An unusual defect and a rare combination: Gerbode defect and subaortic membrane/Nadir bir defekt ve nadir bir kombinasyon: Gerbode defekt ve subaortik membran

A 70-year-old female patient was referred to our department by the neurology clinic for cardiac evaluation. Transthoracic echocardiography revealed normal leftventricular systolic function with dilated leftatrium and right cardiac chambers. Color Doppler echocardiography showed moderate mitral regurgitation, mild aortic valve insufficiency and subaortic membrane 10 mm below the aortic valve, which causes turbulent flow in the leftventricular outflow tract (LVOT). Transmembrane gradient was 30.33 mmHg (Fig. 1). Color flow Doppler echocardiography indicated moderate eccentric flow jet into the right atrium from the septal leaflet of the tricuspid valve (Fig. 2). At first, the flow was thought to be tricuspid regurgitation but it appeared to originate from the membranous septum and to course along the atrial surface of the tricuspid valve consistent with a leftventricular to right atrial (LV-LA) communication. Peak gradient measured through the defect was 70.56 mmHg (Fig. 3). Transesophageal echocardiography showed a small perimembranous defect, 7 mm in size, connecting the leftventricle to right atrium (Fig. 4). Subaortic membrane and the turbulent flow in the LVOT was assessed more comprehensively (Fig. 5). There was a significant shunt with a 1.6 Qp/Qs ratio. Surgical treatment was suggested to the patient but not accepted. Although subaortic membrane is discerned easily by echocardiographic examination, a Gerbode defect (Fig. 6) might be misinterpreted inadvertently as severe pulmonary hypertension. Therefore, if the physician finds eccentric flow which does not resemble tricuspid regurgitation and predominantly huge right atrium, Gerbode defect should be kept in mind and transesophageal echocardiography should be performed for further evaluation.

Acknowledgements

Special thanks to Dr. Mustafa Aydin and Dr. Sait Mesut Dogan for their contribution to our manuscript.