Background: The long-term prognosis of patients with tetralogy of Fallot (TF) who have undergone repair is determined by right ventricular dilatation resulting from residual pulmonary insufficiency. We have studied the values of right and left ventricle systolic function obtained by gated single photon emission computed tomography (SPECT) equilibrium radionuclide angiography (ERNA) in these patients.
Methods: A study population of 62 patients with surgically repaired TF underwent gated-SPECT ERNA to determine ejection fraction of the right and left ventricle and dimensions of the right ventricle and pulmonary infundibulum. Results were compared with those of a group of 11 patients without heart disease.
Results: RVEF (34% vs. 40%, P=0.02) and LVEF (49% vs. 54%, P=0.03) were significantly lower in patients with TF than in the control group. The RVEF and LVEF variation coefficients were 9% and 6.2%, respectively. Volumes of the right ventricle (P=0.003) were significantly greater than those of the control group, although variation coefficients were 15%.
Conclusions: Gated-SPECT ERNA is a non-invasive method of assessing ejection fraction in patients with repaired TF. In these patients, the ejection fraction is decreased in both ventricles, whereas size of the right ventricle is significantly increased. Reproducibility of the RVEF calculation is good, but in the case of volumes it is suboptimal.