© 2013, Wiley Periodicals, Inc. DOI: 10.1111/echo.12480


IMAGE SECTION Section Editor: Brian D. Hoit, M.D.

Systolic Anterior Motion of the Posterior Leaflet in Hypertrophic Cardiomyopathy Mark Anderson, B.S.,* Siddharth Wayangankar, M.D., M.P.H.,† and Chittur A. Sivaram, M.D., F.A.C.C., F.A.S.E.† *Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; and †Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma

(Echocardiography 2014;31:E128–E129) Key words: systolic anterior motion, posterior leaflet, mitral valve Dynamic left ventricular outflow tract (LVOT) obstruction evidenced by an elevated transvalvular pressure gradient in hypertrophic cardiomyopathy has been well documented to be associated with systolic anterior motion (SAM) of the mitral valve. This phenomenon was originally described as a result of abnormal leaflet coaptation creating a “residual” anterior leaflet portion that displaced toward the ventricular septum during systole.1 However, further echocardiographic studies described SAM of the posterior leaflet in 10–12% of patients with dynamic outflow tract obstruction in the setting of elongation of the posterior leaflet.2,3 The abnormally elongated posterior leaflet may be more susceptible to being drawn anteriorly by the Venturi effect from increased ejection velocity through a narrow outflow tract.2 Moreover, the resting outflow tract gradient has been demonstrated to be associated with the degree and duration of contact between the posterior leaflet and the ventricular septum.2 In this report, we present a case of SAM of an elongated posterior leaflet of the mitral valve via transthoracic echocardiography (Acuson Sequoia C512, Siemens, Mountain View, CA, USA) producing persistent dynamic outflow obstruction despite septal myectomy and subsequent revision myectomy (Figs. 1–3). The images are obtained from a 41-year-old female with a history of hypertrophic cardiomyopathy with a peak LVOT gradient of 25 mmHg at rest and 62 mmHg during Valsalva (Fig. 4). This case highlights the therapeutic implications of diagnosing posterior leaflet SAM and the importance of meticulous echocardiographic Address for correspondence and reprint requests: Chittur A. Sivaram M.D., F.A.C.C., F.A.S.E., Cardiovascular Section, Department of Internal Medicine, University of Oklahoma 920 Stanton L. Young Blvd., WP 3010 Oklahoma City, Oklahoma 73104-5020, USA. Fax # 405-271-2619; E-mail: [email protected]


Figure 1. Parasternal long axis showing an elongated posterior leaflet (red arrowheads). LA = left atrium; LV = left ventricle.

Figure 2. Parasternal long axis showing systolic anterior motion of the posterior leaflet (red arrowheads) beyond the prior myectomy (yellow arrowhead). LA = left atrium; LV = left ventricle.

Posterior Mitral Valve Leaflet SAM in HCM


B Figure 3. Apical four-chamber view in early-mid systole showing abnormal coaptation of the mitral valve leaflets (red arrowhead). LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.

Figure 5. A. M-mode across anterior leaflet and base of posterior leaflet showing absence of systolic motion. B. M-mode across the tip of elongated posterior leaflet displaying its systolic anterior motion.

Figure 4. Doppler across left ventricular outflow tract showing a subaortic gradient of 25 mmHg at rest and 62 mmHg with Valsalva.

techniques in these patients. The therapeutic implications are twofold. First, percutaneous interventions represent a suboptimal treatment strategy as the underlying problem is likely related to the structurally enlarged leaflet. Second, as the coaptation point with the ventricular septum is located more apically, surgical treatment may require a more extensive field of myectomy to ensure that the point of obstruction is resected. In addition, this phenomenon creates additional diagnostic implications. M-mode studies in this patient underscore the importance of careful sampling due to the potential for missing posterior leaflet SAM with the traditional scan

plane that includes both the anterior and posterior leaflets (Fig. 5A). Additional scan planes that include only the posterior leaflet are required to demonstrate SAM in this situation and appropriately guide management (Fig. 5B). References 1. Shah PM, Taylor RD, Wong M: Abnormal mitral valve coaptation in hypertrophic obstructive cardiomyopathy: Proposed role in systolic anterior motion of mitral valve. Am J Cardiol 1981;48:258–262. 2. Maron BJ, Harding AM, Spirito P, et al: Systolic anterior motion of the posterior mitral leaflet: A previously unrecognized cause of dynamic subaortic obstruction in patients with hypertrophic cardiomyopathy. Circulation 1983;68:282–293. 3. Moro E, ten Cate FJ, Leonard JJ, et al: Prevalence of systolic anterior motion of the mural (posterior) leaflet of the mitral valve in hypertrophic cardiomyopathy: An echocardiographic study. Int J Cardiol 1987;17:197–205.


Systolic anterior motion of the posterior leaflet in hypertrophic cardiomyopathy.

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