Reversibility of heart block after congenital heart surgeries in pediatrics, is it predictable?
Authors: Hassan W , Ali W , Sayed MS , Aliaa Mahfouz ATM , Hatem Hosny HH , Omnia Kamel OK 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background

AV block is a serious complication of congenital heart diseases(CHD) repair surgeries.it is associated with an increased mortality and morbidity.
Purpose :
Identifying the incidence of Complete Heart Block (CHB) after heart surgeries for CHD, analyzing the patients` specifications and procedural data to evaluate the potential correlations that contribute the HB postoperatively.
Patients and methods :
We enrolled all patients who underwent CHD surgeries from September 2014 till February 2020 and identified the patients who developed postoperative CHB, those patients were divided into two groups, (a group who developed transient CHB and those who developed permanent CHB which required implantation of permanent pacemaker (PPM).
We defined the transient HB as the recovery from an advanced second or third degree HB after the surgery within 10days .
And the presence of advanced second or third degree HB persisting for more than 10 days after cardiac surgery is considered a permanent HB and indicated for PPM implantation according to current guidelines .
Results :
Our cohort includes 2377 CHD surgeries, 46 % female patients, median weight was 12.06 kg at the time of the operation, median height was 85 cm.
Mean age at the time of the operation was 2.7 years in the cohort with transient HB while it was 2.6 years in the cohort who received PPM.
Incidence of HB following those surgeries was 3 %(72) patients, 1.8 %of the patients (43) had transient HB and 1.2% of the patients (21 ) received a PPM.
Recovery from HB was within 7days in 35 patients (82%),Two out of the 43 patients who had transient HB ended up with late onset CHB requiring pacing representing 4.6 % of that cohort, one after one month of recovery and the other one after 11 years from the surgery despite they restored their sinus rhythm within 6 days and 10 days respectively.
We found the highest incidence of postoperative HB associated with VSDs surgeries either isolated or with other complex CHD diseases followed by TOF with no significant difference between transient and permanent groups according to the type of surgery.
The duration of preoperative PR interval suggested the incidence of permanent CHB postoperatively with a P value of 0.005
We found that gender, age, weight and height didn`t affect the outcome, preoperative heart rate and preoperative medications didn`t alter the prognosis, the duration of CBP time and the clamping time were of no statistical significance between the 2 groups with P value of ( 0.38 and 0.33 ).
Conclusion :
Incidence of CHB post CHD surgeries in our center is 3 %, only 1.2 % required PPM.
Various clinical data , ECG criteria , procedural time and duration of the HB except for the preoperative PR interval failed to prove a significant correlation with the incidence of CHB necessitating further investigation to identify the specific risk factors for such complication. Abstract Figure. Incidence of CHB with various surgeries