Substrate Characterization and Outcomes of Catheter Ablation of Ventricular Arrhythmias in Patients With Mitral Annular Disjunction

Abstract

Background: Mitral annular disjunction (MAD) has recently been recognized as an arrhythmogenic entity. Data on the electrophysiological substrate as well as the outcomes of catheter ablation of ventricular arrhythmias in patients with MAD is limited. Methods: Forty patients with MAD (mean age 47±15 years; 70% female) underwent catheter ablation for ventricular arrhythmias. Detailed clinical, electrocardiographic, cardiac imaging, and procedural data were collected. Clinical outcomes were compared between patients who had substrate modification in the MAD area and those who did not. Results: Twenty-three (57.5%) patients had ablation for premature ventricular contractions, 10 (25%) patients for sustained ventricular tachycardia, and 7 (17.5%) patients for premature ventricular contraction-triggered ventricular fibrillation ablation. Mean end-systolic MAD length was 10.58±3.49 mm on transthoracic echocardiography. Seventeen (42.5%) patients had preprocedural cardiac magnetic resonance imaging, and 5 (29%) patients had late gadolinium enhancement. Among the 18 (45%) patients who had abnormal local electrograms (low voltage, long-duration, fractionated, isolated mid-diastolic potentials) during electroanatomical mapping, 10 (25%) patients had abnormal electrograms in the anterolateral mitral annulus or MAD area. Substrate modification was performed in 10 (25%) patients. Catheter ablation was acutely successful in 36 (90%) patients (elimination of premature ventricular contraction or noninducibility of ventricular tachycardia). After a median follow-up duration of 54.08 (interquartile range, 10.67–89.79) months, premature ventricular contraction burden decreased from a median of 9.75% (interquartile range, 3.25–14) before the ablation to a median of 4% (interquartile range, 1–7.75) after the ablation ( P =0.03 [95% CI, 0.055–6.5]). Eight (20.5%) patients had repeat ablation for ventricular arrhythmias. Substrate modification of the MAD was associated with a trend toward lower rates of repeat ablation (0% versus 26.7%; P =0.16). Conclusions: Patients with MAD have a complex arrhythmogenic substrate, and catheter ablation is effective in reducing recurrence of ventricular arrhythmias. Substrate mapping and ablation may be considered in these patients.

Mitral Annular Disjunction

“…CMR is also helpful in detecting myocardial fibrosis, which can be observed in patients with MAD, providing critical information for risk stratification. 8 Importantly, fibrosis is not necessary for a patient to experience serious cardiac events, 9 as illustrated in Case 1, highlighting the complex pathophysiology of arrhythmia generation in this population.…”

Mitral annular disjunction identified peripartum: A case highlighting key features of a recently classified syndrome

“…Currently, it is not the first choice for MAD intervention due to the disruptive nature of shock delivery and not treating MAD at the source. Catheter ablation is a more invasive measure that in one study was successful in 90% of MAD patients in eliminating premature ventricular contractions 19 . Mitral valve surgery but specifically mitral valve repair, is a promising intervention as it is reported that it is not possible to identify any MAD in almost all patients post‐surgery when using TTE 20 .…”

“…17 premature ventricular contractions. 19 Mitral valve surgery but specifically mitral valve repair, is a promising intervention as it is reported that it is not possible to identify any MAD in almost all patients postsurgery when using TTE. 20 A study has reported that 'post-surgery, MAD association with arrhythmic events persisted but VT risk after surgery did not reach significance'.…”

Arrhythmic mitral valve prolapse in 2023: Evidence-based update

“…A recent study demonstrated the efficacy of CA to reduce the VA burden for patients with MVP and MAD ( 45 ). In the presence of MAD, the arrhythmogenic substrate, defined by abnormal local electrograms (low voltage, long-duration, and fractionated, isolated mid-diastolic potentials) on electro-anatomical mapping, was identified in the anterolateral mitral annulus or MAD area ( 45 ). An exhaustive list of studies reporting the results of CA for VAs for patients with MVP or MAD is presented in Table 2 .…”