PP-20 Prenatal sonographic diagnosis of Ebstein anomaly

Objective

Ebstein’s anomaly, which accounts for 1% of congenital cardiac anomalies, is a rare congenital cardiac anomaly with a prevalence of 0.3 -0.5% and an incidence of 1 in 20000 live births. Pathologically, it is characterized by abnormal positioning of the septal and/or posterior leaflet of the tricuspid valve towards the right ventricular apex. The right ventricular area is reduced and the infundibulum is obstructed by the anterior leaflet secondary to atrialization of the portion of the right ventricle between the level of the true annulus and the level of the false annulus. Antenatal diagnosis is usually made by fetal echocardiography. The main findings of this pathology seen on fetal echocardiography are apical displacement of the tricuspid valve and consequent atrialization of the right ventricle, right ventricular failure, cardiomegaly, tricuspid valve insufficiency, ventricular septal defect and atrial septal defect. Antenatal diagnosis is very important because it is a rare congenital cardiac anomaly and mortality is significantly reduced with appropriate neonatal management.  In this report, we aimed to present the prenatal diagnosis of a very rare case of Ebstein anomaly.
 

Case

A 35-year-old patient with gravida 3, parity 2, 22 weeks and 1 day gestation according to the last menstrual period was referred to the prenatal diagnosis and treatment unit of our clinic due to suspicion of cardiac anomaly. In the ultrasonographic examination of the patient, fetal heartbeat was positive, amniotic fluid volume was high, and biometric measurements were compatible with the gestational week. Fetal cardiac examination revealed severely dilated right atrium (figure 1), severe tricuspid regurgitation (tricuspid regurgitation) (figure 2) and severe pulmonary hypoplasia (figure 3). The family was informed in detail about the possible poor fetal/neonatal prognosis of the fetus with Ebstein’s anomaly and invasive prenatal diagnosis was offered as an option. Fetal echocardiography was planned for the patient who did not want to undergo invasive prenatal diagnostic testing. Pregnancy follow-up and delivery were recommended to be performed in a tertiary care center with pediatric cardiovascular surgery facilities.

Discussion

In the multicenter fetal cohort with Ebstein’s anomaly and tricuspid valve dysplasia reported by Freud et al., perinatal mortality was found about 45%. This was considerably higher than other types of congenital heart disease in the current era. However, a greater proportion of fetuses survived to birth compared with previous series of single-center Ebstein’s anomaly and tricuspid valve dysplasia in the last few decades. This can be attributed to a combination of factors, including a lower rate of termination of pregnancy and an increased likelihood that progress in prenatal diagnosis will identify less severely affected fetuses.[3]

Conclusion

The symptoms of Ebstein’s anomaly, a very rare congenital cardiac anomaly, vary depending on the degree of tricuspid regurgitation, whether ventricular function is impaired, whether the infundibulum is obstructed, and whether fetal arrhythmia is present. In this case, which we suspected on the basis of dilatation of the right atrium and the accompanying cardiac findings, the prognosis depends on the severity of the malformation. Severe cases may result in intrauterine death. Accordingly, in cases where surgical treatment is necessary and intrauterine death does not occur, Ebstein anomaly should be considered in cases with abnormally located tricuspid valve, right atrial dilatation, pulmonary stenosis or functional atresia. Since the mortality rate in these cases is significantly reduced with appropriate prenatal and neonatal management, it is important to detect, suspect and investigate further when the first signs appear on a routine ultrasound scan.[4]

Keywords

Ebstein,fetal echo, tricuspid valve

1. McIntosh N, Chitayat D, Bardanis M, Fouron JC. Ebstein anomaly: report of a familial occurrence and prenatal diagnosis. Am J Med Genet. 1992 Feb 1;42(3):307-9.
2. Downing KF, Riehle-Colarusso T, Gilboa SM, Lin AE, Oster ME, Tinker SC, Farr SL; National Birth Defects Prevention Study. Potential risk factors for Ebstein anomaly, National Birth Defects Prevention Study, 1997-2011. Cardiol Young. 2019 Jun;29(6):819-827.
3. Freud LR, Escobar-Diaz MC, Kalish BT, Komarlu R, Puchalski MD, Jaeggi ET, Szwast AL, Freire G, Levasseur SM, Kavanaugh-McHugh A, Michelfelder EC, Moon-Grady AJ, Donofrio MT, Howley LW, Tierney ES, Cuneo BF, Morris SA et al. Outcomes and Predictors of Perinatal Mortality in Fetuses With Ebstein Anomaly or Tricuspid Valve Dysplasia in the Current Era: A Multicenter Study. Circulation. 2015 Aug 11;132(6):481-9. 
4. Yuan SM. Ebstein’s Anomaly: Genetics, Clinical Manifestations, and Management. Pediatr Neonatol. 2017 Jun;58(3):211-215. 

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