By Tammy Gay

““We found that patients who received the implantable device and had it turned on could walk further distances, felt better, had fewer hospitalizations, and a decreased need for intravenous medications.”

William Abraham, M.D., co-director of the Linda and Jack Gill Heart Institute

June 13, 2002– (Lexington, Ky.) – A study of cardiac resynchronization in chronic heart failure patients led by William Abraham, M.D., co-director of the Linda and Jack Gill Heart Institute at the University of Kentucky, indicates significant clinical improvement in patients, according to an article released in the June 13 issue of The New England Journal of Medicine.

Cardiac resynchronization therapy is a new treatment for heart failure that uses an implantable device, the Medtronic InSync® cardiac resynchronization system, to improve the pumping efficiency of the heart. 

“We found that patients who received the implantable device and had it turned on could walk further distances, felt better, had fewer hospitalizations, and a decreased need for intravenous medications,” Abraham said about the multi-center study.

Nearly 600 patients at 45 centers participated in the study, which was conducted between November 1998 and December 2000.  About 60 of these patients were enrolled in the study under the care of Abraham.

The InSync® device with specialized leads, which was approved by the U.S. Food and Drug Administration in August 2001, is designed to provide resynchronization therapy for people who have heart failure and problems with electrical conduction in their hearts.

In healthy people, the four chambers of the heart contract in synchrony to move blood through the body. However, in many patients who have heart failure, the electrical impulses that coordinate the contractions of the heart’s chambers may be impaired. As a result, in up to 50 percent of people who have advanced heart failure, the two lower chambers, called ventricles, no longer contract at the same time. This may worsen the symptoms of the disease, which include shortness of breath, fatigue, and swelling of the feet and ankles.

In cardiac resynchronization therapy, a device is implanted in the upper chest in an attempt to resynchronize the contractions of the ventricles by sending tiny electrical impulses to the heart muscle. Resynchronizing the contractions of the ventricles can help the heart pump blood throughout the body more efficiently and reduce the symptoms.

Cardiac resynchronization therapy, also known as biventricular pacing, is intended to complement standard drug treatment, and dietary and lifestyle modifications.

The device, slightly larger than two stacked silver dollars, is implanted under the skin in the chest area, and three very thin insulated wires (leads), with tiny electrodes on their distal ends, are maneuvered through veins from the device to the heart: One lead is placed to touch the inner wall of the right atrium, another to touch the inner wall of the right ventricle and the third lead is threaded through the coronary sinus and placed to touch the outer wall of the left ventricle.