Cardiac Sarcoidosis With Elevated Cardiac Troponin Mimicking Acute Myocardial Ischemia: A Case Report

Abstract

Cardiac sarcoidosis (CS) is a disease entity with variable presentation causing significant morbidity and mortality. Concurrent signs of myocardial injury as evidenced by troponin elevation add to the complexity of an already challenging diagnosis. We present an unusual case of CS with elevated troponin I mimicking an acute ischemic cardiac event. A 48-year-old female presented with a two-month history of presyncope. Electrocardiogram showed a bifascicular block with concomitant significant troponin I elevation. Two-dimensional echocardiography showed new-onset left ventricular systolic dysfunction with an ejection fraction of 40-45%. A heparin drip was initiated for possible non-ST-elevation myocardial infarction. Coronary angiography showed no evidence of epicardial coronary artery disease but did show an anomalous right coronary artery; however, CT angiography did not reveal any significant stenosis. Further, the telemetry monitor captured intermittent complete atrioventricular blocks. Due to concerns for an infiltrative cardiac disease, a cardiac magnetic resonance was done showing findings consistent with possible CS. CT scan of the chest showed no radiographic evidence of pulmonary sarcoidosis. Fluorodeoxyglucose-positron emission tomography scan showed findings of active inflammation in the myocardium consistent with possible CS. The patient was treated for clinical CS with systemic corticosteroids and methotrexate. Follow-up six weeks later showed clinical improvement of symptoms. Our clinical case encompasses the unique variable presentation of CS including cardiac conduction abnormalities and left ventricular systolic dysfunction. Concomitant troponin I elevation can mimic myocardial ischemia, making the diagnosis more challenging. Treatment strategies aim to mitigate the long-term effects of CS on the heart; however, there is a paucity of data for appropriate pharmacological regimens.

Keywords: cardiac magnetic resonance imaging; cardiac sarcoidosis; case report; sarcoidosis; troponin elevation.

Figure 1. Electrocardiogram showing sinus rhythm with first-degree arteriovenous block, right bundle branch block, and left anterior fascicular block consistent with a bifascicular block.

Figure 2. Coronary angiogram showing an anomalous right coronary artery arising from the left coronary cusp (red arrow).

Figure 3. Electrocardiogram showing sinus rhythm with arteriovenous dissociation and wide QRS rhythm and left bundle branch block.

Figure 4. Phase-sensitive, inversion recovery sequence two-chamber view showing patchy (subendocardial and near-transmural) areas of late gadolinium enhancement in the inferior and inferoseptal wall of the left ventricle (green arrow) consistent with possible active inflammatory phase of cardiac sarcoidosis.

Figure 5. CT coronary angiogram showing an anomalous right coronary artery (red arrows) originating from the left anterolateral wall of the proximal ascending aorta above the sinotubular junction.