Clinical knowledge regarding mitral annulus disjunction (MAD) of mitral-valve-prolapse (MVP) remains limited, controversial and its potential link with untoward outcomes unsubstantiated.

To assess in MVP-patients, MAD prevalence, phenotypic characteristics and long-term outcome (clinical arrhythmic events and excess-mortality).

A cohort of 595 (278 female, age 61±16 years) consecutive patients with isolated MVP, with comprehensive clinical, rhythmic, Doppler-echocardiographic and consistent MAD assessment, was examined. MAD prevalence, associated MVP-phenotype and outcome (survival, clinical arrhythmic events) were analyzed in overall and matched cohort.

MAD presence was common (186–31%) in MVP, generally in younger patients and independently associated with severe myxomatous disease (P≤0.0002). MAD presence was also independently associated with larger left ventricle (P=0.005). Age-matched-cohort survival after MVP diagnosis was not worse with MAD (10-year 93±2% for no-MAD and 97±1% for MAD, P=0.4), even adjusted-comprehensively for MVP characteristics (P=0.8). During follow-up, 170 patients had clinical arrhythmic events [ventricular tachycardia-VT (n=159), arrhythmia ablation (n=14), Cardioverter-defibrillator implantation (n=14) and sudden cardiac death (n=3)]. MAD was independently associated with higher risk of arrhythmic events [adjusted-hazard-ratio 2.60(1.87–3.62), P<0.0001]. MAD link to arrhythmic events was weaker post-mitral-surgery [adjusted-hazard-ratio 2.07 (1.24–3.43), P=0.005] (Figure 1).

MAD is frequent at MVP diagnosis and strongly linked to advanced-myxomatous-degeneration. MAD presence is independently associated with long-term excess-incidence of clinical arrhythmic events. However, within the first 10 years post-diagnosis MAD is not linked to excess-mortality and while reassurance should be provided from the survival point of view, careful monitoring for arrhythmias is in order with MAD.