Arrhythmic Mitral Valve Prolapse

About 1-3% of the general population are a ected by mitral valve prolapse. It is de ned as a >2 mm superior displacement of the mitral valve lea et(s) during systole with or without mitral regurgitation. Generally it is regarded as a benign condition, but the outcome is widely heterogenous. Since the 1980s several complications are reported, for example progressing mitral regurgitation requiring mitral valve surgery, atrial brillation, stroke's in sinus rhythm, congestive heart failure, infective endocarditis, ventricular arrhythmias and even sudden cardiac death [1,2]. The association between sudden cardiac death (SCD) and mitral valve prolapse (MVP) has been discussed in several publications and is of increasing awareness.

But what are the clues for the diagnosis of the arrhythmic mitral valve prolaps? Basso et al. [3] demonstrated for the first time the MRI and histologic evidence of a possible arrhythmic substrate in SCD patients: brosis of the papillary muscle and the inferobasal left ventricular wall suggesting myocardial stretch and friction by the prolapsing mitral lea et. Bilea et prolapse and myxomatous mitral valve disease (MMVD) are more responsible producing myocardial stretch. There are two important echocardiographic signs for the myxomatous mitral valve disease and the risk for malignant ventricular arrhythmias [3].

Firstly, the mitral annular disjunction (MAD) is de ned as a detachement of the roots of the annulus from the ventricular myocardium (Figure 1), producing a gap of 2-10 mm during systole. It is typically under the P1 and P2 scallop, not seen by the surgeons view from the left atrium and positive correlated to the burden of VPB's (as a result of the amount of stretch?). MAD is seen in patients with more segments prolapsing, more bilea et disease and greater volume of prolaps, which are all components of di use myxomatous disease. In this way MAD is speci c for MMVD [4].

Secondly, the Pickelhaube Sign is defined as a high-velocity mid-systolic spike in tissue Doppler velocity pro le of the lateral mitral valve annulus (Figure 2). This phenomenon appears when the prolapsing posterior lea et stretches the posteromedial papillary muscle causing a sharp traction of the adjacent posterobasal left ventricular wall. Usually the velocity surpasses 16 cm/s [5].

The Mitral Annular Disjunction and the Pickelhaube sign are thought to be noninvasive, echocardiographic markers associated with sudden cardiac death of myxomatous mitral valve prolapse. Furthermore these phenomenons are part of risk strati cation recently proposed [6] for SCD in MMVP. Many questions regarding the evaluation, monitoring and therapy of these patients are open and will be discussed in the future.

In conclusion, the arrhythmic mitral valve prolapse is a rare but di cult problem of a quite common and mostly benign condition of the mitral valve. The mitral annular disjunction and the Pickelhaube sign are two important features of the myxomatous mitral valve disease. Therefore It is probably important to look for these signs linked to unexplained sudden cardiac death of young patients with mitral valve prolapse.