Ten Questions Cardiologists Should Be Able to Answer About Cardiac Sarcoidosis: Case-Based Approach and Contemporary Review

Abstract

Sarcoidosis is an inflammatory multisystemic disease of unknown etiology characterized by the formation of noncaseating epithelioid cell granulomas. Cardiac sarcoidosis might be life-threatening and its diagnosis and treatment remain a challenge nowadays. The aim of this review is to provide an updated overview of cardiac sarcoidosis and, through 10 practical clinical questions and real-life challenging case scenarios, summarize the main clinical presentation, diagnostic criteria, imaging findings, and contemporary treatment.

Figure 1

Algorithm to diagnose clinically isolated CS. CMR, cardiac magnetic resonance; CS, cardiac sarcoidosis; CT, computed tomography; FDG, fluorodeoxyglucose; PET, positron emission tomography. ∗ Consider performing CMR and FDG-PET scan to increase diagnostic yield, to assess for fibrosis and inflammation and to guide biopsy. Consider a CT scan of the chest with contrast for optimal evaluation of adenopathy.

Figure 2

Red flags that should warrant further investigation in patients with extracardiac sarcoidosis. Advanced cardiac imaging is recommended in the red panel and could be considered in the orange panel. AVB, atrioventricular block; ECG, electrocardiogram; Echo, echocardiography; HRS, Heart Rhythm Society; LBBB, left bundle branch block; LV, left ventricle; LVEF, left ventricular ejection fraction; NSVT, nonsustained ventricular tachycardia; PHT, pulmonary hypertension; PVC, premature ventricular contractions; RBBB, right bundle branch block; RV, right ventricle; VT, ventricular tachycardia. ∗According to the HRS consensus. ^† Criteria for cardiac involvement of sarcoidosis as per Japanese guidelines.^‡ Associated with increased risk of developing cardiac events.^§ Atrial arrhythmias, junctional rhythm, chronotropic incompetence, incomplete bundle branch block.

Figure 3

Algorithm to diagnose CS in patients with known extracardiac sarcoidosis. CMR, cardiac magnetic resonance; CS, cardiac sarcoidosis; ECG, electrocardiogram; FDG, fluorodeoxyglucose; PET, positron emission tomography. ∗ Consider performing CMR and FDG-PET scan to increase diagnostic yield and to assess for fibrosis and inflammation.

Figure 4

Findings on echocardiogram, cardiac magnetic resonance, and FDG-PET scan consistent with cardiac sarcoidosis. (A) Echocardiogram showing basal septum thinning. (B) Cardiac magnetic resonance showing subepicardial late gadolinium enhancement in the septum and right ventricle free wall. (C) FDG-PET scan showing focal uptake of FDG on the inferoseptal and lateral walls of the left ventricle. FDG, fluorodeoxyglucose; PET, positron emission tomography.

Figure 5

Biopsy-negative patients with highly suspected clinically isolated CS. CS, cardiac sarcoidosis; EBUS, endobronchial ultrasound; FDG, fluorodeoxyglucose; LN, lymph node; PET, positron emission tomography.

Figure 6

Unstable atrioventricular block (AVB) and suspected clinically isolated cardiac sarcoidosis (CS). CT, computed tomography; FDG, fluorodeoxyglucose; MRI, magnetic resonance imaging; PET, positron emission tomography. ∗ Consider inserting a screw-in-lead temporary pacemaker and performing an FDG-PET scan to increase diagnostic yield. ^† Consider performing cardiac magnetic resonance imaging as soon as possible if the device is compatible and FDG-PET scan if not already performed.

Figure 7

Proposed algorithm for treatment and follow-up of cardiac sarcoidosis patients. ECG, electrocardiogram; Echo, echocardiography; FDG, fluorodeoxyglucose; PET, positron emission tomography. ∗ Start immunosuppressive therapy in presence of Mobitz II or third-degree atrioventricular block, frequent ventricular ectopy or nonsustained ventricular tachycardia, sustained ventricular arrhythmias, or significant inflammation in the presence or absence of left ventricular dysfunction. Prednisone started at 0.5 mg/kg/d (maximum dose of 30-40 mg/d). Methotrexate could be considered as first-line therapy with prednisone in case of significant FDG uptake and severe ventricular dysfunction. Methotrexate started at 10 or 15 mg orally or subcutaneous injection once per week. ^† Methotrexate could be increased to 20-25 mg orally or subcutaneous injection once per week.