Circulation, Vol 53, 224-229, Copyright © 1976 by American Heart Association
M Dick 2d, E Krongrad, RE Antar, S Ross, FO Bowman Jr, JR Malm and BF Hoffman
To estimate the effect of distance between the electrode and the signal
source on the amplitude of the His bundle electrogram (HBE) recorded during
open heart surgery, a specially designed probe, containing six pairs of
closely spaced (1 mm) electrodes was placed on the endocardial surface of
the right atrium such that each electrode pair was parallel to the course
of the His bundle. The amplitude of the HBE recorded through electrodes
closest to the His bundle ranged from 0.76 to 2.44 mV, at 1mm from 0.38 to
1.13 mV, at 2mm from 0.27 to 0.86 mV, and at 3 mm from 0.2 to 0.44 mV.
Maximal amplitude of HBE decreased by 57% at 1mm, 73% at 2 mm, and 82% at
3mm. The percent decrease was initially rapid, then declined more slowly at
distances greater than 1 mm, resembling in form data obtained previously in
animal studies by different techniques. Since the maximum HBE was greater
than 1.0 mV in nine of 11 patients, and equal to or greater than 1.0 mV in
only two of 11 patients at 1 mm, and less than 1.0 mV in all patients 2.0
mm from the maximal HBE, the anatomic location of the His bundle can be
estimated from HBE amplitude. Intracardiac electrograms, recorded through
closely spaced bipolar electrodes during open heart surgery, afford
clinically useful precision in locating the specialized conduction tissue
of the heart.
ARTICLES
Intraoperative recording of the His bundle electrogram in man. An assessment of its precision