Three-Dimensional Echocardiographic Assessment of Right Ventricular Global Myocardial Work and Ventricular-Pulmonary Coupling in ATTR Cardiac Amyloidosis.

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 (Ees), afterload (Ea) and RV-PA coupling (Ees/Ea) were estimated using the single-beat volume method.

Results

ATTR-CM showed lower RVEF, GLS and Ees, and a higher RV global myocardial work index (GWI), constructive work (GCW), Ea and reduced 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, Ees and Ea were lower in ATTR-CM. RV-pulmonary coupling displayed strong association with RV 3D strain (r = 0.84, p < 0.001), whereas RV Ees (contractility) was related to RV GWI (r = 0.54, p < 0.001).

Conclusions

ATTR-CM displayed lower RV performance, higher GMW and reduced RV-PA coupling. Myocardial work indices Ees and Ea are novel distinguishers of RV dysfunction phenotypes. The clinical and prognostic value of these novel variables warrant further investigation.