P181 An uncommon mechanism of severe mitral regurgitation due to infective endocarditis mimicking acute myocardial infarction

Abstract

Abstract A 53-year-old man, smoker, with diabetes mellitus, presented to the Emergency Department because of intense chest and abdominal pain, accompanied by dyspnea and high fever (39.5 °C) in the previous 4 days. Physical examination revealed an apical holosystolic murmur, with no signs of peripheral or pulmonary edema. An ECG showed sinus rhythm (90 bpm), complete right bundle branch block and minimal ST elevation in the inferior leads. A transthoracic echocardiography showed a mild reduction in left ventricle ejection fraction (EF 44%) due to akinesia of the infero-lateral wall, and mild mitral regurgitation (MR) due to mitral valve prolapse. An abdominal ultrasound ruled out signs of acute cholecystitis. Blood cultures were collected, and an empirical antibiotic therapy was started. Urgent blood exam showed high Troponin I (72000 ng/L) and high C-reactive protein (290 mg/L). An acute coronary syndrome was suspected based on clinical, ECG and echocardiography exam, and the patient underwent coronary angiography (Figure 1, Panel A) that showed no significant coronary stenosis, except for two small filling defects in the very distal part of both the left anterior descendent and the circumflex coronary arteries suspected for coronary emboli. The patient was then admitted in the coronary care unit, but after just a few hours his clinical and hemodynamic condition deteriorated. A transesophageal echocardiography was performed to rule out mechanical complications related to the acute myocardial infarction and revealed severe MR (Panel D), elongated, hyperechogenic and dysfunctioning antero-lateral papillary muscle (ALPM) with an abnormal mobility suggestive for myocardial abscess, and a mobile mass attached on the aortic valve suggestive for vegetation (Panel B and C). Due to the worsening hemodynamic status, the patient underwent urgent cardiac surgery. Histological analysis confirmed the presence of an abscess of the ALPM due to Staphylococcus Aureus. The patient died after a week because of cerebral hemorrhage. Autopsy reported multiple lungs, renal and cerebral embolic septic infarctions. Learning points coronary artery embolization and papillary muscle abscess are very rare and often fatal consequences of infective endocarditis (IE). High (otherwise unexplained) fever and signs of embolism are minor Duke modified criteria for IE that should lead the physician to look for major criteria, such as positive blood cultures or echocardiography suggestive for IE. Emboli seen in the very distal part of the coronary arteries might have caused the ALPM abscess. Abstract P181 Figure