock syndrome. Indeed, when first used, ventricular assist devices were inserted to bridge patients unable to be separated from cardiopulmonary bypass to eventual recovery. Many successes with ventricular support systems have been recorded in individuals with postcardiotomy cardiogenic shock, acute myocarditis, and in the periinfarction period where stunning of potentially viable myocardial tissue contributed to severe heart failure. From an experimental standpoint, recovery of myocyte function and restoration of more normal myocardial geometry and constitution have been noted. There are many explanations for this, but principally, benefit is related to amelioration of circulatory insufficiency with attenuation of perturbed humoral networks and reduction of myocardial wall stress. It is important to understand how ventricular assist device implantation in select advanced heart failure patients might precipitate recovery of depressed myocardial function.