Mitral valve prolapse (MVP) has been associated with ventricular arrhythmia, originating from inferolateral left ventricle (LV) wall. However, its mechanism remains unclear.

To take advantage of the high prevalence of MVP in Marfan syndrome (MFS) to study the relationship of MVP, mitral annular disjunction (MAD), LV basal hypertrophy and ECG abnormalities.

We included all MFS patients (≥14 yo) without a history of thoracic surgery seen in our center between 2015 and 2017. MVP was identified on echocardiography according to Levine definition and the other cases of abnormal systolic mitral leaflet displacement were defined as billowing. Basal inferolateral hypertrophy (BILH) was defined as basal inferolateral thickness ≥12mm and basal to mild wall thickness ratio ≥1.5. QTc was measured on rest 12-lead ECG (Figure 1).

Two hundred and fifty MFS patients were included. Billowing or MVP (BMVP) was present in 187 (74.80%) patients. MAD was present in 52/235 (22.13%) and was associated with BMVP in all cases. End-systole mitral annular diameter was larger when BMVP was present (mean: 34.82mm vs. 30.53mm, P<0.0001) and in MAD+ than in MAD− (mean: 37.14mm vs. 32.46mm, P<0.0001) with a correlation between MAD length and end-systole mitral annular diameter (r=0.395 P<0.0001). Whereas mitral annular diameter decreased in systole in MAD−, it increased in MAD+ (mean mitral annular diameter (diastolic–systolic): 3.69mm vs. −0.87mm, P<0.0001). BILH was present in 18/175 (10.29%) patients with BMVP vs. in 1/59 (1.69%) without (P=0.0367) and in 9/50 (18%) MAD+ vs. 10/174 (5.75%) MAD− (P=0.006). No electric abnormality on ECGs was associated with MAD or BMVP. In contrast, patients with BILH had a longer QTc than patients without HBIL (mean: 426ms vs. 411.4ms, P=0.0220).

In MFS population, MAD is associated with BMVP, systolic mitral annular dilatation, and BILH but not with ECG abnormalities. Only patients with BILH present a QTc prolongation.