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Right bundle branch block in complete transposition
Insights
In infants with complete transposition, right bundle branch block may indicate right ventricular dysfunction. This finding suggests considering alternative surgical approaches beyond intra-atrial repair.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Electrophysiology
Background:
- Complete transposition of the great arteries (TGA) is a critical congenital heart defect.
- Right ventricular conduction anomalies can occur in infants with TGA.
- The prognostic significance of these anomalies requires further elucidation.
Purpose of the Study:
- To investigate the incidence and implications of right bundle branch block (RBBB) in infants with complete TGA.
- To determine if RBBB is associated with specific clinical presentations or outcomes.
- To evaluate the potential role of RBBB as an indicator for surgical management.
Main Methods:
- Retrospective analysis of 26 infants diagnosed with complete TGA within the first year of life.
- Electrocardiographic (ECG) assessment for the presence and type of RBBB.
- Correlation of ECG findings with clinical data, including hypoxemia, ventricular size, function, and surgical history.
Main Results:
- Two out of 26 infants presented with complete RBBB; 10 showed incomplete RBBB.
- RBBB was not linked to surgical procedures or cardiac catheterization and was absent at birth.
- Complete RBBB cases exhibited prolonged severe hypoxemia, dilated right ventricles, and one instance of depressed right ventricular function.
Conclusions:
- Incomplete RBBB may suggest right ventricular hypertrophy in complete TGA.
- Complete RBBB in this population may signify right ventricular dysfunction and myocardial changes.
- RBBB, particularly complete RBBB, could indicate a need for surgical strategies other than intra-atrial repair.
Abstract:
Two of 26 infants with complete transposition presented with complete right bundle branch block in the first year of life, and 10 showed incomplete right bundle branch block. In no instance was the right ventricular conduction anomaly related to surgery or cardiac catheterization and it was not present at birth. The two cases with complete right bundle branch block had prolonged and severe hypoxemia and markedly dilated right ventricles. One had depressed right ventricular function and died after a Mustard procedure from low output syndrome. Whereas incomplete right bundle branch block may reflect right ventricular hypertrophy, it is suggested that complete right bundle branch block in complete transposition may signify right ventricular dysfunction and possibly irreversible changes of the right ventricular myocardium. It may be a sequel of long-term hypoxemia and pressure overload. Once observed, it is perhaps an indication for an alternative surgical approach other than an intra-atrial repair procedure.