Left Atrial Dynamics During Exercise in Mitral Regurgitation of Primary and Secondary Origin: Pathophysiological Insights by Exercise Echocardiography Combined With Gas Exchange Analysis

The aim of this study was to identify the pattern of exercise left atrial (LA) dynamics, its gas exchange correlates, and prognosis in mitral regurgitation (MR) of primary and secondary origin. The adaptive response and clinical significance of LA function during exercise in MR is undefined. A total of 196 patients with MR (81 with primary MR, 115 with secondary MR) and 54 control subjects underwent exercise stress echocardiography and cardiopulmonary exercise testing with LA function assessment. Patients with MR were divided into 4 groups according to etiology and severity using a cutoff of 3+. LA dynamics was studied using speckle-tracking echocardiography. Compared with control subjects, patients with MR had a lower LA strain and strain rate at rest. Exercise LA strain and LA strain rate progressively worsened from primary MR