THE ADDED VALUE OF MYOCARDIAL WORK IN EARLY DETECTION OF SYSTOLIC DYSFUNCTION IN CARDIAC AMYLOIDOSIS

Aim: The involvement of the heart represents the main determinant of mortality and morbidity for patients with systemic amyloidosis (SA). In cardiac amyloidosis (CA), numbered among the clearest examples of restrictive cardiomyopathies, EF(ejection fraction) often keeps itself preserved (≥ 50%) but this doesn’t mean LV (left ventricle) systolic function couldn’t be impaired, even in the early stages of disease. In this survey we searched for echocardiographic signs of early systolic im- pairment in CA: among them we adopted the analysis of myocardial work (MW), an emerging less load-dependent tool for the evaluation of cardiac performance. Methods: We chose a cohort of patients (n=20; mean age 69±13 years) with AL or ATTR CA and we compared them with a control group (n=18; mean age 62±17 years) without evident cardiac damage. We examined their systolic and diastolic function and we calculated multilayer strain and all the contributors of MW from speckle tracking echocardiography. Results: We found a statistically relevant difference in cardiac mass (138±35 versus 83±23 g/m2) and in signs of both systolic and diastolic function (LAVi, TR Vmax, E/ e’) worsening between patients with CA and the control group. In CA average EF was 52±11% while the reduction in Global Longitudinal Strain (GLS) was significant, re- gardless of the considered wall layer and the stage of diastolic impairment. For our patients ejection fraction to strain ratio (EFSR, 4,41±1,38 vs 3,04±0,55), a simple way to quantify apical sparing, better underlined the dissociation between EF and strain than apex to base ratio. In CA we identified a dramatic decrease in Global Work Index (954±278 vs 2089±354 mmHg%) and Global Constructive Work (1103 ±323 vs 2376±390 mmHg%), with no significant difference between AL and ATTR amyloidosis. Conclusions: The infiltration by amyloid and the consequent increase in cardiac mass lead to an early and often severe weakening of the intrinsic contractility of the heart in both AL and ATTR amyloidosis, even when ejection fraction is normal or slightly reduced. Therefore, we suggest the analysis of MW starting from the first echocardiographic evaluation in patients with known SA or multiple myeloma.