LAUSR

The Authors' reply We thank Dr Garbi and colleagues for their interest in our recently published study. The authors underline that mitral annular disjunction (MAD) cannot be considered a risk factor for sudden cardiac death in mitral valve prolapse (MVP), as it is a widespread anatomical variation of the mitral valve annulus (MVA), also described in histological specimens of hearts without MVP. We agree that the link between MAD and malignant MVP is still speculative, as several factors may be responsible for ventricular arrhythmias, including genetic, structural, mechanical and extravalvular features. However, the evaluation of the impact of MAD on the arrhythmic risk was beyond the aims of our work and further studies are needed. Moreover, the authors argue that MAD should be evaluated in diastole rather than systole by cardiac imaging. We agree that MVA assessment during endsystole may induce the unkeen observer to erroneously interpret the prolapsed distance of the leaflet as MAD. However, the left ventricular myocardium contraction over systole ‘stretches’ the tissue separating the MVA from the ventricular wall, so an accurate framebyframe analysis of optimisedresolution imaging allows the observer to diagnose MAD. Hence, we applied previously described methods for MAD assessment in systole, and when we could not properly distinguish MAD from a posterior leaflet normally attached to the ventricular myocardium and prolapsing along the left atrium wall, MAD evaluation was considered unfeasible. In a minority of cases, we could visualise MAD also in diastole, mainly by transoesophageal echocardiography and cardiac magnetic resonance. How to interpret diastolic MAD visualisation by cardiac imaging is a whole world to discover. In conclusion, we acknowledge that cardiac imaging has several limitations in MAD detection compared with histology. However, our study compares for the first time different imaging techniques in detecting and measuring MAD. Specifically, we found that MAD detection rate depends on spatial resolution and tissue characterisation capacity of imaging techniques, we showed how data obtained by different methods cannot be used interchangeably, and stressed the need to standardise MAD definition. A great effort to refine investigation on MAD is still required for the scientific community.