Abstract: Objective To observe the changes of surface ECG and cell couplings between sinoatrial node cells and myocardial
cells following transplantion of pedicled autologous sinoatrial node tissue graft into the right ventricle of a canine model of
complete atrioventricular block. Methods Ten healthy dogs were randomized into transplantation group and control group.
Pedicled autologous sinoatrial node tissue grafts were transplanted into the right ventricle in the transplantation group, while
the sinoatrial nodes were only excised in the control group after placement of temporary myocardial pacing wires. The
changes of surface ECG were observed at 1, 2, 3 and 4 weeks postoperatively. At 4 weeks, complete atrioventricular block was
induced in the dogs by radiofrequency ablation of the His bundle. The heart rate of the dogs in both groups were recorded
after the injection of isoproternol (ISO) from the femoral vein, and the transplanted tissue graft was observed under optical
and transmission electron microscopes. Results No significant changes occurred in the surface ECG. All the dogs showed ECG
waveforms specific of complete heart block after the ablation, and the ventricular heart rates were similar between the two
groups (P>0.05). The ventricular heart rate did not undergo obvious changes after ISO injection (P>0.05). The transplanted
pedicled autologous sinoatrial node survived in the dogs and the sinoatrial node cells established desmosome junctions with
the myocardial cells, but the number of junctions was not sufficient to support heart pacing. Conclusions Desmosome junction
can occur between ventricular myocardial cells and sinoatrial node cells at the edge of transplanted pedicled autologous
sinoatrial node tissue.