Ectopia Cordis

Ectopia cordis, also known as ectocardia or exocardia, is a rare anomaly characterized by the extrathoracic location of the heart.¹ The displacement of the heart outside the thoracic cavity can be partial or total. In total ectopia cordis, there is a defect at the level of the sternum with absence of subcutaneous tissue and skin covering the heart. According to the location of the heart it may be classified as cervical, thoracic, thoraco-abdominal or abdominal. This anomaly can be isolated or associated with congenital heart disease and = other midline defects. The combination of ectopia cordis with a sternal defect, anterior diaphragmatic hernia, omphalocele and congenital heart disease, is known as Cantrell's pentalogy.²

Q24.8 Other specified congenital malformations of heart

Ectopia cordis is a rare anomaly with an estimated incidence of 5.5 to 7.9 cases per million live births^{.3, 4}  It is more frequent in females and there are no known associated risk factors.

The etiopathogenic mechanism of ectopia cordis is unknown at the moment. Different causes have been proposed, including early chorioamniotic rupture and amniotic band syndrome. It is currently accepted that the anomaly is due to a primary failure in the ventromedial fusion and in the descent of the lateral mesodermal folds between the 4th and 6th week of gestation.^{5, 6} In cervical ectopia cordis, it is believed that there is a failure in the descent of the heart to the thorax during the 3rd week of gestation, which causes it to be trapped above the upper sternal closure point. 

Ectopia cordis can be classified as partial or total, depending on whether the heart is covered by pericardium, subcutaneous tissue and/or skin.⁷ Additionally, depending on the location of the heart, ectopia cordis can be categorized into 4 types^{3, 4, 6, 7}: Cervical (3%), thoracic (60%), thoracoabdominal (7%) and abdominal (30%.)

Ectopia cordis should be considered as an anomaly that is frequently associated with other malformations. In 80% of the cases there is associated heart disease, the most frequent of which include ventricular and atrial septal defects, tetralogy of Fallot and double outlet right ventricle.^{7, 8} Different chromosomal anomalies are also reported as being  associated with the defect, such as mosaicism, trisomy 18, Turner syndrome and triploidies.^{3, 9, 10} Extracardiac malformations associated with ectopia cordis include abnormalities of the abdominal wall, such as umbilical hernia, omphalocele, gastroschisis, diaphragmatic hernia, amniotic band syndrome, and cleft lip/palate. The associated abdominal wall defect may have a broad spectrum, from diastasis of recti to an extensive omphalocele with hepatic and intestinal herniation.⁷ Finally, the combination of an ectopia cordis with sternal defect, anterior diaphragmatic hernia, omphalocele and congenital heart disease is known as Cantrell's pentalogy.

Unknown.

Ultrasonographic diagnosis of ectopia cordis can be made from the first trimester of pregnancy, although it is commonly diagnosed during second trimester ultrasound.¹¹ It is suspected when it is not possible to obtain a normal four-chamber view at the level of the fourth thoracic rib. In the case of thoracic ectopia cordis, the anterior displacement of the heart may be evidenced; it may protrude totally or partially through a defect in the sternum, with or without pericardium, subcutaneous tissue and skin covering it. Color and pulsed Doppler may help to pinpoint the location of the defect, and 3D ultrasound appears to be a useful method to determine the anatomy of the anterior fetal wall and the extension of the lesion.^{5, 12, 13}

The main differential diagnosis is Cantrell’s pentalogy², which is a complex malformation, caused by an extensive defect at the level of the anterior thoracic and abdominal wall, defined by the presence of:

1. Thoraco-abdominal ectopia cordis
2. Lower sternal defect
3. Abdominal wall defect
4. Anterior diaphragmatic defect
5. Pericardial defect and / or congenital heart disease

Although there are published cases in which a certain degree of regression of the defect is documented during the third trimester of pregnancy,^{7, 11} ectopia cordis must be considered as a complex malformation with a poor general prognosis, and without the possibility of prenatal treatment. Associated mortality is very high, especially in the total thoracic form and in the cervical form, which is considered to be lethal.⁵ In the other variants, the prognosis will be determined by the extent of the defect and its association with other anomalies, especially severe congenital heart disease and large abdominal defects.¹⁵ Parents should consider the possibility of performing a fetal cytogenetic study, especially in presence of other associated anomalies.^{3, 10} 3D ultrasound and color Doppler can help detail the arrangement of vascular structures and establish the degree of cardiac exteriorization.¹² Cardiac compression may occur due to fetal activity. There is also risk of arrhythmias and cardiac dysfunction due to gradual inflammation of the pericardium or myocardium exposed to amniotic fluid.

In general, it is recommended to perform an elective cesarean section, since vaginal delivery may cause prolonged cardiac compression and visceral damage.^{5, 14}
Postnatal treatment of ectopia cordis depends on the severity of the cardiac displacement and presence of heart disease or other associated malformations.¹⁵ The presence of a complex heart defect and an extensive omphalocele worsen the prognosis substantially. Ectopia cordis constitutes a neonatal emergency, hence delivery must be planned in a multidisciplinary way in a center with the possibility of performing an EXIT (ex-utero intrapartum treatment). EXIT allows intubation under placental support and to perform the immediate coverage of the defect by prosthesis (usually Silastic®), in order to reduce risk of infections. Acute hypoxemia and cardiac arrest are the most frequent causes of short-term death.¹² Subsequently, surgical repair of the heart defect with its introduction into the thoracic cavity and reconstruction of the thoracic/abdominal wall can be considered.⁴ The possibility of surgical repair has been achieved successfully in some cases, although in general the cardiac anomalies are serious and corrective surgery fails when trying to introduce the heart into the thoracic cavity, which can produce mediastinal compression and constriction of the great vessels and cardiac structures.¹⁶
 

1. Perloff JK. The cardiac malpositions. Am J Cardiol. 2011;108(9):1352-61.

2. Pirasteh A, Carcano C, Kirsch J, Mohammed TL. Pentalogy of Cantrell with Ectopia Cordis: CT Findings. J Radiol Case Rep. 2014;8(12):29-34.

3. Arnaoutoglou C, Meditskou S, Keivanidou A, Manthou M, Anesidis N, Assimakopoulos E, et al. Ectopia cordis in a fetus with mosaic trisomy 16. J Clin Ultrasound. 2010;38(7):386-8.

4. Mohan R, Peralta M, Perez R, Rosenkranz ER, Panthaki ZJ. Chest wall reconstruction in a pediatric patient with ectopia cordis. Ann Plast Surg. 2010;65(2):211-3.

5. Engum SA. Embryology, sternal clefts, ectopia cordis, and Cantrell's pentalogy. Semin Pediatr Surg. 2008;17(3):154-60.

6. Quiroga H. Ectopia cordis: diagnóstico ecográfico en el segundo trimestre de la gestación. Rev Chil Obstet Ginecol. 2004;69(5):372-5.

7. Sadlecki P, Krekora M, Krasomski G, Walentowicz-Sadlecka M, Grabiec M, Moll J, et al. Prenatally evolving ectopia cordis with successful surgical treatment. Fetal Diagn Ther. 2011;30(1):70-2.

8. Gamez JM, de la Fuente A, Garcia F. [Ectopia cordis]. An Pediatr (Barc). 2010;72(3):223.

9. Sepulveda W, Weiner E, Bower S, Flack NJ, Bennett PR, Fisk NN. Ectopia cordis in a triploid fetus: first-trimester diagnosis using transvaginal color Doppler ultrasonography and chorionic villus sampling. J Clin Ultrasound. 1994;22(9):573-5.

10. Shaw SW, Cheng PJ, Chueh HY, Chang SD, Soong YK. Ectopia cordis in a fetus with trisomy 18. J Clin Ultrasound. 2006;34(2):95-8.

11. Hannoun A, Usta IM, Sawaya F, Nassar AH. First trimester sonographic diagnosis of ectopia cordis: a case report and review of the literature. J Matern Fetal Neonatal Med. 2011;24(6):867-9.

12. Fortunato SJ. The use of power Doppler and color power angiography in fetal imaging. Am J Obstet Gynecol. 1996;174(6):1828-31; discussion 31-3.

13. Gun I, Kurdoglu M, Mungen E, Muhcu M, Babacan A, Atay V. Prenatal diagnosis of vertebral deformities associated with pentalogy of Cantrell: the role of three-dimensional sonography? J Clin Ultrasound. 2010;38(8):446-9.

14. Yildirim G, Aslan H, Gungorduk K, Gul A, Unlu E. Prenatal diagnosis of ectopia cordis. Taiwan J Obstet Gynecol. 2008;47(3):346-7.

15. Escobar-Diaz MC, Sunderji S, Tworetzky W, Moon-Grady AJ. The Fetus with Ectopia Cordis: Experience and Expectations from Two Centers. Pediatr Cardiol. 2017;38(3):531-8.

16. Araujo Junior E, Carrilho MC, Toneto BR, Guilhen JCS. Pentalogy of Cantrell: Prenatal Diagnosis, Delivery, and Immediate Postnatal Surgical Repair. J Neonatal Surg. 2017;6(2):32.