DOI: 10.1111/j.1540-8175.2009.01108.x C  2010, Wiley Periodicals, Inc. CASE REPORTS Systolic Anterior Motion of the Mitral Valve in the Absence Left Ventricular Hypertrophy: Role of Mitral Leaflet Elongation and Papillary Muscle Displacement Cemil Izgi, M.D., ∗ Taylan Akgun, M.D.,† Ebubekir Emre Men, M.D., ∗ and Hasan Feray, M.D. ∗ ∗ Cardiology Department, Gaziosmanpasa Hospital, Istanbul, Turkey; and †Kosuyolu Heart & Research Hospital, Istanbul, Turkey We report a 15-year-old patient who presented with exercise dyspnea and limitation of physical activity. Echocardiography revealed significant left ventricular outflow tract obstruction caused by systolic ante- rior motion (SAM) of the mitral valve. The wall thickness of the left ventricle was within normal limits. Elongation of the mitral leaflets and anterior displacement of the posteromedial papillary muscle were apparent in the echocardiographic examination. These two factors have been previously demonstrated to play a central role in the occurrence of SAM in patients with hypertrophic cardiomyopathy. The present case validates that such intrinsic abnormalities of the mitral valve can cause significant SAM even in the absence of left ventricular hypertrophy. (Echocardiography 2010;27:E36-E38) Case Report: A 15 year-old boy was evaluated for decreased functional capacity at our clinic 2 years ago. The patient was complaining of exertional dyspnea and limitation of physical activity. He was com- fortable with daily activities, however his symp- toms were immediately limiting him when he was attempting more than mild exercise. The symptoms were present for more than 2 years. He did not have a history of syncope, presyn- cope, or palpitation. His cardiac examination was normal except for a mild short systolic mur- mur. Electrocardiogram (ECG) was within normal limits. An echocardiographic examination was per- formed. Apparent systolic anterior motion (SAM) of the anterior mitral valve leaflet was observed (Fig. 1A). However, there was no left ventric- ular outflow tract (LVOT) obstruction at rest (Fig. 1B). The systolic function, chamber size, and wall thickness of the left ventricle were found to be normal. Therefore, hypertrophic cardiomy- opathy phenotype was excluded (endocardial borders were clearly visible throughout the left ventricle including the apex). When the patient performed a bedside squatting exercise, SAM be- came severe and caused significant LVOT ob- Address for correspondence and reprint requests: Cemil Izgi, M.D., Gaziosmanpasa Hospital, Cukurcesme Cad. 34245, Gaziosmanpasa, Istanbul, Turkey. Fax: + 90 212 615 3849; E-mail: cemil_izgi@yahoo.com struction. A peak flow velocity of 5.2 m/s (max- imum gradient: 108 mm Hg) was detected at the outflow tract by Doppler examination (Fig. 1C). There was only mild mitral regurgitation. The echocardiographic examination excluded other pathologies that could be a cardiac cause of de- creased functional capacity. There was no fam- ily history of hypertrophic cardiomyopathy and the echocardiographic examination of his parents and his only sibling were within normal limits. A 24-hour ECG monitoring revealed normal sinus rhythm without any occult arrythmias. A detailed examination of the mitral valve structure revealed elongation of the mitral valve leaflets. The anterior leaflet was 3.0 cm and the posterior leaflet was 1.4 cm in length (Fig. 2A). Moreover, parasternal short-axis images revealed an anterior and inward movement of the pos- teromedial papillary muscle (PM) during systole (movie clip S1A). These two factors were pre- viously demonstrated to cause SAM, 1 but SAM was not severe enough to cause LVOT obstruc- tion at rest in our patient. During exercise, with the increased contractility of the posterior wall of the left ventricle, anterior displacement of the posteromedial PM tip was exaggerated. This dis- placement caused increased anterior leaflet slack and its chordae and probably also pulled up the posterior leaflet. The posterior mitral leaflet was coapting with the midportion of the ante- rior leaflet and a distal residual part of the ante- rior leaflet was left uncoapted and free to move E36