Cardiovascular response to physical exercise in adult patients after atrial correction for transposition of the great arteries assessed with magnetic resonance imaging

Abstract

Objective: To assess with magnetic resonance imaging (MRI) cardiovascular function in response to exercise in patients after atrial correction of transposition of the great arteries (TGA).

Methods: Cardiac function at rest and during submaximal exercise was assessed with MRI in 27 patients with TGA (mean (SD) age 26 (5) years) late (23 (2) years) after atrial correction and in 14 control participants (25 (5) years old).

Results: At rest, only right ventricular ejection fraction was significantly lower in patients than in controls (56 (7)% v 65 (7)%, p < 0.05). In response to exercise, increases in right ventricular end diastolic (155 (55) ml to 163 (57) ml, p < 0.05) and right ventricular end systolic volumes (70 (34) ml to 75 (36) ml, p < 0.05) were observed in patients. Furthermore, right and left ventricular stroke volumes and ejection fraction did not increase significantly in patients. Changes in right ventricular ejection fraction with exercise correlated with diminished exercise capacity (r = 0.43, p < 0.05).

Conclusions: In patients with atrially corrected TGA, MRI showed an abnormal response to exercise of both systemic right and left ventricles. Exercise MRI provides a tool for close monitoring of cardiovascular function in these patients, who are at risk for late death.

Figure 1

Short axis images at rest and during exercise at end diastole from a patient with atrially corrected transposition of the great arteries obtained with an ultrafast turbofield echo planar magnetic resonance imaging sequence. The interventricular septum is displaced towards the left ventricle, especially at end systole. Note the image quality of the images obtained at rest and during the exercise protocol.

Figure 2

Percentage change of right ventricular (RV) volumes and function in response to exercise in patients with atrially corrected transposition of the great arteries (TGA) and healthy controls. The abnormal response of the systemic right ventricle of the TGA patients is shown by a significant increase in end diastolic volume and end systolic volume and no change in stroke volume and ejection fraction. *Significant difference in change between patients and controls.