1 23 Journal of Echocardiography ISSN 1349-0222 J Echocardiogr DOI 10.1007/s12574-014-0218-0 An unusual cause of left ventricular outflow tract obstruction: obstructive pannus on the left ventricular side of a mechanical mitral prosthesis Macit Kalçık, Cuneyt Toprak, M. Ozan Gürsoy, Mahmut Yesin, Suleyman Karakoyun & Mehmet Özkan