Abstract 12547: Different Mechanisms of Exercise-Induced Mitral Regurgitation Between Degenerative and Functional Mitral Regurgitation: A Three-Dimensional Transesophageal Echocardiography Study.

Background: Exercise-induced mitral regurgitation (MR) is an important prognosticator regardless of MR etiology. However, different mechanisms of exercise-induced MR according to MR subgroups remain unknown. Measured using three-dimensional (3D) transesophageal echocardiography (TEE), 3D vena contracta area (3D-VCA) has shown to be an accurate parameter to quantify MR. The aims of this study were (1) to investigate the increase between resting 3D-VCA and 3D-VCA after hand-grip exercise (Δ3D-VCA), (2) to compare the Δ3D-VCA between degenerative and functional MR. Methods: Fifty-seven symptomatic patients with moderate to severe MR (degenerative MR, n=30; functional MR, n=27) were prospectively enrolled between May 2017 and May 2018. Using 3D TEE, MV geometry (annular diameters, annular height, averaged tenting height, 3D-VCA) and hemodynamic status were measured immediately before and after 5-minute hand-grip exercise (Figure 1). Results: There was no significant difference in 3D-VCA at rest (38.7±17.2 mm2 in degenerative MR vs. 34.4±14.3 mm2 in functional MR, P =0.32). After hand-grip exercise, the 3D-VCA increased significantly in both MR subgroups, but a larger Δ3D-VCA was observed in functional MR (16.0±9.8 mm2 vs. 5.9±4.7 mm2, P <0.001; Figure 2). In functional MR, a significant augmentation in averaged tenting height was observed after hand-grip exercise (P <0.001). Univariable linear regression analysis revealed the association of Δ3D-VCA with averaged tenting height in functional MR and with blood pressure in degenerative MR (both P <0.01). Conclusions: Hand-grip exercise alters MV geometry and causes an exacerbation of MR. The effects of changes in MV geometry and their association with increased MR severity differs between degenerative and functional MR. [ABSTRACT FROM AUTHOR]