Long-term after arterial switch operation for transposition of the great arteries, abnormal coronary anatomy and altered loading conditions could compromise ventricular function. The current study investigates whether left ventricular function, measured with echocardiographic bi-plane ejection fraction and deformation imaging, in patients long term after arterial switch operation for transposition of the great arteries differs from healthy peers. A cross-sectional cohort study of patients at least 12 years after arterial switch operation was analyzed with bi-plane Simpson's left ventricular ejection fraction (LVEF) and deformation (speckle tracking) echocardiography. 81 patients, median age 20.6 (interquartile range 13.5-28.4) years, were included. LVEF was normal on average at 55.5 ± 6.1%. Global longitudinal strain (GLS) was lower in patients compared to healthy peers throughout all age groups and on pooled average (- 15.4 ± 1.1% vs. - 23.2 ± 0.9%). Although LVEF is normal on average in patients after arterial switch operation for transposition of the great arteries, GLS is impaired compared to healthy peers. The reduced GLS could indicate sub-clinical myocardial dysfunction.

Background: The arterial switch operation (ASO) for transposition of the great arteries has excellent survival, but a substantial number of patients suffer from a reduced exercise capacity. The goal of this study was to identify imaging parameters associated with a reduced exercise capacity in patients after ASO. Methods: A retrospective analysis was performed of ASO patients who underwent cardiopulmonary exercise testing (CPET) between 2007 and 2017. Reduced exercise performance was defined as a reduced workload peak (W peak ) with Z-score <À2 or a peak oxygen uptake indexed for weight (VO 2peak /kg) with Z-score <À2. Data on echocardiography and cardiac magnetic resonance performed within 1 year of the CPET were collected for comparison. Results: A total of 81 ASO patients (age 17 AE 7 years) were included. Reduced exercise performance was found in 22 patients (27%) as expressed by either a reduced W peak and/or a reduced VO 2peak /kg. Main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced W peak (p = 0.031; p = 0.020, respectively). The main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced VO 2peak /kg (p = 0.009; p = 0.019, respectively). No left ventricular parameters were found to be associated with abnormal exercise performance. Conclusion: This study demonstrates that ASO patients frequently experience reduced exercise capacity. Echocardiographic evidence of main pulmonary artery stenosis and increased right ventricular pressure were associated with reduced exercise capacity, and are therefore key to monitor during serial follow-up of ASO patients.

Exercise capacity is reduced and left ventricular ejection fraction is preserved in the long term after an arterial switch operation for transposition of the great arteries.

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