Experimental His-bundle pacing: histopathological and electrophysiological examination.
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.
Amitani
S
S
Division of Cardiology, Shinkyo Hospital, Kagoshima, Japan.
Miyahara
K
K
Sohara
H
H
Kakura
H
H
Koga
M
M
Moriyama
Y
Y
Taira
A
A
Nagano
S
S
Miura
N
N
Misumi
K
K
Sakamoto
H
H
D000818:Animals; D002036:Bundle of His / Q000473:pathology* / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004285:Dogs; D017097:Electric Impedance; D004562:Electrocardiography; D004567:Electrodes, Implanted; D004699:Endocardium / Q000473:pathology / Q000503:physiopathology; D005240:Feasibility Studies; D005500:Follow-Up Studies; D009200:Myocardial Contraction / Q000502:physiology; D010138:Pacemaker, Artificial; D014261:Tricuspid Valve / Q000473:pathology / Q000503:physiopathology; D016276:Ventricular Function / Q000502:physiology