Functional and morphological determinants of left ventricular fibrosis in patients with mitral annular disjunction in cardiac magnetic resonance imaging

Aims The study investigates determinants of left ventricular (LV) fibrosis in patients with inferolateral mitral annular disjunction (MAD). Methods and results This single centre retrospective cohort study included 111 patients [median age 52 years (25th–75th percentile 36–69), 47% female] with inferolateral MAD that underwent cardiac magnetic resonance imaging. Mid-myocardial replacement fibrosis of the basal inferolateral LV wall was present in 27 (24%) patients. Patients with fibrosis were older [63.0 years (25th–75th percentile 53.0–70.0) vs. 47.5 years (25th–75th percentile 34.0–67.5), P = 0.011], more likely to have mitral valve prolapse (MVP) [24/27 (89%) vs. 58/84 (69%), P = 0.041], had larger isolated posterior prolapse size [5.0 mm (25th–75th percentile 5.0–5.0) vs. 3.0 mm (25th–75th percentile 2.0–4.0), P = 0.041], were more likely to have bileaflet MVP [17/27 (63%) vs. 30/84 (36%), P = 0.013], had larger MAD distance [6.0 mm (25th–75th percentile 5.0–9.0) vs. 5.0 mm (25th–75th percentile 3.0–8.0), P = 0.018] and were more likely to exhibit an accelerated longitudinal motion of the basal inferolateral LV segment [20/27 (74%) vs. 26/84 (31%), P < 0.001]. Multivariable logistic regression revealed that age [odds ratio (OR) 1.06, confidence interval (CI) 1.02–1.10, P = 0.001] and accelerated longitudinal motion of the basal inferolateral LV segment (OR 11.10, CI 2.83–43.60, P = 0.001) were significantly associated with replacement fibrosis. Bileaflet MVP (OR 4.28, CI 1.51–12.13, P = 0.006) and MAD size (OR 1.24, CI 1.01–1.52, P = 0.041) were associated with an accelerated motion of the basal inferolateral LV segment. Conclusion Age and accelerated longitudinal motion of the basal inferolateral LV segment are independent determinants of replacement fibrosis of the basal inferolateral wall in patients with MAD. The presence of bileaflet MVP and MAD size are significantly associated with this accelerated movement pattern.