Left atrial fibrosis correlates with extent of left ventricular myocardial delayed enhancement and left ventricular strain in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is associated with increased left ventricular (LV) mass, decreased myocardial strain, and the presence of LV fibrosis and scar. The relationship between LV scar and fibrosis with left atrial (LA) fibrosis in the setting of HCM has not been examined. The purpose of this study is to demonstrate a correlation between the degree of LA fibrosis and LV parameters in subjects with HCM. Twenty-eight subjects with HCM were imaged on a 1.5T MRI scanner with cine, LV and LA late gadolinium enhancement (LGE) sequences. LA LGE and LA measurements were correlated with LV measurements of volumes, mass, strain, and LGE. Other clinical conditions and medication usage were also examined and evaluated for correlation with LA and LV parameters. LV LGE was identified in 24 (86%) of the cases and LA LGE was identified in all of the cases. Extent of LA fibrosis significantly correlated with percent LV LGE (r = 0.64, p = 0.001), but not with indexed LV mass or maximum wall thickness. Extent of LA fibrosis also moderately correlated with decreased LV global strain (radial, r = - 0.50, p = 0.013; circumferential, r = 0.47, p = 0.02; longitudinal, r = 0.52, p = 0.013). Increased LA systolic volume correlated moderately with LV end diastolic volume (r = 0.50, p = 0.006). Patients on therapy with Renin-Angiotensin-Aldosterone System (RAAS) Inhibition had significantly less LA LGE compared to those without (18.6% vs 10.8%, p = 0.023). LA fibrosis, as measured by LGE, is prevalent in HCM and is correlated with LV LGE. The correlation between LA and LV LGE might suggest either that LA fibrosis is a consequence of LV remodeling, or that LA and LV fibrosis are both manifestations of the same cardiomyopathic process. Further study is warranted to determine the causality of LA scar in this population.