Noninvasive Assessment of Autonomic Cardiovascular Function in Patients after Arterial Switch Operation for Transposition of the Great Arteries

Background: Children born with transposition of the great arteries (TGA) must undergo corrective surgery for survival, arterial switch being the standard surgical procedure. The sympathetic innervation of the heart may be damaged during the operation. This study was designed to determine whether adults who were born with TGA and who had arterial switch operation (ASO) in infancy exhibit denervation of the heart, measured as heart rate variability (HRV) with electrocardiography (ECG). Methods: Nine patients with transposition of the great arteries (four men and five women; mean age 26 ± 1 years) who underwent the ASO at a mean age of 85 ± 35 days, and nine healthy adults (five men and five women; mean age 26 ± 2) were included in the study. Cardiac autonomic nerve function was determined by the variation in RR intervals during maximal deep breathing, monitored by continuous ECG. The mean values were calculated for each group from six inspirations (I) and expirations (E), and the E:I ratios were calculated. Results: The E:I ratio did not differ between patients with an arterial switch and healthy controls (P = 0.161). Two patients had signs of denervation of the heart up to 30 years after the arterial switch operation. Conclusions: Reinnervation of the heart may take place in patients who have undergone the ASO in infancy, and these patients would not necessarily suffer from autonomic dysfunction. The HRV, measured by ECG, has the potential to identify arterially switched patients at risk of developing silent myocardial ischemia.