1356345 - “That’s one MAD Ventricular: Ventricular Fibrosis Secondary to Mitral Annular Disjunction”

A 28-year-old woman with a past medical history of long-standing mitral valve prolapse (MVP), mitral regurgitation, Raynaud’s syndrome, narcolepsy, and palpitations was followed in our outpatient Cardiology clinic annually for several years. The patient’s annual transthoracic echocardiogram (TTE) demonstrated a preserved left ventricular ejection fraction (LVEF) of 60%, anterior leaflet and posterior leaflet myxomatous proliferation, mitral annular disjunction (MAD), and mild-moderate late systolic mitral regurgitation. Over the last year, she started having palpitations that corresponded to PVCs captured on her apple watch. The patient denied syncopal events.  Cardiac MRI (CMR) was ordered to further evaluate for arrhythmogenic MVP and MAD.

Diagnostic Techniques and Their Most Important Findings: Comprehensive CMR was performed on 1.5T Siemens Magnetom Aera scanner. Patient was in sinus rhythm with heart rate of 82 bpm. Steady- state free precession (SFFP) cine imaging demonstrated normal LV end-diastolic volume of 134 mL and normal LV ejection fraction of 56%. Left ventricular global long-axis strain preserved at -22%. RV size and function were normal with an RVEF of 45%. Bileaflet mitral valve prolapse was visualized by SFFP LVOT stack cine images (Figure 1). Native T1 was calculated at 1017 ms, T2 52 ms, and ECV quantified at 28%. Although global ECV was within normal range there was obvious demonstration of focal elevation at level of mid anterolateral and mid inferolateral segments consistent with findings of interstitial myocardial fibrosis (Figure 2). Phase contrast imaging demonstrated mild mitral valve regurgitation with a regurgitant fraction calculated at 28%. SFFP LVOT cine demonstrate a MAD distance of 11 mm (Figure 3).

Learning Points from this Case:

Mitral annular disjunction has been associated with severe myxomatous mitral valve disease. The severity of the myxomatous mitral valve has been proposed to carry the risk of ventricular arrhythmias and sudden cardiac death (1). Even though the diagnosis can be made with TTE and TEE, the findings can be subtle since they can only be visualized during ventricular systole. CMR is the preferred imaging modality for the evaluation of MAD. While MAD is commonly seen in conjunction with MVP and mitral regurgitation, it is important to note it can present in isolation and carries the same risk of sudden cardiac death(2). Although our patient had MAD with MVP there was a demonstration of only mild mitral regurgitation suggesting that assessment of regurgitation severity may not always be sufficient to stratify a patient’s prognosis, as evident by our patient’s lateral wall fibrosis. Following these findings, a surgical consultation for minimally invasive mitral valve repair was scheduled as there is evidence in the literature suggesting a reduction of arrhythmia burden with mitral valve repair even in the absence of significant MR.(3)