3D modelling of atrial and ventricular shape and function in a patient following the new modified Mustard operation

There is a continuing need to perform inflow correction of “simple” TGA in a large subset of patients, who are not candidates for the arterial switch operation, particularly in developing countries. This is because of a lack of resources, centres and expertise to perform the neonatal switch operation. This subsequently results in the “late” presentation of patients who are severely cyanosed and have thin-walled, banana-shaped left ventricles which are not suitable for switching. Inflow correction by the Mustard1 and Senning2 operations can transform the lives of these patients. However, there is continuing concern about the relatively impaired exercise capacity and long-term results of these patients, thought to be due to the fact that the right ventricle is not suitable for support of the systemic circulation. There is growing evidence that the right ventricle can function normally into old age in certain patients with corrected TGA (AV and VA discordance). Ourselves and others3–5 believe that the less-than-optimal results after the Mustard operation are, at least in part, due to an impaired pattern of left and right ventricular filling, produced by the relatively narrow, rigid, non-contractile channels in the atria, resulting in significant loss of the conduit, reservoir and contractile functions of the atria. In an attempt to correct this, we have modified the Mustard operation to include a larger part of the contractile atrial wall into the SVC and IVC channels including both atrial appendages. We have previously described the three dimensional shape and function of the atria and ventricles following the unmodified Mustard operation6.