Can noncompaction of the left ventricle be diagnosed antenatally?

Prenatal Diagnosis of Left Ventricular Noncompaction

Yes, noncompaction of the left ventricle can be diagnosed antenatally through fetal echocardiography, though it requires careful evaluation and expertise in fetal cardiac imaging. 1, 2

Diagnostic Criteria and Imaging Techniques

Left ventricular noncompaction (LVNC) is defined as a type of cardiomyopathy characterized by:

• Ventricular trabeculations that are more than twice the thickness of the compacted myocardium
• Typically measured at the mid left ventricular posterolateral wall 3

Fetal Echocardiography Findings

• Prominent and excessive ventricular trabeculations
• Deep intertrabecular recesses in the left ventricle
• Non-compaction/compaction ratio (N/C ratio) ≥2.0 is the key diagnostic feature 1
• Trabeculated myocardium with blood-filled recesses in continuity with the ventricular cavity 4

Timing of Diagnosis

• Most reliable diagnosis can be made at 18-22 weeks gestation
• Early echocardiography may be performed as early as 13-14 weeks with high accuracy in over 90% of cases 3
• First trimester detection is possible but has limitations and may require follow-up imaging 3

Clinical Implications and Management

Prenatal diagnosis of LVNC is important because:

1. High mortality risk: LVNC is associated with significant cardiac complications and poor prognosis 5, 3
2. Systolic dysfunction: Fetal LVNC often presents with depressed left ventricular function 5, 2
3. Familial occurrence: Awareness of potential genetic/familial patterns is crucial for counseling 5
4. Associated anomalies: LVNC may coexist with other cardiac defects such as coarctation of the aorta 6

Management Approach

• Multidisciplinary team involvement (maternal-fetal medicine, pediatric cardiology)
• Serial fetal echocardiography to monitor cardiac function
• Delivery planning at a center with advanced neonatal cardiac care
• Genetic counseling and potential testing

Diagnostic Pitfalls and Considerations

1. Overdiagnosis risk: LVNC can be overdiagnosed due to normal trabeculation patterns in fetal development 3

   • Some hypertrabeculation can persist in healthy hearts
   • LVNC as a distinct disease is rare

2. Ventricular involvement patterns: Unlike postnatal cases where LVNC predominantly affects the left ventricle, fetal LVNC may involve:

   • Left ventricle only (most common)
   • Right ventricle only
   • Both ventricles (biventricular NCCM) 1, 2

3. Diagnostic accuracy: Requires experienced fetal echocardiographers to differentiate from normal fetal cardiac development 3

4. Need for follow-up: A repeat fetal echocardiogram in the second trimester is recommended even if initial screening is performed in the first trimester 3

Careful evaluation of trabeculation patterns, measurement of the non-compaction to compaction ratio, and assessment of ventricular function are essential for accurate prenatal diagnosis of this rare but potentially serious cardiomyopathy.