Refinement of echocardiographic criteria for left ventricular noncompaction

Background: Left ventricular hypertrabeculation/noncompaction (LVNC) is a cardiac abnormality whose echocardiographic criteria are still controversial. Cooperation between echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following pilot study.

Methods and results: Echocardiograms proposed for inclusion into a registry were reviewed. Three experts with 17-26 years experience with LVNC agreed on a common definition of LVNC: 1. >3 prominent trabeculous formations along the left ventricular endocardial border visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands; 2. trabeculations move synchronously with the compacted myocardium, 3. trabeculations form the noncompacted part of a two-layered myocardial structure, best visible at end-systole; and 4. perfusion of the intertrabecular spaces from the ventricular cavity is present at end-diastole on color-Doppler echocardiography or contrast echocardiography. During 3 sessions 115 cases (37% females, mean 57 years) were reviewed. Eleven patients (18% females, mean 60 years) were excluded because of <4 trabeculations (n=5), lack of a two-layered myocardial structure (n=1) and poor image quality (n=5). The observers agreed on inclusion or exclusion in all cases. Consensus was achieved that measurements of the thickness of the myocardial layers, and calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements.

Conclusions: When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of more than three trabeculations as well as a two-layered myocardium are required. Since these criteria are not anatomically controlled, a comparison of echocardiographic images with pathoanatomic findings for assessing sensitivity and specificity is urgently needed.