Insuffisance Mitrale: Apport de L’échographie Tridimensionnelle

Case report

A 43-year-old man presented to the emergency department with palpitations. The ECG showed an atypical flutter with a 2:1 ventricular response rate. The patient experienced a spontaneous cardioversion and was prescribed a beta-blocking agent. He was sent for a cardiological evaluation 1 month later.

At that time, he had stopped his medication for two weeks and confessed a permanent arrhythmia for more than a week. He complained of dyspnoea on modest exertion like climbing stairs. The cardiac examination was impressive for an irregular tachyarrhythmia and a loud systolic murmur over the precordium, with maximal intensity in the apical region. There were no signs of left or right cardiac insufficiency. ECG showed an atypical flutter with an irregular ventricular response rate at approximatively 120 beats/min without signs of left ventricular hypertrophy or repolarisation abnormalities.

The transthoracic echocardiography confirmed the presence of a severe mitral regurgitation due to prolaps of the middle scallop of the posterior leaflet with ruptured chordae. The regurgitant orifice area was 1.5 cm² using the PISA method. The left ventricle was not dilated nor hypertrophied with a preserved systolic function. Pulmonary systolic pressure was calculated at 30 mm Hg using the velocity of the tricuspid regurgitation jet.

The patient was anticoagulated and prescribed metoprolol at increasing doses to control the ventricular response rate. A transoesophageal real-time 3 dimensional examination was undertaken as part of the preoperative evaluation. 2-dimensional views (fig. 1A–D) confirmed an extensive prolaps of the anterior and middle scallop of the posterior leaflet with ruptured chordae and severe consecutive regurgitation (effective regurgitant orifice area 1.7 cm² by PISA). Real-time 3-dimensional views (fig. 2) nicely showed in one image the whole extension of the prolaps, which ultimately concerned mainly the anterior scallop with extension to the anterior portion of the middle scallop, with only a very limited juxtacommissural portion of preserved tissue. The size and shape of the regurgitant orifice could be well appreciated. Using a dedicated software (QLAB, Philipps Medical Systems), the mitral annulus and the leaflets could be reconstructed and quantified (fig. 3). Measurements like the various diameters of the annulus and its area, the area of the anterior and posterior leaflet, as well as the area of the prolapsing posterior leaflet could be obtained.

This imaging technique definitively refines our evaluation of mitral valve prolaps [1,2] and will provide cardiologists and cardiosurgeons with a lot of new informations to help them better plane mitral valve repair and also better understand failed mitral plasties.