Pacemaker tune-up works chemical wonders on damaged hear...( Using pacemakers to electrically ret...),Health

Using pacemakers to electrically retune a heart damaged by long bouts of a wobbling heartbeat, where one heart muscle wall is beating sooner than the other, leads to fast improvements in the tissue levels of more than a dozen proteins key to the organs health, scientists at Johns Hopkins report in experiments in dogs.

The teams findings, published online this week in the journal Circulation, are believed to be the first detailed chemical analysis of the pacemakers biological effects on the heart and could serve as the basis for more strategic use of combined device-plus-drug treatments for people with congestive heart failure.

Our results really help explain how pacemakers act much like a drug, actually changing the biology of the heart, and also explain why people can feel so much better after just two to six months with the device, says study senior study investigator and cardiologist David Kass, M.D., a professor at the Johns Hopkins University School of Medicine and its Heart Institute.

We are learning that pacemaker therapy does profoundly more than just mechanically correct how the heart beats; in fact, it produces major chemical changes that benefit the muscle, says lead investigator Khalid Chakir, Ph.D., a postdoctoral cardiology research fellow at Hopkins.

Each year, more than a half-million Americans are diagnosed with congestive heart failure, when the heart weakens and cannot pump enough blood to the rest of the body. One-quarter of those affected, typically men and women over age 50, will suffer from a pendulating, non-uniform contraction, requiring implantation of a pacemaker. The device electrically stimulates both sides of the heart at the same time, as part of so-called cardiac resynchronization therapy to restore unison to the heartbeat.

Current treatments with pacemakers, scientists say, can block the ill effects of an uneven heartbeat, extending peoples lives for months to years or help
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