Isolated cardiac sarcoidosis: A focused review of an under-recognized entity

Abstract

There is accumulating evidence for the existence of a phenotype of isolated cardiac sarcoidosis (ICS), or sarcoidosis that only involves the heart. In the absence of biopsy-confirmed cardiac sarcoidosis (CS), existing diagnostic criteria require the presence of extra-cardiac sarcoidosis as an inclusion criterion for the diagnosis of CS. Consequently, in the absence of a positive endomyocardial biopsy, ICS is not diagnosable by current guidelines. Therefore, there is uncertainty regarding the epidemiology, pathobiology, clinical characteristics, prognosis, and optimal treatment of ICS. This review will summarize the available data related to the prevalence and prognosis of ICS and will discuss challenges surrounding the diagnosis and management of this under-recognized entity.

A joint procedural position statement on imaging in cardiac sarcoidosis: from the Cardiovascular and Inflammation & Infection Committees of the European Association of Nuclear Medicine, the European Association of Cardiovascular Imaging, and the American Society of Nuclear Cardiology

“…70 However, these estimates are biased as the lower specificity of PET in some studies may reflect the fact that this test is more sensitive for identifying cardiac sarcoidosis than the JMHW criteria. Indeed, the requirement of histologically proven extracardiac sarcoidosis by the JMHW criteria limits identification of isolated cardiac sarcoidosis, whereby the disease is confined only to the heart, 71 particularly if endomyocardial biopsy is negative. Likewise, the lower sensitivity of FDG-PET in some studies may reflect the reduced specificity of the JMHW criteria.…”

Joint SNMMI–ASNC expert consensus document on the role of 18F-FDG PET/CT in cardiac sarcoid detection and therapy monitoring

“…Importantly, both sets of criteria still require a histologic or clinical diagnosis of extracardiac sarcoidosis (extraCS) and therefore remain of limited utility for identifying isolated CS, which may be more common than previously reported, with estimates of 20%-50% in various studies. 36 In addition to requiring histologic confirmation of extraCS, the JMHW criteria require a combination of major and minor electrocardiographic, imaging, and nonspecific EMB findings, and the HRS criteria require at least 1 of 7 clinical, electrocardiographic, or imaging diagnostic criteria. In contrast to the JMHW criteria, the diagnostic criteria of HRS include advanced cardiac imaging with dedicated cardiac PET and responsiveness to immunosuppressive treatment and thus may have a higher sensitivity for CS.…”

Inter- and Intraobserver Agreement of 18F-FDG PET/CT Image Interpretation in Patients Referred for Assessment of Cardiac Sarcoidosis

“…The other patient had isolated CS (endomyocardial biopsy proven). Isolated CS is an increasingly recognized phenomenon, described in up to 20% of patients (20).…”