Insights into the effects of Friedreich ataxia on the left ventricle using T1 mapping and late gadolinium enhancement.

Abstract

BackgroundThe left ventricular (LV) changes which occur in Friedreich ataxia (FRDA) are incompletely understood.MethodsCardiac magnetic resonance (CMR) imaging was performed using a 1.5T scanner in subjects with FRDA who are homozygous for an expansion of an intron 1 GAA repeat in the FXN gene. Standard measurements were performed of LV mass (LVM), LV end-diastolic volume (LVEDV) and LV ejection fraction (LVEF). Native T1 relaxation time and the extracellular volume fraction (ECV) were utilised as markers of left ventricular (LV) diffuse myocardial fibrosis and late gadolinium enhancement (LGE) was utilised as a marker of LV replacement fibrosis. FRDA genetic severity was assessed using the shorter FXN GAA repeat length (GAA1).ResultsThere were 93 subjects with FRDA (63 adults, 30 children, 54% males), 9 of whom had a reduced LVEF (ConclusionAn association between diffuse interstitial LV myocardial fibrosis and genetic severity in FRDA was present independently of FRDA-related LV structural changes. Localised replacement fibrosis was found in a minority of subjects with FRDA and was not associated with LV structural change or FRDA genetic severity in subjects with a normal LVEF.