Mitral valve prolapse and sport: how much prolapse is too prolapsing?

This editorial refers to ‘How to manage an athlete with mitral valve prolapse’, by E. Cavarretta et al., pp. 1110–1117. ‘The function of wisdom is to discriminate between good and evil’—Marcus Tullius Cicero When in 1966 Barlow first demonstrated on angiography that mid-systolic click and late systolic murmur were correlated with the protrusion of the mitral valve leaflets causing a late systolic regurgitation,1 probably he would have never imagined that almost 60 years later this entity would have been at the heart of controversies on several aspects, ranging from diagnosis to aetiology, prognosis and evolution. The mitral valve prolapse, the most common cardiac valve disorder, is generally considered a benign condition. So, why so much interest in this condition? Because of its association with the most scaring symptom that a physician could face: the sudden cardiac death (SCD). The mitral valve prolapse is indeed associated with a 10-year mortality risk of 5%.2 The association with this dramatic manifestation has been first described in the 80s.3,4 Scaring, one of the first studies on the arrhythmic potential of the mitral valve prolapse showed a high prevalence of serious ventricular arrhythmias in paediatric patients on exercise testing.5 Since then, many efforts have been spent with the purpose to identify red flags that could help in distinguish prolapse with a benign prognosis from that with an increased predisposition to arrhythmogenic SCD. Even though the improvement of imaging technologies have significantly contributed in clarifying the definition and diagnosis,6 the pathophysiology and the correlation to arrhythmias and SCD continue to be intensely debated.