Abstract 16003: A Case of Ventricular Fibrillation Arrest in a Healthy Young Female With Newly Discovered Mitral Annular Disjunction

Abstract

Introduction: Mitral annular disjunction (MAD) is an under-recognized cause of ventricular arrhythmias. Case Presentation: A previously healthy, athletic 43-year-old female suddenly collapsed during a staff meeting at a medical center. Cardiopulmonary resuscitation was initiated and she was found to be in ventricular fibrillation, requiring three defibrillation shocks to achieve ROSC. EKG was notable for prolonged QTc without signs of pre-excitation or Brugada syndrome. Patient denied any personal or family cardiac history but endorsed frequent palpitations in the past. No electrolyte derangements were identified. Coronary angiography revealed normal origins of the coronary arteries and no evidence of obstructive disease. Transthoracic echocardiogram demonstrated normal left ventricular systolic function, normal wall thickness, and no regional wall motion abnormalities. There was mild bileaflet mitral valve prolapse with mild mitral regurgitation and mitral annular disjunction measuring 0.7 cm. Cardiac MRI was obtained and demonstrated biventricular dilation (consistent with athlete’s heart) with evidence of MAD. The myocardium was normal with no evidence of late enhancement. She underwent dual-chamber cardioverter-defibrillator implantation for secondary prevention. Discussion: Mitral annular disjunction is a structural abnormality involving atrial displacement of the mitral annulus, leading to an abnormal separation between the posterior mitral valve leaflet and basal ventricular myocardium during systole. Etiology of MAD remains unclear. It is estimated to be present in 8.7% of the general population and in over 30% of individuals with mitral valve prolapse. This case presents an example of a previously healthy patient with sudden cardiac arrest. After extensive workup, MAD was identified as the most likely trigger for her new onset arrhythmia. This case highlights the severe, and potentially fatal, arrhythmias that can arise from MAD. It is important to recognize MAD seen on echocardiograms and counsel patients on potential complications. Patients with MAD and increased risk factors should undergo further evaluation with cardiac MRI and/or electrophysiology studies.