Left atrial strain tracks abnormal ventricular mechanics in Fabry disease

BackgroundsFabry disease (FD) is an X-linked lysosomal disorder with ventricular myocardial involvement that drives morbidity and mortality. Early diagnosis of cardiac involvement can be difficult. This study explored whether abnormal left atrial (LA) strain by cardiovascular magnetic resonance (CMR) may be an early sign of ventricular involvement in FD. MethodsA multicenter, multinational cohort of FD patients was assembled with images centralized for corelab analysis. Adult gene-positive FD patients and healthy volunteers (HV) underwent CMR. LA strain analyses included manually contouring the LA in end-diastole and end-systole to calculate LA volumes and ejection fraction, then semi-automatic analysis for LA reservoir strain. ResultsThere were n=214 FD patients (mean age 45{+/-}15 years, 39% males) and n=76 HV (49{+/-}15 years, 53% males). CMR results in FD: LVEF 73% (IQR=9), LV mass indexed (LVMi) 89{+/-}39g/m2, 99 (46%) had left ventricular hypertrophy (LVH), 36% had late gadolinium enhancement. In FD, LA strain correlated with LVMi (r=-0.52, p<0.01), LV global longitudinal strain (GLS) (r=-0.61,p<0.01), and native myocardial T1 (r=0.34, p<0.01). FD had abnormal LA strain in overt disease (LVH +ve) compared to HVs (p<0.01). LVH-negative FD did not differ in LA strain compared with HV (p>0.5). FD with low T1+LVH-negative did not differ in LA strain compared with normal T1/LVH-negative FD or HV (p>0.3). ConclusionsLA strain is abnormal in FD with LVH (overt disease) and correlates with LVMi, native T1, and GLS. LA strain is normal in FD with early disease (LVH negative+low T1) and normal in FD with no myocardial disease (LVH negative + normal T1). These findings indicate that LA strain is a consequence of abnormal LV mechanics such as LVH and abnormal GLS, rather than isolated myocardial sphingolipid deposition. KEY MESSAGESO_ST_ABSWhat is already known on this topicC_ST_ABSFabry disease is an X-linked lysosomal disorder with potential cardiac complications. Progressive ventricular myocardial involvement drives morbidity and mortality and can be detectable through advanced imaging techniques like cardiovascular magnetic resonance. Early diagnosis of cardiac involvement can be difficult. What this study addsLA strain is abnormal in overt Fabry disease with left ventricular hypertrophy (LVH) and correlates with left ventricular mass, native T1, and global longitudinal strain (GLS). LA strain is normal in Fabry with early disease (LVH negative+low T1) and normal in FD with no myocardial disease (LVH negative + normal T1). These findings indicate that LA strain is a consequence of abnormal LV mechanics such as LVH and abnormal GLS, rather than isolated myocardial sphingolipid deposition. How this study might affect researchThere is a need to identify markers of early cardiac involvement in Fabry disease.