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Reversible severe mitral regurgitation caused by systolic anterior motion of the mitral valve in the absence of left ventricular hypertrophy: A case report
Journal of Cardiology Cases 13 (2016) 42–44
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
Reversible severe mitral regurgitation caused by systolic anterior motion of the mitral valve in the absence of left ventricular hypertrophy: A case report Kitae Kim (MD)a,*, Toshiaki Toyota (MD)a, Yoko Fujii (RDCS)b, Takeshi Kitai (MD)a, Atsushi Kobori (MD)a, Natsuhiko Ehara (MD)a, Makoto Kinoshita (MD)a, Shuichiro Kaji (MD)a, Tomoko Tani (MD)a, Yutaka Furukawa (MD)a a b
Department of Cardiovascular Medicine, Kobe City Medical Center General Hospital, Kobe, Japan Department of Clinical Laboratory, Kobe City Medical Center General Hospital, Kobe, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 8 January 2015 Received in revised form 4 July 2015 Accepted 5 August 2015
A 67-year-old woman with exertional dyspnea was referred to our hospital. Transthoracic echocardiography revealed severe mitral regurgitation and significant left ventricular (LV) outflow tract obstruction due to prominent systolic anterior motion (SAM) of the mitral valve without LV hypertrophy. Oral bisoprolol remarkably attenuated SAM. Two- or three-dimensional echocardiographic analysis demonstrated the elongation of anterior and posterior mitral leaflets and interventricular septum (IVS) bulging due to narrow aorto-mitral angle. In the present case, elongation of mitral leaflet and hyperkinetic motion of left ventricle, and IVS bulging due to narrow aorto-mitral angle possibly play important roles in the development of SAM. ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Keywords: Mitral regurgitation Systolic anterior motion Left ventricular outflow tract obstruction Beta-blocker
Introduction Systolic anterior motion (SAM) of the mitral valve was first reported as a feature of hypertrophic cardiomyopathy (HCM), and it had previously been considered as a specific finding to HCM [1]. However, SAM may be detected in the absence of left ventricular outflow tract (LVOT) obstruction, and even seen without typical echocardiographic findings of HCM. It has been shown that SAM can be experimentally produced by the administration of dobutamine in normal dogs with a high success rate [2]. A possible role of structural changes of mitral valve during
* Corresponding author at: Department of Cardiovascular Medicine, Kobe City Medical Center General Hospital, 2-1-1, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan. Tel.: +81 78 302 4321; fax: +81 78 302 7537. E-mail address: [email protected] (K. Kim).
the development of SAM has also been reported such as leaflet elongation and papillary muscle displacement [3–6]. Herein, we present a clinical case of severe mitral regurgitation (MR) and SAM, which was dramatically attenuated by beta-blocker therapy. The findings in this case seem to be informative with respect to the mechanisms of SAM and consequent MR. Case report A 67-year-old woman was referred to our hospital due to a 2month history of dyspnea on mild exertion. Physical examination and laboratory test revealed no obvious triggers for left ventricular (LV) hyperkinetic motion such as infection, dehydration, anemia, and hyperthyroidism. The 12-lead electrocardiogram results were normal. Transthoracic echocardiography revealed severe mitral regurgitation and significant LV outflow tract obstruction (peak
http://dx.doi.org/10.1016/j.jccase.2015.08.005 1878-5409/ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
K. Kim et al. / Journal of Cardiology Cases 13 (2016) 42–44
Fig. 1.
Two-dimensional transthoracic echocardiography and color flow imaging before initiation of a beta-blocker. (a) Apical long-axis view. Prominent systolic anterior motion of the mitral valve with septal contact can be seen, and the mitral leaflets bended at the mid-portion, resulting in loss of coaptation. Left ventricular wall motion is hyperkinetic, and there is no concentric or asymmetric left ventricular hypertrophy. (b) Color flow imaging shows severe mitral regurgitation with the jet directed posteriorly, and significant left ventricular outflow tract obstruction (peak velocity was 5.8 m/s).
velocity was 5.8 m/s) due to prominent systolic anterior motion (SAM) of the mitral valve without LV hypertrophy. LV wall motion was hyperkinetic, with an ejection fraction of 74%, and interventricular septum (IVS) bulging due to narrow aorto-mitral angle was observed. Anterior mitral leaflet bended at its mid-portion, resulting in loss of coaptation (Fig. 1a and b; Additional movie files show this in more detail (see Additional files 1 and 2)]. Four days after the initiation of bisoprolol treatment (2.5 mg daily), the LV wall motion was normalized, and SAM of the mitral leaflet was significantly reduced. IVS bulging due to narrow aortic mitral angle was still observed, but MR and LVOT obstruction almost completely disappeared (Fig. 2a and b, and Additional files 3–5). Measurement of the mitral leaflet lengths using threedimensional reconstruction by transesophageal echocardiography indicated elongation of the leaflets with an anterior leaflet length of 2.2 cm and a posterior leaflet length of 1.7 cm, respectively (normal ranges, 1.8 0.3 cm for anterior leaflet, 1.1 0.2 cm for posterior leaflet [4]). The narrowest LVOT diameter during systole was 1.4 cm (see Additional file 5). Cardiac magnetic resonance imaging revealed no structural abnormalities including displacement of papillary muscles. Bisoprolol was increased to 5 mg daily, and was
Fig. 2.
43
well tolerated by her. After that, she has never complained of dyspnea on exertion. Discussion As the main mechanism of SAM, the Venturi theory has been widely accepted. Venturi effect is created by high velocity flow caused by LVOT obstruction, and lifts the mitral valve toward the septum. However, several studies demonstrated that SAM began before the start of LV ejection in patients with HCM, which cannot be explained by the Venturi theory [7]. Thus, structural changes may play a primary role in the development of SAM in HCM patients. Klues et al. analyzed the structure of mitral valves pathologically in HCM patients and showed that 62 (66%) of 94 mitral valves had a constellation of structural malformations, including increased leaflet area and elongation of the leaflets [4]. Increases in mitral leaflet area and papillary muscle displacement were also shown in patients with HCM using real-time 3dimensional echocardiography [6]. Levine et al. showed in normal dogs that experimental anterior papillary muscle displacement displaced mitral valve anteriorly, shifted the coaptation point
Two-dimensional transthoracic echocardiography and color flow imaging after initiation of a beta-blocker. (a) Left ventricular wall motion was normokinetic, and systolic anterior motion of the mitral leaflet was significantly reduced. (b) Color flow imaging. Mitral regurgitation and left ventricular outflow obstruction almost completely disappeared.
K. Kim et al. / Journal of Cardiology Cases 13 (2016) 42–44
44
toward the insertion of the leaflets, and created longer distal residual leaflets that moved anteriorly [5]. In patients after mitral valve plasty, an excess of valvular tissue and an undersized annuloplasty were considered as major factors that contribute to the development of SAM. A narrow aorto-mitral angle, a hyperkinetic small ventricle, an IVS bulging, and an abnormal configuration of the anterior leaflet were also considered as additional potential contributing factors [8]. In the present case, elongation of mitral leaflet and hyperkinetic motion of left ventricle, and IVS bulging due to narrow aorto-mitral angle possibly play important roles in the development of SAM. Henein et al. reported that in 80% of the patients with exertional dyspnea and negative exercise test, SAM of the mitral valve and high velocity flow in the LVOT appeared during dobutamine stress echocardiography, which were associated with basal septal hypertrophy [9]. In contrast, the present patient did not have any obvious triggers which cause hyperkinetic LV motion. Although there are several previous reports regarding SAM of the mitral valve without LV hypertrophy [10,11], the present case is rare, because the attenuation of SAM by oral beta-blocker therapy was dramatic, and severe MR and LVOT obstruction completely disappeared. Once severe MR occurred, LV hyperkinetic motion might be enhanced, leading to a vicious circle that progressively exacerbated SAM, LVOT obstruction, and MR. Betablocker therapy might terminate the vicious circle, eliminating SAM, LVOT obstruction, and MR. Further studies are necessary to clarify the precise mechanism of SAM in the absence of LV hypertrophy. Conflict of interest All authors declare that they have no conflict of interest regarding this manuscript. Disclosures None.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jccase.2015.08. 005. References [1] Maron BJ, Epstein SE. Hypertrophic cardiomyopathy. Recent observations regarding the specificity of three hallmarks of the disease: asymmetric septal hypertrophy, septal disorganization and systolic anterior motion of the anterior mitral leaflet. Am J Cardiol 1980;45:141–54. [2] Sakurai S, Tanaka H, Yoshimura H, Nakao S, Tahara M. Production of systolic anterior motion of the mitral valve in dogs. Circulation 1985;71:805–12. [3] Jiang L, Levine RA, King ME, Weyman AE. An integrated mechanism for systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy based on echocardiographic observations. Am Heart J 1987;113:633–44. [4] Klues HG, Maron BJ, Dollar AL, Roberts WC. Diversity of structural mitral valve alterations in hypertrophic cardiomyopathy. Circulation 1992;85:1651–60. [5] Levine RA, Vlahakes GJ, Lefebvre X, Guerrero JL, Cape EG, Yoganathan AP, Weyman AE. Papillary muscle displacement causes systolic anterior motion of the mitral valve. Experimental validation and insights into the mechanism of subaortic obstruction. Circulation 1995;91:1189–95. [6] Kim DH, Handschumacher MD, Levine RA, Choi YS, Kim YJ, Yun SC, Song JM, Kang DH, Song JK. In vivo measurement of mitral leaflet surface area and subvalvular geometry in patients with asymmetrical septal hypertrophy: insights into the mechanism of outflow tract obstruction. Circulation 2010;122:1298–307. [7] Sherrid MV, Gunsburg DZ, Moldenhauer S, Pearle G. Systolic anterior motion begins at low left ventricular outflow tract velocity in obstructive hypertrophic cardiomyopathy. J Am Coll Cardiol 2000;36:1344–54. [8] Mihaileanu S, Marino JP, Chauvaud S, Perier P, Forman J, Vissoat J, Julien J, Dreyfus G, Abastado P, Carpentier A. Left ventricular outflow obstruction after mitral valve repair (Carpentier’s technique). Proposed mechanisms of disease. Circulation 1988;78:I78–84. [9] Henein MY, O’Sullivan C, Sutton GC, Gibson DG, Coats AJ. Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly. J Am Coll Cardiol 1997;30:1301–7. [10] Doi T, Ayukawa H, Hoshiyama Y, Hatakeyama Y, Sasaki Y, Inenaga K, Hwang MW, Takeoka R, Iwase T, Kawai C. Systolic anterior motion (SAM) of the posterior mitral leaflet: left ventricular outflow tract obstruction in a patient without left ventricular hypertrophy. Int J Cardiol 2006;109:271–2. [11] Izgi C, Akgun T, Men EE, Feray H. Systolic anterior motion of the mitral valve in the absence left ventricular hypertrophy: role of mitral leaflet elongation and papillary muscle displacement. Echocardiography 2010;27:E36–8.
Contents lists available at ScienceDirect
Journal of Cardiology Cases journal homepage: www.elsevier.com/locate/jccase
Case Report
Reversible severe mitral regurgitation caused by systolic anterior motion of the mitral valve in the absence of left ventricular hypertrophy: A case report Kitae Kim (MD)a,*, Toshiaki Toyota (MD)a, Yoko Fujii (RDCS)b, Takeshi Kitai (MD)a, Atsushi Kobori (MD)a, Natsuhiko Ehara (MD)a, Makoto Kinoshita (MD)a, Shuichiro Kaji (MD)a, Tomoko Tani (MD)a, Yutaka Furukawa (MD)a a b
Department of Cardiovascular Medicine, Kobe City Medical Center General Hospital, Kobe, Japan Department of Clinical Laboratory, Kobe City Medical Center General Hospital, Kobe, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 8 January 2015 Received in revised form 4 July 2015 Accepted 5 August 2015
A 67-year-old woman with exertional dyspnea was referred to our hospital. Transthoracic echocardiography revealed severe mitral regurgitation and significant left ventricular (LV) outflow tract obstruction due to prominent systolic anterior motion (SAM) of the mitral valve without LV hypertrophy. Oral bisoprolol remarkably attenuated SAM. Two- or three-dimensional echocardiographic analysis demonstrated the elongation of anterior and posterior mitral leaflets and interventricular septum (IVS) bulging due to narrow aorto-mitral angle. In the present case, elongation of mitral leaflet and hyperkinetic motion of left ventricle, and IVS bulging due to narrow aorto-mitral angle possibly play important roles in the development of SAM.
Keywords: Mitral regurgitation Systolic anterior motion Left ventricular outflow tract obstruction Beta-blocker
Introduction Systolic anterior motion (SAM) of the mitral valve was first reported as a feature of hypertrophic cardiomyopathy (HCM), and it had previously been considered as a specific finding to HCM [1]. However, SAM may be detected in the absence of left ventricular outflow tract (LVOT) obstruction, and even seen without typical echocardiographic findings of HCM. It has been shown that SAM can be experimentally produced by the administration of dobutamine in normal dogs with a high success rate [2]. A possible role of structural changes of mitral valve during
* Corresponding author at: Department of Cardiovascular Medicine, Kobe City Medical Center General Hospital, 2-1-1, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan. Tel.: +81 78 302 4321; fax: +81 78 302 7537. E-mail address: [email protected] (K. Kim).
the development of SAM has also been reported such as leaflet elongation and papillary muscle displacement [3–6]. Herein, we present a clinical case of severe mitral regurgitation (MR) and SAM, which was dramatically attenuated by beta-blocker therapy. The findings in this case seem to be informative with respect to the mechanisms of SAM and consequent MR. Case report A 67-year-old woman was referred to our hospital due to a 2month history of dyspnea on mild exertion. Physical examination and laboratory test revealed no obvious triggers for left ventricular (LV) hyperkinetic motion such as infection, dehydration, anemia, and hyperthyroidism. The 12-lead electrocardiogram results were normal. Transthoracic echocardiography revealed severe mitral regurgitation and significant LV outflow tract obstruction (peak
http://dx.doi.org/10.1016/j.jccase.2015.08.005 1878-5409/ß 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
K. Kim et al. / Journal of Cardiology Cases 13 (2016) 42–44
Fig. 1.
Two-dimensional transthoracic echocardiography and color flow imaging before initiation of a beta-blocker. (a) Apical long-axis view. Prominent systolic anterior motion of the mitral valve with septal contact can be seen, and the mitral leaflets bended at the mid-portion, resulting in loss of coaptation. Left ventricular wall motion is hyperkinetic, and there is no concentric or asymmetric left ventricular hypertrophy. (b) Color flow imaging shows severe mitral regurgitation with the jet directed posteriorly, and significant left ventricular outflow tract obstruction (peak velocity was 5.8 m/s).
velocity was 5.8 m/s) due to prominent systolic anterior motion (SAM) of the mitral valve without LV hypertrophy. LV wall motion was hyperkinetic, with an ejection fraction of 74%, and interventricular septum (IVS) bulging due to narrow aorto-mitral angle was observed. Anterior mitral leaflet bended at its mid-portion, resulting in loss of coaptation (Fig. 1a and b; Additional movie files show this in more detail (see Additional files 1 and 2)]. Four days after the initiation of bisoprolol treatment (2.5 mg daily), the LV wall motion was normalized, and SAM of the mitral leaflet was significantly reduced. IVS bulging due to narrow aortic mitral angle was still observed, but MR and LVOT obstruction almost completely disappeared (Fig. 2a and b, and Additional files 3–5). Measurement of the mitral leaflet lengths using threedimensional reconstruction by transesophageal echocardiography indicated elongation of the leaflets with an anterior leaflet length of 2.2 cm and a posterior leaflet length of 1.7 cm, respectively (normal ranges, 1.8 0.3 cm for anterior leaflet, 1.1 0.2 cm for posterior leaflet [4]). The narrowest LVOT diameter during systole was 1.4 cm (see Additional file 5). Cardiac magnetic resonance imaging revealed no structural abnormalities including displacement of papillary muscles. Bisoprolol was increased to 5 mg daily, and was
Fig. 2.
43
well tolerated by her. After that, she has never complained of dyspnea on exertion. Discussion As the main mechanism of SAM, the Venturi theory has been widely accepted. Venturi effect is created by high velocity flow caused by LVOT obstruction, and lifts the mitral valve toward the septum. However, several studies demonstrated that SAM began before the start of LV ejection in patients with HCM, which cannot be explained by the Venturi theory [7]. Thus, structural changes may play a primary role in the development of SAM in HCM patients. Klues et al. analyzed the structure of mitral valves pathologically in HCM patients and showed that 62 (66%) of 94 mitral valves had a constellation of structural malformations, including increased leaflet area and elongation of the leaflets [4]. Increases in mitral leaflet area and papillary muscle displacement were also shown in patients with HCM using real-time 3dimensional echocardiography [6]. Levine et al. showed in normal dogs that experimental anterior papillary muscle displacement displaced mitral valve anteriorly, shifted the coaptation point
Two-dimensional transthoracic echocardiography and color flow imaging after initiation of a beta-blocker. (a) Left ventricular wall motion was normokinetic, and systolic anterior motion of the mitral leaflet was significantly reduced. (b) Color flow imaging. Mitral regurgitation and left ventricular outflow obstruction almost completely disappeared.
K. Kim et al. / Journal of Cardiology Cases 13 (2016) 42–44
44
toward the insertion of the leaflets, and created longer distal residual leaflets that moved anteriorly [5]. In patients after mitral valve plasty, an excess of valvular tissue and an undersized annuloplasty were considered as major factors that contribute to the development of SAM. A narrow aorto-mitral angle, a hyperkinetic small ventricle, an IVS bulging, and an abnormal configuration of the anterior leaflet were also considered as additional potential contributing factors [8]. In the present case, elongation of mitral leaflet and hyperkinetic motion of left ventricle, and IVS bulging due to narrow aorto-mitral angle possibly play important roles in the development of SAM. Henein et al. reported that in 80% of the patients with exertional dyspnea and negative exercise test, SAM of the mitral valve and high velocity flow in the LVOT appeared during dobutamine stress echocardiography, which were associated with basal septal hypertrophy [9]. In contrast, the present patient did not have any obvious triggers which cause hyperkinetic LV motion. Although there are several previous reports regarding SAM of the mitral valve without LV hypertrophy [10,11], the present case is rare, because the attenuation of SAM by oral beta-blocker therapy was dramatic, and severe MR and LVOT obstruction completely disappeared. Once severe MR occurred, LV hyperkinetic motion might be enhanced, leading to a vicious circle that progressively exacerbated SAM, LVOT obstruction, and MR. Betablocker therapy might terminate the vicious circle, eliminating SAM, LVOT obstruction, and MR. Further studies are necessary to clarify the precise mechanism of SAM in the absence of LV hypertrophy. Conflict of interest All authors declare that they have no conflict of interest regarding this manuscript. Disclosures None.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jccase.2015.08. 005. References [1] Maron BJ, Epstein SE. Hypertrophic cardiomyopathy. Recent observations regarding the specificity of three hallmarks of the disease: asymmetric septal hypertrophy, septal disorganization and systolic anterior motion of the anterior mitral leaflet. Am J Cardiol 1980;45:141–54. [2] Sakurai S, Tanaka H, Yoshimura H, Nakao S, Tahara M. Production of systolic anterior motion of the mitral valve in dogs. Circulation 1985;71:805–12. [3] Jiang L, Levine RA, King ME, Weyman AE. An integrated mechanism for systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy based on echocardiographic observations. Am Heart J 1987;113:633–44. [4] Klues HG, Maron BJ, Dollar AL, Roberts WC. Diversity of structural mitral valve alterations in hypertrophic cardiomyopathy. Circulation 1992;85:1651–60. [5] Levine RA, Vlahakes GJ, Lefebvre X, Guerrero JL, Cape EG, Yoganathan AP, Weyman AE. Papillary muscle displacement causes systolic anterior motion of the mitral valve. Experimental validation and insights into the mechanism of subaortic obstruction. Circulation 1995;91:1189–95. [6] Kim DH, Handschumacher MD, Levine RA, Choi YS, Kim YJ, Yun SC, Song JM, Kang DH, Song JK. In vivo measurement of mitral leaflet surface area and subvalvular geometry in patients with asymmetrical septal hypertrophy: insights into the mechanism of outflow tract obstruction. Circulation 2010;122:1298–307. [7] Sherrid MV, Gunsburg DZ, Moldenhauer S, Pearle G. Systolic anterior motion begins at low left ventricular outflow tract velocity in obstructive hypertrophic cardiomyopathy. J Am Coll Cardiol 2000;36:1344–54. [8] Mihaileanu S, Marino JP, Chauvaud S, Perier P, Forman J, Vissoat J, Julien J, Dreyfus G, Abastado P, Carpentier A. Left ventricular outflow obstruction after mitral valve repair (Carpentier’s technique). Proposed mechanisms of disease. Circulation 1988;78:I78–84. [9] Henein MY, O’Sullivan C, Sutton GC, Gibson DG, Coats AJ. Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly. J Am Coll Cardiol 1997;30:1301–7. [10] Doi T, Ayukawa H, Hoshiyama Y, Hatakeyama Y, Sasaki Y, Inenaga K, Hwang MW, Takeoka R, Iwase T, Kawai C. Systolic anterior motion (SAM) of the posterior mitral leaflet: left ventricular outflow tract obstruction in a patient without left ventricular hypertrophy. Int J Cardiol 2006;109:271–2. [11] Izgi C, Akgun T, Men EE, Feray H. Systolic anterior motion of the mitral valve in the absence left ventricular hypertrophy: role of mitral leaflet elongation and papillary muscle displacement. Echocardiography 2010;27:E36–8.