The infiltration of left atria in patients with ATTR-CM can have various effects, all of which can be tracked in different ways. This study provides some insight into how it can be tracked, and its clinical significance.
The involvement of left atrial pathology in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) is of significant clinical interest. This study, published in Cardiovascular Imaging, attempts to characterize left atrial pathology in explanted hearts with ATTR-CM. The study relied on using echocardiographic speckle-tracking in a large cohort of patients with ATTR-CM, and to better understand the association with mortality or other clinically significant factors that affect this population.
To assess the presence, type, and extent of the studied ATTR-CM atria congo red staining and immunohistochemistry were conducted. Echo speckle tracking was used to evaluate left atrial reservoir, conduit, contractile function, and stiffness in 906 patients with ATTR-CM. Extensive amyloid infiltration was noted in the atria, with loss of normal architecture, vessel remodeling, capillary disruption, and subendocardial fibrosis. Echo speckle tracking demonstrated increased atrial stiffness, which remained independently associated with prognosis after adjusting for known predictors. Atrial contraction was absent in 22.1% of patients whose electrocardiograms showed sinus rhythm atrial electromechanical dissociation (AEMD), and patients with AEMD had poorer prognosis than those with sinus rhythm and effective mechanical contraction.
The authors conclude by noting that left atrial infiltration, including effects such as a loss of normal tissue architecture, is a phenotype of ATTR-CM, with atrial function decreasing over time along with an increase in stiffness, which was also noted as a strong predictor of mortality. AEMD, identified through myocardial deformation analysis, emerged as a distinctive phenotype that can help identify patients in sinus rhythm that have a poor prognosis.
Bandera, F., Martone, R., Chacko, L., Ganesananthan, S., Gilbertson, J. A., Ponticos, M., Lane, T., Martinez-Naharro, A., Whelan, C., Quarta, C., Rowczenio, D., Patel, R., Razvi, Y., Lachmann, H., Wechelakar, A., Brown, J., Knight, D., Moon, J., Petrie, A., . . . Fontana, M. (2022). Clinical Importance of Left Atrial Infiltration in Cardiac Transthyretin Amyloidosis. JACC: Cardiovascular Imaging, 15(1), 17-29. https://doi.org/10.1016/j.jcmg.2021.06.022