Left atrial mechanics in moderate mitral valve disease: earlier markers of damage

While the impairment of left atrial (LA) mechanics in mitral valve disease is well known, the exact onset of reservoir, conduit, and contractile dysfunction in mitral stenosis (MS) and mitral regurgitation (MR) remains unclear. We aimed to clarify the LA deformation mechanics in patients with moderate mitral valve disease. We conducted a prospective observational study of 80 patients with moderate isolated MR, 80 patients with moderate isolated MS, and 64 age-matched controls without mitral valve disease. Strain (ɛ) and strain rate (SR) on speckle tracking echocardiography were assessed as indicators of LA and right atrium (RA) reservoir (ɛsys, SRs), conduit (ɛe, SRe), and contractile (ɛa, SRa) functions. Conventional echocardiographic parameters of the left ventricle (LV) were also assessed. Comparisons were conducted according to mitral valve pathology (MR patients, MS patients, controls). The mean LV ejection fraction, end-diastolic diameter, and global longitudinal strain did not differ across the groups. The pulmonary artery systolic pressure, LA volume indexed to body surface area, and LA mechanics were significantly impaired in mitral valve disease (patients vs controls). While LA ɛ did not vary between MR and MS, MR patients had better LA SRs and SRe but worse SRa (p < 0.01). SRe > - 0.65% had higher specificity for MS, with an area under the curve of 0.85 (p < 0.01). RA mechanics were significantly impaired in mitral valve disease (patients vs controls) but did not vary significantly with disease pathology (MS vs MR). Patients with moderate mitral valve disease exhibit early and pathology-specific changes in the LA deformation mechanics, manifesting mainly as impaired contractile-phase SR in MR and impaired conduit-phase SR in MS. Our findings highlight SR as a potentially useful early marker of LA dysfunction in relation to mitral valve disease.