Papillary Muscle Dysfunction Attenuates Ischemic Mitral Regurgitation in Patients With Localized Basal Inferior Left Ventricular Remodeling
Insights From Tissue Doppler Strain Imaging
Takeshi Uemura, MD*,
Yutaka Otsuji, MD, FACC*,1,*,
Kenichi Nakashiki, MD*,
Shiro Yoshifuku, MD*,
Yuko Maki, MD*,
Bo Yu, MD*,
Naoko Mizukami, MD*,
Eiji Kuwahara, MD*,
Shuichi Hamasaki, MD*,
Sadatoshi Biro, MD*,
Akira Kisanuki, MD*,
Shinichi Minagoe, MD*,
Robert A. Levine, MD, FACC and
Chuwa Tei, MD, FACC*
* First Department of Internal Medicine, Graduate School of Medicine, Kagoshima University, Kagoshima, Japan
Massachusetts General Hospital, Boston, Massachusetts
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Figure 1 Expected potential and opposing effects of papillary muscle (PM) dysfunction resulting in exaggeration or attenuation of leaflet tethering and mitral regurgitation (MR). (Middle panel) Remodeling of the adjacent left ventricular (LV) wall, which accompanies PM dysfunction, causes outward displacement of the PM and thereby induces augmented leaflet tethering with MR. (Right panel) In the presence of adjacent LV wall remodeling, PM dysfunction per se results in systolic PM elongation or less shortening, which thus attenuates tethering and MR. LA = left atrium.
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Figure 3 Methods used to evaluate papillary muscle (PM) function. Normal systolic PM thickening seen by two-dimensional echocardiography is shown in the left upper and lower panels and the right panel shows normal systolic PM longitudinal shortening as assessed by tissue strain imaging.
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Figure 4 Scatter plots showing the relationships between the mitral regurgitation (MR) fraction and medial papillary muscle (PM) peak systolic strain (left panel) or medial PM tethering distance (right panel). The MR fraction was significantly correlated with the medial PM tethering distance in all of the subjects taken together and those in group 1. While the MR fraction did not show a significant correlation with the PM systolic strain in all of the subjects with variable degrees of associated left ventricular (LV) remodeling, there was a significant correlation in group 1 patients with LV remodeling of a similar location and extent.
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Figure 5 A patient with significant ischemic mitral regurgitation (MR) despite good papillary muscle (PM) function shown by normal systolic PM thickening on two-dimensional echocardiography (left upper and lower panels) and normal systolic PM longitudinal shortening with strain imaging (right panel). The medial PM tethering distance (arrows) is long and can explain the MR.
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Figure 6 A patient with trace mitral regurgitation (MR) despite poor papillary muscle (PM) function shown by absent systolic PM thickening on two-dimensional echocardiography (left upper and lower panels) and systolic PM longitudinal elongation as assessed by strain imaging (right panel). The medial PM tethering distance (arrows) is normal and can explain the lack of significant MR.
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1 = lateral papillary muscle (PM) tethering distance;