RESUMO
BACKGROUND AND AIM OF THE STUDY: The relationship between mitral valve (MV) resistance and left atrial (LA) mechanical function is unknown. Hence, the study aim was to investigate the relationship between LA mechanics and MV resistance, compared to conventional indices such as mitral valve area (MVA) and transmitral gradient, in patients with rheumatic mitral stenosis (MS). METHODS: The study population consisted of 73 patients with MS and 30 age- and gender-matched controls. MV resistance was calculated and LA strain parameters were assessed from the apical four-chamber view by speckle tracking echocardiography (LA reservoir strain, LA pump strain, LA strain rate (SR)) in all subjects. RESULTS: The MS group has a markedly higher MV resistance (94 +/- 46 versus 67 +/- 22 dynes x s x cm(-5), p = 0.003) and lower LA reservoir strain (24.5 +/- 7.4% versus 36.6 +/- 3.8%, p < 0.001), LA pump strain (12.0 +/- 5.0% versus 17.1 +/- 3.4%, p < 0.001) and SR (1.23 +/- 0.33 versus 1.4 +/- 0.29, p = 0.017) values compared to controls. Moreover, both LA reservoir strain and LA pump strain correlated with MV resistance more closely than did MVA and transmitral gradients. Multiple linear regression analysis revealed only MV resistance to be an independent predictor of LA reservoir strain, while MV resistance, indexed left atrial volume and mean gradient were independent predictors of LA pump strain. CONCLUSION: It can be concluded that, in patients with MS, mitral valve resistance was more closely related to LA mechanics measurements than were conventional indices of MS.
