Fetal Heart Screening by ISUOG: Basic Views (4-Chamber, Outflow Tracts, 3-Vessel)
General Approach to Cardiac Screening
Cardiac screening is one of the key parts of the second-trimester examination. According to ISUOG recommendations, the examination of the heart should begin with the assessment of situs, cardiac axis, and rhythm (ISUOG Practice Guidelines: fetal cardiac screening, 2023).
Basic Views for Routine Screening
The structural review of the heart during routine screening should include the following views:
| View | Purpose |
|---|---|
| Four-chamber view (4-chamber) | Basic assessment of the heart chamber structure |
| Outflow tract views | Assessment of the outflow tracts |
| Three-vessel view | Assessment of the major vessels |
Change in Practice
This is a significant change compared to the more limited practice of the past. It reflects the current consensus that an isolated four-chamber view is insufficient for routine screening (ISUOG Practice Guidelines: fetal cardiac screening, 2023).
Regulatory Framework
The requirements are outlined in the updated practice guidelines: Carvalho JS, Axt-Fliedner R, Chaoui R, et al. ISUOG Practice Guidelines (updated): fetal cardiac screening. Ultrasound Obstet Gynecol. 2023;61:788-803. Additional details of the mid-trimester protocol are in ISUOG Practice Guidelines (updated): performance of the routine mid-trimester fetal ultrasound scan (Ultrasound Obstet Gynecol. 2022;59(6):840-856).
Frequently asked questions
Where does the ISUOG fetal heart examination begin?
With the assessment of situs, cardiac axis, and rhythm (ISUOG Practice Guidelines: fetal cardiac screening, 2023).
What views are included in routine cardiac screening?
The four-chamber view, outflow tract views, and the three-vessel view.
Is the 4-chamber view alone sufficient for routine screening?
No. According to the current ISUOG consensus, an isolated four-chamber view is insufficient for routine screening.
At what stage of the examination is cardiac screening performed?
It is one of the most important parts of the second-trimester examination.