Implications of atrial volumes in surgical corrected Tetralogy of Fallot on clinical adverse events

Background: While left atrial (LA) size has been shown as a strong predictor of cardiovascular diseases in various studies, the role of right atrial (RA) enlargement, especially in the growing population of patients with congenital heart diseases (CHD) is largely unknown. We sought to evaluate (1) RA and LA volumes in patients with repaired Tetralogy of Fallot (TOF) and assess correlations to (2) functional parameters and (3) clinical adverse events. Methods: 169 patients with repaired TOF were enrolled following a targeted protocol for Cardiovascular magnetic resonance imaging (CMR), Cardiopulmonary exercise tests (CPET), Echocardiography and Measurement of NT-proBNP. Clinical history was assessed at enrollment and during a median Follow-up of 23 months (IQR 9–40). The primary clinical endpoint was a composite of all cause mortality, aborted sudden cardiac death and sustained VT. Prespecified secondary surrogate endpoint included worsening heart failure (NYHA III–IV), non-sustained VT and sustained supraventricular tachycardia. Results: RA Systolic indexed volume (RASVi) correlated with LA Systolic indexed volume (LASVi) (r = 0.59, p < 0.001) and both correlated with the patient age (r = 0.52, p < 0.001; r = 0.59, p < 0.001 respectively). Patients in the upper tertil of RASVi (>58 ml/m 2 ) had higher NT-proBNP levels, longer QRS duration, larger ventricle diameters, higher RV mass and lower peak oxygen uptake. RASVi was associated with the primary composite adverse event at univariate Cox-regression analysis (HR: 1.044, CI: 1.008–1.08, p = 0.01). Bayesian Multivariate model averaging revealed RASVi as predictor of secondary surrogate adverse outcome (HR: 1.06, CI: 1.053–1.068, Pb = 0,889). Conclusion: Among patients with repaired TOF, RA dilatation is an independent predictor for adverse clinical events. As such, routine assessment of RA volumes could be useful to further improve decision-making and management of these patients in the future.