Mitral Annular Disjunction: Epidemiology, Diagnostic Methods, Prognosis, and Novel Implications

Abstract

Mitral annular disjunction (MAD) is an increasingly recognized structural abnormality of the mitral valve apparatus, often associated with mitral valve prolapse and a heightened risk of ventricular arrhythmias and sudden cardiac death. It is defined by a separation between the mitral annulus and the left ventricular myocardium, best visualized during systole. In this review, we present an updated and comprehensive overview of MAD, drawing from recent large-scale imaging studies, expert consensus documents, and newly proposed classifications such as true versus pseudo-MAD. We discuss its prevalence, anatomical features, and diagnostic challenges across multiple imaging modalities, including transthoracic and transesophageal echocardiography, cardiovascular magnetic resonance, and computed tomography. We also explore its pathophysiological role in arrhythmogenesis, its prognostic implications, and current management strategies. Special attention is given to risk stratification based on imaging and cardiac rhythm findings, and we propose a practical clinical framework to guide decision-making. This review aims to support clinicians in recognizing MAD as a potentially arrhythmogenic condition that requires systematic evaluation and follow-up.

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

Figure 1

Transthoracic echocardiographic images demonstrating mitral annular disjunction (MAD). Parasternal long-axis view (left) and apical four-chamber view (right) reveal a distinct separation between the posterior mitral annulus (white arrows) and the basal inferolateral left ventricular myocardium (yellow brackets). The arrows highlight the disjunction plane in systole. MAD is visualized as a systolic detachment of the mitral annulus from the ventricular wall, most prominently affecting the posterior annulus.

Figure 2

Cardiovascular magnetic resonance (CMR) image demonstrating mitral annular disjunction (MAD). In this long-axis cine frame, the blue arrow indicates the region of disjunction, seen as a systolic separation between the posterior mitral annulus (white arrows) and the basal inferolateral left ventricular myocardium. This finding is characteristic of MAD and best appreciated during systole on CMR cine imaging.

Figure 3

Proposed algorithm for arrhythmic risk stratification and management in patients with mitral annular disjunction (MAD). Abbreviations: MAD, mitral annular disjunction; CT, computed tomography; CMR, cardiovascular magnetic resonance; ILR, implantable loop recorder; EP, electrophysiologic; ICD, implantable cardioverter defibrillator.