Experimental His‐Bundle Pacing: Histopathological and Electrophysiological Examination

Abstract

His-bundle pacing gives a more physiological ventricular contraction in comparison to right ventricular apical pacing. However the problems of lead fixation and stability of long-term His-bundle pacing are yet unsolved. We used six adult beagles, in which a screw-in lead was anchored in the His-bundle region for observation of the pacing conditions and histopathologic changes of the conduction system over the course of 2 months. In the results, a satisfactory fixation was obtained using a conventional screw-in lead and no histological influence on the conduction system was observed. The pacing threshold at the time of implantation was 1.15 +/- 0.69 V (3.23 +/- 3.08 mA) in the pulse width of 0.5 ms. R wave amplitude, the impedance and slew rate were 7.28 +/- 2.04 mV, 409 +/- 102 Ohm, and 0.65 +/- 0.41 V/s, respectively. Two months later, these parameters changed to 2.83 +/- 1.06 V (10.4 +/- 5.71 mA), 5.63 +/- 1.62 mV, 310 +/- 71.3 Ohm, and 0.49 +/- 0.22 V/s, respectively. These results suggest the feasibility of clinical application of permanent His-bundle pacing.

Prevention of Ventricular Desynchronization by Permanent Para-Hisian Pacing After Atrioventricular Node Ablation in Chronic Atrial Fibrillation

“…The latter observation could mean that, despite a partial "pre-excitation" of the superior portion of the interventricular septum, the conduction in the His-Purkinje system allows the stimulus to be conducted to the ventricular myocardium simultaneously, activating both ventricles in a synchronous fashion. The hypothetical possibility of damaging the His bundle using the helix of the screw-in lead must be considered, however, even if it has not been reported in preliminary studies (28,30).…”

Permanent His-Bundle Pacing After Atrioventricular Node Ablation in a Patient With Chronic Atrial Fibrillation and Mitral Regurgitation

“…17 Permanent direct His-bundle pacing in humans was recently reported by Deshmukh et al 12 Hisbundle pacing produces synchronous ventricular depolarization and obviously preserves cardiac function in comparison with RVA or high septal pacing. 13 Furthermore, His-bundle pacing does not appear to disturb mitral valve apposition or worsen MR in comparison with RV pacing.…”

Successful Use of an Acceleration Rate Response Pacemaker with a Transvenous Steroid-Eluting Screw-in Lead for Third-Degree Atrioventricular Block in a Labrador Retriever

“…The tensile force needed to remove the screw-in type lead is less than that needed to remove the tined type. Only minimum cylindrical fibrous tissue corresponding to the tip of the lead was observed macroscopically with the screw-in type [2]. In another study, the steroid-eluting screw-in lead created only a small area of fibrous tissue and a slight inflammatory cell infiltration, with no distinct pathological damage [1].…”

“…extraction and the histological findings at the site where the lead connects to the endocardial wall [2]. The tensile force needed to remove the screw-in type lead is less than that needed to remove the tined type.…”