Establishment of left bundle branch pacing animal model and evaluation of of histology and electrophysiological parameters
Objective To establish a left bundle branch pacing (LBBP)model and determine the correlation be-tween the implantation of LBBP pacing electrodes and pacing parameters. Methods Five healthy beagles were se-lected for the study.The LBBP model in canines was established under the guidance of three-dimensional mapping system.Gross staining and histopathological examination of the canine hearts were conducted to determine the loca-tion of the pacing electrodes after procedure.The correlation between the implantation site and pacing parameters during LBBP was confirmed. Results All five canines successfully achieved the establishment of the LBBP model,and the potential of his bundle and left bundle branch(LBB)was detected.Pacing parameters recorded during the procedure were as follows:pacing threshold was (0.80±0.19)V/0.5ms;R-wave amplitude was (10.6±3.5)mV;time from stimulation retrograde to His bundle activation (Stim-Retro-His)was (15.5±3.0)ms;time from stimu-lation to left ventricular activation (Stim-LVAT )was (47.8±5.5)ms;pacing QRS duration was (95.0±8.9)ms;time from stimulation to QRS end (Stim-QRSend)was (97.0±9.2)ms.The interval myocardial refractory period was (268.0±10.5)ms,and the LBB refractory period was (310.0±15.5)ms.All electrode tips passed through the interventricular septum to reach or approach the left conduction system,with an average interventricular septum thickness of(11.8±1.3)mm,and the electrode depth of (11.4±2.5)mm. Conclusion This study successfully established a LBBP animal model.The relationship between the implantation site and pacing was confirmed that Stim-Retro-His≤20 ms and a sudden shortening of Stim-LVAT by ≥10 ms could be used as important criteria to confirm LBB capture.
CardiologyLeft bundle branch pacingHistological evaluationElectrophysiological parametersElectrocardiogramCanine model
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