Who Should Have a Fetal Heart Scan

2 Who Should Have a Fetal Heart Scan



Lisa K. Hornberger



I. GENERAL INFORMATION AND BACKGROUND



A. Level I or second trimester obstetric ultrasound




1. General fetal anatomical ultrasound exam is performed in the majority of low-risk pregnancies at 18 to 22 weeks of gestation to screen for congenital anomalies.


2. Personnel responsible include obstetricians, radiologists, and sonographers.



B. Level II or specialized fetal anatomical ultrasound




1. Specialized ultrasound is performed when an anomaly is suspected on the basis of history or biochemical abnormalities or when the results of either the limited or standard scan suggest the presence of fetal pathology.


2. Specialized ultrasound is performed by obstetricians, perinatologists, radiologists, and sonographers who have additional expertise in obstetric ultrasound.



C. Fetal echocardiography




1. Two-dimensional and Doppler echocardiographic evaluation includes detailed assessment of the cardiac anatomy, blood flow, heart rate and rhythm, and heart function.


2. Fetal echo is performed in pregnancies at risk for or with suspected structural, functional, or rhythm-related fetal heart disease.


3. Responsible personnel include:


a. Pediatric cardiologists with expertise in fetal and pediatric echocardiography.


    (1) They are knowledgeable about the nuances of congenital heart disease, including the medical and surgical outcomes.

    (2) They are knowledgeable about structural, functional, and rhythm-related fetal heart disease.

b. Obstetrics or radiology personnel with training in fetal echocardiography but with assistance from pediatric cardiologists for interpretation of the findings and prenatal counseling.



II. INDICATIONS


Indications for fetal echocardiography can be divided into three categories: maternal, fetal, and familial.



A Maternal indications




1. Maternal metabolic disorders.


a. Type 1 or 2 diabetes mellitus (preconception).


    (1) Reported incidence is twofold to fivefold higher than that of the general population.

    (2) Presence of fetal heart disease is not consistently linked to maternal hemoglobin A1c.

    (3) Major structural defects include such conditions as (but not limited to):

       (a) D-Transposition of the great arteries.

       (b) Hypoplastic left heart syndrome.

       (c) Tetralogy of Fallot.

       (d) Pulmonary atresia.

       (e) Tricuspid atresia.

    (4) Hypertrophic cardiomyopathy.

       (a) Hypertrophic cardiomyopathy typically does not evolve until late in gestation.

       (b) It is not itself an indication for fetal echocardiography because most affected infants are clinically well after birth and the pathology regresses spontaneously after birth.

b. Phenylketonuria.


    (1) Risk of defects is 14%, particularly with phenylalanine levels greater than 600 μmol/L up to 8 weeks’ gestation.

    (2) Specific lesions.

       (a) Left heart obstruction.

       (b) Tetralogy of Fallot.

2. Maternal congenital (or familial) heart disease.


a. Congenital heart disease: Risk depends upon the specific lesion (Table 2-1) but in general ranges from 5% to 13%.


b. Cardiomyopathy.


    (1) Risk depends upon the type of inheritance and age at presentation.

    (2) Most patients present in adolescence and are not identified prenatally.

3. Maternal autoimmune disease, specifically those associated with anti-Ro or anti-La autoantibodies (4%-25% risk in affected women).


a. Fetal atrioventricular heart block typically appears after 17 weeks’ gestation in a mother with autoantibodies and with or without clinical autoimmune disease.


b. Fetal cardiomyopathy with endocardial fibroelastosis.


4. Exposure to teratogens such as:


a. Alcohol: Atrial and ventricular septal defects.


b. Valproic acid.


    (1) Atrial and ventricular septal defects.

    (2) Aortic and pulmonary valve obstruction.

    (3) Coarctation of the aorta.

Related posts:

  1. Outcome of Fetal Congenital Heart Defects
  2. Ventricular Septal Defect
  3. Pulmonary Atresia and Intact Ventricular Septum
  4. Suggested Views for Fetal Heart Imaging

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Jun 18, 2016 | Posted by in CARDIOLOGY | Comments Off on Who Should Have a Fetal Heart Scan

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