Mitral annular disjunction and mitral valve prolapse: echocardiographic-MRI insights into cardiac function

Mitral annular disjunction (MAD) may accompany mitral valve prolapse (MVP) and is linked to ventricular arrhythmias. Its impact on global cardiac performance (specifically cardiac index (CI) and output (CO)), remains incompletely defined. Cardiac MRI (CMR) allows precise measurement of MAD, assessment of mitral annular dynamics, and detection of myocardial fibrosis via late gadolinium enhancement (LGE). We investigated both CMR and TTE metrics in patients with varying degrees of MAD compared to MVP-only.

Fifty-six patients who underwent CMR and TTE (mean age 61, 33 female) were divided into MAD ≥2 mm and MVP (the "MAD + MVP" group, n = 41) or MVP-only (n = 15). MAD was classified as <5 mm, ≥5 mm, and ≥ 10 mm in peak systole after excluding pseudo-MAD. LV volume, stroke volume, ejection fraction, cardiac output (CO), cardiac index (CI), mitral regurgitation (MR), and LGE were assessed. Any MAD was associated with lower CI versus MVP-only (p = 0.03). MAD ≥5 mm and MAD ≥ 10 mm showed reduced CO (p = 0.04 and 0.04, respectively) and CI (p = 0.04 and 0.03, respectively) versus MVP-only. LGE was more frequent in MAD ≥ 10 mm than in MAD < 10 mm (p = 0.028). MR incidence, volume, or fraction did not differ across groups. TTE showed agreement with CMR in MAD detection and quantification (p = 0.269), with minimal inter-observer variability (p < 0.001).

MAD is associated with impaired cardiac performance independent of MR and with increased myocardial fibrosis in severe cases. These findings suggest heightened electromechanical stress in MAD compared to MVP-only, which needs to be clinically correlated. TTE reliably detects and quantifies MAD, supporting its use alongside CMR for assessment of MAD.