INTRODUCTION:
In patients who underwent an atrial switch repair (Mustard or Senning procedures) (1) for complete transposition of the great arteries (D-TGA), the morphological right ventricle (RV) acts as a systemic ventricle and the systemic atrioventricular (AV) valve is anatomically the tricuspid valve (TV). Chronic systemic pressure load on the RV might lead to ventricular dysfunction, progressive tricuspid regurge (TR), and heart failure (HF). (2) In patients who underwent atrial switch repair, the systemic ventricular function is an independent predictor of exercise capacity. Therefore, atrial switch operations are accompanied by increased morbidity and delayed mortality, mainly because of heart failure (3) and ventricular tachycardia due to dysfunction of the systemic RV (4). In these patients, RV function deterioration is a progressive and accumulating condition. (5) So, accurate assessment of RV function and the contractile reserve is mandatory to anticipate the need for heart failure treatment in these patients.
The systemic RV function can be assessed by several imaging modalities including angiography, radionuclide imaging, and magnetic resonance imaging (). (6) However, echocardiography is still used predominantly for the assessment of RV function, as it is noninvasive, applicable, available, and inexpensive modality.
Theoretically, stress echocardiography (SE) may deliver more information about the myocardial contractile reserve, and the behavior of the TR during stress. Myocardial contractile reserve measured by stress testing has been defined as the difference of ventricular function at rest and under loading conditions. As, Dobutamine acts directly and mostly on b-1 adrenergic receptors of the myocardium, producing an increase in heart rate and contractility, dobutamine stress echocardiography (DSE) can assess contractile reserve in such patients. (8)
RV has a complex geometry, so, the assessment of systemic RV function and RV contractile reserve by echocardiography is better to be based on quantitative assessment. Two-dimensional (2D) speckle tracking echocardiography () has established as a valuable tool to assess global and regional myocardial deformation. (9,10) 2D Myocardial speckle tracking strain (S) is a consistent Doppler and angle independent technique that quantitatively measures ventricular geometry and systemic RV myocardial dysfunction. (11-14)
To redefine the role of echocardiography in the functional assessment of systemic right ventricular contractile reserve in post-Senning children, we aimed to quantitatively assess the systemic RV contractile reserve in such patients by interrogating speckle-tracking based global longitudinal strain (GLS) measurement during Dobutamine Stress Echocardiography (DSE).