Sudden Cardiac Death and Life-Threatening Arrhythmias in Cardiac Sarcoidosis

Quick Takes

  • Almost all patients with clinically manifest cardiac sarcoidosis will benefit from an implantable cardioverter-defibrillator (ICD).
  • A positive myocardial biopsy identifies patients at highest risk of a life-threatening ventricular arrhythmia.
  • Serial risk assessment is appropriate in the minority of patients with cardiac sarcoidosis who do not have a Class I or IIa indication for an ICD.

Study Questions:

How effective are the current implantable cardioverter-defibrillator (ICD) guidelines for identifying patients with cardiac sarcoidosis (CS) who are at risk of sudden cardiac death (SCD) or sustained ventricular tachycardia (SVT)?


The subjects of this study were 398 patients with CS who were entered into a Finnish registry in 1988–2017. The diagnosis of CS was considered definite in 193 patients who had a positive myocardial biopsy and probable in 205 patients based on the Heart Rhythm Society (HRS) diagnostic criteria. The primary outcome was SCD (actual or aborted), or SVT during follow-up in patients with and without an ICD.


Based on HRS guidelines, 85% of patients had a Class I or IIa indication for an ICD upon entry into the registry. A total of 294 patients (74%) received an ICD. During a median of 4.8 years of follow-up, the annual incidence of SCD was 10.7% in patients with an ICD and 4.8% in patients without an ICD. By multivariate analysis, a positive myocardial biopsy was an independent predictor of SCD, but the presence of a Class I or IIa indication was not. Among the patients without a Class I or IIa indication for an ICD upon entry into the registry, the 5-year incidence of SCD, SVT, or the emergence of a Class I/IIa ICD indication was 53%.


Patients with CS who do not present with a Class I/IIa indication for an ICD have approximately a 5% annual risk of SCD. All patients with clinically manifest CS may be appropriate candidates for an ICD.


The findings of this study make it clear that all patients with CS and a positive myocardial biopsy should receive an ICD. In addition, an ICD should be strongly considered, even if a Class I/IIa ICD indication is not present, in patients with probable CS. The HRS criteria for probable CS consist of a positive extracardiac biopsy plus one or more of the following: corticosteroid or immunosuppressive therapy responsive cardiomyopathy or heart block; high-degree heart block, a left ventricular ejection fraction <50%, patchy uptake on fluorodeoxyglucose positron emission tomography, late gadolinium enhancement on cardiac magnetic resonance imaging, or a positive cardiac gallium scan.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Computed Tomography, Magnetic Resonance Imaging, Nuclear Imaging

Keywords: Arrhythmias, Cardiac, Biopsy, Cardiomyopathies, Death, Sudden, Cardiac, Defibrillators, Implantable, Diagnostic Imaging, Gadolinium, Heart Block, Heart Failure, Immunosuppression, Magnetic Resonance Imaging, Positron-Emission Tomography, Risk, Sarcoidosis, Tachycardia, Ventricular, Ventricular Function, Left

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