Left ventricular non-compaction & hypertrabeculation
Two-layered myocardium, deep recesses filled with colour — and the much commoner benign hypertrabeculation it must not be confused with.
Numbers to remember
- Classic echo ratio: non-compacted to compacted layer >2 in end-systole, short axis [14]
- Hypertrabeculation alone is common in athletes, pregnancy, black patients and anaemia — it is a phenotype, not a diagnosis [14,150]
- What decides prognosis is LV function, thrombus and arrhythmia, not the trabeculae [14,140]
Questions echo must answer
The 2023 ESC cardiomyopathy guideline treats non-compaction as a phenotypic trait (LV hypertrabeculation) that may accompany other cardiomyopathies or be a normal variant, rather than a separate cardiomyopathy [14].
- Is the trabeculation excessive?A thin compacted epicardial layer with a thick, spongy endocardial layer, deep intertrabecular recesses that fill from the cavity on colour Doppler [14].
- Is the ventricle otherwise abnormal?LV size, EF and GLS. A normal-sized, normally contracting ventricle with prominent trabeculae is usually benign [14,150].
- ComplicationsApical thrombus inside the recesses, mitral regurgitation, biventricular involvement [140].
- ContextAthlete, pregnancy, family history, neuromuscular disease, coexisting HCM or DCM phenotype [14].
Acquisition protocol
- PSAX at the papillary and apical levelsMeasure the non-compacted (N) and compacted (C) layers at end-systole where trabeculation is maximal [14].
- Apical views, zoomed on the apexLower the depth; use contrast if the apex is poorly seen — contrast both outlines the recesses and excludes thrombus [140].
- Colour Doppler, low NyquistFlow entering the recesses from the cavity confirms they communicate with it.
- LV functionBiplane EF and GLS [1,16].
- RVLook for RV hypertrabeculation.
- N/C ratio in end-systole, short axis
- Colour flow into recesses
- EF and GLS
- Apical thrombus excluded (contrast if needed)
- Mitral regurgitation
Diagnosis & severity
| Feature | Supports pathological LVNC | Supports benign hypertrabeculation |
|---|---|---|
| LV function | Reduced EF or GLS | Normal |
| LV size | Dilated | Normal |
| Distribution | Apex, mid-lateral and inferior walls, extensive | Limited, apical |
| Context | Family history, arrhythmia, embolism | Athlete, pregnancy, anaemia |
Echo criteria based on the N/C ratio are sensitive but not specific; CMR measures the trabeculated mass more reliably [14].
Thresholds that change management
- Reduced EF → treat as heart failure with reduced EF (GDMT); ICD decisions follow the general heart-failure and arrhythmia criteria, not the trabeculae [11,12,38].
- LV thrombus → anticoagulation; reassess with contrast or CMR [140].
- Normal function in an athlete or pregnant patient → reassure; no treatment because of the trabeculae alone [14,150].
- Family history or genetic cardiomyopathy → cascade screening with echo and ECG [14].
Pitfalls & mimics
- Over-diagnosis Prominent trabeculae are common in healthy people; the ratio alone over-calls LVNC [14,150].
- False tendons and papillary muscles Normal structures, not recesses.
- Apical thrombus Can hide in recesses or be mimicked by them — use contrast [140].
- Near-field clutter An apical artefact can look like trabeculation; change the angle and depth.