Morphological and Functional Characteristics of the Right Ventricle Functioning as a Systemic Ventricle for Decades...

Area of Science:

• Cardiology
• Pediatric Cardiac Surgery
• Adult Congenital Heart Disease

Background:

• Complete transposition of the great arteries (TGA) is a critical congenital heart defect.
• The Mustard procedure reroutes blood flow, making the right ventricle the systemic pump.
• Long-term outcomes and cardiac morphology after the Mustard procedure require further investigation.

Purpose of the Study:

• To investigate the long-term clinical and cardiac morphologic findings in adults who underwent the Mustard procedure for TGA.
• To assess the adaptation of the systemic right ventricle decades after the Mustard procedure.

Main Methods:

• Retrospective analysis of clinical data and cardiac morphology in 4 adult patients.
• Detailed examination of right and left ventricular walls, myofiber size, and intramural coronary arteries.

Main Results:

• Patients survived >30 years post-Mustard procedure, with 3 undergoing heart transplantation.
• The systemic right ventricle exhibited significant hypertrophy (thicker walls, larger myofibers) compared to the left ventricle.
• Right ventricular walls showed evidence of scarring, and intramural coronary arteries were numerous, large, thick-walled, and often narrowed.

Conclusions:

• The Mustard procedure facilitated long-term survival by allowing the right ventricle to adapt as the systemic pump.
• Significant morphologic changes in the systemic right ventricle underscore the challenges of long-term single-ventricle physiology management.
• The findings are a testament to the Mustard procedure's ability to provide time for ventricular adaptation.