Using new DNA microarray technology, researchers have found significant changes in the expression pattern of hundreds of genes in heart muscle cells after mechanical pumps are used to take over from failing hearts. This finding represents a first step, they say, in a line of research that could help predict how heart failure patients will respond when supported by a left ventricular assist device (LVAD). These devices are employed when the heart’s left ventricle — the chamber of the heart that pumps blood throughout the body — is too weak to pump enough blood to nourish the body’s tissues. They have been used as successful short-term “bridges to heart transplant” and are increasingly being considered as long-term heart failure destination therapy, also known as “bridge to recovery.”