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Background: Right ventricular (RV) function is inadequately investigated and routinely overlooked in transthyretin amyloid cardiomyopathy (ATTR-CM). Novel imaging distinguishers between intrinsic RV myocardial disease in ATTR-CM and primary RV overload disorder phenotypes may enhance mechanistic and pathophysiological understanding of RV dysfunction. We aimed to investigate RV performance in ATTR-CM employing comprehensive 2D and 3D echocardiography, and to compare these indices with primary RV afterload disease.

Methods: We investigated conventional and novel indices of RV contractile function, myocardial work and ventricular–vascular coupling in 21 well-characterized ATTR-CM patients, 10 PAH patients and 12 healthy controls. RV long axis function and pulmonary artery (PA) systolic pressure were evaluated using 2D Doppler echocardiography. RV ejection fraction (RVEF), volumes, global longitudinal strain (GLS) and novel myocardial work indices were analyzed by 3D echocardiography. RV elastance (E_es), afterload (E_a) and RV-PA coupling (E_es/E_a) were estimated using the single-beat volume method.

Results: ATTR-CM showed lower RVEF, GLS and E_es, and a higher RV global myocardial work index (GWI), constructive work (GCW), E_a and RV-PA coupling compared with controls. RV EF, stroke volume, GLS and circumferential strain did not differ between ATTR-CM and PAH. However, GWI, GCW, E_es and E_a were lower in ATTR-CM. RV–pulmonary coupling displayed strong association with RV 3D strain (r = 0.84, p < 0.001), whereas RV E_es (contractility) was related to RV GWI (r = 0.54, p < 0.001).

Conclusions: ATTR-CM displayed lower RV performance, higher global myocardial work and higher RV-PA coupling than controls. Myocardial work indices E_es and E_a are novel distinguishers of RV dysfunction phenotypes. The clinical and prognostic value of these novel variables warrant further investigation.

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an infiltrative disease of the myocardium in which extracellular deposits of amyloid cause progressive cardiac impairment.

Objectives: We aimed to evaluate left atrial (LA) deformation and its association with left ventricular (LV) deformation using LA-LV strain loops in patients with ATTR-CM and patients with left ventricular hypertrophy (LVH). We hypothesized that LA strain in ATTR-CM patients is abnormal and more independent of LV strain, compared to LVH patients.

Methods: Retrospective study based on echocardiographic data including 30 patients diagnosed with ATTR-CM based on an end diastolic interventricular septal (IVSd) thickness of ≥14mm, and 29 patients with LVH (IVSd ≥14mm and no ATTR-CM diagnosis) together with 30 controls. LV global longitudinal strain (LV-GLS) and LA strain, assessed as peak atrial longitudinal strain (PALS), were acquired and plotted to construct LA-LV strain loops and using regression line to determine a LA-LV strain slope.

Results: Significantly lower PALS and LA-LV strain slope values were detected in ATTR-CM patients compared to LVH patients (p=0.004 and p=0.014 respectively). A ROC curve demonstrated similar area under the curve (AUC) using PALS (AUC 0.72) and LA-LV slope (AUC 0.71), with both resulting in higher values than recorded for LV-GLS (AUC 0.62).

Conclusions: LA deformation demonstrates an independent ability to differentiate ATTR-CM from LVH. Combining LV strain and LA deformation analysis displays the mechanical LA/LV dissociation in ATTR-CA and potentially unmasks LA amyloid infiltration, this could potentially enable quicker diagnosis and initiation of treatment for ATTR-CM.