Mitral Valve Prolapse and Mitral Annular Disjunction Arrhythmic Syndromes: Diagnosis, Risk Stratification and Management

Abstract

Although mitral valve prolapse (MVP) is usually considered a benign clinical condition, it has been linked with ventricular arrhythmias and sudden cardiac death in patients with a certain "arrhythmic" phenotype, raising awareness and mandating a specific risk stratification protocol. Mitral annular disjunction (MAD) is considered a "red flag" in malignant MVP syndrome along with bileaflet myxomatous prolapse, female gender, negative or biphasic T waves in the inferior leads, fibrosis in the papillary muscles or inferobasal wall detected by cardiac magnetic resonance imaging and complex arrhythmias of right bundle branch morphology. MAD seems to play a critical role in the chain of morphofunctional abnormalities which lead to increased mechanical stretch and subsequent fibrosis mainly in the papillary muscles, forming the vulnerable anatomic substrate prone to arrhythmogenesis, and associated with long-term severe ventricular arrhythmias. Arrhythmogenesis in MVP/MAD patients is not fully understood but a combination between a substrate and a trigger has been established with premature ventricular contraction triggered ventricular fibrillation being the main mechanism of sudden cardiac death (SCD). Certain characteristics mostly recognized by non-invasive imaging modalities serve as risk factors and can be used to diagnose and identify high risk patients with MAD, while treatment options include catheter ablation, device therapy and surgical intervention. This review focuses on the clinical presentation, the arrhythmogenic substrate, and the incidence of ventricular arrhythmias and SCD in MAD population. The current risk stratification tools in MAD arrhythmogenic entity are discussed.

Keywords: mitral annular disjunction; mitral valve prolapse; sudden cardiac death; ventricular arrhythmias.

Fig. 1.

Echocardiographic findings of mitral valve prolapse and mitral annular disjunction. (a) Transthoracic parasternal long axis echocardiographic view of a bileaflet mitral valve prolapse during end-diastole. (b) Mitral annular disjunction is revealed during end-systole. (c) The “Pickelhaube” sign (spiked systolic lateral mitral annular velocity $>$16 cm/s) may serve as an early indicator of mechanical stress even in the absence of fibrosis. (d) Longitudinal strain (GLS) with supranormal values in the basic inferior/lateral wall of the left ventricle.

Fig. 2.

Cardiac magnetic resonance findings of mitral annular disjunction (MAD) arrhythmic syndrome. (a) MAD with a distance of 8.51 mm in the posterolateral wall (red arrow). (b,c) Late gadolinium enhancement (LGE) localized at the posteromedial papillary muscle and at the inferior wall of the left ventricle (red arrows).

Fig. 3.

Electroanatomical mapping and ablation of premature ventricular contraction (PVC) arising from the posteromedial papillary muscle. (a) Typical PVC arising from the posteromedial papillary muscle (left superior axis with RBBB morphology). (b) PVC mapping demonstrating Purkinje potentials preceding the local ventricular activation. (c) Catheter ablation at the earliest activation site led to “warm-up” effect with the same PVC morphology. (d) Merge of electroanatomical 3-D and cardiac CT models demonstrating the papillary muscles (marked in blue). The posteromedial papillary muscle along with the ablation points are shown in multiple views (white arrows).

Fig. 4.

Diagnosis, risk stratification and management of mitral annular disjunction (MAD) arrhythmic syndrome. Abbreviations: CMR, cardiac magnetic resonance imaging; EPS, electrophysiological study; GLS, global longitudinal strain; ICD, implantable cardioverter defibrillator; ILR, implantable loop recorder; LV, left ventricle; LGE, late gadolinium enhancement; MVP, mitral valve prolapse; NSVT, non-sustained VT; PVC, premature ventricular complex; QTc, corrected QT interval; SCD, sudden cardiac death; TTE, transthoracic echocardiography; VT/VF, ventricular tachycardia/ventricular fibrillation.