Mitral Annular Disjunction: A Potential Cause for Ventricular Arrhythmia in Patients with Anomalous Aortic Origin of a Coronary Artery (QF_TH_033)

Description of Clinical Presentation:
Case 1: An 18-year-old female with exertional chest pain was diagnosed with anomalous aortic origin of the right coronary artery (RCA, R-AAOCA) from the left coronary artery (LCA, Figure 1A). She has a history of mitral valve prolapse (MVP) and premature ventricular contractions. Invasive stress testing showed significantly impaired coronary flow, leading to surgical transection and reimplantation of the RCA. Post-surgery, her anatomy and stress test were normal (Figure 1B-C), but a 3-beat run of ventricular tachycardia (VT) was detected on Holter monitor (Figure 1D). Cardiac MRI revealed MVP and mitral annular disjunction (MAD) with a MAD distance of 4.4 mm (Figure 1E), which could explain the VT. No myocardial scar was noted (Figure 1E).




Case 2: A 47-year-old man experienced chest pain during soccer and was diagnosed with VT and anomalous aortic origin of the LCA (L-AAOCA) from the right aortic sinus with an intraseptal course. Cardiac MRI showed no myocardial scarring or fibrosis. Suspected ischemia-induced VT led to transconal unroofing of the LCA, which appears patent postoperatively (Figure 2A). VT recurred 3 months later. Upon review, MAD was identified and its distance measured 8 mm (Figure 2B). We recommended further invasive stress testing of the repaired LCA.


Diagnostic Techniques and Their Most Important Findings:
Cardiac MRI is essential in the diagnosis and assessment of MAD and AAOCA.



- MAD can be detected on a cine SSFP of the long axis left ventricular outflow tract. The posterior mitral valve hinge point should be carefully identified in MVP when measuring MAD distance to avoid overestimation.



- Dobutamine stress perfusion cardiac MRI (Figure 1C) is helpful in identifying AAOCA patients with ischemia.



- Phase-sensitive inversion recovery and T1 mapping before and after contrast provide a comprehensive assessment of myocardial scarring and fibrosis.


 

Learning Points from this Case:
Both MAD and AAOCA have been linked to ventricular arrhythmia and sudden cardiac arrest, though data on their co-occurrence are limited. This abstract presents 2 patients with AAOCA who had ventricular arrhythmia both before and after AAOCA surgeries. MAD should be considered a potential cause of ventricular arrhythmia when stress tests rule out ischemia. MAD may occur with MVP or independently. Future research should include the prevalence of MAD in AAOCA and their long-term follow-up to understand their risk for malignant arrhythmias.