Current pacemaker therapy requires the use of an electronic pacemaker and implantable leads (What is a Pacemaker? ). There have been reports of leadless pacemakers that use an implantable yet leadless means to pace the heart (Nanostim Leadless Pacemaker). A group has recently reported results of their study examining the implantation of pacemaker-related genes. (Biological Pacemaker using Genes) A biological pacemaker has the advantages of no indwelling hardware and may eliminate risk of infection from traditional pacemakers.
Cingolani et al utilized a right femoral vein transvenous approach to deliver pacemaker-related genes to the atrioventricular (AV) junction. Genes expressing dominant-negative inward rectifier potassium channel (Kir2.1AAA) and hyperpolarization-activated cation channel (HCN2) genes were used; these are responsible for the pacemaker current (If, HCN2) and suppression of the inward rectifier current (Kir2.1). This overexpression results in junctional pacemaker activity for up to 2weeks. They found a septal activation pattern similar to those seen during sinus rhythm; thus, this biological pacemaker may not cause dyssynchrony seen in right ventricular (RV) apical pacing.
Aside from gene overexpression, pluripotent stem cells and specific factors (T box transcription factors) may offer biological pacemaker activity as well. Obviously, these are all preclinical techniques that may offer an exciting alternative to current electronic, implantable pacemakers.