Introduction: Cardiac amyloidosis (AC) is described as one entity. However, several subtypes of amyloid can infiltrate the heart: light chain amyloid (AL) and tranthyretin amyloid (ATTR) are the most common.

Objective: The purpose of this study is to characterize the specific findings of the CA subtypes as a tool to aid differential diagnosis between AL and ATTR CA.

Methods: Consecutive patients with CA were evalua-ted by clinical examination, electrocardiogram, cardiac biomarkers and comprehensive echocardiography with both conventional measurements and myocardial de-formation study of the left ventricle (LV), left atrium (LA) and right ventricle (RV).

Results: 32 consecutive patients with cardiac amyloido-sis (CA) were included, 13 with ATTR (group ATTR) and 19 with AL amyloidosis (group AL). Patients in AL group were significantly older (50 ± 12 vs. 60 ± 8 y o, p=0.01), with higher levels of cardiac biomarkers (NT-proBNP 3066 ± 3720 vs. 11755 ± 9114 pg/mL, p=0.02; hsTnI 0.005 ± 0.008 vs. 0.147 ± 0.161 ng/mL, p=0.04), all the patients in AL group presenting pericardial fluid (53 vs. 100%, p=0.002). At similar LV volumes (LVEDV 88 ± 25 vs. 75 ± 38 mL, p=ns),) ejection fraction (50 ± 8 vs. 49 ± 16%, p=ns) and LV wall thickness (LVMi=166 47 vs. 168 ± 41 g/m2, p=ns), they had lower LV GLS (-12.1 ± 3.8 vs. -8.9 ± 4.5%, p=0.04). Also no difference was identified between the apical sparing pattern (sep-tal LS bazal/apical 0.33 ± 0.17 vs. 0.25 ± 0.27, p=ns) or between the values of systolic or diastolic velociti-es measured by TDI (average mitral S’, average mitral e’). Diastolic dysfunction was present in both groups, without any significant difference between them (E/A 2.1 ± 1.0 vs. 2.2 ± 1.6, p=ns; E/e’ 22.5 ± 17.1 vs. 19.9 ± 6.0, p=ns), suggesting high filling pressures. LA functi-on parameters were also lower in AL pts (LAEF – 4CV 35 ± 21 vs. 24 ± 8%, p=0.05; LA Systolic Strain 17.4 ± 11.9 vs. 10.5 ± 5.0%, p=0.02; LA ESR -1.0 ± 0.8 vs. -0.61 31 s-1, p=0.03), with the same dimensions of LA (LAVi 46 ± 21 vs. 45 ± 14 mL/m², p=ns). In terms of RV analysis the only parameters that showed significant difference were 6 segments RV strain (-15 ± 4 vs. -10 8%, p=0.09) and sPAP value (36.6 ± 12.0 vs. 48.6 ± 17.2 mmHg, p=0.04). Using ROC curves, the best pre-dictors for AL diagnosis were NTproBNP (AUC 0.937) and troponin levels (AUC 0.958), as well as LV GLS and pericardial fluid presence (both AUC 0.750).

Conclusions: At similar LV wall thickness and ejection fraction, cardiac dysfunction appears to be more severe in AL patients, with lower global LV longitudinal stra-in, worse LA function, higher systolic PAP and cardiac biomarkers.