VIDEO 07-24. Thinning, akinesis, and increased echogenicity of the interventricular septum due to an old anterior myocardial infarction. There is systolic left ventricular dysfunction and biatrial enlargement. There is apical tethering of the mitral valve, with localized calcification at the papillary muscle tip. Note that there is no secundum atrial septal defect. The thin membrane of the intact fossa ovalis simply does not reflect any ultrasound back at the transducer.