Dobutamine stress testing for the evaluation of atrial and diastolic ventricular function in Fontan patients

Objective To assess the atrial and ventricular diastolic function response to dobutamine stress in Fontan patients, and to relate these measurements to exercise capacity and events during the follow-up.Methods We performed a secondary analysis of a cross-sectional multicentre study of Fontan patients with intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) modification. Subjects underwent cardiac MRI during rest and low-dose dobutamine stress, and cardiopulmonary exercise testing. Atrial and diastolic ventricular function parameters were derived from volume-time curves. Medical records were abstracted for a composite endpoint of death, listing for transplant, arrhythmia and reintervention. Spearman's r correlation tests and Cox proportional hazards models were used to assess the relation between the dobutamine response for atrial and diastolic ventricular function and outcomes, including exercise capacity.Results We included 57 patients (26 ECC; 31 ILT) aged 12.8 (IOR (10.3-15.5)) years. During dobutamine stress atrial cyclic volume change increased (3.0 (0.4-5.9) mL/m(2), p