Early Impairment of Right Ventricular Morphology and Function in Transthyretin-Related Cardiac Amyloidosis

Background: Our study aimed to evaluate right ventricular (RV) morphology and strain (S) in the early stage of familial transthyretin (TTR) cardiac amyloidosis (CA). Methods and Results: Thirty‑seven patients with transthyretin mutation underwent 99mTc‑3,3‑diphosphono‑1,2 propanodicarboxylic acid (99mTc‑DPD) scans and/or cardiac magnetic resonance (CMR) to identify TTR CA. Each patient underwent echocardiography to quantify RV dimensions, tricuspid annular plane systolic excursion (TAPSE), systolic pulmonary artery pressure (sPAP), longitudinal (L) strain of the RV free wall, left ventricular (LV) septal thickness (ST), ejection fraction, E/E’, LV global (G) L, radial (R), and circumferential (C) S. 99mTc‑DPD and CMR revealed the accumulation in 22 of 37 patients (CA group) and no accumulation in 15 patients (no‑CA group). Left ventricular (LV) septal thickness (ST) was higher (P < 0.0001) while LV ejection fraction and E/E’ were lower (P < 0.05) in the CA group than the no‑CA group. LV‑global longitudinal strain (LS) was lower (P < 0.0001) in the CA‑group than the no CA‑group, whereas LV‑global circumferential strain and LV‑global radial strain were similar. The CA group showed higher values of RV dimensions (P < 0.05) and sPAP (0.02) and a lower (P = 0.002) TAPSE. Globally, RV‑LS was lower (P = 0.005) in the CA group than the no‑CA group. Basal and mid segments of the RV free wall showed a lower LS in the CA group than the no‑CA group (P < 0.01), while apical S was similar between groups. Conclusions: RV deformation, particularly in basal and mid segments, is early impaired in CA.