© 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.