How different types of cardiomyopathy with hypertrophic phenotype affect left atrial remodeling and function

Abstract Background Left atrial (LA) dysfunction is a common feature in hypertrophic cardiomyopathies. How the underlying etiology and pathophysiology of different cardiomyopathies affects LA remodeling and function remains unexplored. Purpose The aim of our study is to investigate the influence of various cardiomyopathies with hypertrophic phenotype on LA remodeling and function. Methods Patients with left ventricular (LV) hypertrophic phenotype who underwent cardiac magnetic resonance (CMR) were included. A group of patients with a normal CMR was included as a control group. CMR acquisitions used for clinical indication of heart failure diagnosis and etiology were retrospectively analyzed to obtain LA reservoir, conduit, and booster strain, left atrioventricular coupling index (LACI) and LA sphericity. Differences between groups were assessed. To investigate the independent clinical associates of LA reservoir, conduit and booster strain, multivariable linear regression analyses were performed. Results A total of 375 individuals were analyzed including 321 patients diagnosed with LV hypertrophy and 54 patients with a normal CMR. Of the 321 patients with LV hypertrophy, 148 were diagnosed with hypertrophic cardiomyopathy (HCM), 35 with cardiac amyloidosis (CA), 41 with hypertensive cardiomyopathy (HTN) and 97 with severe asymptomatic aortic stenosis (AS). CMR LA characteristic and strain analysis results are summarized in Figure 1. The indexed LA end-systolic volume (iLAVmax), indexed LA end-diastolic volume (iLAVmin) and LA sphericity were larger in patients with CA when compared to other groups (all p<0.05). CA patients displayed more left atrioventricular uncoupling (lower LACI) when compared to individuals with HCM, HTN, AS, and controls (all p<0.001), while no significant differences were observed across other groups. CA patients exhibited lower LA reservoir and booster strains compared to the other groups (all p<0.05), whereas no significant differences were observed across other hypertrophic phenotype diseases. Age, iLAVMax and LACI were independently associated with all the three LA strain components (Figure 2, all p<0.05). Conclusions LA remodeling and function are affected differently across the various etiologies of LV hypertrophy. CA patients exhibit more pronounced atrial involvement, whereas those with HCM, asymptomatic AS, and HTN display similar patterns of atrial dysfunction and remodeling. Additionally, CMR-derived iLAVmax and LACI are independently correlated with LA function.