What are the implications and management of an echogenic intracardiac focus found during a fetal ultrasound examination in a pregnant woman?

Echogenic Intracardiac Focus: Clinical Implications and Management

What It Is and What It Means

An isolated echogenic intracardiac focus (EIF) is a normal variant that requires no further evaluation when aneuploidy screening is negative. 1

An EIF is defined as a small (<6 mm) echogenic area in either cardiac ventricle that is as bright as surrounding bone and visualized in at least 2 separate planes. 1 These represent micro-calcifications of papillary muscles and do not represent a structural or functional cardiac abnormality—they are not associated with cardiac malformations in the fetus or newborn. 1

Prevalence and Ethnic Variation

• EIFs are identified in 3-5% of karyotypically normal fetuses. 1
• Significant ethnic variation exists: 8.1% in Middle Eastern women, 6.9% in Asian American women, 6.7% in African American women, 3.4% in Hispanic women, and 3.3% in White women. 1
• Some studies show prevalence up to 30% among women of Asian descent. 1
• Left-sided EIFs are most common (84.8-90% of cases), followed by bilateral (10-11.6%), and right-sided (3-3.6%). 2, 3

Association with Aneuploidy

The risk of trisomy 21 with isolated EIF is minimal:

• Isolated EIFs have a positive likelihood ratio of 1.4-1.8 for trisomy 21, with the lower confidence interval extending to or below 1. 1
• A 2013 meta-analysis demonstrated a positive LR of 0.95, showing no association between isolated EIF and trisomy 21. 1
• EIF does not alter the risk of trisomy 21. 4

Management Algorithm

For Patients WITHOUT Prior Aneuploidy Screening:

Offer noninvasive aneuploidy screening with cell-free DNA (cfDNA) or quad screen if cfDNA is unavailable or cost-prohibitive. 1

• Provide counseling to estimate the probability of trisomy 21. 1
• Do NOT recommend diagnostic testing (amniocentesis) solely for isolated EIF. 1

For Patients WITH Negative Serum or cfDNA Screening:

No further evaluation is needed—treat as a normal variant. 1

• No indication for fetal echocardiography. 1
• No indication for follow-up ultrasound imaging. 1
• No indication for postnatal evaluation. 1

Important Caveats and Pitfalls

Location Matters for Cardiac Risk:

• Right-sided EIF carries a higher risk of cardiac structural defects compared to left-sided EIF. 2, 3
• One study found 3.2% of fetuses with isolated EIF had cardiac defects, with significantly more cases in those with right ventricular EIF. 2
• However, the overall absolute risk remains low (estimated 4 per 10,000 pregnancies for persistent right-sided EIF). 3

Persistence into Third Trimester:

• EIFs that persist beyond 28 weeks gestation may warrant additional attention. 5
• Persistent EIF in late trimester is associated with higher risk of pathogenic copy number variations (20% vs. 2.22% before 28 weeks). 5
• Persistent EIF may indicate heart development defects after birth, with one study showing 36% of children with EIF diagnosed with congenital heart disease postnatally (primarily patent foramen ovale and ventricular septal defects). 5

When EIF is NOT Isolated:

• If multiple soft markers or structural abnormalities are present, diagnostic testing (amniocentesis) is recommended rather than screening alone. 6
• Multiple soft markers substantially increase the risk of aneuploidy compared to isolated findings. 6
• The presence of cardiac defects, especially outflow tract abnormalities, with soft markers strongly indicates need for diagnostic testing. 6

Common Errors to Avoid:

• Do not order fetal echocardiography for isolated left-sided EIF with negative aneuploidy screening. 1
• Do not schedule follow-up ultrasounds solely to monitor EIF resolution. 1
• Do not cause unnecessary parental anxiety by overstating the risk when EIF is truly isolated. 7
• Consider fetal echocardiography only if EIF is right-sided or persists into third trimester. 5, 2, 3

Special Considerations

For Patients Who Previously Declined Screening:

• Practices should establish standardized protocols for how isolated soft markers will be documented and managed. 1
• Some practices may treat isolated EIF as a normal variant and not discuss it, while others may use it as an opportunity to re-offer aneuploidy evaluation. 1
• Patients should be informed before the ultrasound examination of how findings will be handled to enhance shared decision-making. 1