Myocardial Characterization of Arrhythmogenic Mitral Valve Prolapse (STAMP: STretch and Myocardial Characterization in Arrhythmogenic Mitral Valve Prolapse)

Myocardial Characterization of Arrhythmogenic Mitral Valve Prolapse

Mitral valve prolapse (MVP) is a frequent affection of the mitral valve or its sub-valvular apparatus with a prevalence of 2-3% in the general population. This valvular disease is generally considered as benign, but may at term evolve toward mitral valve regurgitation of various severity and/or arrhythmia.

Mitral valve prolapse is routinely diagnosed using transthoracic echocardiography and only patients with significant mitral regurgitation will undergo subsequent examination (24-hour external loop recording, exercise ECG, cardiac MRI) and a close follow-up.

External loop recording and exercise ECG have an interest in the identification of patients presenting with arrhythmic complications, such as premature ventricular contractions, and in the global evaluation of hemodynamic consequences of the mitral regurgitation.

More recently, detection of myocardial fibrosis among patients with MVP and severe ventricular arrhythmia has been identified. Fibrosis could evolve independently of the valvular regurgitation's severity and could be a substrate (myocardial scar) leading to ventricular arrhythmia. However, no study has specifically characterized myocardial lesions among patients with MVP and none, or not significant, mitral regurgitation. Using cardiac magnetic resonance imaging (MRI), gold standard technique in myocardial imaging and characterization, and echocardiography, particularly speckle-tracking imaging, identification of static (fibrosis) and/or dynamic (ventricular systolic deformation patterns using speckle-tracking strain) myocardial lesions.

Identification of patients with impaired deformation patterns, fibrosis or with premature ventricular contractions may isolate a sub-group of patients with a higher risk of severe ventricular arrhythmia for whom a closer follow-up could be justified.

Inclusion Criteria:

• Mitral valve prolapse diagnosed in echocardiography
• Signed written consent
• Affiliation to social security
• No contraindication to MRI or exercise ECG
• Age above 18

Exclusion Criteria:

• Mitral valve prolapse with severe regurgitation and instable hemodynamic state requiring urgent surgery
• Prior MRI with contrast within the last month
• Prior diagnosis of primary cardiomyopathy potentially responsible for myocardial fibrosis
• Contraindication to exercise ECG: severe handicap, poor physical capacity
• Contraindication to MRI: implantable device, claustrophobia, metal debris
• Renal insufficiency with creatinine clearance <30 ml/min or prior serious side effect related to infusion of a magnetic contrast agent
• Pregnant or breast-feeding women
• Minors <18 years old
• Mental illness or incapacity with incapacity to obtain informed consent