Mitral Annular Disjunction in Out-of-Hospital Cardiac Arrest Patients – a Retrospective Cardiac MRI Study

Abstract

Background: Mitral annular disjunction (MAD), defined as defective attachment of the mitral annulus to the ventricular myocardium, has recently been linked to malignant arrhythmias. However, its role and prognostic significance in patients requiring cardio-pulmonary resuscitation (CPR) remains unknown. This retrospective analysis aimed to describe prevalence and significance of MAD by cardiac magnetic resonance (CMR) imaging, in out-of-hospital cardiac arrest (OHCA) patients. Methods: Eighty-six patients with OHCA and a CMR scan 5 days after CPR (interquartile range (IQR): 49 days before – 9 days after) were consecutively enrolled. MAD was defined as disjunction-extent ≥1mm in CMR long-axis cine-images. Medical records were screened for laboratory parameters, comorbidities and prior arrhythmias. Results: In 34 patients (40%), no underlying cause for OHCA was found during hospitalization despite profound diagnostics. Unknown-cause OHCA patients showed a higher prevalence of MAD compared to definite-cause patients (56% vs. 10%, p<0.001) and had a MAD-extent of 6.3mm (IQR: 4.4-10.3); moreover, these patients were significantly younger (43 years vs. 61 years, p<0.001), more often female (74% vs. 21%, p<0.001) and had fewer comorbidities (hypertension, hypercholesterolemia, coronary artery disease, all p<0.005). By logistic regression analysis, presence of MAD remained significantly associated with OHCA of unknown cause (odds ratio: 8.49, 95% confidence interval: 2.37-30.41, p=0.001) after adjustment for age, presence of hypertension and hypercholesterolemia. Conclusions: MAD is rather common in OHCA patients without definitive aetiology undergoing CMR. Presence of MAD remains independently associated to OHCA without identifiable trigger. Further research is needed to understand the exact role of MAD in OHCA patients.