Prevalence, Genetics, and Imaging Characteristics of Patients with Mitral Valve Prolapse and Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND

Concomitant arrhythmogenic right ventricular cardiomyopathy (ARVC) and mitral valve prolapse (MVP) has only been described in case reports. Little is known about genetic and phenotypic characteristics of these patients.

OBJECTIVE

To describe the prevalence, genetics, and imaging characteristics of MVP in ARVC patients.

METHODS

We identified 111 definite ARVC cases through medical record review, arrhythmia/cardiomyopathy targeted gene panels, and contrast cardiac magnetic resonance data. MVP was diagnosed on echocardiography as mitral leaflet displacement >2 mm above the annular plane in systole, "borderline MVP" defined as ≤2 mm.

RESULTS

We found MVP/borderline MVP in 14% of ARVC patients. Cardiac arrest occurred in 20% of those with MVP/borderline MVP compared to 16% without valve abnormalities. Among 69 ARVC patients with identified genetic variants, PKP2 mutations were highly prevalent (64%), particularly in those with MVP (83%). Most MVPs had posterior prolapse (73%) and trace/mild mitral regurgitation (87%). None had mitral annular disjunction. ARVCs with MVP had higher LV mass (93 vs. 75 g/m2, p = 0.02) and a higher prevalence of LV wall motion abnormalities (27% vs. 5%, p = 0.02) compared to ARVCs without valve abnormalities.

CONCLUSIONS

MVP is prevalent in ARVC and characterized by PKP2 variants in most cases. Typical features of arrhythmic MVP like bileaflet involvement and annular disjunction are rare in ARVC with MVP; features of arrhythmogenic left-sided cardiomyopathy - increased LV mass index and wall motion abnormalities - are more common. Further studies are needed to understand the role of MVP in arrhythmic risk stratification of ARVC.