More than one quarter of patients hospitalized with congestive heart failure are readmitted within 30 days of discharge, with total annual costs surpassing $20 billion. In patients presenting with acute heart failure symptoms and chest pain, differentiating acute coronary syndrome from acute myocarditis is challenging. Newer imaging modalities, such as cardiac magnetic resonance imaging, can provide invaluable diagnostic information. We describe a case of acute myocarditis with recurrent admissions for congestive heart failure, initially misidentified as acute coronary syndrome and treated with anti-thrombotic therapy. We were able to make the definitive diagnosis using cardiac magnetic resonance imaging and avoid an invasive endomyocardial biopsy.
Clinical Summary
A 61-year-old man with polysubstance abuse, hypertension, and known coronary artery disease with prior stents was admitted with chest pain and shortness of breath. The initial troponin was elevated (2.4 ng/ml). His electrocardiography showed ST-T changes. A diagnosis of acute coronary syndrome was considered, and appropriate therapy was commenced. Transthoracic echocardiogram revealed severe systolic dysfunction with a left ventricular ejection fraction of 20% to 25%. The patient continued to have chest pain with further elevation of troponins (22.6 μg/L) despite standard medical therapy (including aggressive antithrombotic therapy). Coronary angiography showed nonobstructive coronary artery disease, patent stents, and significant global hypokinesis. The medical therapy was intensified by addition of glycoprotein IIb-3a inhibitors. The patient continued to have chest pain, and his troponin peaked (at 312 μg/L) despite aggressive medical management. The troponin eventually trended down, and his chest pain improved. He was optimized on medical therapy and discharged to home. The patient was readmitted 5 days later with symptoms of congestive heart failure exacerbation. During this admission, cardiac magnetic resonance imaging was performed with T2-weighted edema imaging (Figure 1), which demonstrated an abnormal increase in signal suggestive of myocardial edema in the inferior and inferolateral walls (Figure 1, arrows). Resting perfusion images showed no perfusion defects. The extremely elevated troponins and the highly suggestive findings on cardiac magnetic resonance imaging led to the diagnosis of acute myocarditis. Biopsy was not performed because of the high risk of complications and the low likelihood of altering treatment. His symptoms resolved with medical treatment, and he was discharged with a plan to follow up with heart failure service as an outpatient.
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–Irbaz Bin Riaz, MBBS, MM, Avtar Singh, MD, Rajesh Janardhanan, MD, MRCP
This article originally appeared in the June 2014 issue of The American Journal of Medicine.
