Mitral annular disjunction and ventricular arrhythmias after mitral valve surgery: true, longer, inferolateral disjunctions matter

This commentary refers to ‘Mitral annular disjunction and mitral valve prolapse: long-term risk of ventricular arrhythmias after surgery’, by K. Lodin et al., https://doi.org/10.1093/eurheartj/ehaf195 and the discussion piece ‘Is true-MAD what we are truly looking for in arrhythmic risk stratification?’, by S. Figliozzi et al., https://doi.org/10.1093/eurheartj/ehag242. We thank Drs Figliozzi and Santkowski for their thoughtful commentary on our study of long-term risk of ventricular arrhythmias (VA) in patients with mitral annular disjunction (MAD) and mitral valve prolapse (MVP) undergoing mitral valve surgery.1 Their questions raise important considerations regarding MAD assessment and arrhythmogenesis in MAD, which we address point-by-point. First, they question our focus on true inferolateral MAD, given the limitations of transthoracic echocardiography (TTE) in detecting small disjunctions. In the UK Biobank study of participants undergoing cardiac magnetic resonance (CMR),2 MAD was found among 76% of the cohort, predominantly in the anterior or inferior wall, and only rarely in the inferolateral wall. MAD in the anterior and inferior wall therefore likely represents a normal anatomical variant, whereas inferolateral MAD appears less benign, being associated with MVP, VA, and myocardial fibrosis.3