Mechanism of ischaemic mitral regurgitation. a | Mechanism of ischaemic mitral regurgitation caused by increased mitral leaflet tethering owing to left ventricular remodelling after MI (shaded wall) with outward bulging (three arrows on the outer surface of the heart). Leaflet closure is restricted by increased tethering forces on the leaflets exerted via the chordae (arrows within the heart, exceeding normal on the left). b | Echocardiogram from a patient with inferior wall infarction and tethered mitral leaflets (arrows in left panel) with characteristic anterior leaflet bend and concavity towards the LA indicating chordal tethering, mitral regurgitation orifice (small arrows in right panel), and mitral regurgitant flow (large arrow in right panel). Abbreviations: Ao, aorta; LA, left atrium; LV, left ventricle; MI, myocardial infarction; MR, mitral regurgitation; PM, papillary muscle.