Cuillier F, MD*, Deshayes M**, Lemaire P**, Carasset G, MD***

* Department of Gynecology, ***   Sonogapher, Moufia’street  **  Department of Gynecology, Saint Clothilde Clinic, de la Réunion, France.

Definition: An abnormal calcification in the heart is called a "hyperechogenic focus". In postnatal life, dystrophic calcification of the myocardium is a non-specific reflection of severe myocardial injury. It occurs in areas of necrosis, fibrosis and hemorrhage in the presence of normal serum levels of calcium and phosphorus 1.

Case report: This is a 29-year-old woman, G2P1. The nuchal translucency and the triple test were normal. At 13, 23 and 32 weeks, the fetal scans were normal. At 37 weeks, the patient had some uterine contractions and she came to our unit for a routine scan. A scan revealed an abnormal calcification on the right heart (Figures 1-2-3-4). The calcification was seen in the tricuspid valve (Figure 5-6), which seems dysplastic (Figure 7-8). The screening tests for fetal infection were negative (Rubella, Toxoplasmosis, CMV, Herpes, MNI, Coxsackie, Enterovirus and Chikungunya).

The baby born at 41 weeks (2800g). The cardiac physical exam and the ECG were normal. The postnatal scan confirmed the diagnosis. The left ventricle was normal, but the right myocardium was hypertrophic. There was a tricuspid dysplasia. Indeed the tricuspid valve and the chordae were hyperechoic and dysplastic. The septal valve was against the wall, and the two other tricuspid valves have a normal mobility. Nevertheless the global cardiac function was normal, in particular, the tricuspid function. There was either a normal atrioventricular and ventricular connections. Aorta and pulmonary artery had normal size. At one-month-old, the baby is healthy.

Scan at 38 weeks showing prominent echogenicity of the right ventricular wall and echogenic focus within the apical region of the right ventricle

Four chamber view at 38 weeks showing interventricular septal defect (membranous type).

Long axis view at 38 weeks. Note the echogenic focus within the right intraventricular wall. The hyperechogenic outline on the right heart is also demonstrated.

Prevalence: In the fetal life, the majority of pericardium abnormalities involve pericardial effusion and tumors. Vettraino et al described only five cases in more than 170.000 scans in their unit (1). In the other hand, an echogenic focus limited to the myocardium is the more common prenatal finding.  Antenatal, echogenic focus have been found in 5% of second and third trimester fetuses and are generally regarded as a normal variant (2). The neonatal echocardiograms and follow-up studies showed usually normal cardiac anatomy and function.

Pathogenesis: Calcification of the myocardium has been classified as either dystrophic or metastatic.

• Dystrophic classification is more common and may occur in areas of necrosis, hemorrhage of fibrosis of the myocardium, without abnormal levels of calcium or phosphorus in the blood. The calcium deposition is related to low production of carbon dioxide in slowly metabolizing tissue, with consequent development of a local zone of relative alkalinity and reduced solubility of calcium. Dystrophic calcification occurs in cases of infarction, hypoxia and virus infection (6).
  In adult life, an echogenic pericardium may be related to acute fibrin strands, fibrous connective tissue, tumors, fat, blood clots and calcifications. It can also occur in patients affected by systemics diseases (rheumatics), chronic dialed patients and asbestos workers.
  In fetal life, the origin of echogenic myocardium focus is not clear. Echogenic focus have been described in various anatomic areas of the fetus, especially brain, liver and cardiac papillary muscle (1) and there is a concern for underlying fetal infection, viral or parasitic. Pathology correlates have shown these focus are associated with areas of dystrophic calcification or mineralization.
• Metastatic calcifications are seen in adult life.

Etiology: Mechanisms of dystrophic calcification include hypoxia, hemorrhage, infarction and infection by viruses or parasites. During adult life, the most likely cause of the transient inflammation of the pericardium can be an specific viral, bacterial or immunological mediated pericarditis (2), which can cause cardiac calcification.

During fetal life, several infectious of dystrophic calcification myocarditis have been reported, including Coxsackie B1, B2, B3 and B4, Coxsackie A3, echovirus II and entero viruses and toxoplasma infection (3). A recent case report described either a case of a maternal first episode of primary herpes simplex type II infection leading to calcifications within the right cardiac ventricular wall and interventricular septum. But the fetus had additional findings as pericardial effusion, echogenic bowel and lagging fetal growth. The most striking features were the dystrophic calcified myocarditis (4). About our patient, she did not have any history of viral infection.

Echogenic focus within the cardiac papillary muscles has been extensively studied in association with trisomy 21 and other karyotypic abnormalities (4). Ibba report an unusual case of a likely fetal pericarditis which was characterized by the ultrasound appearance of a markedly echogenic outline of the heart (2). The appearance progressively resolved during the pregnancy. The newborn was healthy.

Maternal cocaine abuse during first trimester has also been implicated as a possible cause of fetal myocardial damage and subsequent calcification (5-6). Cardiac tumors that may appear echogenic or calcified include rhabdomyomas, fibromas and pericardial teratomas (7). Calcification of the wall of a congenital aneurysm has been reported either. There are also reports of calcification of the infundibulum and pulmonary valves in twin pregnancies in cases of twin-to-twin transfusion due to chronic volume overloading (6). But the hypotrophic fetus has either a myocardiohypertrophy of entire cardiac wall, and the cardiac calcification is homogenous.

Sonographic findings: The sonographic finding is an abnormal hyperechoic zone, which has the same echogenicity as the bone. This zone can be punctual, isolated or multiple.

Implications for target examinations: A detailed examination of the fetus is necessary, as a serology tests.

Differential diagnosis: The differential diagnosis includes:

• Ischemia due to early heart failure: is an exceptional event. The area shows essentially no change on a follow-up sonogram few days latter.
• Hyperechogenic focus: but there is a cord punctual calcification.
• Idiopathic arterial calcification of child: is an unusually genetically inherited autosomal recessive condition characterized by extensive arterial calcification and stenosis of large and medium sized artery. These calcification deposits are seen along the internal elastic membrane of arteries accompanied by fibrous thickening of the intima resulting in lamina narrowing (8).
• Rhabdomyomas: may occur as single or multiple lesions within the ventricles and may be detected prenatally. Nevertheless, rhabdomyoma is most commonly seen as a homogeneous, echogenic, intracardiac mass and is commonly located in the septum. They are often multiple, occurring in more than one chamber and may produce arrhythmias. Fibroma or teratoma can be calcified either.
• Endocardial fibroelastosis: calcification is seen on all the thick endocardial (9).

Associated anomalies: Calcifications within the intraventricular wall could cause arrhythmias as the electrical pathways of the Purkinje system pass through this structure.

Prognosis: Unlike the adult population, myocardial calcifications in the fetus are not common and do not appear to be associated with short term pathological conditions or abnormalities of cardiac function. Nevertheless, it is necessary to perform a cardiac examination regularly after birth.

Management: A fetal echocardiogram and a maternal serological screening can be considered to complete evaluation. A neonatal echocardiogram must be performed.

References

1- Vettraino I.M., Hoprasart J., Bronsteen R.A., Comstock C.H.- Clinical implications of the prenatal sonographic finding of fetal myocardial echogenic foci. J Ultrasound Obstet Gynecol 2005 ; 24 : 195-9.

2- Ibba R.M., Zoppi M.A., Floris M., Putzolu M., Monni G.- Transient hyperecgogenicity of teh fetal pericardium : a case report. Ultrasound Obstet Gyencol 2000 ; 16 : 197-9.

3- Martin A., Roth P., Arbez-Gindre F., Cattin, Maillet R.- Cardiopathie fœtale et pseudo-tumeur calcifiée du ventricule gauche. Med Foet Echo Gyn 2005 ; N°62 : 23-5.

4- Mitra A.G., O’Malley D.P., Banks P.M., Kelley M.- Myocardial calcification in a fetus. J Ultrasound Med 2004 ; 23 : 1385-90.

5- Lee Ivan- Answer to the case of the week 129. Leewww.thefetus.net/.

6- Hadju J., Marton T., papp C., Hruby E., Papp Z.- Calcification of the fetal heart-four case reports and a literrature review. Prenat Diagn 1998 ; 18 : 1186-90.

7- Chan Y., Sampson A.- massive myocardial calcification in second-trimester fetuses : antenatal dtection and causes. Ultrasound Obstet Gynecol 2005 ; 25 : 193-6.

8- Samson L.M., Ash K.M., Murdison K.A.- Aorto-pulmonary calcification : an unsual manifestation of idiopathic calcification of infancy evident antenatally. Obstet Gynecol 1995 ; 85 : 863-5.

9- Sosa Olavarria A.- Endocardial fibroelastosis. Sosawwwthefetus.net 2001-09-18-11.