Myocardial Deformation Imaging and Rare Cardiomyopathies with Hypertrophic Phenotype: A Review Focused on Fabry Disease, Friedreich Ataxia and Amyloidosis

Tissue Doppler and deformation imaging, including Doppler-derived strain and speckle tracking, have significantly improved our understanding of cardiac mechanics in both physiological and pathological states. The various modes of left ventricular deformation (longitudinal, circumferential, radial and twist) leading to systolic contraction can nowadays be quantified. One of the best applications of deformation imaging is in the area of hypertrophic cardiomyopathies. Deformation imaging allows the evaluation of global and regional myocardial performance and the noninvasive characterization of abnormal intramural myocardial mechanics. In this review, we discuss the role of myocardial deformation imaging derived by echocardiography in the assessment of rare hypertrophic phenotype including Fabry disease, Friedreich ataxia and amyloidosis. Deformation imaging allows for early identification of myocardial dysfunction in many hypertrophic disorders, at an earlier stage than that provided by standard imaging or echocardiographic techniques. This allows for the implementation of appropriate therapy before significant disease progression has occurred and prior to the development of advanced myocardial fibrosis. Thus therapy would likely be more effective and may potentially lead to improvement in patient outcome. Additionally strain imaging allows to better monitoring the efficacy of therapy by assessing the progression and regression of myocardial involvement. Finally, findings on strain imaging carry important prognostic information in many hypertrophic disorders.