Mechanisms and predictors of ischemic mitral regurgitation at rest and on exertion in patients at early stage of myocardial infarction

Aim. Determination of the mechanisms and predictors of ischemic mitral regurgitation (IMR) at rest and on exertion in patients at early stage of myocardial infarction (MI).

Material and methods. Seventy-seven patients with inferoposterior MI and 79 patients with anteroseptal apical MI were examined on the 7th day at rest and after exertion. We determined the degree of IMR (according to the PISA method), posteromedial and anterolateral papillary muscle (PM) displacement, closure height of the mitral valve (MV), systolic and diastolic mitral valve orifice area, volume of the left ventricle (LV), LV contractility index, deformation of the infarction regions, general LV deformation, deformation and systolic dyssinchrony of the PM.

Results. IMR was more common in inferior MI (42% vs 28%). LV volumes in cases with anteroseptal apical MI and IMR were greater and LV deformation was less than in patients without IMR. In inferoposterior MI and IMR, differences were observed in the index of local contractility and function of the posteromedial PM. The differences in MI of both localizations and IMR compared with MI without IMR were the areas of the mitral orifice and dyssinchrony of the PM. The degree of IMR after exertion did not depend on the degree of IMR at rest. Predictors of IMR at rest in MI of both localizations were the apical displacement of MV closure and the area of the mitral orifice. In inferoposterior, posteromedial PM displacement, deformation of the infarcted areas, PM dyssinchrony were also predictors. In anteroseptal apical MI, the area of the mitral orifice was the predictor of IMR. Predictors of anteroseptal apical MI after physical exertion after inferior MI were mitral orifice areas, contractility index, displacement and deformation of the posteromedial PM. In anteroseptal apical MI, the IMR predictors were MV closure height and systolic area of mitral orifice.

Conclusion. The study confirms the significance of changing the spatial orientation of the MV structures in MI of both localizations, impaired regional contractility in inferoposterior MI and LV volume in anteroseptal apical MI at early stage of the disease.

1. Pierard LA, Carabello BA. Ischaemic mitral regurgitation: Pathophysiology, outcomes and the conundrum of treatment. Eur Heart J. 2010;31:2996-3005. doi:10.1093/eurheartj/ehq411.

2. Varma PK, Krishna N, Jose RL, et al. Ischemic mitral regurgitation. Ann Card Anaesth. 2017;20(4):432-9. doi:10.4103/aca.ACA_58_17.

3. Meris A, Amigoni M, Verma A, et al. Mechanisms and predictors of mitral regurgitation after high-risk myocardial infarction. J Am Soc Echocardiogr. 2012;25:535-42. doi:10.1016/j.echo.2012.01.006.

4. Agricola E, Oppizzi M, Pisani M, et al. Ischemic mitral regurgitation: mechanisms and echocardiographic classification. Eur J of Echocardiоgг. 2008;9:207-21. doi:10.1016/j.euje.2007.03.034.

5. Szymanski C, Levine RA, Tribouilloy C, et al. Impact of mitral regurgitation on exercise capacity and clinical outcomes in patients with ischemic left ventricular dysfunction. Am J Cardiol. 2011;108:1714-20. doi:10.1016/j.amjcard.2011.07.045.

6. Lang RM, Badano LP, Mor-Avi V, et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging J Am Soc Echocardiogr. 2015;28:1-39. doi:10.1016/j.echo.2014.10.003.

7. Dudzinski DM, Hung J. Echocardiographic assessment of ischemic mitral regurgitation. Cardiovasc Ultrasound. 2014;12:46. doi:10.1186/1476-7120-12-46.

8. Lancellotti P, Tribouilloy C, Hagendorff A, et al. Recommendations for the echocardiographic assessment of native valvular regurgitation: An executive summary from the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2013;14:611-44. doi:10.1093/ehjci/jet105.

9. Tigen K, Karaahmet T, Dundar C, et al. The importance of papillary muscle dyssynchrony in predicting the severity of functional mitral regurgitation in patients with nonischaemic dilated cardiomyopathy: a two dimensional speckle tracking echocardiography study. Eur J Echocardiogr. 2010;11:671-6. doi:10.1093/ejechocard/jeq040.

10. Kılıcgedik A, Kahveci G, Gurbuz S, et al. Papillary muscle free strain in patients with severe degenerative and functional mitral regurgitation Arq Bras Cardiol. 2017;108(4):339-46. doi:10.5935/abc.20170035.