The Journal of Thoracic and Cardiovascular Surgery, Vol 85, 839-850, Copyright © 1983 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Implantation of atrioventricular synchronous and atrioventricular universal pacemakers
S Furman and DL Hayes
Implantation of pacemakers which sense in the atrium and the ventricle
requires understanding of both antegrade conduction, from the atrium to the
ventricle, and retrograde conduction, from the ventricle to the atrium. Of
53 patients undergoing pacemaker implantation, 25 (47%) had retained VA
conduction and 25% of those with complete heart block had 1:1 retrograde
(VA) conduction. Determination of both conduction intervals is made by
recording the intrinsic deflections of the atrium and the ventricle and
measuring the interval. Antegrade intervals (IDA leads to IDV) for those
with intact conduction ranged from 189 to 325 msec (mean 212 msec).
Retrograde intervals (StV leads to IDA) for those with intact VA conduction
ranged from 110 to 346 msec (mean 235 msec). Of 16 patients having VDD and
DDD pacemakers implanted without conduction studies, seven (44%) developed
pacemaker-mediated tachycardia. The prevention of pacemaker-mediated
reentry tachycardia requires knowledge of the VA conduction interval (if it
exists) and programming of the atrial refractory period so that retrograde
P waves fall within it and are unsensed.