Comparison of echocardiographic parameters in Fabry cardiomyopathy and light-chain cardiac amyloidosis

Background Aims Fabry cardiomyopathy (FC) and light-chain amyloid cardiomyopathy (AL) present with concentric left ventricular (LV) hypertrophy/remodeling and diastolic rather than systolic dysfunction. Direct comparisons are difficult due to rarity and confounded by variability of LV thickness. To compare LV diastolic and systolic properties between patients with FC and AL in a cohort matched for interventricular septal thickness (IVS). Methods Results A two-center echocardiographic analysis was performed, comprising 118 patients with IVS >= 12 mm (FC and AL 59 patients each) matched by IVS. Fabry cardiomyopathy patients had larger LV end-diastolic diameter (47.7 [44.0-50.9] vs 45.0 [41.5-49.0] mm, P = 0.002), better LV ejection fraction (EF 68.7 [63.4-74.0] vs 63.0 [54.0-70.0]%, P = 0.001) and midwall fractional shortening (midFS 14.8 [13.0-16.1] vs 12.1 [8.9-15.0]%, P = 0.006). LV EF <40% was rare in both (2% vs 7%, P = 0.17). AL patients expressed higher LV diastolic dysfunction grade (III in 26% vs 4%, II in 21% vs 12% and I in 54% vs 84%, P = 0.004), with higher E/e' ratio (13.6 [10.2-18.8] vs 9.8 [7.5-12.3], P < 0.0001). Average E/e' ratio and midFS were significantly associated with NYHA severity in both groups (P < 0.05 for all). Conclusions Matched AL patients had worse LV diastolic function than FC, driven by E/e'. Significant LV systolic dysfunction was rare overall. MidFS and E/e' were associated with heart failure severity in both groups.