Right ventricular outflow tract assessment by cross-sectional echocardiography in tetralogy of Fallot.

Cross-sectional echocardiographic (CSE) studies were obtained in 29 children with tetralogy of Fallot. In this study we evaluated the capability of CSE to record the right ventricular outflow tract (RVOT) and compared the severity of infundibular obstruction determined by CSE with cineangiographic (cine) determinations. In addition, we examined capabilities of CSE and M-mode echocardiography (M-mode) to record the diagnostic features of tetralogy of Fallot, including RVOT obstruction, aortic overriding, ventricular septal defect, and presence of the pulmonary valve. An excellent correlation (r = 0.925) was found for the combined pre- and post-repair patients studied by CSE vs cine, while the correlation (r = 0.805) for M-mode was not as good. The difference was even more striking for the unrepaired patients, in which the correlation (r = 0.746) for CSE was much better than for M-mode (r = 0.374). In the unrepaired patients, CSE allowed easier detection of the ventricular septal defect than M-mode (95% for CSE vs 76% for M-mode). The pulmonary valve was recorded in 90% by CSE, but in only 26% by M-mode. Aortic overriding was recorded in all unrepaired patients both by CSE and M-mode. These data indicate that CSE is better than M-mode for recording the RVOT dimensions, ventricular septal defect, and the pulmonary valve in unrepaired patients with tetralogy of Fallot.