Experimental study of the effects of multi-site sequential ventricular pacing on the prophylaxis of ventricular fibrillation

Previous studies report a significant prophylactic effect on the occurrence of atrial fibrillation by simultaneous multi-site atrial pacing. We invest igated the effects of multi-site sequential ventricular pacing (MSVP), whic h may be preferable to simultaneous multi-site pacing in terms of the proph ylaxis of the occurrence of ventricular fibrillation (VE), Needle electrodes were inserted at ten different epicardial sites on both v entricles for MSVP in 12 adult beagle dogs. Four premature ventricular extr astimuli (PVE) were introduced to provoke VF reproducibly from a separate e lectrode in the left ventricle. The 4 PVE were applied to try to provoke VF during MSVP in a comparable fashion to the activation sequence during sinu s rhythm. We compared the prophylactic effects of MSVP on the inducibility of VF by changing the number of stimulation sites to either 1, 3, 5, or 10 epicardial sites. We performed a total of 363 trials of induction and suppression of VF. The occurrence rates of VF by the 4 PVE for the various number of epicardial st imulation sites of MSVP, i.e., at 1, 3, 5, and 10 sites, were 0.8263, 0.428 6, 0.4450, and 0.2857, respectively (p < 0.05). There was a significant pro phylactic effect of MSVP on the inducibility of VF, and this effect became stronger as the number of MSVP sites was increased from 3 to 10. The hemody namic state was relatively stable during MSVP. MSVP seems to be a promising method with which to reduce the occurrence of VF, and a larger number of stimulation sites would be more effective in ter ms of the prophylaxis of VF.