LVADs improve heart pumping ability; may eliminate need for transplant.

Use of a left ventricular assist device (LVAD) reverses the down regulation of beta-adrenergic receptors that is characteristic of heart failure, according to an autopsy study reported in the August 21 issue of Circulation.

"This is important because the beta-adrenergic nervous system is the main way the heart increases its performance during stress," said Christine Schomisch Moravec, MD of the Cleveland (OH) Clinic Foundation. The finding supports the contention that "the ability of the failing human heart to respond to the sympathetic nervous system is not irreversible."

Moravec and colleagues obtained hearts at the time of transplantation from 19 heart transplant recipients who had received LVADs, 23 heart transplant patients who had not, and 15 organ donors who had no history of heart disease but whose hearts were unsuitable for transplantation. The researchers assessed the effects of the beta-blocker isoproterenol on cardiac muscle contractility and quantified beta-adrenergic receptor density. They found that, compared with the other hearts, those that had received LVAD support for any length of time showed a significantly greater response to beta-adrenergic stimulation and greater density of beta-adrenergic receptors.

"Before the study, we assumed that when the heart was no longer able to respond to stimulation of the beta-adrenergic nervous system, there was no way to make that better," Moravec said. "However, the ability of the heart to recover means that perhaps patients with heart failure will not need heart transplants. There may be medical ways to heal the heart, through drugs or other therapies."