The role of myocardial strain assessment using cardiac magnetic resonance imaging in patients with non-compacted left ventricular myocardium: determination of subclinical contractility disorder

BACKGROUND: Non-compacted left ventricular myocardium is a phenotypic variant of the myocardium structure with increased trabecularity and the formation of two distinct layers: compacted and non-compacted. It is known that patients with non-compacted left ventricular myocardium gradually develop contractile dysfunction, leading to chronic heart failure. Increased trabecularity can be observed both in healthy individuals and in certain non-ischemic heart diseases, particularly in dilated cardiomyopathy. In some cases, their differential diagnosis may be complicated, especially when the left ventricle ejection fraction is not reduced or is moderately reduced, and left ventricular dilation is minimal. Recently, publications have reported that myocardial strain parameters assessed using echocardiography and/or cardiac magnetic resonance imaging can detect subclinical disorders of myocardial contractility. AIM: To assess the myocardial strain parameters using cardiac magnetic resonance imaging in patients with non-compacted left ventricular myocardium and preserved left ventricle ejection fraction compared with patients with dilated cardiomyopathy and healthy controls, and to determine the diagnostic value of these parameters for detecting subclinical disorders of myocardial contractility. METHODS: This multicenter, observational, retrospective, cross-sectional study included patients with non-compacted left ventricular myocardium with preserved left ventricle ejection fraction (group 1), healthy volunteers (group 2), and patients with dilated cardiomyopathy (group 3). All patients underwent CMR with intravenous contrast administration. RESULTS: A total of 112 participants were enrolled: 16 patients with non-compacted left ventricular myocardium with preserved left ventricle ejection fraction (group 1), 51 patients in the control group without pathological changes in heart chambers according to cardiac magnetic resonance imaging (group 2), and 45 patients with dilated cardiomyopathy (group 3). Mutations in the MYH7, MYBPC3, TTN, and DES genes had been previously detected in all patients with non-compacted left ventricular myocardium with preserved left ventricle ejection fraction. Analysis of the myocardial strain parameters revealed a decrease in the global and segmental strain parameters in patients with dilated cardiomyopathy; a decrease in longitudinal and circumferential strain in patients with non-compacted left ventricular myocardium compared with the control group in the middle and apical segments, and a decrease in radial strain in all segments. CONCLUSION: Myocardial strain assessment can serve as a valuable diagnostic tool for detecting early contractility disorders in patients with non-compacted left ventricular myocardium with preserved left ventricle ejection fraction.