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Conduction system in two cases of sudden death two years after the Mustard procedure
Insights
Sudden death in children after the Mustard procedure may stem from surgical damage to the sinoatrial (SA) and atrioventricular (AV) nodes. Preserving these structures during surgery is crucial for preventing arrhythmias.
Area of Science:
- Cardiology
- Pediatric Surgery
- Electrophysiology
Background:
- The Mustard procedure is a palliative surgery for complete transposition of the great arteries.
- Arrhythmias and sudden cardiac death are known long-term complications following this procedure.
Observation:
- Serial section examination of the conduction system in two children who died suddenly post-Mustard procedure.
- Both children exhibited complex arrhythmias, including junctional rhythms and atrioventricular (AV) block.
- Histopathological analysis revealed significant fibrosis and surgical injury to the sinoatrial (SA) node and its approaches, as well as the AV node approaches.
Findings:
- Marked fibrosis of the SA and AV node approaches was observed in both cases.
- In one child, the SA node was directly injured by sutures; in the other, it was significantly fibrosed.
- These findings suggest surgical trauma to the conduction system's critical components as a cause of fatal arrhythmias.
Implications:
- Highlights the critical importance of preserving the SA node, AV node, and their surrounding pathways during the Mustard procedure.
- Emphasizes the need for meticulous surgical technique to prevent long-term conduction abnormalities and sudden death.
- Suggests that careful intraoperative assessment and avoidance of injury to the conduction system are paramount for improved outcomes in pediatric patients undergoing this surgery.
Abstract:
This report describes a serial section examination of the conduction system in two children who died suddenly 2 years following the Mustard procedure for complete transposition. The first child manifested sinus rhythm alternating with junctional rhythm in the last year of life. The second child, 2 months before death, had first-degree atrioventricular (AV) block which progressed to second-degree block with 2:1 conduction alternating with a junctional rhythm with AV dissociation. Examination of the conduction system in both cases revealed the approaches to the sinoatrial (SA) and the AV nodes to be markedly fibrosed. In addition, in Case 1 the SA node was interrupted by sutures and in Case 2 the SA node was considerably fibrosed. The arrhythmias produced and the probable cause of sudden death in both cases may be related to surgical injury to the approaches to the SA and AV nodes. This study and the review of the literature emphasize the necessity of maintaining the integrity of the SA node, the approaches to the SA and AV nodes, and the superior preferential pathway while performing the Mustard procedure for complete transposition.
