الفهرس 
VENTRICULAR SEPTAL DEFECTOnly 14 pages are availabe for public view
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Abstract
D
espite the advances in management of congenital heart diseases, injury to the conduction system during surgical repair may still occur leading to different degrees of heart block. The incidence of conduction system injury during cardiac surgery ranges between 1% and 3%.
Post-operative Electrophysiological changes occur mainly in children who had cardiac repair near the conduction system or when the conduction system is manipulated intra-operatively Local edema, inflammation and direct insult to atrioventricular node (AVN) or adjacent conduction system contribute to development of heart block during or after surgical repair. Certain types of cardiac surgeries such as VSD repair and tetralogy of fallout (TOF) repair are associated with higher incidence of heart block during early post-operative stage.
Electrophysiological changes usually appear during or shortly after surgery and they are often a transient complication. Majority of children who develop heart block after surgery recover within a few days and the conduction system reclaims its normal sinus rhythm thereafter. Few published papers reported late presentation of heart block following cardiac repair of congenital heart disease, which is defined as a heart block that occurred 30 days after cardiac surgery with a temporary period of normal rhythm. Late presenting heart block may appear after months or years of impermanent normal sinus rhythm.
In general, incidence of late presenting heart block after cardiac repair was described between 0.3% and 0.7% in most of reported pediatric studies. There are, however, a few reports describing higher incidence reaching up to 1–2% in children undergoing cardiac repair.
Most of the patients who developed late presenting heart block were noted to have early transient block intra or post-operatively.
The causes of this late presenting Electrophysiological changes or heart block are related to progressive fibrosis and slow sclerosis extending over conduction pathways, which are congenitally fragile.
Symptoms leading to diagnosis of late presenting heart block vary according to the type of heart block ranging from asymptomatic presentation where the diagnosis is incidentally discovered during routine exam to a more striking symptomatic presentation that may include syncope, dizziness, shortness of breath, signs of congestive heart failure and even sudden death.
The current study aimed to detect early electrophysiological changes after closure of VSD and to investigate the risk factors for these electrophysiological changes.
This was a Cross sectional Prospective study, non-randomized that was carried during the period from October 2020 to December 2022. The study included 200 children undergone open cardiac surgery for Ventricular septal defect closure in Ain Shams University hospitals, cardiothoracic department.
Summary of our results:
• There were no instances of reoperation or 30-day readmissions. However, there were four cases (2.0%) of 30-day mortality.
• The majority of patients (94.5%) did not experience residual VSD.
• A notable proportion of patients (20.5%) exhibited ECG changes, with the most common being sinus bradycardia Our study revealed that a notable proportion of patients (20.5%) exhibited ECG changes, with the most common being sinus bradycardia with junctional escape rhythms (24) patients, junctional ectopic tachycardia (10) patients, supraventricular tachycardia (2) patients, premature complex (2) patients, 2nd degree block (4) patients and 3rd degree block (2) patients.
• According to the associated cardiac congenital anomalies, the percentage was found significantly higher in patients with ECG changes (73.2%) than those without ECG changes (42.1%) with p-value <0.001. Also, according to the type of associated cardiac congenital anomalies, the percentage of patients with CAVC, pulmonary stenosis and small pulmonary artery was found significantly higher in patients with ECG changes (41.5%, 4.9%, 4.9%; respectively) than those without ECG changes (25.8%, 0.0%, 0.0%; respectively) with p-value = 0.049, 0.005 and 0.005; respectively.
• There was statistically significant increase in the percentage of patients with residual VSD among patients with ECG changes (17.1%) than patients without ECG changes (2.5%) with p-value <0.001 while no statistically significant relation found between presence of ECG changes and 30 days mortality rate among the studied patients with p-value = 0.140.
• The total bypass time and aortic cross clamp time was found significantly higher in patients with ECG changes than patients without ECG changes with p-value <0.001 and <0.001; respectively and the percentage of patients needs intraoperative cardiac pacing was found significantly higher in patients with ECG changes (63.4%) than patients without ECG changes (0.0%) with p-value <0.001.
• There was no statistically significant relation found between 30 days mortality rate and patient’s age and body weight with p-value = 0.986 and 0.175; respectively.
• There was no statistically significant relation found between residual VSD and patient’s age and body weight with p-value = 0.093 and 0.902; respectively.
• There was statistically significant increase in ICU stay duration (hours) in patients with failure to thrive/congenital heart failure and patients with rising pulmonary vascular resistance than those without with p-value = 0.037 and 0.002; respectively, while no statistically significant relation found between ICU stay duration (hours) and aortic insufficiency with p-value = 0.434.
• There was statistically significant increase in the median (IQR) of ICU stay duration (hours) postoperatively in patients who need NICU admission, those with associated cardiac congenital anomalies, patients with CAVC and those with extra-cardiac congenital anomalies with p-value = 0.002, <0.001, <0.001 and <0.001; respectively, while no statistically significant relation found between ICU stay duration (hours) and need for mechanical ventilation preoperative and also presence of teralogy of fallot with p-value = 0.491 and 0.952.
• Down Syndrome was found in 29 (14.5%) among our cases. there was no statistically significant relation found between 30 days mortality rate and Down Syndrome and Tetralogy of Fallot.
• The univariate logistic regression analysis showed that all the parameters were found significantly associated with occurrence of ECG changes among the studied patients except CAVC was found not significantly associated with p-value = 0.051. Also, the multivariate logistic regression analysis shows that the most important factors associated with occurrence of ECG changes was found outlet VSD type with OR (95% CI) of 6.345 (2.411 – 16.699) and p-value <0.001 followed by mitral valve repair as an concomitant procedure with OR (95% CI) of 3.831 (1.421 – 10.327) and p-value = 0.008 and lastly aortic cross clamp time >45 minutes with OR (95% CI) of 2.270 (1.013 – 5.090) and p-value = 0.047.
CONCLUSION
In conclusion, our study revealed that ECG changes were relatively common after VSD closure (20.5%), with higher occurrence among patients with certain associated cardiac congenital anomalies.
While ECG changes were linked to factors like more extended bypass and aortic cross-clamp times and they were not associated with 30-day mortality.
Patients with ECG changes also experienced extended ICU stays and when they have history of failure to thrive/congenital heart failure and rising pulmonary vascular resistance.
The study’s multivariate analysis highlighted outlet VSD type, mitral valve repair, and prolonged aortic cross-clamp times as significant factors influencing the development of ECG changes.
These findings emphasize the importance of tailored monitoring and care for VSD patients, particularly those with identified risk factors, to optimize postoperative outcomes.
LIMITATIONS
This study had several limitations:
Firstly, it was a non-randomized study, which may introduce selection bias and limit the generalizability of the findings.
Secondly, the study was conducted in a single institution, with different teams in postoperative care .
No genetic investigations were performed to evaluate the genetic contribution of arrhythmias associated with VSD closure.
Furthermore, the study focused on early electrophysiological changes after VSD closure, and long-term follow-up data were not included.
Future studies should consider larger sample sizes, multi-center designs, longer follow-up periods, and incorporate interventions to mitigate the risk of ECG changes and associated complications.
RECOMMENDATIONS
• It is recommended that clinicians carefully monitor patients undergoing closure of VSD for early electrophysiological changes, particularly those with associated cardiac congenital anomalies that required longer aortic cross clamp times.
• Intraoperative cardiac pacing should be considered for patients with VSD who are at risk for ECG changes.
• Close attention should be paid to the potential prolonged ICU and hospital stay due to pre-operative failure to thrive and rising pulmonary vascular resistance .
• Additionally, efforts should be made to minimize bypass and aortic cross clamp times to reduce the risk of ECG changes and associated complications.
• Further research is warranted to explore preventive strategies and optimize patient outcomes.