Mitral Stenosis and Subaortic Membrane in Hypertrophic Cardiomyopathy : A Rare Multimodality Imaging Based Diagnosis

Mitral Stenosis and Subaortic Membrane in Hypertrophic Cardiomyopathy : A Rare Multimodality Imaging Based Diagnosis | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Echocardiography This is a preprint and has not been peer reviewed. Data may be preliminary. 23 May 2025 V1 Latest version Share on Mitral Stenosis and Subaortic Membrane in Hypertrophic Cardiomyopathy : A Rare Multimodality Imaging Based Diagnosis Authors : Aditi Parimoo 0009-0003-0796-729X , Dhiraj Kumar [email protected] , and Ajay Mahajan Authors Info & Affiliations https://doi.org/10.22541/au.174802518.86773854/v1 Published Echocardiography Version of record Peer review timeline 254 views 151 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Hypertrophic cardiomyopathy (HCM) is characterised by dynamic LVOT obstruction and is frequently associated mitral valve abnormalities commonly leading to mitral regurgitation. We describe a case of HCM with dynamic as well as fixed LVOTO due to the presence of a subaortic membrane along with concomitant mitral stenosis due to anomalous insertion of papillary muscles. This case represents a very rare scenario of mitral inflow and mitral outflow obstruction along with coexistent fixed and dynamic LVOTO in a case of HCM. Mitral Stenosis and Subaortic Membrane in Hypertrophic Cardiomyopathy : A Rare Multimodality Imaging Based Diagnosis A 22 year old female presented to the out-patient department with a history of progressive dyspnea on exertion for the past 2 years. On clinical examination, she had a low volume pulse. Her blood pressure was 80/66 mm Hg in her right arm. Palpation revealed a heaving apex in the 6th intercostal space. On auscultation, a grade 4/6 ejection systolic murmur was noted in the right 3rd intercostal space and a grade 3/6 pansystolic murmur was noted at the apex. The clinical findings pointed towards left ventricular outflow tract (LVOT) obstruction with mitral regurgitation (MR) and so, a transthoracic echocardiography (TTE) was performed. TTE findings revealed asymmetric septal hypertrophy and systolic anterior motion (SAM) of anterior mitral leaflet (AML) suggestive of obstructive hypertrophic cardiomyopathy (OHCM).[Figure 1A] There was concomitant mitral regurgitation due to SAM and narrowing of the LVOT due to massive septal hypertrophy. Moreover, there was moderate-severe aortic regurgitation and a tiny, restrictive perimembranous ventricular septal defect (VSD). [Figure 1B & 1C] Interestingly, severe mitral stenosis was also noted in the patient. The short axis views showed a mitral valve area of 0.9 mm 2 . [Figure 1D] On continuous wave doppler interrogation, both dynamic and fixed LVOT obstruction jets were noted. [Figure 1E & 1F]. A cardiac MRI was performed. The MRI showed patchy late gadolinium enhancement of the myocardium. [Figure 1G] It also confirmed massive asymmetric septal hypertrophy and SAM leading to dynamic LVOTO and MR. There was apical displacement of the papillary muscles causing tethering of AML and funnelling of the mitral valve apparatus with direct attachment of the leaflets to the papillary muscles. [Figure 1H] The presence of severe aortic regurgitation as well as fixed LVOTO led to a strong suspicion of a subaortic membrane. Finally, a multi-slice computed tomography (MSCT) was performed. The excellent spatial resolution of the CT was able to demonstrate a fibromuscular band near the calcified tip of AML and attached to the basal septum. [Figure 1I] This was a rare case demonstrating concomitant mitral inflow and mitral outflow obstruction along with coexistent fixed and dynamic LVOTO in a case of HCM. Abnormalities of the mitral valve apparatus are known to co-exist with HCM and include leaflet elongation, thickened mitral leaflets, anomalous insertion of papillary muscles and apically displaced papillary muscles. (1) While MR is commonly described, presence of coexisting mitral stenosis (MS) is rare. Although rare, presence of a subaortic membrane in HCM has also been described and contributes to fixed LVOT obstruction and sometimes, aortic regurgitation. (2) Our patient had anomalous insertion of apically displaced papillary muscles into the mitral leaflets leading to funnelling of the mitral apparatus causing SAM, MR as well as MS. The presence of a subaortic membrane further contributed to LVOTO and AR. To our knowledge, this represents a unique combination of anomalies in a patient with HCM that has rarely been reported and highlights the importance of multimodality imaging and a high index of suspicion in diagnosing complex cases. Figure 1 A: M-Mode across tip of AML in PLAX view showing SAM. B: 4-Chamber view showing MR. C: PLAX view showing aortic regurgitation & restrictive perimembranous VSD. D: SAX view showing MV area of 0.7 cm 2 by planimetry. E: Continuous wave doppler interrogation across LVOT showing fixed LVOTO and AR. F: Continuous wave doppler interrogation across LVOT showing dynamic LVOTO. G: Cardiac MR(CMR) images showing late gadolinium enhancement. H: CMR showing direct attachment of papillary muscles to mitral leaflets. I: CT image showing presence of fibromuscular band near the calcific tip of AML and attached to the basal septum. References Molisana M, Selimi A, Gizzi G, D’Agostino S, Ianni U, Parato VM. Different mechanisms of mitral regurgitation in hypertrophic cardiomyopathy: A clinical case and literature review. Front Cardiovasc Med. 2022 Oct 28;9:1020054. Kannappan M, Maron BJ, Rastegar H, Pandian NG, Maron MS, Rowin EJ. Underappreciated occurrence of discrete subaortic membranes producing left ventricular outflow obstruction in hypertrophic cardiomyopathy. Echocardiography. 2017; 34: 1247–1249. Information & Authors Information Version history V1 Version 1 23 May 2025 Peer review timeline Published Echocardiography Version of Record 9 Aug 2025 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Echocardiography Keywords hypertrophic cardiomyopathy mitral valve apparatus multimodality imaging subaortic membrane Authors Affiliations Aditi Parimoo 0009-0003-0796-729X King Edward Memorial Hospital and Seth Gordhandas Sunderdas Medical College View all articles by this author Dhiraj Kumar [email protected] King Edward Memorial Hospital and Seth Gordhandas Sunderdas Medical College View all articles by this author Ajay Mahajan King Edward Memorial Hospital and Seth Gordhandas Sunderdas Medical College View all articles by this author Metrics & Citations Metrics Article Usage 254 views 151 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Aditi Parimoo, Dhiraj Kumar, Ajay Mahajan. 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