JCMR 2021; 23.131. Impaired left atrial reservoir and conduit strain in patients with atrial fibrillation and extensive left atrial fibrosis-Article

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This study examined how left atrial (LA) function relates to atrial fibrosis in patients with atrial fibrillation (AF) using advanced cardiovascular magnetic resonance (CMR). The researchers enrolled 105 AF patients scheduled for first pulmonary vein isolation; 94 had usable cine images and 82 had assessable fibrosis scans. Nineteen healthy subjects served as controls. All AF patients were scanned in sinus rhythm.<br /><br />The study measured LA phasic strain—reservoir, conduit, and contractile strain—using CMR feature tracking, and quantified LA fibrosis with 3D late gadolinium enhancement (LGE). Compared with healthy controls, AF patients had significantly worse LA function across all strain phases, larger LA volumes, and lower emptying fractions. Specifically, reservoir strain, conduit strain, and contractile strain were all reduced in AF.<br /><br />When AF patients were divided by the median amount of LA fibrosis, those with more extensive fibrosis had lower reservoir strain and conduit strain than those with less fibrosis. Contractile strain, however, did not differ between the two fibrosis groups. LA conduit strain showed the strongest association with fibrosis extent.<br /><br />The study also found that persistent AF was associated with larger atrial volumes than paroxysmal AF, but there were no significant differences in LA strain or fibrosis between the two AF subtypes in this cohort. Right atrial changes were less pronounced.<br /><br />Overall, the findings suggest that impaired passive LA function—especially reservoir and conduit strain—is linked to more extensive LA fibrosis in AF. The authors conclude that LA strain may be a useful marker of atrial remodeling, but further studies are needed to understand the biological basis and clinical implications, including whether these measures can help predict outcomes or guide therapy.

Keywords

left atrial function

atrial fibrillation

atrial fibrosis

cardiovascular magnetic resonance

CMR feature tracking

late gadolinium enhancement

LA strain

reservoir strain

conduit strain

atrial remodeling