Diagnostic value of rigid body rotation in noncompaction cardiomyopathy

The diagnosis of noncompaction cardiomyopathy (NCCM) remains subject to controversy. Because NCCM is probably caused by an intrauterine arrest of the myocardial fiber compaction during embryogenesis, it may be anticipated that the myocardial fiber helices, normally causing left ventricular (LV) twist, will also not develop properly. The resultant LV rigid body rotation (RBR) may strengthen the diagnosis of NCCM. The purpose of the current study was to explore the diagnostic value of RBR in a large group of patients with prominent trabeculations.

The study comprised 15 patients with dilated cardiomyopathy, 52 healthy subjects, and 52 patients with prominent trabeculations, of whom a clinical expert in NCCM defined 34 as having NCCM. LV rotation patterns were determined by speckle-tracking echocardiography and defined as follows: pattern 1A, completely normal rotation (initial counterclockwise basal and clockwise apical rotation, followed by end-systolic clockwise basal and counterclockwise apical rotation); pattern 1B, partly normal rotation (normal end-systolic rotation but absence of initial rotation in the other direction); and pattern 2, RBR (rotation at the basal and apical level predominantly in the same direction).

The majority of normal subjects had LV rotation pattern 1A (98%), whereas the 18 subjects with hypertrabeculation not fulfilling diagnostic criteria for NCCM predominantly had pattern 1B (71%), and the 34 patients with NCCM predominantly had pattern 2 (88%). None of the patients with dilated cardiomyopathy showed RBR. Sensitivity and specificity of RBR for differentiating NCCM from "hypertrabeculation" were 88% and 78%, respectively.

RBR is an objective, quantitative, and reproducible functional criterion with good predictive value for the diagnosis of NCCM as determined by expert opinion.