RESUMO
Left ventricular [LV] twist is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of LV function. We sought to assess the impact of chronic pure mitral regurgitation [MR] on the torsional mechanics of the left human ventricle using tissue Doppler imaging. Nineteen severe MR patients with a normal LV ejection fraction and 16 non-MR controls underwent conventional echocardiography and apical and basal short-axis color Doppler myocardial imaging [CDMI]. LV rotation at the apical and basal short-axis levels was calculated from the averaged tangential velocities of the septal and lateral regions, corrected for the LV radius over time. LV twist was defined as the difference in LV rotation between the two levels, and the LV twist and twisting/untwisting rate profiles were analyzed throughout the cardiac cycle. LV twist and LV torsion were significantly lower in the MR group than in the non-MR group [10.38° +/- 4.04° vs. 13.95° +/- 4.27°; p value = 0.020; and 1.29 +/- 0.54 °/cm vs. 1.76 +/- 0.56 °/cm; p value = 0.021, respectively], both suggesting incipient LV dysfunction in the MR group. Similarly, the untwisting rate was lower in the MR group [-79.74 +/- 35.97 °/s vs.-110.96 +/- 34.65 °/s; p value = 0.020], but there was statistically no significant difference in the LV twist rate. The evaluation of LV torsional parameters in MR patients with a normal LV ejection fraction suggests the potential role of these sensitive variables in assessing the early signs of ventricular dysfunction in asymptomatic patients