Successful Minimally Invasive Mitral Valve Replacement in a Post-thymectomy Patient with Myasthenia Gravis: A Case Report

Presented is a case of a 68-year-old Filipino, female, a known case of Myasthenia Gravis, post-thymectomy maintained on pyridostigmine, with a history of hypertension and Mitral Valve Prolapse who was admitted for acute heart failure symptoms. Diagnostics revealed a torn chordae tendineae of the mitral valve and the patient was subsequently advised to undergo mitral valve replacement due to acute decompensation. Pre operative coronary evaluation showed angiographically normal coronary arteries while CT aortogram showed no distinct evidence of aortic aneurysm, stenosis, dissection or severe calcification of thoraco-abdominal aorta and iliac-femoral vessels. The patient underwent minimally invasive mitral valve replacement with a bioprosthetic valve, however suddenly experienced ptosis and respiratory depression while at the recovery room which were attributed to stress from surgery and missed doses of Pyridostigmine while undergoing surgery. She was closely monitored at the Intensive Care Unit and her symptoms gradually resolved upon resumption of Pyridostigmine. Despite the unanticipated respiratory depression and ptosis, the patient was able to complete 5 days of phase I cardiac rehabilitation post operatively and was discharged well and improved. The case reported may be the first locally documented ruptured chordae tendineae with coinciding Myasthenia Gravis who underwent minimally invasive valve replacement with successful treatment outcomes.