Assessment of right ventricular function during exercise with quantitative Doppler tissue imaging in children late after repair of tetralogy of Fallot

Doppler tissue imaging (DTI) has been developed to assess ventricular wall-motion velocity quantitatively for patients with various types of heart disease. This technique has a possibility of assessing right ventricular (RV) function reserve during exercise. To investigate RV function during exercise using DTI, 21 patients (9.3 +/- 3.3 years) who had undergone operation for tetralogy of Fallot at 1 to 3 years of age and 19 age-matched healthy children were studied. Echocardiography combined with DTI was performed at rest and during supine bicycle submaximal exercise. DTI of tricuspid annulus movement during systole (Sa) was obtained from a 4-chamber view. RV pressure was estimated by maximal tricuspid regurgitation (TR) velocity. The peak value of the first derivation of RV pressure (peak dP/dt) was measured from the continuous wave Doppler-derived TR profile. Adequate spectral Doppler recordings of TR were obtained in all participants. However, 9 healthy children and 2 patients with tetralogy of Fallot were excluded from the study because of an inability to determine the entire spectral TR velocity envelope during exercise. Therefore, data were analyzed in 29 participants. At rest, the mean RV pressure for patients was higher than that in control subjects (27 +/- 4 vs 18 3 mm Hg, P < .01). The mean Sa and RV peak dP/dt for patients were lower than those in control subjects (6.7 +/- 1.6 vs 8.8 +/- 1.7 cm/s and 464 +/- 77 vs 550 +/- 80 mm Hg/s, P < .01, respectively). Sa and RV peak dP/dt in the two groups increased significantly during exercise. However, the magnitude of increases in Sa and peak dP/dt was significantly less for patients than in control subjects (37 +/- 16 vs 66 +/- 19% and 42 +/- 10 vs 80 +/- 13%, P < .01, respectively). The magnitude of increase in Sa correlated with that in RV peak dP/dt (r = 0.84, P < .01). Results of DTI show high correlation with RV peak dP/dt during exercise. This technique has a potential as a useful indicator of the effect of exercise on RV systolic function. An insufficient increase in Sa suggests impaired response to exercise of RV in patients with tetralogy of Fallot.