Arrhythmogenic Mitral Valve Prolapse Revisited: A Not Uncommon Cause of Youthful Sudden Death in Athletes and Women.

Background: Sudden deaths (SDs) in young people, including competitive athletes, albeit uncommon, are usually attributable to genetic, congenital or acquired cardiovascular conditions. However, it is under-appreciated that mitral valve prolapse (MVP), a relatively common valvular heart disease, is associated with SD in this youthful population.

Methods: Forty-three MVP-related SDs were identified from 2 large cardiovascular registries with pathologic, clinical, and demographic findings reported.

Results: Events occurred in both sexes, but females were unexpectedly common (49%); median age was 22 ± 8 years, and 29 (67%) were engaged in competitive sports, including 17 with preparticipation examination. Of the 43 MVP cases, 21 died suddenly during or just after vigorous exercise, including 6 during organized sports. Sixteen (37%) had been evaluated by a cardiologist, resulting in confirmed MVP diagnosis in 11. Pathologic findings characteristic of MVP included bileaflet myxomatous involvement (in all cases) and areas of interstitial or replacement myocardial fibrosis (in 79%), most evident in posterolateral left ventricular wall.

Conclusions: Arrhythmogenic myxomatous degeneration (MVP) is an under-recognized cause of SD in young people, including competitive athletes, disproportionally affecting females and requires a high index of clinical suspicion. Frequency of left ventricular fibrosis in these young people with MVP suggests a mechanism for ventricular tachyarrhythmias and SD, relevant to future risk stratification.