Enhancing cardiac screening in the second and third trimesters

An important new resource for OBGYN clinicians, ‘Second- and Third-Trimester Screening for Congenital Heart Defects: A Practical Approach | Article | GLOWM’ features in the Ultrasound in Obstetrics volume of GLOWM's Continuous Textbook of Women's Medicine. Authored by leading expert Dr Greggory R. DeVore, this chapter provides an invaluable, hands-on guide to optimizing fetal heart screening.

Why fetal heart screening matters

Congenital heart disease (CHD) remains the most prevalent birth defect, surpassing the incidence of conditions like trisomy 21 and neural tube defects. Despite its high prevalence, the emphasis on prenatal detection of CHD has historically lagged behind that of other malformations. However, with advancements in ultrasound technology and growing expertise, the landscape of fetal cardiac screening is continually evolving.

Expert insights for confident clinical practice

The chapter meticulously details the cardiac anatomical landmarks and views, such as the four-chamber view (4CV), left and right ventricular outflow tract (LVOT/ RVOT) views and the three-vessel-and-trachea view (3VTV), essential for a thorough screening examination. Accompanying videos and other interactive elements are integrated throughout the chapter, offering dynamic visual aids to help clinicians master the techniques for determining fetal situs, orienting the 4CV within the chest and accurately measuring cardiac size and dimensions.

It also delves into the intricacies of evaluating each cardiac structure, providing practical tips for assessing the anatomy of the left and right ventricles, the interventricular septum, and the left and right atria, including crucial features like the pulmonary vein entry into the left atrium and the foramen ovale. Furthermore, it offers detailed strategies for identifying the outflow tracts, resolving previous imaging deficiencies in fully visualizing the aortic arch, and understanding the vital role of color and power Doppler in detecting shunting ventricular defects or valve regurgitation.

Beyond structural assessment, Dr DeVore's work covers evaluation of fetal heart rate using M-mode ultrasound to identify rhythm disturbances. A dedicated section clarifies the often-misunderstood topic of pericardial effusion, distinguishing it from a normal hypoechogenic rim and highlighting its significance as a potential marker for aneuploidy and other fetal pathologies, especially when observed in the second trimester.

Clues to identifying fetuses with CHD

A key takeaway, and one emphasized by Dr DeVore, is that the non-cardiologist performing a screening examination is not expected to provide the final diagnosis of a CHD. Instead, their critical role is to identify changes in the screening examination anatomy that would suggest a cardiac defect is present. This nuanced understanding helps OBGYN clinicians to screen their patients effectively and make timely, appropriate referrals to fetal cardiologists when suspicious findings arise, thereby improving patient care pathways.

This comprehensive chapter enriched with practical recommendations and a study assessment option for CPD points, stands as an indispensable resource. It reinforces the standard of care for fetal heart screening and equips OBGYN clinicians with the knowledge and tools to enhance early detection of CHDs, ultimately leading to better outcomes for mothers and babies.

Explore the full article here: Second- and Third-Trimester Screening for Congenital Heart Defects: A Practical Approach | Article | GLOWM