Effect of Exercise on Left Atrium Mechanics in Mild Mitral Stenosis.

Objective: A significant number of individuals with mild mitral stenosis (MS) experience exertional symptoms that are disproportionate to the hemodynamic severity of their condition. This study aims to determine whether exercise-induced left atrial (LA) dysfunction occurs in these patients and whether it is related to the development of symptoms.

Methods: In this observational study, we recruited 46 patients with mild MS. Echocardiographic measurements were initially taken at rest, followed by a maximal exercise stress test. Patients were then returned to the echocardiography laboratory for post-exercise measurements.

Results: Our study cohort exhibited considerably higher left atrial volume index (LAVI) values (mean: 40.52 ± 18.27) compared to those of a healthy population. Furthermore, the LA reservoir strain (mean: 17.1 ± 8.33) was reduced relative to reference values. Following exercise, there was no change in the LA reservoir strain. However, trans-mitral pressure gradients and systolic pulmonary artery pressures increased. The post-exercise mean trans-mitral gradient was identified as the sole predictor of symptom development in patients with mild MS.

Conclusion: The LA reservoir strain is already reduced in individuals with mild MS, and exercise does not lead to further decline in LA reservoir function in these cases. To our knowledge, this study is the first to explore the effects of exercise on LA mechanics in MS.