Cardiac Function After Repair of Tetralogy of Fallot: How are the Atria Performing? Pilot Study by Cardiac Magnetic Resonance Imaging

The atria of the heart function as reservoir, conduit, and active pump and are critical for ventricular filling and cardiac output. We sought to evaluate right (RA) and left atrial (LA) function in patients after tetralogy of Fallot (TOF) repair by using cardiovascular magnetic resonance. Twelve TOF patients, age 16.7 ± 6.1 years, weight 50.9 ± 14.9 kg, were compared to 10 healthy volunteers, age 18.8 ± 6.8 years, weight 52.3 ± 20.8 kg. Both atria and both ventricles were imaged in short-axis planes by Steady State Free Precession. Volume changes and all derived atrial functional parameters were calculated from the volume/time curves obtained after segmentation on the cine images. Blood flow across the AV valves was used to define ventricular diastolic dysfunction. TOF patients showed similar maximal RA volume compared to controls, but increased volumes at mid-diastole (p < 0.05), resulting in a decreased cyclic volume change and atrial filling fraction (p < 0.01), and a decreased passive emptying volume and fraction (p < 0.01). In patients with diastolic dysfunction, conduit volume was increased (p < 0.05), and active emptying volume and fraction tended to be increased, respectively. No significant changes were found in LA, except for a decreased passive emptying fraction (p < 0.05). RA function and particularly reservoir function are impaired in TOF patients. The RA conduit/reservoir ratio is increased and reflects the lost of the ability of the atrium to fill the ventricle by pulsatile flow.