How are left atrial mechanics and deformation altered in patients with chronic primary mitral regurgitation compared to controls?
In chronic primary mitral regurgitation, left atrial deformation is increased across all phases, but unchanged LA ejection fraction and reduced contractile tissue velocity suggest a reduced contractile contribution to left ventricular filling.
AIMS: To study global and regional left atrial (LA) mechanics in chronic primary mitral regurgitation (MR) with echocardiography. METHODS AND RESULTS: LA volumes during reservoir, conduit, and contractile phases were measured in 27 MR patients and 25 controls. LA ejection fraction (EF) and ejection force were calculated. Reservoir (SR-R), conduit (SR-C), and contractile phase (SR-A) strain rates, and reservoir phase strain were obtained. LA volumes were higher in MR in all phases. In MR, ejection force was increased (21.5 vs. 12.3 kdynes, P = 0.001); reservoir phase strain (32.91 +/- 14.26%), SR-R (2.65 +/- 0.87), SR-C (-2.02 +/- 0.58), and SR-A (-2.55 +/- 1.31 s(-1)) were increased (23.14 +/- 7.96%, 1.62 +/- 0.53, -1.29 +/- 0.59, -1.98 +/- 0.65 s(-1), in controls, respectively, P < or = 0.004). Regional deformation correlated with corresponding volumetric parameters. Despite enhanced SR-A in MR, LA EF was unchanged (31.34 vs. 29.23%, P = ns), and LA contractile tissue velocity (A') was reduced (-5.39 +/- 1.95 vs. -6.91 +/- 1.80 cm/s, P = 0.006). The LA contractile contribution to left ventricular filling was significantly reduced in MR. CONCLUSION: LA deformation is increased in all phases in MR. Unchanged LA EF and reduced A' may reflect the reduced contractile contribution to left ventricular filling.
Borg et al. (Tue,) studied this question.