Today at morning report at the VA, we talked about left ventricular non-compaction:
– defined by prominent LV trabeculae (2:1 ratio of trabeculae to myocardial wall); deep intertrabecular recesses, and thin compacted layer.
Here are some echo images:
Here is a schematic to help you visualize what’s going on:
– it is debated whether LVNC in adults is a distinct cardiomyopathy or an anatomic variant / morphologic trait shared by different types of cardiomyopathies. AHA classifies it as a genetic cardiomyopathy and it is associated with mutations in genes implicated in other genetic cardiomyopathies (ie HOCM). However, there is emerging evidence that pathogenic mechanisms leading to non-compaction or increased trabeculation may occur in adult life (found de novo in pregnant women, athletes, patients with sickle cell anemia).
– An important thing to note is that there are no genome-wide association studies because the challenge is that there are many phenotypic variants; so, a limitation of genetic studies is that most only screened genes associated with other cardiomyopathies (sarcomere mutations of HOCM).
– There is no gold standard for the diagnosis of LVNC, but TTE and cMRI with contrast are the best tools; if trabecula are biopsied, myocytes are histologically normal so biopsy is not part of the diagnostic work-up. Of note, it is common for either LV dilation or hypertrophy to be present and this does not influence the diagnosis but hypokinesis of non-trabeculated segments can strengthen the diagnosis of cardiomyopathy 2/2 LVNC. An important part of imaging is to distinguish true LVNC meeting criteria from hyper-trabeculation that is considered not pathologic.
– guidelines suggest that familial LVNC should be diagnosed by screening family members with TTE; genetic testing is not recommended routinely because does not change management
- Patients are treated based on presence of cardiac dysfunction (ie GDMT for HFrEF) / arrhythmias
- oral anticoagulation is administered to patients with LV dysfunction, proven thrombi, arrhythmias (atrial fibrillation is common) but debated in their absence
– sudden cardiac death is a complication but not clear if this is related to the functional phenotype (reduced EF, HOCM) rather than LVNC itself. Clinical predictors for appropriate ICD therapy are not available
Find out more in this great review article: https://www.ncbi.nlm.nih.gov/pubmed/25443708