Mitral Annular Disjunction: Pathophysiology, Pro-Arrhythmic Profile and Repair Pearls

Abstract

Mitral annular disjunction (MAD) is a structural abnormality defined by a distinct separation of the mitral valve annulus-left atrial wall continuum and the basal aspect of the posterolateral left ventricle. This anomaly is often observed in patients with myxomatous mitral valve prolapse. Importantly, MAD has been strongly associated with serious ventricular arrhythmias and predisposes to sudden cardiac death. Therefore, we have to emphasize the need to diagnose this morphologic and functional abnormality in routine practice in order to facilitate optimal mitral valve repair and minimize patient risks. Nevertheless, clinical knowledge regarding MAD still remains limited. In the present review, we aim to shed light on several aspects of MAD, including distinct anatomical and pathophysiological characteristics, imaging modalities, association with ventricular arrhythmias, and current methods of treatment.

Keywords: lethal arrhythmias; mitral disjunction; mitral regurgitation; mitral surgery; mitral valve prolapse; mitral valve repair; ventricular arrhythmias.

Fig. 1.

Transthoracic echocardiogram of a 60-year-old female patient. (A) Preoperative views showing mitral annular disjunction (left) and severe mitral regurgitation and during systole (right). The distance between mitral valve leaflet-atrial wall and left ventricle is measured 1.48 cm (yellow bidirectional arrow). (B) Postoperative views after mitral valve repair with a 34 mm ring. No mitral annular disjunction is identified. No mitral regurgitation is detected. LV, Left Ventricle; LA, Left Atrium; AO, Ascending Aorta; RVOT, Right Ventricular Outflow Tract.