Although sarcoidosis is considered a systemic disease, the details of its pathobiology remain obscure. The lungs are involved most often, usually as part of multi-organ disease but also as isolated pulmonary sarcoidosis.1Baughman R.P. Teirstein A.S. Judson M.A. et al.Clinical characteristics of patients in a case-control study of sarcoidosis.,2Alnaimat F. Al Oweidat K. Alrwashdeh A. et al.Sarcoidosis in Jordan: a study of the clinical phenotype and disease outcome. Extrapulmonary single-organ involvement is also a possible though much rarer manifestation, with isolated cutaneous sarcoidosis topping the respective statistics.3James W.E. Koutroumpakis E. Saha B. et al.Clinical features of extrapulmonary sarcoidosis without lung involvement. In countering the significance of isolated cardiac sarcoidosis (CS), Birnie et al4Birnie D.H. Nery P.B. Beanlands R.S. Counterpoint: Should isolated cardiac involvement be considered a significant manifestation of sarcoidosis? No. emphasize the nonexistence of “truly isolated CS.” However, as we pointed out in our initial editorial, this is a theoretical issue only, because the co-existence with myocardial involvement of invisible extracardiac granulomas is clinically irrelevant and impossible to prove or disprove with certainty. Isolated CS is, above all, a diagnostic challenge. Once CS is confirmed, its care is independent of extracardiac involvment.We agree with Birnie et al4Birnie D.H. Nery P.B. Beanlands R.S. Counterpoint: Should isolated cardiac involvement be considered a significant manifestation of sarcoidosis? No. on the necessity of myocardial histology for the diagnosis of CS in the absence of extracardiac disease and also with their view of lymph nodes being equal to extracardiac organs in PET scan. We disagree, however, on the prevalence of isolated CS. Birnie et al4Birnie D.H. Nery P.B. Beanlands R.S. Counterpoint: Should isolated cardiac involvement be considered a significant manifestation of sarcoidosis? No. emphasize their study from Ottawa5Juneau D. Nery P. Russo J. et al.How common is isolated cardiac sarcoidosis? Extra-cardiac and cardiac findings on clinical examination and whole-body 18F–fuorodeoxyglucose positron emission tomography. showing a prevalence of only 3%, whereas we believe the true figure is much higher because our nationwide study showed a prevalence exceeding 20%.6Simonen P. Lehtonen J. Kandolin R. et al.F-18-fluorodeoxyglucose positron emission tomography-guided mediastinal lymph node sampling in the diagnosis of cardiac sarcoidosis. Unfortunately, no other clinical study has used whole-body PET scan and required myocardial histology for the diagnosis of isolated CS. The difference in these observations defies explanation; however, other data support a higher prevalence than that reported from Ottawa. Because isolated CS is potentially fatal and difficult to diagnose, its detection may be delayed to the coroner’s examination. The Finnish cause-of-death registry files for the years 1998 to 2015 revealed 24 patients presenting with cardiac manifestations and undergoing diagnostic examinations without CS being detected before sudden death and forensic autopsy.7Ekström K. Lehtonen J. Nordenswan H.-K. et al.Sudden death in cardiac sarcoidosis: an analysis of clinical and cause-of-death registries. As detailed in the supplement to the paper,7Ekström K. Lehtonen J. Nordenswan H.-K. et al.Sudden death in cardiac sarcoidosis: an analysis of clinical and cause-of-death registries. in 10 of them (42%) sarcoid granulomas were found in the heart only. In another autopsy study, Tavora et al8Tavora F. Cresswell N. Li L. Ripple M. Solomon C. Burke A. Comparison of necropsy findings in patients with sarcoidosis dying suddenly from sarcoidosis versus dying suddenly from other causes. found that 10 of 25 victims (40%) of CS-related sudden death did not have granulomas outside the heart. These data imply that studies, like that from Ottawa,5Juneau D. Nery P. Russo J. et al.How common is isolated cardiac sarcoidosis? Extra-cardiac and cardiac findings on clinical examination and whole-body 18F–fuorodeoxyglucose positron emission tomography. ignoring contemporaneous cases detected only at autopsy may underestimate the prevalence of isolated CS.Birnie et al4Birnie D.H. Nery P.B. Beanlands R.S. Counterpoint: Should isolated cardiac involvement be considered a significant manifestation of sarcoidosis? No. raise giant cell myocarditis as a condition potentially mistaken for CS on cardiac PET scan. This is not a simple issue, however, because giant cell myocarditis and CS share many clinical and histological characteristics in addition to unknown cause. Whether they are genuinely different disease entities, or different phenotypes of a single T cell-mediated inflammatory cardiomyopathy, is still discussed.9Ekström K. Räisänen-Skolowski A. Lehtonen J. Nordenswan H.K. Mäyränpää M.I. Kupari M. Idiopathic giant cell myocarditis or cardiac sarcoidosis? A retrospective audit of a nationwide case series. In the latter scenario, giant cell myocarditis represents fulminant isolated CS.

We conclude our side of the debate by hoping that clinicians seeing patients with apparently idiopathic atrioventricular block, ventricular tachyarrhythmia, or nonischemic heart failure keep in mind both the possibility of CS and the fact that injurious granulomas can be confined to the heart. This may be vital for the patient.

ReferencesBaughman R.P. Teirstein A.S. Judson M.A. et al.

Clinical characteristics of patients in a case-control study of sarcoidosis.

Am J Respir Crit Care Med. 164: 1885-1889Alnaimat F. Al Oweidat K. Alrwashdeh A. et al.

Sarcoidosis in Jordan: a study of the clinical phenotype and disease outcome.

Arch Rheumatol. 35: 226-238James W.E. Koutroumpakis E. Saha B. et al.

Clinical features of extrapulmonary sarcoidosis without lung involvement.

Chest. 154: 349-356Birnie D.H. Nery P.B. Beanlands R.S.

Counterpoint: Should isolated cardiac involvement be considered a significant manifestation of sarcoidosis? No.

Chest. 160: 36-38Juneau D. Nery P. Russo J. et al.

How common is isolated cardiac sarcoidosis? Extra-cardiac and cardiac findings on clinical examination and whole-body 18F–fuorodeoxyglucose positron emission tomography.

Int J Cardiol. 253: 189-193Simonen P. Lehtonen J. Kandolin R. et al.

F-18-fluorodeoxyglucose positron emission tomography-guided mediastinal lymph node sampling in the diagnosis of cardiac sarcoidosis.

Am J Cardiol. 116: 1581-1585Ekström K. Lehtonen J. Nordenswan H.-K. et al.

Sudden death in cardiac sarcoidosis: an analysis of clinical and cause-of-death registries.

Eur Heart J. 40: 3121-3128Tavora F. Cresswell N. Li L. Ripple M. Solomon C. Burke A.

Comparison of necropsy findings in patients with sarcoidosis dying suddenly from sarcoidosis versus dying suddenly from other causes.

Am J Cardiol. 104: 571-577Ekström K. Räisänen-Skolowski A. Lehtonen J. Nordenswan H.K. Mäyränpää M.I. Kupari M.

Idiopathic giant cell myocarditis or cardiac sarcoidosis? A retrospective audit of a nationwide case series.

ESC Heart Fail. 7: 1362-1370Article InfoFootnotes

FINANCIAL/NONFINANCIAL DISCLOSURES: None declared

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DOI: https://doi.org/10.1016/j.chest.2020.12.039

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© 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

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