Noncompacted myocardium has been previously described as the presence of persistent intramyocardial sinusoids. However, the latter is associated with congenital obstructive lesions of the left or right ventricular outflow tract, such as pulmonary atresia with intact ventricular septum [1]. In such patients, regression of the embryogenic sinusoid is impaired during ontogenesis by ventricular pressure overload, resulting in deep recesses that communicate with both the ventricular cavity and the coronary artery system [2,3].By contrast, isolated noncompaction of the left ventricular myocardium (INVM) is an idiopathic cardiomyopathy characterized by an altered structure of the myocardial wall as a result of intrauterine arrest of compaction of the myocardial fibers in the absence of any coexisting congenital lesion [4]. There is continuity between the left ventricular (LV) cavity and the deep intertrabecular recesses that are filled with blood from the ventricular cavity without evidence of communication to the epicardial coronary artery system [5,6].
AbstractIsolated noncompaction of the left ventricular myocardium (INVM) is associated with a high incidence of heart failure.However, it is difficult to determine accurately left ventricular (LV) systolic function because of the trabeculated ventricles. The purpose of this study was to clarify whether strain imaging could detect regional myocardial systolic function in 2 patients with INVM. We recorded myocardial strain profiles at the basal, mid-, and apical portions of the LV free wall and ventricular septum (VS) in the apical LV long-axis view. Case 1 (15-year-old male) was referred to our hospital because of ECG abnormalities. Case 2 (83-year-old female) was admitted to our hospital for congestive heart failure.Two-dimensional echocardiography in both patients showed numerous prominent trabeculations and deep intertrabecular recesses at the apex of the LV wall. Because of the trabeculations, it was difficult to determine accurately LV ejection fraction by 2-dimensional echocardiography. The percent fractional shortening of the LV (%FS) in both cases was within a normal range. However, the peak systolic strains at the apical, mid-, and basal portions of the LV free wall were lower in Case 2 (-12, -12, and -11%, respectively) than in Case 1 (-33, -37, and -37%, respectively). The peak systolic strains at the apical, mid-, and basal portions of the VS were also lower in Case 2 (-11, -16, and -11%, respectively) than in Case 1 (-27, -27, and -29%, respectively). We conclude that strain measurements are useful for evaluating regional myocardial systolic function in patients with INVM. (J Echocardiogr 2005; 3: 40-45) Key words: isolated noncompaction of the left ventricular myocardium, strain imaging, regional myocardial systolic function