The echocardiographic paradox index in patients with a repaired tetralogy of Fallot

Objectives. Right ventricular (RV) volume is very important for pulmonary valve replacement after the total correction of tetralogy of Fallot (TOF), and we attempted to identify a convenient echocardiographic index that is well correlated with the volumetric data obtained through magnetic resonance imaging (MRI). Design. All patients who underwent cardiac MRI and echocardiography at Sejong General Hospital for evaluating pulmonary regurgitation after TOF total correction were included. The paradox index is the amount of paradoxical motion of the interventricular septum on the short-axis echocardiographic view. The paradox index was compared to several cardiac MRI indices. Results. Fifty-four patients were included. The paradox index for all patients was 1.22 ± 0.12 (1.06-1.67), and the index of the operation group was significantly higher than that of the non-operation group (1.26 ± 1.12 vs1.16 ± 1.12, P = 0.009). The paradox index was well correlated with the RV systolic and diastolic volumes, as measured by cardiac MRI (P = 0.002 and 0.003). Using a simple linear regression analysis, a paradox index of 1.24 corresponded to a RV diastolic volume of 160 ml/m². Conclusions. The paradox index could help to indicate the time for an MRI analysis of the RV volume in patients after TOF total correction.