Severe Mitral Regurgitation Triggered by Myocardial Ischemia in Hypertrophic Cardiomyopathy With Abnormalities of the Mitral Valve Complex

Figures

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  Figure 1. Transthoracic Echocardiography Demonstrating Severe MR Without LVOT Obstruction (A) Parasternal long-axis view with color Doppler imaging obtained after alcohol septal ablation (4 years before the current admission), demonstrating mild to moderate MR. (B) Parasternal long-axis view with color Doppler imaging at the current admission, revealing severe MR with a broad regurgitant jet. (C) Parasternal long-axis mitral valve–focused view during systole, demonstrating markedly impaired mitral leaflet coaptation with persistent leaflet separation observed during systole (red arrowheads). (D) LVOT velocity time integral (VTI) measured on admission showing a peak pressure gradient (PG) of 3.9 mm Hg. (E and F) Apical 4-chamber (E) and parasternal long-axis (F) views showing an abnormally developed papillary muscle extending toward and attaching near the apical region (yellow arrowheads). (G and H) Apical 3-chamber view during systole (G) and diastole (H). Severe hypokinesis of the apical left ventricular wall is observed (red dotted outline in G), with attachment of the abnormal papillary muscle to the affected region (yellow arrowheads). LVOT = left ventricular outflow tract; MR = mitral…

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  Figure 2. Coronary Angiography Demonstrating Newly Developed RCA Occlusion at the Current Admission (A) Right coronary angiogram on admission (LAO view) showing total occlusion of the RCA in the middle portion (yellow arrowhead). (B) Left coronary angiogram on admission (LAO cranial view) showing collateral flow from the LCA to the posterior descending branch of the RCA (red arrowheads). (C and D) Right coronary angiogram obtained immediately before alcohol septal ablation performed 4 years before the current admission (C: LAO view, D: RAO view). No significant stenosis or occlusions were observed. LAO = left anterior oblique; LCA = left coronary artery; RAO = right anterior oblique; RCA = right coronary artery.

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  Figure 3. Cardiac Magnetic Resonance Imaging Obtained 6 Years Before the Current Admission Demonstrating Anomalous Papillary Muscle Morphology of the Mitral Valve Apparatus (A) Cine short-axis image showing multiple hypertrophied papillary muscles, including anteriorly displaced papillary muscles (yellow arrowheads). (B) Cine 4-chamber view showing a prominent papillary muscle extending toward and in close proximity to the mitral leaflets. (C) Magnified view of the white boxed region in (B), highlighting the thickened papillary muscle adjacent to the mitral valve leaflet (yellow arrowheads). (D and E) Cine 4-chamber (D) and 2-chamber (E) views showing an anomalous papillary muscle extending toward and attaching near the apical region (yellow arrowheads).

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  Figure 4. Macroscopic and Histopathological Features of the Resected Mitral Valve Apparatus (A) Gross appearance of the anterior mitral leaflet with attached thickened chordae tendineae (yellow arrowheads). (B) Low-power histological overview of the anterior mitral leaflet, chordae tendineae, and papillary muscles (Elastica van Gieson stain). The chordae tendineae were markedly shortened (13 mm from the papillary muscle to the leaflet) compared with a normal mitral valve apparatus. (C) Middle-power view of the thickened anterior mitral leaflet, corresponding to the boxed area in (B) (hematoxylin and eosin stain). (D and E) High-power views of the anterior mitral leaflet showing increased elastic fibers (D, elastic Masson trichrome stain) and myxoid degeneration appearing as a pale blue extracellular matrix (E, Alcian blue stain), corresponding to the boxed area in (C). (F) Middle-power view of the papillary muscle (Elastica van Gieson stain) corresponding to the boxed area in (B). (G) High-power view of the papillary muscle (elastic Masson trichrome stain) corresponding to the boxed area in (F) demonstrating vacuolar degeneration of cardiomyocytes consistent with ischemic injury. ALB =…

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  Visual Summary. Mechanisms Underlying Severe Mitral Regurgitation in Hypertrophic Cardiomyopathy After Alcohol Septal Ablation Multimodality imaging demonstrated that severe MR in HCM after ASA resulted from the combined effects of structural abnormalities of the mitral valve complex and ischemia-induced papillary muscle dysfunction. Cardiac MRI revealed morphological abnormalities of the mitral valve apparatus, while coronary angiography identified RCA occlusion, leading to papillary muscle ischemia and regional wall motion abnormalities. Echocardiography demonstrated severe MR associated with mitral leaflet tethering. The patient subsequently developed symptomatic heart failure and underwent surgical treatment, including mitral valve replacement and CABG. Histopathological examination of the resected mitral valve complex confirmed degenerative changes of the mitral leaflets and intrinsic abnormalities of the chordae. Yellow arrowheads indicate papillary muscle abnormalities on cardiac MRI. On echocardiographic images, the red dotted line highlights severe hypokinesis of the apical segment, and white arrowheads indicate hypertrophied papillary muscles. ASA = alcohol septal ablation; CABG =…