Transposition of the Great Arteries

Abstract

Abstract-Many patients with ventriculoarterial discordance have survived to adulthood. Those with complete transposition of the great arteries have often had an atrial switch procedure (Mustard or Senning operation) performed, which leaves the morphological right ventricle (RV) supporting the systemic circulation. RV failure and tricuspid regurgitation are common. Some patients may ultimately require cardiac transplantation. Sinus node dysfunction is increasingly common with longer follow-up, and some patients need pacemaker implantation. Atrial arrhythmias are frequent, and atrial flutter may be a marker for sudden death. Patients with an arterial switch procedure are also surviving to adulthood. Long-term problems include coronary stenoses, distortion of the pulmonary arteries, dilatation of the neoaortic root, and aortic regurgitation. Patients with congenitally corrected transposition have both atrioventricular and ventriculoarterial discordance and therefore also have a morphological RV and delicate tricuspid valve in the systemic circulation. Associated defects, such as abnormalities of the tricuspid valve, ventricular septal defect, and pulmonary stenosis, occur in the majority of patients. Heart block occurs with increasing age. Atrial arrhythmias occur frequently, and their occurrence should prompt a search for a hemodynamic problem. Progressive tricuspid regurgitation occurs with age and is associated with deterioration of RV function. Surgical treatment should be considered at the earliest sign of RV dilatation or dysfunction. All patients should be seen periodically in a center where expertise in the clinical evaluation, imaging, and hemodynamic assessment of adult congenital heart disease is available.

Cardiac Conduction System in Congenitally Corrected Transposition of the Great Arteries and Its Clinical Relevance

“…As the right and left conduction bundles relate anatomically to the respective ventricles, septal activation occurs in the opposite direction, namely from right to left 4. This leads to a mirror image pattern in the precordial leads leading to a reversal of the normal QRS morphology, with Q waves evident in V1 and a dominant R wave but no Q wave in V6.…”

“…The reasons for this are multifactorial in etiology, but increasingly long‐term single‐site ventricular pacing is recognized as a factor 23. Approximately 75% of patients with ccTGA will have other significant structural lesions including varying VSDs, pulmonary stenosis or atresia, and Ebsteinoid malformation of the left‐sided, systemic tricuspid valve, and for that reason surgery is mandated in the vast majority 4. Due to the decreased long‐term survival after conventional (physiologic) surgical repair, a more anatomic surgical approach has been adopted to recruit the morphologic left ventricle to the systemic circulation 24.…”

“…More specifically, deterioration in systemic right ventricular (RV) function and worsening systemic AV valve regurgitation have been shown to be associated with subpulmonary univentricular (UniV) pacing 23, 32. Potential causes include changes in septal activation causing a septal “shift” and secondary dilatation of the systemic AV annulus with subsequent right AV valve regurgitation 4. Pacing‐induced ventricular dyssynchrony may also play an important role in the functional deterioration of the systemic RV in patients with ccTGA.…”

“…The incidence has been reported to be around 1/33 000 live births, accounting for ≈0.05% of congenital heart malformations 2. Although a familial recurrence of heart defects in subjects with ccTGA has been reported,3 the etiology of this malformation is not currently known 1, 4…”

Long‐Term Outcomes of Tricuspid Valve Surgery in Patients With Congenitally Corrected Transposition of the Great Arteries

“…Consequently, many patients with CCTGA are referred in adulthood. In these patients, incidence and degree of tricuspid regurgitation (TR) increase over time,5, 8 and TR has been identified as a major contributor to right ventricular (RV) failure and decreased survival 2, 9, 10, 11, 12. Traditionally, TR was considered secondary to dysfunction of morphological RV, which cannot sustain the systemic circulation, and tricuspid valve (TV) surgery was mostly described as unbeneficial in the early days 10, 13, 14, 15.…”