Mitral Annular Disjunction: Regional Strain Abnormalities Associated With Life-Threatening Ventricular Arrhythmias

Mitral annular disjunction (MAD) has been linked to malignant ventricular arrhythmias in mitral valve prolapse, but the mechanisms and risk predictors are not well established. We aimed to identify clinical and echocardiographic factors with a focus on left ventricular (LV) strain.

We retrospectively studied 69 patients with MAD confirmed on echocardiogram. Clinical data and echocardiographic measurements were collected, including chamber dimensions, MAD distance, mitral regurgitation grade, and 2D global and segmental longitudinal strain by speckle-tracking. Univariate and multivariate logistic regression analyses were performed to determine independent predictors of arrhythmia.

All patients had preserved LV ejection fraction. Patients with arrhythmias demonstrated trends toward larger chamber dimensions and a larger MAD distance. Global longitudinal strain did not significantly differ between groups. Differences between patients with and without life-threatening arrhythmias localized specifically to the inferolateral region at the mid-ventricular level, where mid-inferolateral strain was significantly worse in arrhythmic patients (median -12.6% [IQR 13.5] vs. -18.9% [IQR 6.0], p = 0.0069). In univariate models, factors associated with arrhythmias included larger LV chamber diameters, greater MAD distance, a history of syncope, and worse strain in the mid-inferior and mid-inferolateral segments. On exploratory multivariate analysis, mid-inferolateral strain impairment appears to be independently associated with LTA (OR 1.11 per 1% strain increase, p = 0.012).

In patients with MAD, impaired mid-inferolateral segment strain was associated with LTA, suggesting that regional myocardial deformation may provide incremental arrhythmic risk stratification beyond global measures. These findings are, however, exploratory, hypothesis-generating and require confirmation in larger, prospective cohorts with independent validation to ascertain clinical utility.