Differentiating transthyretin cardiac amyloidosis among left ventricular hypertrophy phenotypes: the role of right and left ventricular global longitudinal strain

Abstract Introduction Left ventricular hypertrophy (LVH) may result from various cardiomyopathies, complicating the differentiation of transthyretin cardiac amyloidosis (ATTR-CA) from other LVH phenotypes. The overlap in echocardiographic features can hinder timely diagnosis and limit access to targeted therapeutic interventions. Objectives Assess the diagnostic accuracy of right ventricular (RV) and left ventricular (LV) global longitudinal strain (GLS) to discriminate ATTR-CA in patients (pts) evaluated for suspected CA at a Cardiomyopathy Clinic in a regional hospital in Portugal. Methods Retrospective single-center study of 96 adult pts followed from 2018 to 2024. Inclusion criteria: pts aged ≥ 60 years with LV wall thickness ≥ 12mm and at least one cardiac/extracardiac red flag for CA. Baseline clinical data were collected, and speckle tracking echocardiography was used to analyze RV and LV GLS at the time of diagnosis. Pts were classified in the ATTR-CA group (group 1) and the non-ATTR-CA group (group 2) according to the ESC algorithm for the diagnosis of ATTR-CA. Group comparisons were performed. Results 96 pts were included (median age 79 [IQR 10] yrs, 77% male). Following the diagnostic workup, 52 pts (54%) were assigned to group 1, and 44 pts (46%) to group 2, which included 19 with hypertrophic cardiomyopathy, 13 with hypertensive heart disease, 3 with valvular heart disease, and 9 with multifactorial heart disease. Group 1 pts were older (81 [IQR 8] vs 78 [IQR 10] yrs, p=0.006) and more frequently had overweight (58 vs 32%, p=0.011) and chronic kidney disease (62 vs 39%, p=0.025). Regarding heart failure characterization, the majority of pts had a LV ejection fraction > 50% (67 vs 84%, p=0.06). Pts with CA had greater interventricular septum thickness (18.5±3.2 vs 15.7±2.8mm, p