Left ventricular (LV) dilation can stretch apart the mitral valve annulus causing the chordae tendinae to be pulled taut (particularly to the posterior leaflet). This restricts leaflet motion (Carpentier type III) over the cardiac cycle causing malcoaptation and associated mitral regurgitation (MR). Classically, with type III MR, the regurgitation jet is directly ipsilateral to the pathology.
Type III MR is divided into leaflet restriction during both systole and diastole (type IIIa) as seen with rheumatic heart disease and restriction only during diastole (type IIIb) often seen with ischemic and dilated cardiomyopathy
This TEE example in ischemic cardiomyopathy shows midesophageal four-chamber and long-axis views with an MR jet directly posteriorly hugging the wall of the left atrium (LA) – the Coandă effect.