Systolic Myocardial Mechanics in Patients with Anderson-Fabry Disease with and without Left Ventricular Hypertrophy and in Comparison to Nonobstructive Hypertrophic Cardiomyopathy

Objectives: Anderson-Fabry disease (AFD) is a lysosomal storage disease, which can involve the heart, mimicking hypertrophic cardiomyopathy (HCM). The underlying mechanism of disease in AFD is an infiltrative, diffuse process, whereas HCM is a primary heart muscle condition with patchy distribution, which may prompt differences in myocardial mechanics. The aim of this study was to assess myocardial mechanics in AFD according to the presence of left ventricular hypertrophy (LVH) compared to nonobstructive HCM (NHCM) and healthy controls. Methods and Results: We carried out a single-center, retrospective study in a small, genetically confirmed AFD cohort, which was divided into a subgroup with LVH (LVH+, n = 19), and without LVH (LVH, n = 21). Comparison groups were healthy controls (n = 40) and NHCM patients (n = 19). Vector Velocity Imaging was applied to two-dimensional echocardiography studies for assessment of longitudinal strain (LS), circumferential strain (CS), and base-to-apex CS gradients. AFD LVH+ patients had lower global LS than AFD LVH patients (14 +/- 4% vs 17 +/- 3%, P < 0.05), but similarly lowered global CS (24 +/- 5% vs 22 +/- 5%, P = ns). AFD LVH+ and NHCM had similarly lowered global LS compared to normals, but significantly lower global CS was observed in AFD LVH+ (24 +/- 5% vs 28 +/- 4%, P < 0.05), whereas it was significantly increased in NHCM (31 +/- 2% vs 28 +/- 4%, P < 0.05). Unlike NHCM, in both AFD subgroups, patients lost their normal base-to-apex CS gradient. Conclusions: AFD patients without LVH already show abnormal systolic myocardial mechanics. Relevant differences in myocardial mechanics between AFD patients with LVH compared to NHCM reflect the different underlying mechanisms of disease.