Predictors of Left Ventricular Fibrosis in Mitral Annular Disjunction: Cardiac Magnetic Resonance Imaging Study

Mitral annular disjunction (MAD) is an anatomical anomaly increasingly recognized for its association with myocardial fibrosis and malignant arrhythmias. Identifying predictors of this fibrosis is crucial for risk stratification. This study aimed to define the functional and morphological predictors of left ventricular (LV) fibrosis in patients with MAD using cardiac magnetic resonance imaging (CMR).

In a retrospective single-center study, 60 patients with CMR-confirmed MAD were evaluated. Late gadolinium enhancement (LGE) was used to identify LV fibrosis, categorizing patients into two groups: those without fibrosis (Group I, n = 50) and those with fibrosis (Group II, n = 10). Clinical, volumetric, and feature-tracking strain parameters were compared between groups, and univariate logistic regression was performed to identify predictors of fibrosis.

The prevalence of LV fibrosis was 16.7%. Patients with fibrosis (Group II) demonstrated significant LV remodeling, in the form of higher indexed end-diastolic and end-systolic volumes (ESV) (LVEDVI: 116.2 vs. 98.4 mL/m², p = 0.032; LVESVI: 47.5 vs. 38.2 mL/m², p = 0.023), and markedly impaired biventricular strain, including LV global circumferential strain (LV GCS: -13.6 vs. -17.8, p = 0.0004) and right ventricular strain (RV GLS: -19.9 vs. -24.4, p = 0.028; RV GCS: -7.8 vs. -11.5, p = 0.003). On univariate analysis, the severity of mitral regurgitation (MR) (OR = 4.86, p = 0.049) and impaired LV global longitudinal strain (GLS) (OR = 1.44 per 1% reduction, p = 0.034) were identified as significant predictors of LV fibrosis.

In patients with MAD, the hemodynamic burden of significant MR and subclinical LV dysfunction, quantified by impaired LV GLS, are key significant predictors on univariate analysis of myocardial fibrosis. CMR, particularly tissue characterization with LGE and myocardial strain analysis, provides critical insights for enhanced risk assessment, potentially guiding early intervention strategies in high-risk individuals.