OBJECTIVE: To determine the morphological and functional changes in the right ventricle in pulmonary atresia with intact ventricular septum (PAIVS) for assessing the candidates for the different therapeutic procedures currently available. METHODS: Thirty-one patients underwent cineangiocardiographic study with axial projections. Their ages ranged from 1 to 50 days (x = 9.6), and 28 of them were studied during the first month of life. The statistical analysis comprised the following: chi-square test, Kruskal-Wallis test for the mean and standard deviation, multiple regression, and the 95% confidence interval (95%CI) was calculated. The significance level adopted was alpha < 0.05. RESULTS: The patients were divided into 3 groups according to the angiographic morphology of the right ventricle (RV): group A – tripartite RV (n=16); group B – bipartite RV (n=9); and group C – unipartite RV (n=6). The diameter of the tricuspid valve was 10.28 ± 2.67 mm (A); 7.82 ± 3.41 (B); and 5.27 ± 0.57 (C) (P=0.0005). Pulmonary atresia was of the valvular type in all group A patients and of the infundibular type in all group C patients (P<0.0001). Coronary-cavitary connections were rare (2/16) in group A patients, but occurred in all group C patients (P=0.0006), with retrograde opacity of the aorta (flow from the RV to the aorta) in 2 group A patients and in all group C patients (P=0.0003). Three patients (2 in group C and 1 in group A) had right-ventricular-dependent coronary circulation. Isolated moderate/severe tricuspid regurgitation showed a tendency towards being more frequent in group A (P=0.0525). The angle of the ductus arteriosus with the descending aorta was as follows: 104.06 ± 8.98 in group A; 79.17 ± 33.08 in group B; and 39.0 ± 6.52 in group C (P=0.0016). The correlation between the diameter of the tricuspid valve and the angle of the ductus arteriosus with the descending aorta was 0.6568 (P=0.0002). CONCLUSION: Because of the heterogeneity of the morphology of the RV in patients with pulmonary atresia with intact ventricular septum, knowledge about all these data is required for selecting candidates for the different therapeutic procedures.