Comparative analysis of right atrial function in arrhythmogenic right ventricular cardiomyopathy and dilated cardiomyopathy using cardiac magnetic resonance-feature tracking.

Background: Although the importance of right atrial (RA) function is being increasingly acknowledged, comparative studies investigating RA dysfunction in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM) remain limited. This study aimed to compare RA function between ARVC and DCM using cardiac magnetic resonance-feature tracking (MR-FT). Methods: This retrospective study (June 2018 to December 2022) included 38 patients with ARVC, 98 patients with DCM, and 72 sex- and age-matched healthy controls (HC). RA deformation parameters, including RA reservoir strain (εs), conduit strain (εe), and booster strain (εa), as well as RA peak positive strain rate (SRs), peak early negative strain rate (SRe), and peak late negative strain rate (SRa), were assessed using the MR-FT technique. Group differences in RA deformation parameters were analyzed using one-way analysis of variance (ANOVA) and Kruskal-Wallis test. Pearson and Spearman correlation methods were performed to explore the correlation between RA deformation parameters and RA emptying fractions (RAEFs). Results: Patients with ARVC exhibited greater right ventricular (RV) end-diastolic volumes than those with DCM (P<0.001). Compared with HC, both ARVC and DCM patient cohorts had lower RA εs {49.5%±14.4% Conclusions: Despite the more pronounced RV dilation in patients with ARVC, those with DCM exhibited significantly greater impairment in RA function with lower MR-FT-derived RA strain and SR values. ARVC and DCM showed different pathological patterns in RA dysfunction.