Purpose Flail mitral leaflet has been well identified by two-dimensional echocardiography (2-D Echo). Direction of the mitral regurgitation (MR) jet on color Doppler has been used to distinguish this condition from other causes of MR. We describe an additional color flow Doppler manifestation which can help in confirming the diagnosis: local systolic turbulence centered at the site of the flail leaflet itself.
Methods Fourteen patients had flail mitral leaflet on 2-D Echo (Table). The diagnosis was based mainly on lack of normal mitral leaflet apposition in systole, with abnormal systolic pointing of the flail component of the leaflet into the left atrium.
Results All patients had moderate or severe MR. On 2-D color Doppler Echo, intense local turbulence with prominent yellow-cyan components centered at the site of the flail leaflet was noted in 11 out of the 14 patients (79%) with flail mitral leaflet. All 14 patients exhibited an eccentric systolic jet which was in a direction opposite to that of the flail mitral leaflet. The intense focal turbulence could be distinguished spatially from the vena contracta of the MR jet, on frame-by-frame viewing. In 20 other patients with MR but no flail leaflet, the color flow Doppler pattern appeared as a smooth turquoise or blue stream, often admixed with small elements of orange and yellow; no localized turbulence was noted in any of them.
Conclusions This new color flow Doppler sign of flail mitral leaflet may help in its echocardiographic diagnosis, when the 2-D appearances of flail leaflet are not clear due to poor acoustic windows or inconspicuous component of a small partly flail mitral leaflet.