176-31: Malignant Bileaflet Mitral Valve Prolapse Syndrome: Case Report on Possible Mechanism of Sudden Cardiac Arrest/Death and Treatment Outcome

Abstract

Purpose of Study: Malignant bileaflet mitral valve prolapse (MVP) syndrome is relatively a new clinical entity which is associated with sudden cardiac arrest/death (SCAD) secondary to ventricular fibrillation (VFib). Little has been described on treatment.We describe here, possible mechanism of SCAD and treatment outcome of a case of malignant bileaflet MVP syndrome. Method(s): A 56 year-old lady presented with out of hospital VFib arrest while walking. Past medical history including bileaflet MVP with mitral regurgitation (MR). No significant family history of SCAD. She was successfully resuscitated and underwent therapeutic hypothermia. ECG showed sinus rhythm with normal QTc. There were two ventricular ectopics (VEs) of different configurations. Normal coronary angiogram. Transthoracic echocardiography (TTE) showed mild left ventricular dysfunction, bileaflet MVP with severe MR. No late gadolinium enhancement on cardiac magnetic resonance. Flecainide challenge test was negative. During adrenaline challenge test, she developed frequent non-sustained ventricular tachycardia of multiple configurations (figure 1). Genetic screening in particular long QT genes were negative. Result(s): She was subsequently started bisoprolol 5mg bid. She underwent single chamber implantable cardioverter defibrillator (ICD) implantation (secondary prevention) prior discharge. She, however, had appropriate ICD shock for VFib 4 months post ICD implantation. The VFib was triggered by VEs of short-long-short sequence (figure 2). She subsequently received two further episodes of appropriate ICD shocks for VFib. The triggers (VEs) was thought to be arising from papillary muscles (figure 1) possibly due to mechanical stretching in the setting of severe bileaflet MVP. Accordingly, she underwent successful mitral valve repair (MVR). Post MVR TTE showed trivial MR with preserved left ventricular systolic function. The VEs burden was high prior MVR and significantly reduced as well as no further episode of ICD therapy two month post MVR. Conclusion(s): To the best of our knowledge, this is the first description of MVR reducing VEs burden in malignant bileaflet MVP. This suggest treating the underlying mechanical abnormality (prolapsed mitral valve and consequent stress on papillary muscles) may abolish VEs as a trigger for fatal arrhythmia. Further studies would be needed to confirm this hypothesis (Figure Presented).