Could Gene Therapy Replace Pacemakers?

A new study in dogs reveals two genes responsible for controlling heartbeat rhythm and re-coordinating the action of the heart's right and left ventricles. These genes may be part of the molecular pathway affected by pacemakers, researchers report in the 14 September issue of theScience Translational MedicineUsing gene therapy or drugs to activate these genes in heart failure patients may help people who cannot use a pacemaker—or possibly replace pacemakers altogether, the study authors proposeWe have demonstrated that an existing clinical pacemaker therapy is also inducing very unique changes in the heart muscle itself, and in this sense is as complex as any drug, gene, or cell therapy might be,senior author of the study and professor of cardiology at Johns Hopkins University.Like rowers in unison, the human heart works most efficiently when its two ventricles contract together simultaneously to pump blood into circulation. In some patients with heart failure, the ventricles beat out of sync, sloshing blood from one side of the heart to the other rather than pumping blood out to the body— an added burden on an already damaged heart.Soon after its development, researchers realized that an implanted pacemaker,therapy, could resynchronize the ventricles and make the heart work better. Today, it is well known that hearts treated stronger and healthier. Althoughis used worldwide, researchers remain in the dark as to what causes the heart to fail in the first place, and whyso effectiveGiven the unusual success researchers thought perhaps the pacemaker was altering molecular pathways in the heart—and maybe these changes could be translated into another type of heart failure treatment, such as a drug or a gene therapy.Nuclear scan imaging of right and left heart ventricles in a patient who received successfultherapy. Both sides of the left ventricle are moving inward together and the volume inside the heart gets smaller. This result is more ejection of blood to the body.