Right atrial strain predicts collagen mRNA levels in human right atrium

Abstract Background Structural remodelling, which includes increased fibrosis and collagen production, is a hallmark of atrial cardiomyopathy. Echocardiographic strain measurements allow detailed assessment of atrial function. We investigated the association between right atrial (RA) strain and collagen mRNA levels in human RA. Methods RA biopsies were collected from 21 patients undergoing elective coronary artery bypass grafting in the prospective observational study CONSIDER-AF. Tissue mRNA levels of collagen type I (Col1A) and of collagen type III (Col3A) were quantified using real-time qPCR on ViiA 7 real-time PCR system. Echocardiographic RA strain (reservoir, conduit, and booster function) was measured in the four-chamber view using the designated software Philips QLAB. We performed uni- and multivariable linear regression analysis to elucidate the relationship between RA strain and collagen mRNA levels. Results There was a strong correlation between RA reservoir strain and Col1A mRNA levels (p=0.0152, r²=0.2608, Fig A) and Col3A mRNA levels (p=0.0058, r²=0.3374, Fig B) as well as between RA conduit strain and Col1A mRNA levels (p=0.0301, r²=0.2141, Fig C) and Col3A mRNA levels (p=0.0232, r²=0.2430, Fig D). However, there was no correlation between RA booster function and Col1A levels (p=0.5572, Fig E) or Col3A levels (p=0.3426, Fig F). Multivariate regression analysis revealed that RA conduit and RA reservoir function are predictors for Col1A and Col3A mRNA levels independent from clinical covariates (age, sex, body-mass index, systolic blood pressure). Discussion Our findings show that RA strain measurements are associated with RA collagen mRNA levels in humans and therefore highlight the potential of strain analysis to identify structural remodelling in atrial cardiomyopathy.FigureTable