Left Ventricular Non-Compaction
Etiology
Left ventricular noncompaction (LVNC) or 'spongy myocardium' is a rare congenital cardiomyopathy that is characterized by presence of myocardium with 2 layers – compacted epicardial layer and noncompacted endocardial layer with trabeculation and deep intertrabecular recesses that communicate with the left ventricular cavity.
Predominant location is in the midventricular and apical segments.
Clinical manifestation
Extensive remodelling of the left ventricle often leads to systolic dysfunction and classical triad of complications in advanced disease – heart failure, ventricular arrhythmias and systemic embolic events, due to stagnation of blood in the recesses.
There is also a high prevalence of associated neuromuscular disorders in patients with LVNC (metabolic myopathies, M. Becker, M. Duchenne, myotonia, etc.) and genetic counselling is advised.
Echocardiography findings
- When looking for LVNC, make sure you are viewing the apical region in good image resolution and contrast. If the apical windows are suboptimal, use intravenous ultrasound contrast to better visualize intertrabecular recesses.
- A ratio >2 of noncompacted to compacted myocardium layers diameter measured at end systole is a proposed diagnostic criteria. In contrast MRI criteria refer to non-compacted (NC): compacted (C) myocardium diameter ratio > 2.3 in end-diastole.
- Evidence of direct blood flow from the LV cavity into intertrabecular recesses by colour Doppler.
- Rule out presence of thrombus within the recesses.
- Rule out involvement of the right ventricle.
Video 1 LVNC, A4C view - dilated LV (EDD 65 mm) with diffuse hypokinesis, note the extensive trabeculation in mid-ventricular segments of lateral wall and the apex. There is no visible thrombi in the intertrabecular recesses.
Video 2 LVNC, A4C view
Video 3 LVNC, A3C view - note the trabeculation of the lateral wall and apex of the LV
Image 1 LVNC, dilated left ventricle (LVEDD 63 mm), PLAX view
Image 2 LVNC, Global longitudinal strain assessment (-12,2%), hypokinesis of the basal segments of the septum and anterior wall
Video 4 LVNC, A4C view - trabeculation of the lateral wall and the apex of LV, the LV is not dilated, but there is diffuse hypokinesis.
Video 5 LVNC, PSAX view midventricular - long trabeculae with deep intertrabecular recesses.
Video 6 LVNC, A2C - noncompaction of the apical ½ of the LV
Video 7 LVNC, Global longitudinal strain assessment (-13,9%)
Video 8 LVNC, A4C view - distinctive trabeculation anterolaterally and laterally in apical ⅔ of LV wall, no apparent thrombi within the recesses.
Video 9 LVNC, PSAX view - epicardial layer of compacted myocardium transitions into a non compacted layer of trabeculae and intertrabecular recesses.
Image 3 LVNC, PSAX view - diameter of the noncompacted layer/height of the trabeculae is measured at 16 mm.
Management (Image 4)
Towbin, Jeffrey & McKenna, William & Abrams, Dominic & Ackerman, Michael & Calkins, Hugh & Darrieux, Francisco & Daubert, James & de Chillou, Christian & DePasquale, Eugene & Desai, Milind & Estes, N. A. Mark & Hua, Wei & Indik, Julia & Ingles, Jodie & James, Cynthia & John, Roy & Judge, Daniel & Keegan, Roberto & Krahn, Andrew & Zareba, Wojciech. (2019). 2019 HRS Expert Consensus Statement on Evaluation, Risk Stratification, and Management of Arrhythmogenic Cardiomyopathy. Heart Rhythm. 16. 10.1016/j.hrthm.2019.05.007.
References
1. Finsterer J, Stöllberger C, Towbin JA. Left ventricular noncompaction cardiomyopathy: cardiac, neuromuscular, and genetic factors. Nat Rev Cardiol. 2017 Apr;14(4):224-237. doi: 10.1038/nrcardio.2016.207. Epub 2017 Jan 12. PMID: 28079110.
2. Towbin, Jeffrey & McKenna, William & Abrams, Dominic & Ackerman, Michael & Calkins, Hugh & Darrieux, Francisco & Daubert, James & de Chillou, Christian & DePasquale, Eugene & Desai, Milind & Estes, N. A. Mark & Hua, Wei & Indik, Julia & Ingles, Jodie & James, Cynthia & John, Roy & Judge, Daniel & Keegan, Roberto & Krahn, Andrew & Zareba, Wojciech. (2019). 2019 HRS Expert Consensus Statement on Evaluation, Risk Stratification, and Management of Arrhythmogenic Cardiomyopathy. Heart Rhythm. 16. 10.1016/j.hrthm.2019.05.007.
