Morphofunctional Abnormalities of Mitral Annulus and Arrhythmic Mitral Valve Prolapse

Area of Science:

• Cardiology
• Cardiac Imaging
• Pathology

Background:

• Arrhythmic mitral valve prolapse (MVP) involves myxomatous leaflets and left ventricular (LV) fibrosis.
• The study investigates morphofunctional mitral valve abnormalities contributing to regional myocardial stretch.

Purpose of the Study:

• To identify specific mitral valve abnormalities associated with LV fibrosis in arrhythmic MVP.
• To explore the relationship between these abnormalities and mechanical myocardial stretch.

Main Methods:

• Cardiac magnetic resonance imaging (CMR) was used to assess morphofunctional characteristics in MVP patients with and without LV late gadolinium enhancement.
• Quantitative measurements included mitral annulus disjunction, annular diameters, posterior systolic curling, and LV wall thickness.
• Histological analysis of the mitral annulus was performed in sudden death cases.

Main Results:

• MVP patients with LV fibrosis exhibited significantly higher mitral annulus disjunction, end-systolic and end-diastolic annular diameters, posterior systolic curling, and basal to mid LV wall thickness ratio.
• A strong linear correlation was observed between mitral annulus disjunction and posterior systolic curling (R=0.85).
• Histology confirmed longer mitral annulus disjunction in sudden death patients with MVP and LV fibrosis.

Conclusions:

• Mitral annulus disjunction is a constant feature in arrhythmic MVP with LV fibrosis.
• Posterior systolic curling, driven by excessive leaflet mobility, causes mechanical stretch leading to myocardial hypertrophy and scarring.
• These mitral annulus abnormalities and midsystolic click may help identify MVP patients requiring arrhythmic risk stratification.