Journal of Cardiology Cases (2011) 3, e90—e93
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Case Report
Acute inferolateral ST-elevation myopericarditis diagnosed by delayed enhancement cardiac computed tomography Ricardo Krieger Azzolini (MD) a, Fernando Arturo Effio Solis (MD) a, Paulo Cury Rezende (MD) a, Claudio Campi (MD, PhD) a,b, Henrique Lane Staniak (MD) a, Rodolfo Sharovsky (MD, PhD) a, Alexandre Volney Villa (MD) b, Paulo Andrade Lotufo (MD, PhD) a, Márcio Sommer Bittencourt (MD) a,∗ a b
University Hospital, University of São Paulo Medical School, São Paulo, Brazil Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil
Received 9 October 2010; received in revised form 12 November 2010; accepted 16 November 2010
KEYWORDS Myocarditis; Cardiac computed tomography
Summary A 20-year-old man with no previous medical history presented to the Emergency Department (ED) complaining of 3 h of chest pressure. He denied drug abuse or risk factors for coronary artery disease. He had no symptoms of viral infection. Physical examination was unremarkable. The first electrocardiogram (ECG) showed a 4 mm ST-segment elevation in the inferior leads and no PR depression. His troponin and CK-MB levels were abnormal. Urgent coronary angiography showed no lesions. Echocardiography was normal. The patient was investigated with cardiac computed tomography (CT) and late enhancement imaging. Cardiac anatomy and coronary arteries were normal in the first pass images. Later image acquisition showed an inferolateral enhancement. Since cardiac magnetic resonance (CMR) is the gold standard for myocarditis evaluation, the patient was transferred for CMR evaluation which showed edema and late enhancement in the same myocardial territory diagnosed by CT. The patient was discharged with a diagnosis of myocarditis and presented asymptomatic at 1 month follow-up. This is the first report to show the topographic correlation of the ECG ST elevation with the myocarditis diagnosed by CT and CMR. Since CT is more widely available, its use in myocarditis diagnosis might become part of its routine work up. © 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
∗ Corresponding author at: Internal Medicine Division, University Hospital, University of Sao Paulo Medical School, Av. Lineu Prestes, 2565, Butantã 05508-000, Sao Paulo, Brazil. Tel.: +55 11 30919241; fax: +55 11 38128004. E-mail address:
[email protected] (M.S. Bittencourt).
1878-5409/$ — see front matter © 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jccase.2010.11.003
Acute inferolateral ST-elevation myopericarditis diagnosed by delayed enhancement cardiac computed tomography
Introduction Myocarditis is a rare but serious differential diagnosis for patients presenting with acute chest pain. However, making the correct diagnosis is not always easy. Both cardiac magnetic resonance (CMR) and myocardial biopsy are considered the gold standard for the diagnosis, but they are not available for most hospitals and are complicated to perform in critically ill patients. Cardiac computed tomography (CT) has been occasionally used to evaluate late myocardial enhancement in acute myocardial infarction [1] with comparable results to CMR. One case report has also recently described its use in myocarditis [2]. However, no previous case report demonstrated the use of cardiac CT for the evaluation of acute ST elevation myocarditis, nor has the ECG correlation to CT been documented. In this report we present the case of an acute ST elevation myocarditis, and its correlation with cardiac CT and CMR.
Case report A 20-year-old man with no past medical history presented to the Emergency Department (ED) with a 3-day episodic chest pressure with no dyspnea or associated symptoms. He had 3 episodes of pain, as a ‘‘pressure’’, during 2—5 h without irradiation, dyspnea, worsening with exercise, vomiting, diaphoresis nor improvement with any chest position. He went to the ED because of a new acute intense pain episode which started 3 h prior to presentation. He had no use of illicit substances nor known risk factors for coronary disease. He had no fever or symptoms of a recent viral infection. Clinical examination revealed a pulse of 75 bpm, blood pressure of 120/70 mmHg and he was afebrile. Physical examination was unremarkable, including cardiac auscultation. The electrocardiogram (ECG) showed a ST-segment elevation of 4 mm in the inferior leads (D II, D III, and aVF) and no PR depression (Fig. 1). Laboratory evaluation showed elevated values of troponin I (21.48 ng/mL; normal < 0.06) and creatine kinase (CK)-MB (84.8 ng/mL; normal < 4.0 ng/mL). The patient underwent emergency invasive coronary angiography to rule out acute ST elevation myocardial infarction. Coronary angiography was normal as was the ventricular function. CK-MB was 97.10 ng/mL 2 h after ED arrival, and
Figure 1
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59.3 ng/mL 6 h later. At that time, he had a presumed diagnosis of perimyocarditis. Echocardiography was normal, with an ejection fraction of 79%. Since CMR was not locally available, the patient underwent cardiac CT for late enhancement evaluation as part of a myocarditis work up. The cardiac CT was performed in a 64 slice (Philips Brilliance, Philips Healthcare, Andover, MA, USA) CT with a gantry rotation of 330 mS, 120 kV, and 150 mAs as a prospective (‘‘step and shoot’’) examination with a contrast injection rate of 5.5 mL/s and a total contrast volume of 100 mL. A second scan was performed 10 min later for the evaluation of late enhancement with the same scanner set up. The patient was pre-medicated with betablockers and the exam was performed with a heart rate of 58 bpm. The cardiac CT showed normal coronary arteries and normal myocardial perfusion on the first pass images. Late images were reconstructed with thicker slices of 5 mm and analyzed at various levels with a center of 100—150 and a window of 150—300. The late images showed enhancement of the inferolateral walls (Figs. 2 and 3). The patient was then treated as having myocarditis. Since cardiac CT is not yet standardized for myocarditis evaluation, the patient was referred to a reference center for CMR investigation three days later. The CMR was performed in a Philips Achieva 1.5T (Philips Healthcare) as the routine protocol for myocarditis which included functional evaluation, T2 weighted triple-IR images (with TE ≈ 100 ms) to access myocardial edema and gadolinium delayed enhancement images. Delayed enhancement MR described nontransmural subepicardial delayed hyperenhancement of the inferior and lateral walls in basal and middle segments, compatible with perimyocarditis. Myocardial edema was described in the same segments. The myocardial function was normal with ejection fraction of 61% (Figs. 2 and 3).
Discussion Myocarditis is an inflammatory disease of the myocardial tissue, most often resulting from a common viral infection. Other causes of myocarditis include other specific pathogens, toxic or hypersensitivity drug reactions, giantcell myocarditis, or sarcoidosis [3]. As a disease with a broad
Electrocardiogram showing significant ST elevation in the inferior leads.
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Figure 2 Short-axis views. (A) Cardiac magnetic resonance (CMR) triple-inversion recovery T2-weighted image view showing inferolateral wall edema. (B) CMR delayed enhancement technique showing scattered focal area of subepicardial gadolinium concentration in a similar location. Findings are characteristic of acute myocarditis (arrows). (C) Cardiac computed tomography delayed enhancement with the same pattern of enhancement (arrows).
Figure 3 Four chamber long-axis views. (A) Cardiac magnetic gadolinium delayed enhancement showing subepicardial hyperenhancement (arrow). (B) Cardiac CT delayed enhancement (arrows).
spectrum, acute myocarditis often occurs together with a pericardial involvement, although they are rarely of equivalent intensity [4]. The diagnosis of perimyocarditis can be difficult in the setting of an ED, and it can be confused both with other causes of cardiomyopathy or with acute coronary syndrome. Although the ECG can suggest a pericardial involvement when it shows typical alterations such as diffuse ST-segment elevation and PR-segment depression, a finding of a focal ST-elevation can mislead to a diagnosis of acute coronary syndrome, moreover when there is a myocardial involvement causing elevation of the cardiac biomarkers [5]. Currently, the diagnosis is made by a combination of clinical presentation, serum cardiac biomarkers, and echocardiography, with endomyocardial biopsy remaining as the gold standard, depending on the presenting characteristics and disease severity [3,6].
As a noninvasive procedure, CMR, particularly using delayed enhancement sequences, is being used in increasing frequency for the diagnosis of myocarditis and may be used to localize sites for endomyocardial biopsy [7—10]. The delayed enhancement in CMR occurs because the contrast media leaks to the interstitial space due to inflammation. As it stays out of the vessel, it cannot be washed away and is held for a longer time, which allows it to be seen in the delayed enhancement images. Case report data suggest that the late enhancement CT can show similar findings from those obtained from CMR imaging with the advantage that CT has the potential utility for simultaneous evaluation of the coronary artery anatomy and myocardial inflammation with better accessibility and economic diagnosis [11]. The delayed enhancement mechanism in cardiac CT is similar to what happens in CMR.
Acute inferolateral ST-elevation myopericarditis diagnosed by delayed enhancement cardiac computed tomography None of the previous case reports was able to demonstrate direct topographic correlation between the ECG findings and both cardiac CT and CMR images. The present case report is the first to demonstrate that the high spatial resolution of cardiac CT correlates well not only with CMR images, but also with ECG correspondent myocardial walls. Of note in this population, radiation exposure might be a significant concern. However, the use of prospective gating, as used in the present case, as well as lowering peak tube voltage can reduce the exposure. Our report emphasizes the adequate image quality of those resources, with a low radiation exposure 3.8 mSv. We therefore conclude that patients with suspected myocarditis might be adequately investigated with cardiac CT imaging instead of CMR with the advantage of concomitant coronary evaluation and a more readily availability of the method.
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