Early detection of right atrial dysfunction in patients with hypertrophic cardiomyopathy using cardiac magnetic...

The importance of right heart evaluation in hypertrophic cardiomyopathy (HCM) is being increasingly acknowledged in both clinical practice and research. Cardiac magnetic resonance-feature tracking (CMR-FT) has emerged as a valuable approach for quantifying cardiac function and myocardial deformation. This study aimed to evaluate whether early right atrial (RA) dysfunction in patients with HCM, with or without RA enlargement (RAE), could be detected with CMR-FT.

A total of 143 patients with HCM, divided into an RAE group (n=25) and a non-RAE group (n=118), along with 70 age- and gender-matched healthy controls were retrospectively included from June 2023 to July 2024 at three tertiary hospitals. RA reservoir strain (εs), conduit strain (εe), booster strain (εa), peak positive strain rate (SRs), peak early negative strain rate (SRe), and peak late negative strain rate (SRa) were obtained using CMR-FT. The Chi-square test, one-way analysis of variance (ANOVA) with post-hoc analysis, linear regression analysis, intraclass correlation coefficients (ICCs), and Bland-Altman plots were applied for statistical analysis.

The HCM RAE group had significantly greater indexed RA maximum, pre-atrial contractile, and minimum volumes than did both the healthy control group and the HCM non-RAE group (all P values <0.05); there were no significant differences between the healthy control group and the HCM non-RAE group. Both the RAE and non-RAE groups exhibited significantly lower RA εs (31.77%±10.08% vs. 31.62%±13.04% vs. 48.34%±12.45%), εe (15.36%±7.12% vs. 16.66%±8.71% vs. 28.83%±11.04%), εa (16.40%±7.50% vs. 14.97%±7.04% vs. 19.51%±5.81%), SRs (1.69±0.81 vs. 1.78±0.81 vs. 2.10±0.70 s^-1), SRe (-1.29±0.61 vs. -1.32±0.70 vs. -2.25±1.04 s^-1), SRa (-1.68±0.80 vs. -1.66±0.84 vs. -2.14±0.70 s^-1), and RA emptying fraction (RAEF) booster values than control group (all P values <0.05), while there was no difference in RAEF total or RAEF passive between the three groups. Simple linear regression analysis revealed significant correlations between RA strain parameters and right ventricular ejection fraction (RVEF) (εs and RVEF: r=0.56, P<0.001; εe and RVEF: r=0.48, P<0.001; εa and RVEF: r=0.42, P<0.001). The reproducibility indices of RA deformation parameters were reasonably good, with all ICCs >0.75 and narrow limits of agreement in the Bland-Altman plots.

Patients with HCM exhibit impaired RA reservoir, conduit, and booster pump function even in the presence of normal RA volumes. CMR-FT-derived RA strain and strain rate may serve as more sensitive indicators than traditional RAEF metrics for identifying early RA dysfunction in patients with HCM.