Subaortic membrane mimicking hypertrophic cardiomyopathy. (4th November 2015)

• Record Type: Journal Article
• Authors: Anderson, Mark Joseph; Arruda-Olson, Adelaide; Gersh, Bernard; Geske, Jeffrey
• Is Part Of: BMJ case reports. Volume 2015
• Publication Date: 2015-11-04
• Subjects: Medicine -- Case studies -- Periodicals; 610.5
• DOI: 10.1136/bcr-2015-212321
• Languages: English
• ISSNs: 1757-790X

Abstract

Abstract : A 34-year-old man was referred for progressive angina and exertional dyspnoea refractory to medical therapy, with a presumptive diagnosis of hypertrophic cardiomyopathy (HCM). Transthoracic echocardiography (TTE) revealed asymmetric septal hypertrophy without systolic anterior motion of the mitral valve leaflet and with no dynamic left ventricular outflow tract (LVOT) obstruction. However, the LVOT velocity was elevated at rest as well as with provocation, without the characteristic late peaking obstruction seen in HCM. Focused TTE to evaluate for suspected fixed obstruction demonstrated a subaortic membrane 2.2 cm below the aortic valve. Coronary CT angiography confirmed the presence of the subaortic membrane and was negative for concomitant coronary artery disease. Surgical resection of the subaortic membrane and septal myectomy resulted in significant symptomatic relief and lower LVOT velocities on postoperative TTE. This case reminds the clinician to carefully evaluate for alternative causes of LVOT obstruction, especially subaortic membrane, as a cause of symptoms mimicking HCM.