Magic of Advanced Imaging and Immunotherapy in Cardiac Sarcoidosis

Abstract

This case report emphasizes the role of advanced imaging and immunotherapy in the diagnosis and management of cardiac sarcoidosis (CS).CASE PRESENTATION: A 52-year-old healthy male presented with near-syncope for 5 days. He had a blood pressure of 164/67 mmHg and a heart rate of 43 bpm. Electrocardiogram revealed complete-heart-block (CHB) with a ventricular rate of 38/min. Troponin T and electrolytes were normal, and Lyme's serology was negative. Echocardiogram was normal. Cardiac magnetic resonance imaging (CMR) revealed late gadolinium enhancement (LGE) affecting the mid inferior segment at the right ventricle (RV) insertion site (Figure 1). A cardiac and whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan showed focal areas of increased FDG uptake in the LV involving mid and basal anteroseptal segments, mid inferoseptal segment, basal inferolateral, and basal inferior segments with normal perfusion (Figure 2). The scan also revealed hypermetabolic bilateral hilar and mediastinal lymphadenopathy. A diagnosis of CS was made. An Implantable-Cardioverter-defibrillator (ICD) was placed and the patient was discharged on 40mg of prednisone and 20mg of leflunomide. Within 4 months, he went from 100% RV pacing to 0%. Eventually, the corticosteroid was tapered off. At follow-up after 1.5 years, RV pacing remained 0% on Leflunomide 20mg.DISCUSSION: One should always suspect CS in young patients with high-grade AV block. During the workup of CHB (Figure 3), the 2017 Japanese Circulation Society Working Group Criteria for diagnosing CS was followed (1). The patient had 2 characteristic findings strongly suggestive of sarcoidosis: (a) hilar lymphadenopathy and (b) significant tracer accumulation in the myocardium and hilar lymph nodes on FDG-PET scan. He also met 2 major criteria strongly suggestive of CS: (a) LGE on CMR and (b) abnormal myocardial FDG uptake. These findings, per the criteria, establish the clinical diagnosis of CS. The mainstay of treatment for CS is corticosteroids þ/steroid-sparing agents to decrease intra-cardiac inflammation (1). CHB patients with CS have a high risk of ventricular arrhythmias, hence should receive ICD (2). The addition of antimetabolite adjuvants is more effective than corticosteroids alone (3). They may reduce the total time of glucocorticoid therapy and keep patients in remission.CONCLUSIONS: Clinical diagnosis of CS can be established with FDG-PET imaging and CMR. CS patients with advanced heart block should receive ICD. Corticosteroids are the mainstay of treatment. Immunotherapy is an effective adjunct that can help taper the glucocorticoids and keep patients in remission. Early introduction of these agents should be considered in these patients.