Unusual Presentation of Listerial Myocarditis and the Diagnostic Value of Cardiac Magnetic Resonance

Listeria monocytogenes is an infrequent cause of bacterial myocarditis. Myocarditis without evidence of endocarditis is even rarer. Management in such cases involves early diagnosis, antibiotic therapy, and emergency treatment of arrhythmias. We report the case of a 47-year-old man who presented with features of acute ST-segment-elevation myocardial infarction complicated by ventricular tachycardia that necessitated urgent electrical cardioversion. Contrast-enhanced cardiac magnetic resonance images revealed hypertrophy, necrosis, and a mass that was determined to be an abscess caused by L. monocytogenes. Antibiotic treatment led to resolution of the listerial myocarditis. In addition to reporting our patient's case, we discuss the comparative advantages of cardiac magnetic resonance versus transthoracic echocardiography in characterizing myocarditis, upon presentation and in follow-up evaluation.