Journal of Applied Physiology, Vol 42, Issue 2 235-239, Copyright © 1977 by American Physiological Society
Lack of electrical interaction between proximal bundle branches and subjacent muscle
D. A. Lathrop and J. C. Bailey
Microelectrode techniques were used to assess the importance of
subthreshold electrotonic interactions between the canine proximal bundle
branches and adjacent septal myocardium, and vice versa. Bundle branch
action potential duration, maximal rising velocity of phase O, current
threshold requirements for all-or-none depolarization, transmembrane
voltage, and spontaneous frequency were not altered by adjacent septal
muscle activation. Activation of the proximal bundle branches did not
change the transmembrane voltage of immediately subjacent muscle cells;
likewise, all-or-none activation of ventricular septal muscle did not
effect a voltage change in the overlying proximal bundle branches. We
conclude that a high ohmic resistance barrier between proximal bundle
branch and subjacent muscle precludes significant electrotonic interactions
between these neighboring structures.
