Background: Right dominant heart (RDH) in fetuses can occur with a number of cardiac as well as noncardiac anomalies. Analysis of the enlargement of the right cardiac chamber in the fetus remains a major challenge for sonographers and echocardiographers. The aim of this study was to report the experience with prenatal diagnosis of RDH in the fetuses over a 7-year period.
Methods: Fetuses with prenatal diagnosis of RDH from July 2009 to July 2016 were evaluated in two different categories: according to the gestational age, Group I (n = 154, second trimester) and Group II (n = 298, third trimester); and according to the fetal echocardiography diagnosis, Group A (n = 452, abnormal cardiac structure) and Group B (n = 90, normal cardiac structure). Differences in categorical variables were assessed by Chi-square exact test and continuous variables were evaluated by independent Student's t-test or Mann-Whitney U-test depending on parametric or nonparametric nature of the data.
Results: Over a 7-year period, 452 fetuses were referred for the assessment of suspected RDH. Left-sided obstructive lesions were observed most frequently in the fetuses with RDH. When comparing Group I with Group II and Group A with Group B, the latter groups exhibited significant differences in the right/left ventricle (RV/LV) ratio (1.435 vs. 1.236, P = 0.002; 1.309 vs. 1.168, P = 0.047), RV width Z-score (1.626 vs. 1.104, P < 0.001; 1.553 vs. 0.814, P = 0.014), and above +2 cutoff percentages (14.3% vs. 22.5%; P = 0.038; 21.5% vs. 12.2%, P = 0.046). Multivariable logistic regression revealed no variables associated with perinatal survival.
Conclusions: The study demonstrates that RDH warrants careful attention to the possible presence of a structural cardiac anomaly, especially left-sided obstructive lesions. A diagnosis of RDH is best supported by a combination of the RV Z-score and RV/LV ratio. Most of the fetuses with RDH and structurally normal hearts had favorable outcomes.