Inheritance of Imaging Parameters of Arrhythmic Risk in Mitral Valve Prolapse: A Pedigree Study

Area of Science:

• Cardiology
• Genetics
• Medical Imaging

Background:

• Mitral valve prolapse (MVP) is highly heritable, with a subset of patients experiencing sudden cardiac arrest (SCA) or sudden cardiac death (SCD).
• The inheritance patterns of imaging features associated with arrhythmic MVP are not well understood.

Purpose of the Study:

• To investigate the inheritance of phenotypic imaging features in families with mitral valve prolapse (MVP).
• To identify imaging markers associated with arrhythmic MVP and sudden cardiac events (SCA/SCD).

Main Methods:

• Recruited 23 MVP probands (9 with SCA/SCD, 14 with ventricular ectopy) and their families.
• Utilized 2D and speckle-tracking echocardiography, and 48-hour Holter monitoring.
• Assessed mitral annular disjunction, curling, global longitudinal strain, and mechanical/electrical dispersion.

Main Results:

• Multigenerational SCA/SCD occurred in 14% of extended pedigrees.
• Arrhythmic MVP cases showed more bileaflet involvement, mitral annular disjunction, curling, and abnormal valvular-myocardial mechanics compared to nonarrhythmic cases.
• SCA cases exhibited the highest mechanical dispersion; family members with normal valves had reduced global longitudinal strain and increased mechanical dispersion.

Conclusions:

• Familial MVP-associated SCA/SCD is rarely multigenerational and not solely linked to mitral annular disjunction.
• SCA in MVP may result from combined abnormal mechanics and increased dispersion.
• Mildly abnormal strain parameters in family members with normal valves suggest an underlying myopathy independent of MVP expression.