The Journal of Thoracic and Cardiovascular Surgery, Vol 83, 141-148, Copyright © 1982 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Sinus and atrioventricular nodal function: Preoperative and early postoperative assessment in children
GS Wolff, G Kaiser, A Casta, AS Pickoff, AV Mehta, D Tamer, OL Garica, PL Ferrer, K Smith and H Gelband
Ninety-three rapid atrial pacing studies were performed in 38 children to
compare preoperative and early postoperative function of the sinus and
atrioventricular (AV) nodes. The interval between the preoperative and
postoperative studies was under 6 months in the majority of patients.
Postoperative studies were performed within 48 hours of operation and
between 4 and 8 days after operation. Sinus nodal function as measured by
sinus nodal recovery time (SNRT) was an unreliable index in determining
depression since the number who improved postoperatively (10/55) was nearly
equal to the number that worsened (12/55). The majority who had abnormal
function postoperatively demonstrated a junctional rather than sinus
recovery focus. This finding appears a more definitive and more
reproducible indicator of sinus node depression in the postoperative
patient. Postoperative AV nodal function was decreased (as measured by the
cycle length [CL] at which Wenckebach periodicity occurred) in 15 of 55
studies (27%) of the entire group. There was nearly an equal chance for
improvement (24%) in function. This also applied to those patients who had
sequential studies. Therefore, this method of assessment for AV nodal
function was unreliable, or else the operation did not affect the node
significantly. The latter is unlikely in view of late postoperative data.
The greatest utility of this test was to determine the capability for AV
conduction in certain patients with slow escape rhythms in the absence of
surface P waves, and to differentiate complete heart block from AV
dissociation when atrial activity was absent. Despite the variability of
effects on the sinus and AV nodes in these patients, those who demonstrated
depression had a significantly higher incidence of dysrhythmias (80% of
patients with sinus nodal depression and 100% of patients with AV nodal
depression).
