Cardiac Sarcoidosis

Background

• Cardiac sarcoidosis refers to cardiac manifestations of sarcoidosis, which is a systemic disease of unknown cause, characterized by the formation of noncaseating granulomas, myocardial inflammation, and myocardial fibrosis.
• Three primary cardiac manifestations may include any of:
  • conduction disturbances (most commonly development of bundle branch block and varying degrees of atrioventricular block)
  • ventricular and atrial arrhythmias
  • heart failure

Evaluation

• No formal diagnostic criteria for cardiac sarcoidosis have been established, but 3 guidelines have proposed criteria
• Suspect cardiac sarcoidosis in patients with extracardiac sarcoidosis plus:
  • cardiac symptoms, such as palpitations, presyncope or syncope, or symptoms of heart failure (such as dyspnea)
  • electrocardiogram (ECG) abnormalities, such as atrioventricular block, ventricular arrhythmias (including sustained and nonsustained ventricular tachycardia), unexplained pathological Q waves in ≥ 2 leads, and less commonly, supraventricular arrhythmias (most commonly atrial fibrillation)
• In all patients with suspected cardiac sarcoidosis and known extracardiac sarcoidosis:
  • obtain a 12-lead electrocardiography (ECG) (Strong recommendation)
  • consider echocardiography to screen for cardiac involvement (Weak recommendation)
• Consider advanced cardiac imaging with cardiac magnetic resonance (CMR) or 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with suspected cardiac sarcoidosis and any of the following: (Weak recommendation)
  • significant symptoms (palpitations lasting > 2 weeks), presyncope, or syncope
  • abnormal 12-lead ECG or ambulatory Holter monitor
  • abnormal echocardiography

Management

• Manage left ventricular dysfunction according to the established guidelines for heart failure (see Heart Failure With Preserved Ejection Fraction (HFpEF) and Heart Failure With Reduced Ejection Fraction (HFrEF) for additional information).
• Consider immunosuppressive therapy (typically corticosteroids) to control an ongoing active inflammation to potentially prevent the formation of fibrosis and scar tissue that may lead to the development of conduction defects, arrhythmias, and ventricular dysfunction.
• For conduction abnormalities:
  • use guideline-directed indications for a permanent pacemaker implantation for atrioventricular (AV) block (Strong recommendation)
  • consider immunosuppressive therapy in patients with Mobitz type II or third-degree AV block (Weak recommendation)
  • consider implantable cardioverter defibrillator (ICD) in patients with an indication for a permanent pacemaker (Weak recommendation)
• For ventricular arrhythmias:
  • consider immunosuppressive therapy, as it can be useful in patients with: (Weak recommendation)
    • frequent ventricular ectopy or nonsustained ventricular tachycardia and evidence of myocardial inflammation
    • sustained ventricular arrhythmia and evidence of myocardial inflammation
  • consider antiarrhythmic medical therapy in patients with ventricular arrhythmias refractory to immunosuppressive therapy (Weak recommendation)
  • consider catheter ablation in patients with ventricular arrhythmias refractory to immunosuppressive and antiarrhythmic drug therapy or incessant ventricular arrhythmias
• For atrial arrhythmias:
  • offer anticoagulation to patients with atrial fibrillation if sufficiently high risk using CHADS₂ or CHA₂DS₂-VASc score (Strong recommendation)
  • avoid antiarrhythmic drug therapy with class I agents in patients with atrial arrhythmia associated with cardiac sarcoidosis (Strong recommendation)
• For prevention of sudden cardiac death ICD implantation is indicated in patients with: (Strong recommendation)
  • spontaneous sustained ventricular arrhythmias, including aborted cardiac arrest
  • left ventricular ejection fraction ≤ 35% despite optimal medical therapy for heart failure and period of immunosuppressive therapy if active inflammation present
• Consider an ICD implantation independent of ventricular function for any of the following: (Weak recommendation)
  • indication for permanent pacemaker implantation
  • unexplained syncope or near syncope with suspected arrhythmic etiology
  • inducible sustained ventricular arrhythmias defined as either
    • > 30 seconds of monomorphic or polymorphic ventricular tachycardia
    • clinically relevant ventricular fibrillation (triple premature beats of < 220 milliseconds considered nonspecific response)