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This Article Full Text Full Text (PDF) All Versions of this Article: 294/5/H2106    most recent 01128.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Neilan, T. G. Articles by Hung, J. PubMed PubMed Citation Articles by Neilan, T. G. Articles by Hung, J.

Progressive nature of chronic mitral regurgitation and the role of tissue Doppler-derived indexes

¹Cardiac Ultrasound Laboratory, ²Cardiology Laboratory of Integrative Physiology and Imaging, and ³Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts

Submitted 28 September 2007 ; accepted in final form 11 February 2008

The aim of this study was to determine whether severe mitral regurgitation (MR) is progressive and whether tissue-Doppler (TD)-derived indexes can detect early left ventricular (LV) dysfunction in chronic severe MR. Percutaneous rupture of mitral valve chordae was performed in pigs (n = 8). Before MR (baseline), immediately after MR (post-MR), and at 1 and 3 mo after MR, cardiac function was assessed using conventional and TD-derived indexes. The severity of MR was quantified using regurgitant fraction and effective regurgitant orifice area (EROA). In all animals, MR was severe. On follow-up, the LV dilated progressively over time, but LV ejection fraction did not decrease. With the increase in LV dimensions, the forward stroke volume remained unchanged, but the mitral annular dimensions, EROA, and regurgitant fraction increased (EROA = 41 ± 2 and 51 ± 2 mm² post-MR and at 3 mo, respectively, P < 0.01). Peak systolic myocardial velocities, strain, and strain rate increased acutely post-MR and remained elevated at 1 mo but declined by 3 mo (anterior strain rate = 2.9 ± 0.1 and 2.4 ± 0.2 s^–1 post-MR and at 3 mo, respectively, P < 0.001). Therefore, in a chronic model of MR, serial echocardiography demonstrated that MR begets MR and that those TD-derived indexes that initially increased post-MR decreased to baseline before any changes in LV ejection fraction.

effective regurgitant orifice area; strain; strain rate