Histologic diagnostic rate of cardiac sarcoidosis: evaluation of endomyocardial biopsies

Life-Threatening Ventricular Tachyarrhythmia in Isolated Cardiac Sarcoidosis Compared With Cardiac Sarcoidosis With Extracardiac Involvement

Although isolated cardiac sarcoidosis (CS) is not uncommon, little is known about the risk of life-threatening ventricular tachyarrhythmia. We aimed to evaluate the incidence of ventricular tachyarrhythmia in patients with isolated CS. A total of 94 patients with CS were enrolled. Isolated CS was diagnosed by histologic or clinical confirmation in the heart alone. The end points were sudden cardiac death, ventricular fibrillation, sustained ventricular tachycardia, or implantable cardioverter-defibrillator therapy for ventricular fibrillation or sustained ventricular tachycardia. A total of 25 patients were diagnosed with isolated CS, and 69 were diagnosed with CS with extracardiac involvement. As the initial cardiac manifestation leading to the CS diagnosis, 10 patients (40%) with isolated CS had ventricular tachyarrhythmia. Over the median follow-up of 48 months after the CS diagnosis, sudden cardiac death occurred in 2 patients (8%) with isolated CS. Ventricular fibrillation or sustained ventricular tachycardia, including implantable cardioverter-defibrillator therapy, occurred in 15 patients (60%) with isolated CS and 13 (19%) with CS with extracardiac involvement. The rate of ventricular tachyarrhythmia was higher in patients with isolated CS than in those with CS with extracardiac involvement (log-rank, p <0.01). Cox proportional hazard analysis showed that isolated CS was independently associated with ventricular tachyarrhythmia. A total of 2 or more ventricular tachyarrhythmias more frequently occurred in patients with isolated CS (52% vs 13%, p <0.01). Electric storm more frequently occurred in patients with isolated CS (24% vs 6%, p = 0.01). In conclusion, patients with isolated CS have ventricular tachyarrhythmia at a higher rate than those with CS with extracardiac involvement.

Feasibility and Role of Cardiac Magnetic Resonance in Intensive and Acute Cardiovascular Care

Cardiac magnetic resonance (CMR) is established as a key imaging modality in a wide range of cardiovascular diseases and has an emerging diagnostic and prognostic role in selected patients presenting acutely. Recent technical advancements have improved the versatility of this imaging technique, which has become quicker and more detailed in both functional and tissue characterization assessments. Information derived from this test has the potential to change clinical management, guide therapeutic decisions, and provide risk stratification. This review aims to highlight the evolving diagnostic and prognostic role of CMR in this setting, whilst also providing practical guidance on which patients can benefit the most from CMR and which information can be derived from this test that will impact clinical management.

Extrapulmonary sarcoidosis

Sarcoidosis is a chronic disease of unknown origin that develops when a genetically susceptible host is exposed to an antigen, leading to an exuberant immune response characterized by granulomatous inflammation. Although lung involvement is almost universal as well as the leading cause of morbidity and mortality, virtually any organ can be affected. In particular, sarcoidosis of the heart, nervous system, and eyes can be devastating, leading to death, debilitation and blindness, and a multidisciplinary approach involving expert specialists is required for prompt diagnosis and appropriate treatment. Sarcoidosis of the skin can be disfiguring, thus posing a substantial psychologic and social impact on the patients. The diagnosis is often straightforward in the presence of compatible clinical manifestations in patients with biopsy-proven sarcoidosis, but is challenging when extrapulmonary signs/symptoms occur in isolation. Corticosteroids remain the first line therapy, with immunosuppressive or biologic agents being reserved to patients failing or experiencing side effects from steroids or developing refractory disease.

A framework for exclusion of alternative diagnoses in sarcoidosis

Sarcoidosis is a multisystem granulomatous syndrome that arises from a persistent immune response to a triggering antigen(s). There is no "gold standard" test or algorithm for the diagnosis of sarcoidosis, making the diagnosis one of exclusion. The presentation of the disease varies substantially between individuals, in both the number of organs involved, and the manifestations seen in individual organs. These qualities dictate that health care providers diagnosing sarcoidosis must consider a wide range of possible alternative diagnoses, from across a range of presentations and medical specialties (infectious, inflammatory, cardiac, neurologic). Current guideline-based diagnosis of sarcoidosis recommends fulfillment of three criteria: 1) compatible clinical presentation and/or imaging 2) demonstration of granulomatous inflammation by biopsy (when possible) and, 3) exclusion of alternative causes, but do not provide guidance on standardized strategies for exclusion of alternative diagnoses. In this review, we provide a summary of the most common differential diagnoses for sarcoidosis involvement of lung, eye, skin, central nervous system, heart, liver, and kidney. We then propose a framework for testing to exclude alternative diagnoses based on pretest probability of sarcoidosis, defined as high (typical findings with sarcoidosis involvement confirmed in another organ), moderate (typical findings in a single organ), or low (atypical/findings suggesting of an alternative diagnosis). This work highlights the need for informed and careful exclusion of alternative diagnoses in sarcoidosis.

Isolated cardiac sarcoidosis: A clinical challenge

Sarcoidosis is an inflammatory disease characterised by non-caseating granulomas of unclear aetiology. Isolated cardiac sarcoidosis (ICS) is rare and occurs when there is granulomatous infiltration of myocardial tissue without evidence of extracardiac sarcoidosis. The heterogeneity in clinical manifestations often presents a diagnostic challenge which leads to delays in treatment initiation. Our case highlights the often quiescent presentation of ICS, the importance of early treatment and the diagnostic challenges that contribute to its underdiagnosis.

Impact of extracardiac sarcoidosis on clinical outcomes in patients with cardiac sarcoidosis: Importance of continued screening for cardiac involvement

BACKGROUND

The prognostic impact of extracardiac sarcoidosis remains unknown in cardiac sarcoidosis (CS). We aimed to evaluate the influence of extracardiac sarcoidosis on clinical outcomes and the effect of continued outpatient visits for screening of cardiac involvement.

METHODS

Ninety-nine patients with CS were divided into two groups: patients with systemic CS who had prior extracardiac sarcoidosis, patients with isolated CS who had no prior extracardiac sarcoidosis. Patients with systemic CS were divided according to the continuation of outpatient visits. The endpoint was cardiac death, fatal ventricular arrhythmia, or hospitalization for heart failure.

RESULTS

At the time of diagnosing CS, patients with isolated CS had a higher prevalence of high-grade atrioventricular block or fatal ventricular arrhythmia, and left ventricular contractile dysfunction than those with systemic CS. Over a median follow-up of 42 months, cardiac events occurred in 19 (37%) of 52 patients with systemic CS and in 27 (57%) of 47 patients with isolated CS. The event-free survival rate was worse in patients with isolated CS than in those with systemic CS. Cox proportional hazard analysis showed that the absence of prior extracardiac sarcoidosis was an independent predictor of adverse outcomes. Patients with systemic CS who ceased outpatient visits had a lower left ventricular ejection fraction with severe heart failure symptoms and a worse event-free survival rate than those who continued outpatient visits.

CONCLUSIONS

The presence of extracardiac sarcoidosis is associated with clinical outcomes. The cessation of screening for cardiac involvement after diagnosing extracardiac sarcoidosis is associated with adverse outcomes.

Cardiac sarcoidosis and neurosarcoidosis - multidisciplinary approach for diagnosis

PURPOSE OF REVIEW

The current review aims to highlight the role of multidisciplinary approach in the diagnosis of patients with cardiac and neurosarcoidosis. Multidisciplinary approach integrates the available clinical information, imaging and histopathological results aiming to reach a definite or at least provisional diagnosis and allow appropriate management. Multidisciplinary approach is the reference standard for diagnosis of interstitial lung disease and should be strongly considered in complex clinical conditions such as cardiac sarcoidosis (CS) and neurosarcoidosis.

RECENT FINDINGS

Histopathological confirmation of noncaseating granulomatous inflammation provides a definite diagnosis of sarcoidosis involving any organ. However, a provisional high confidence or even definite clinical diagnosis can be reached using multidisciplinary evaluation of all available evidence. The diagnosis of cardiac sarcoidosis and neurosarcoidosis requires the integration of different expertise based on the current diagnostic criteria sets. Identifying typical or at least compatible patterns on advanced imaging modalities (CMR and Fluro-Deoxy-Glucose Positron Emission Tomography (FDG-PET)) seems key for the diagnosis of CS, while a confident diagnosis of extra-cardiac disease supports an at least provisional diagnosis. Similarly, in neurosarcoidosis integrating compatible MRI appearances and cerebrospinal fluid results in patients with systemic sarcoidosis allows an at least provisional diagnosis. Exclusion of alternative differential diagnoses is crucial and requires high clinical suspicion, imaging review expertise and appropriate tests performance.

SUMMARY

There have been considerable advances in the diagnostic approach of patients with cardiac and neurosarcoidosis. Multidisciplinary approach for both diagnosis and management is required to reach a confident clinical diagnosis and should be applied when possible.

Cardiac Sarcoidosis: Utilizing Cardiac MRI and PET-CT

PURPOSEOF REVIEW

Cardiac sarcoidosis is an inflammatory condition that has been associated with deleterious cardiac manifestations. The diagnosis of cardiac sarcoidosis is challenging and can be guided by advanced cardiac imaging.

RECENT FINDINGS

Endomyocardial biopsy lacks sensitivity in confirming a diagnosis of cardiac sarcoidosis. Studies have shown that the use of cardiac magnetic resonance imaging (MRI) and cardiac Positron Emission Testing (PET) are associated with increased sensitivity and specificity in the diagnosis of cardiac sarcoidosis. Cardiac MRI and cardiac PET CT, although distinct entities, are complimentary in the diagnosis, prognostication of major cardiac events, and aid in the treatment algorithm in patients with cardiac sarcoidosis.

Comparing the diagnostic performance of [18F]FDG PET/CT and [18F]FDG PET/MRI for detecting cardiac sarcoidosis: A meta-analysis

PURPOSE

This meta-analysis aimed to evaluate the comparative diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI in detecting cardiac sarcoidosis.

METHODS

An extensive search was conducted in the PubMed and Embase databases to identify available publications up to November 2023. Studies were included if they evaluated the diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI in patients with cardiac sarcoidosis. Sensitivity and specificity were evaluated using the DerSimonian and Laird method, with subsequent transformation via the Freeman-Tukey double inverse sine transformation. Publication bias was assessed using funnel plots and Egger's test.

RESULTS

16 articles involving 1361 patients were included in the meta-analysis. The overall sensitivity of [18F]FDG PET/CT in detecting cardiac sarcoidosis was 0.77(95%CI: 0.62-0.89), while the overall sensitivity of [18F]FDG PET/MRI was 0.94(95%CI: 0.84-1.00). The result indicated that [18F]FDG PET/MRI appears to a higher sensitivity in comparison to [18F]FDG PET/CT(P = 0.02). In contrast, the overall specificity of [18F]FDG PET/CT in detecting cardiac sarcoidosis was 0.90(95%CI: 0.85-0.94), while the overall specificity of [18F]FDG PET/MRI was 0.79(95%CI: 0.53-0.96), with no significant difference in specificity (P = 0.32).

CONCLUSIONS

Our meta-analysis indicates that [18F]FDG PET/MRI demonstrates superior sensitivity and comparable specificity to [18F]FDG PET/CT in detecting cardiac sarcoidosis. However, the small number of PET/MRI studies limited the evidence of current results. To validate these results, larger, prospective studies employing a head-to-head design are needed.

Management of cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a form of inflammatory cardiomyopathy associated with significant clinical complications such as high-degree atrioventricular block, ventricular tachycardia, and heart failure as well as sudden cardiac death. It is therefore important to provide an expert consensus statement summarizing the role of different available diagnostic tools and emphasizing the importance of a multidisciplinary approach. By integrating clinical information and the results of diagnostic tests, an accurate, validated, and timely diagnosis can be made, while alternative diagnoses can be reasonably excluded. This clinical expert consensus statement reviews the evidence on the management of different CS manifestations and provides advice to practicing clinicians in the field on the role of immunosuppression and the treatment of cardiac complications based on limited published data and the experience of international CS experts. The monitoring and risk stratification of patients with CS is also covered, while controversies and future research needs are explored.

A rare case of pericardial sarcoidosis presenting as chest pain

Key Clinical Message

Pericardial sarcoidosis is an uncommon cause of chest pain to consider, and it requires a heightened level of suspicion and thorough history gathering. If there is suspicion of inflammatory disease, pursuing advanced imaging and biopsies is crucial, as early immunosuppressive treatment can enhance outcomes.

Abstract

Pericardial involvement in sarcoidosis is a rare condition with limited research. This case study discusses a 52-year-old African American woman who presented with subacute chest pain and was diagnosed with pericardial sarcoidosis. Diagnostic evaluation revealed extensive lymphadenopathy and pericardial effusion, and a pericardial biopsy confirmed non-caseating granulomatous inflammation. Treatment with steroids and methotrexate resulted in clinical improvement. Eight months follow-up showed near resolution of pericardial disease. This case emphasizes the importance of considering cardiac sarcoidosis in sarcoidosis patients, utilizing advanced imaging for accurate diagnosis, and tailoring treatment to the level of cardiac involvement.

Case of stage 0 pulmonary sarcoidosis pathologically diagnosed via transbronchial lung cryobiopsy

A 45-year-old male was diagnosed with arrhythmia during a routine health examination. Findings from different modalities, such as echocardiography and radiography, were consistent with cardiac involvement in sarcoidosis. There was no ocular involvement or superficial lymph node enlargement. A chest computed tomography scan did not reveal any pulmonary lesions or bilateral hilar lymphadenopathy. To pathologically diagnose systemic sarcoidosis, transbronchial lung cryobiopsy was performed. Results showed pathological evidence of noncaseating epithelioid granulomas. Herein, we present a case in which sarcoidosis diagnosis was confirmed via transbronchial lung cryobiopsy despite the absence of respiratory lesions on computed tomography scan.

Utility of new FDG-PET/CT guidelines for diagnosing cardiac sarcoidosis in patients with implanted cardiac pacemakers for atrioventricular block

Diagnosing cardiac sarcoidosis (CS), especially in isolated cases, is challenging, particularly due to the limitations of endomyocardial biopsy, leading to potential undiagnosed cases in pacemaker-implanted patients. This study aims to provide real world findings to support new guideline for CS using 18F-fluoro-deoxyglucose positron-emission tomography computed tomography (FDG-PET/CT) which give a definite diagnosis of isolated CS (iCS) without histological findings. We examined consecutive patients with cardiac pacemakers for atrioventricular block (AV-b) attending our outpatient pacemaker clinic. The patients underwent periodical follow-up echocardiography and were divided into two groups according to echocardiographic findings: those with suspected CS and those without suspected CS. Patients suspected of having nonischemic cardiomyopathy underwent FDG-PET/CT for CS diagnosis. We investigated the utility of the new guideline for CS using FDG-PET/CT. Among the 272 patients enrolled, 97 patients were implanted with cardiac pacemakers for AV-b. Twenty-two patients were suspected of having CS during a median observation period of 5.4 years after pacemaker implantation. Of these, one did not consent, and nine of 21 cases (43%) were diagnosed with definite CS according to the new guidelines. Five of these nine patients were diagnosed with iCS using FDG-PET/CT. The number of patients diagnosed with definite CS using the new guidelines tended to be approximately 2.3 times that of the conventional criteria (p = 0.074). Three of the nine patients underwent steroid treatment. The composite outcome, comprising all-cause death, heart failure hospitalization, and a substantial reduction in left ventricular ejection fraction, were significantly lower in patients receiving steroid treatment compared to those without steroid treatment (p = 0.048). The utilization of FDG-PET/CT in accordance with the new guidelines facilitates the diagnosis of CS, including iCS, resulting in approximately 2.3 times as many diagnoses of CS compared to the conventional criteria. This guideline has the potential to support the early identification of iCS and may contribute to enhancing patient clinical outcomes.

Cardiac Sarcoidosis

Cardiac involvement is a major cause of morbidity and mortality in patients with sarcoidosis. It is important to distinguish between clinical manifest diseases from clinically silent diseases. Advanced cardiac imaging studies are crucial in the diagnostic pathway. In suspected isolated cardiac sarcoidosis, it's key to rule out alternative diagnoses. Therapeutic options can be divided into immunosuppressive agents, guideline-directed medical therapy, antiarrhythmic medications, device/ablation therapy, and heart transplantation.

Prospective Analysis of Immunosuppressive Therapy in Cardiac Sarcoidosis With Fluorodeoxyglucose Myocardial Accumulation: The PRESTIGE Study

BACKGROUND

Fluorodeoxyglucose positron emission tomography (18F-FDG-PET) can noninvasively assess active inflammatory myocardium in patients with cardiac sarcoidosis (CS). Prednisolone (PSL) is the initial drug of choice for active CS; however, its efficacy has not been prospectively evaluated. Moreover, there are no alternative systematic treatment strategies.

OBJECTIVES

The goal of this study was to evaluate the efficacy of methotrexate (MTX) in patients refractory to PSL assessed by using cardiac metabolic activity (CMA) in 18F-FDG-PET.

METHODS

A total of 59 patients with active CS were prospectively enrolled. CMA (standardized uptake value × accumulation area) was used as an indicator of active inflammation, and a 6-month regimen of PSL therapy was introduced, followed by a second FDG scan. Poor responders to PSL therapy (CMA reduction rate <70%) and patients with recurrent CS (CMA reduction rate ≥70% after initial PSL therapy but CMA recurred after an additional 6 months of therapy) were randomly assigned to the MTX or repeat PSL (re-PSL) therapy groups for another 6 months.

RESULTS

Fifty-six patients completed the initial 6-month PSL therapy regimen. Median CMA reduced from 203.3 to 1.0 (P < 0.001), and 47 patients were allocated to the response group, 9 to the poor response group, and 2 to the recurrent group. Accordingly, 11 patients were randomly assigned to the MTX (n = 5) or re-PSL (n = 6) groups. After 6 months, neither group showed a significant reduction in CMA values. MTX was comparable to re-PSL in reducing CMA.

CONCLUSIONS

The 6-month regimen of PSL was a potent therapeutic tool for active CS. When MTX was added to low-dose PSL in patients refractory to the initial PSL therapy, there was no significant difference compared with re-PSL. Further studies are needed to evaluate the therapeutic potential of MTX for active CS, including how MTX works when it is administered in higher doses or for longer periods.

Acute cardiovascular complications of immune-mediated systemic inflammatory diseases

Immune-mediated systemic inflammatory conditions (IMIDs) are associated with an increased risk of atherosclerosis and adverse cardiovascular (CV) events secondary to pathogenic inflammation and derangements in the innate and adaptive immune responses inherent to the underlying rheumatic diseases. As the intersection of cardio-rheumatology continues to expand, a multi-disciplinary approach must be considered to optimize clinical outcomes and long-term survival. This review will highlight acute cardiac manifestations of systemic inflammatory diseases and propose a clinically relevant framework for diagnosis, management, and the role of integrated multimodality imaging.

High-sensitivity Cardiac Troponin T Is a Useful Biomarker for Predicting the Prognosis of Patients with Systemic Sarcoidosis Regardless of Cardiac Involvement

Objective Cardiac involvement defines the prognosis for patients with systemic sarcoidosis. Despite advancements in techniques for diagnosing cardiac lesions, there remains significant room for improvement in cardiac screening and prognostic prediction. The present study therefore assessed the prognostic factors associated with cardiovascular events in patients with sarcoidosis. Methods We retrospectively studied 132 patients with systemic sarcoidosis and evaluated the clinical data obtained between 2009 and 2022. A Kaplan-Meier survival analysis and Cox proportional hazards models were used to evaluate the associations between cardiovascular events and prognostic factors. Results The median age of the patients at the diagnosis was 64.0 (55.0-71.0) years old. During a mean follow-up period of 6.3±3.2 years, 28 patients suffered from cardiovascular events. Patients in the event group had more severe heart failure symptoms, more frequent ventricular tachycardia, higher serum high-sensitivity cardiac troponin T (hs-cTnT) values [0.025 (0.017-0.044) vs. 0.011 (0.007-0.019) ng/mL, p<0.001], and lower left ventricular ejection fraction values than those in the non-event group. These trends were observed even if the patients were not diagnosed with cardiac involvement at the time of enrollment. A multivariate analysis revealed that hs-cTnT was an independent biomarker for the prediction of cardiac events (hs-cTnT >0.014 ng/mL: HR: 7.31, 95% confidence interval: 2.20 to 24.28, p<0.001). Conclusion Hs-cTnT is a useful biomarker for predicting cardiovascular events in patients with sarcoidosis, even if cardiac involvement is not detected at the initial evaluation.

Long-Term Outcomes of Cardiac Sarcoid: Prognostic Implications of Isolated Cardiac Involvement and Impact of Diagnostic Delays

Background Isolated cardiac sarcoid (iCS) is reported to have more severe clinical presentation and greater risk of adverse events compared with cardiac sarcoid (CS) with extracardiac involvement (nonisolated CS). Delays in diagnosing specific organ involvement may play a role in these described differences. Methods and Results A retrospective observational study of patients with CS over a 20-year period was conducted. Objective evidence of organ involvement and time of onset based on consensus criteria were identified. CS was confirmed by histology in all patients from myocardium only (iCS) or extracardiac tissue (nonisolated CS). The primary end point was a composite of mortality, orthotopic heart transplant, and durable left ventricular assist device implantation. CS was isolated in 9 of 50 patients (18%). Among baseline characteristics, iCS and nonisolated CS differed significantly only in the frequency of sustained ventricular tachycardia at presentation (78% versus 37%; P=0.03) and delay in CS diagnosis >6 months (67% versus 5%; P<0.01). A nonsignificant trend toward lower left ventricular ejection fraction and more frequent heart failure in iCS was observed. Over a median follow-up of 9.7 years (95% CI, 6.8-10.8), 18 patients reached the primary end point (13 deaths, 2 orthotopic heart transplants, and 3 durable left ventricular assist device implantations). The 1-, 5-, and 10-year event-free survival rates were 96% (95% CI, 85%-99%), 79% (95% CI, 64%-88%), and 58% (95% CI, 40%-73%), respectively, without differences between groups. There were no significant predictors of the primary end point, including delayed CS diagnosis. Conclusions Long-term outcomes were similar between iCS and nonisolated CS in patients with histologically documented sarcoid. Diagnostic delays may contribute to differences in the dominant clinical presentation, despite similar outcomes.

Real-Life Utilization of Criteria Guidelines for Diagnosis of Cardiac Sarcoidosis (CS)

Despite the increasing recognition of cardiac involvement in systemic sarcoidosis, the diagnosis of cardiac sarcoidosis (CS) remains challenging. Our aim is to present a comprehensive, retrospective case series of CS patients, focusing on the current diagnostic guidelines and management of this life-threatening condition. In our case series, patient data were collected retrospectively, including hospital admission records and rheumatology and cardiology clinic visit notes, detailing demographic, clinical, laboratory, pathology, and imaging studies, as well as cardiac devices and prescribed medications. Cases were divided into definite and probable CS based on the 2014 Heart Rhythm Society guidelines as well as presumed CS based on imaging criteria and clinical findings. Overall, 19 CS patients were included, 17 of whom were diagnosed with probable or presumed CS based on cardiac magnetic resonance imaging (CMR) and/or cardiac positron emission tomography using 18F-Fluorodeoxyglucose (PET-FDG) without supporting endomyocardial biopsy (EMB). The majority of CS patients were male (53%), with a mean age of 52.9 ± 11.8, with CS being the initial manifestation of sarcoidosis in 63% of cases. Most patients presented with high-grade AVB (63%), followed by heart failure (42%) and ventricular tachyarrhythmia (VT) (26%). This case series highlights the significance of utilizing updated diagnostic criteria relying on CMR and PET-FDG given that cardiac involvement can be the initial manifestation of systemic sarcoidosis, requiring prompt diagnosis and treatment to prevent morbidity and mortality.

High-risk and low prevalence disease: Cardiac sarcoidosis and some of its mimics

In this narrative review of cardiac sarcoidosis, based on a literature search using the terms "cardiac sarcoidosis", "tuberculous myocarditis", "Whipple's disease and myocarditis", and"idiopathic giant cell myocarditis", I have defined cardiac sarcoidosis as a disorder which can be diagnosed either by documentation of the presence of sarcoid-related granulomas in myocardial tissue or by documentation of the association of the presence of sarcoid-related granulomas in extracardiac tissue and symptoms such as complete heart block, ventricular tachyarrhythmia, sudden death or dilated cardiomyopathy which are typical of cardiac sarcoidosis. The differential diagnosis of cardiac sarcoidosis includes granulomatous myocarditis attributable to underlying causes such as such as tuberculosis, Whipple's disease, and idiopathic giant cell myocarditis. Diagnostic pathways for cardiac sarcoidosis include biopsy of cardiac and extracardiac tissue, nuclear magnetic resonance imaging, positron emission tomography, and a diagnostic trial of empiric therapy. Problem areas include differentiation between noncaseating granulomatosis attributable to sarcoidosis versus noncaseating granulomatosis attributable to tuberculosis and whether or not the workup of suspected cardiac sarcoidosis should always include evaluation of biopsy tissue by molecular methods for M tuberculosis DNA as well as by mycobacterium tuberculosis culture. The diagnostic significance of necrotising granulomatosis is also unclear. Evaluation of patients on long term immunotherapy should also take due account of the risk of tuberculosis attributable to the use of tumor necrosis factor-alpha antagonists.

Machine-Learning-Based Diagnostics of Cardiac Sarcoidosis Using Multi-Chamber Wall Motion Analyses

BACKGROUND

Hindered by its unspecific clinical and phenotypical presentation, cardiac sarcoidosis (CS) remains a challenging diagnosis.

OBJECTIVE

Utilizing cardiac magnetic resonance imaging (CMR), we acquired multi-chamber volumetrics and strain feature tracking for a support vector machine learning (SVM)-based diagnostic approach to CS.

METHOD

Forty-five CMR-negative (CMR(-), 56.5(53.0;63.0)years), eighteen CMR-positive (CMR(+), 64.0(57.8;67.0)years) sarcoidosis patients and forty-four controls (CTRL, 56.5(53.0;63.0)years)) underwent CMR examination. Cardiac parameters were processed using the classifiers of logistic regression, KNN(K-nearest-neighbor), DT (decision tree), RF (random forest), SVM, GBoost, XGBoost, Voting and feature selection.

RESULTS

In a three-cluster analysis of CTRL versus vs. CMR(+) vs. CMR(-), RF and Voting classifier yielded the highest prediction rates (81.82%). The two-cluster analysis of CTRL vs. all sarcoidosis (All Sarc.) yielded high prediction rates with the classifiers logistic regression, RF and SVM (96.97%), and low prediction rates for the analysis of CMR(+) vs. CMR(-), which were augmented using feature selection with logistic regression (89.47%).

CONCLUSION

Multi-chamber cardiac function and strain-based supervised machine learning provides a non-contrast approach to accurately differentiate between healthy individuals and sarcoidosis patients. Feature selection overcomes the algorithmically challenging discrimination between CMR(+) and CMR(-) patients, yielding high accuracy predictions. The study findings imply higher prevalence of cardiac involvement than previously anticipated, which may impact clinical disease management.

Cardiac Sarcoidosis: A Literature Review of Current Recommendations on Diagnosis and Management

Cardiac sarcoidosis (CS) is a rare multisystem disorder characterized by granulomatous infiltration of the myocardium, which can lead to significant morbidity and mortality. Its clinical manifestations range from asymptomatic conduction abnormalities to severe heart failure (HF) and sudden cardiac death. This comprehensive review aims to provide an overview of the diagnosis, clinical features, and current medical management strategies for CS. Additionally, the role of implantable cardioverter-defibrillators (ICDs) and the potential use of positron emission tomography in guiding management decisions are explored. A comprehensive understanding of the medical management of CS is essential for improving patient outcomes and guiding future research endeavors.

Diagnosis of cardiac sarcoidosis: histological evidence vs. imaging

INTRODUCTION

The prognosis for cardiac sarcoidosis (CS) remains unfavorable. Although early and accurate diagnosis is crucial, the low detection rate of endomyocardial biopsy makes accurate diagnosis challenging.

AREAS COVERED

The Heart Rhythm Society (HRS) consensus statement and the Japanese Circulation Society (JCS) guidelines are two major diagnostic criteria for the diagnosis of CS. While the requirement of positive histology for the diagnosis in the HRS criteria can result in overlooked cases, the JCS guidelines advocate for a group of 'clinical' diagnoses based on advanced imaging, including cardiovascular magnetic resonance and 18F-fluorodeoxyglucose positron emission tomography, which do not require histological evidence. Recent studies have supported the usefulness of clinical diagnosis of CS. However, other evidence suggests that clinical CS may sometimes be inaccurate. This article describes the advantages and disadvantages of the current diagnostic criteria for CS, and typical imaging and clinical courses.

EXPERT OPINION

The diagnosis of clinical CS has been made possible by recent developments in multimodality imaging. However, it is still crucial to look for histological signs of sarcoidosis in other organs in addition to the endomyocardium. Additionally, phenotyping based on clinical manifestations such as heart failure, conduction abnormality or ventricular arrhythmia, and extracardiac abnormalities is clinically significant.

Diagnoses, management patterns, and outcomes of cardiac sarcoidosis in South Africa

Background

Sarcoidosis is an idiopathic multiorgan disease characterized by tissue infiltration by noncaseating granulomas. Clinical cardiac involvement is reported in approximately 5% of patients. However, the frequency of cardiac involvement is found to be higher on autopsy and in advanced imaging studies such as cardiac magnetic resonance imaging.

Objective

The purpose of this study was to determine contemporary diagnoses, management, and outcomes of cardiac sarcoidosis (CS) in South Africa.

Methods

Clinical records of patients diagnosed with CS between January 2000 and December 2021 were reviewed.

Results

Twenty-two patients were diagnosed with CS during the study period. The patients had a mean (± SD) age of 45.2 ± 12.3 years at the time of presentation. CS diagnostic rates increased from 4.5% in 2000-2005 to 45.5% in 2016-2021. Fifteen of the 22 patients (68.2%) were newly diagnosed with sarcoidosis at the time of CS diagnosis, and 9 of the 15 (60%) had pulmonary involvement. Of the 22 patients diagnosed with CS, 13 (59.1%) presented in combination with heart block, 10 (45.5%) with ventricular arrhythmias, and 4 (18.2%) with heart failure. Five endomyocardial biopsies were performed, and all were nondiagnostic. However, 8 of 8 endobronchial ultrasound (EBUS)-guided biopsies of thoracic lymph nodes were diagnostic of sarcoidosis and, notably, excluded tuberculosis. Fourteen patients (63.6%) were treated with corticosteroids, 7 (31.8%) with azathioprine, 9 (40.9%) with amiodarone, and 16 (72.7%) with a cardiac implantable electronic device. After a mean follow-up period of 64.5 ± 50.5 months, no deaths had occurred.

Conclusion

CS diagnostic rates have increased over time. Diagnostic endomyocardial biopsies have a low diagnostic yield, whereas EBUS-guided biopsy of thoracic lymph nodes is of crucial diagnostic utility.

Management of the arrhythmic manifestations of cardiac sarcoidosis

Cardiac sarcoidosis (CS) is characterised by a high burden of arrhythmic manifestations and cardiac electrophysiologists play an important role in both the diagnosis and management of this challenging condition. CS is characterised by the formation of noncaseating granulomas within the myocardium, which can subsequently lead to fibrosis. Clinical presentations of CS are varied and depend on the location and extent of granulomas. Patients may present with atrioventricular block, ventricular arrhythmias, sudden cardiac death or heart failure. CS is being increasing diagnosed through use of advanced cardiac imaging, however endomyocardial biopsy is often still required to confirm the diagnosis. Due to the low sensitivity of fluoroscopy-guided right ventricular biopsies, three-dimensional electro-anatomical mapping and electrogram-guided biopsies are being investigated as a means to improve diagnostic yield. Cardiac implantable electronic devices are often required in the management of CS, either for pacing or for primary or secondary prevention of ventricular arrhythmias. Catheter ablation for ventricular arrythmias may also be required, although this is often associated with high recurrence rates due to the challenging nature of the arrhythmogenic substrate. This review will explore the underlying mechanisms of the arrhythmic manifestations of CS, provide an overview of current clinical practice guidelines, and examine the important role that cardiac electrophysiologists play in managing patients with CS.

Cardiac sarcoidosis: a comprehensive review of risk factors, pathogenesis, diagnosis, clinical manifestations, and treatment strategies

Cardiac Sarcoidosis (CS) is a deadly consequence of systemic sarcoidosis that inflames all three layers of the heart, especially the myocardium-clinical signs of CS range from asymptomatic disease to abrupt cardiac death. CS generally remains undiagnosed secondary to a lack of definitive diagnostic criteria, a high percentage of false negative results on endomyocardial biopsy, and ill-defining clinical manifestations of the disease. Consequently, there is a lack of evidence-based recommendations for CS, and the present diagnostic and therapeutic management depend on expert opinion. The aetiology, risk factors, clinical symptoms, diagnosis, and therapy of CS will be covered in this review. A particular emphasis will be placed on enhanced cardiovascular imaging and early identification of CS. We review the emerging evidence regarding the use of Electrocardiograms (ECGs), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) imaging of the heart to identify and quantify the extent of myocardial inflammation, as well as to guide the use of immunotherapy and other treatment regimens, such as ablation therapy, device therapy, and heart transplantation, to improve patient outcomes.

Volume-based 18 F-FDG PET analysis of cardiac sarcoidosis using the descending aorta as a reference tissue

OBJECTIVE

18 F-FDG PET can be used to calculate the threshold value of myocardial volume based on the mean standardised uptake value (SUV mean ) of the aorta to detect highly integrated regions of cardiac sarcoidosis. The present study investigated the myocardial volume when the position and number of volumes of interest (VOIs) were changed in the aorta.

METHODS

The present study examined PET/computed tomography images of 47 consecutive cardiac sarcoidosis cases. VOIs were set at three locations in the myocardium and aorta (descending thoracic aorta, superior hepatic margin and near the pre-branch of the common iliac artery). The volume was calculated for each threshold using 1.1-1.5 times the SUV mean (median of three cross-sections) of the aorta as the threshold to detect high myocardial 18 F-FDG accumulation. The detected volume, correlation coefficient with the visually manually measured volume and the relative error were also calculated.

RESULTS

The optimum threshold value for detecting high 18 F-FDG accumulation was 1.4 times that of the single cross-section of the aorta and showed the smallest relative errors of 33.84% and 25.14% and correlation coefficients of 0.974 and 0.987 for single and three cross-sections, respectively.

CONCLUSION

The SUV mean of the descending aorta may be detected in good agreement with the visual high accumulation by multiplying the same threshold constant for both single and multiple cross-sections.

In Vivo Fibroblast Activation of Systemic Sarcoidosis: A 68Ga-FAPI-04 PET/CT Imaging Study

A 47-year-old female with cardiac dysfunction and lymphadenopathy underwent ¹⁸FDG PET/CT and ⁶⁸Ga-FAPI-04 imaging for tumor screening. Mild uptake in the left ventricular wall was detected on the oncology ¹⁸FDG PET/CT. True myocardiac-involvement could not be distinguished with physiological uptake. The following ⁶⁸Ga-FAPI-04 showed intense heterogeneous uptake in the left ventricular wall, particularly in the septum and apex area, corresponding with the late gadolinium enhancement regions shown by cardiac MR. Intense uptake was also noted in the mediastinal and bilateral hilar lymph nodes. Endomyocardial biopsy demonstrated sarcoidosis.

Cardiac sarcoidosis

The diagnostic yield of endomyocardial biopsy in cardiac sarcoidosis (CS) is quite low because of the patchy involvement, and for the diagnosis of CS, existing guidelines required histological confirmation. Therefore, especially for isolated CS, diagnosis consistent with the guidelines cannot be made in a large number of patients. With recent developments in imaging modalities such as cardiac magnetic resonance and 18-fluorodeoxyglucose positron emission tomography, diagnosing CS has become easier and diagnostic criteria for CS not compulsorily requiring histological confirmation have been suggested. Despite significant advances in diagnostic tools, large-scale studies that can guide treatment plans are still lacking, and treatment has relied on the experience accumulated over the past years and the consensus of experts. However, opinions vary, depending on the situation, which is quite puzzling for the physician treating CS. Moreover, with the advent of new immunosuppressant agents, these new drugs have been applied under the assumption that the effect of immunosuppression is not much different from that of other well-known autoimmune diseases that require immunosuppression. However, we should wait to see the beneficial effects of these new immunosuppressants before we attempt to apply these agents in our clinical practice. This review summarises the widely used diagnostic criteria, current diagnostic modalities and recommended treatments for sarcoidosis. We have added our opinions on selecting or modifying diagnostic and treatment plans from the diverse current recommendations.

Regional extracellular volume within late gadolinium enhancement-positive myocardium to differentiate cardiac sarcoidosis from myocarditis of other etiology: a cardiovascular magnetic resonance study

BACKGROUND

Cardiovascular magnetic resonance (CMR) plays a pivotal role in diagnosing myocardial inflammation. In addition to late gadolinium enhancement (LGE), native T1 and T2 mapping as well as extracellular volume (ECV) are essential tools for tissue characterization. However, the differentiation of cardiac sarcoidosis (CS) from myocarditis of other etiology can be challenging. Positron-emission tomography-computed tomography (PET-CT) regularly shows the highest Fluordesoxyglucose (FDG) uptake in LGE positive regions. It was therefore the aim of this study to investigate, whether native T1, T2, and ECV measurements within LGE regions can improve the differentiation of CS and myocarditis compared with using global native T1, T2, and ECV values alone.

METHODS

PET/CT confirmed CS patients and myocarditis patients (both acute and chronic) from a prospective registry were compared with respect to regional native T1, T2, and ECV. Acute and chronic myocarditis were defined based on the 2013 European Society of Cardiology position paper on myocarditis. All parametric measures and ECV were acquired in standard fashion on three short-axis slices according to the ConSept study for global values and within PET-CT positive regions of LGE.

RESULTS

Between 2017 and 2020, 33 patients with CS and 73 chronic and 35 acute myocarditis patients were identified. The mean ECV (± SD) in LGE regions of CS patients was higher than in myocarditis patients (CS vs. acute and chronic, respectively: 0.65 ± 0.12 vs. 0.45 ± 0.13 and 0.47 ± 0.1; p < 0.001). Acute and chronic myocarditis patients had higher global native T1 values (1157 ± 54 ms vs. 1196 ± 63 ms vs. 1215 ± 74 ms; p = 0.001). There was no difference in global T2 and ECV values between CS and acute or chronic myocarditis patients.

CONCLUSION

This is the first study to show that the calculation of regional ECV within LGE-positive regions may help to differentiate CS from myocarditis. Further studies are warranted to corroborate these findings.

Additional diagnostic value of electron microscopic examination in endomyocardial biopsy in patients with suspected non-ischemic cardiomyopathy

BACKGROUND

Electron microscopy enables a finely detailed analysis of ultra-structural features, and hence, it generally has an added diagnostic value to light microscopy alone. However, no studies have verified the additional diagnostic value of electron microscopic examination in patients with suspected non-ischemic cardiomyopathy.

METHODS

A total of 294 consecutive patients with non-ischemic cardiomyopathy who underwent endomyocardial biopsy were prospectively enrolled. Patients were divided into three groups according to left ventricular morphology assessed using echocardiography. Myocardial specimens were collected from the right ventricular septum and examined by light microscopy. Electron microscopy was performed subsequently to evaluate the additional diagnostic value.

RESULTS

Altogether, 294 patients were analyzed, including 160 (55 %), 96 (33 %), and 35 (12 %) patients who were diagnosed with primary, secondary, and unclassified cardiomyopathy, respectively. In patients with dilated cardiomyopathy-like morphology, the detection rate of disease-specific histological findings was relatively low compared to that in patients with other cardiac morphologies. The additional diagnostic value of electron microscopy was observed in eight patients, including five with Fabry disease, one with cardiac amyloidosis, one with mitochondrial cardiomyopathy, and one with triglyceride deposit cardiomyovasculopathy. Among the 18 cardiac amyloidosis cases, electron microscopy detected amyloid fibrils in all patients, whereas light microscopy could not detect amyloid deposition in 1 patient. Among one of five patients with Fabry disease, light microscopy did not show obvious vacuolated cardiomyocytes, but zebra bodies were detected by electron microscopy, leading to the diagnosis of cardiac Fabry disease. The diagnostic value of electron microscopic examination in patients with cardiac sarcoidosis was not observed.

CONCLUSIONS

The additional diagnostic value of electron microscopy was observed in patients with secondary cardiomyopathy, in whom light microscopy did not show disease-specific histological findings. Electron microscopy should be performed in cases where secondary cardiomyopathy is strongly suspected with no disease-specific findings by light microscopy.

Access to cardiac PET/CT by sarcoidosis patients and cost-effectiveness analysis of cardiac PET/MR compared to the standard of care

IMPORTANCE

Cardiac sarcoidosis is associated with a high mortality rate. Given multiple barriers to obtaining cardiac PET imaging, we suspect individuals with access to this imaging modality are not representative of the Sarcoid patient population, which in the United States are predominantly Black females.

OBJECTIVE

To evaluate the demographics of patients with cardiac PET access and the cost-effectiveness of cardiac PET/MR imaging relative to standard of care.

DESIGN

This is a retrospective, observational study. The demographic information of patients with suspected cardiac sarcoidosis and cardiac PET/CT imaging within a national registry of sarcoidosis were reviewed (n = 4561). An individual-level, continuous, time-state transition model was used for the evaluation of long-term cost-effectiveness for the combined cardiac PET/MR compared to standard of care cardiac MR followed by cardiac PET/CT.

RESULTS

Patients who underwent cardiac PET in the national registry had 88.35% higher odds of being male (p < 0.001) and 43.82% higher odds of being White (p = 0.003) than their counterparts who did not have cardiac PET imaging. Combined cardiac PET/MR had overall lower total lifetime costs ($8761 vs $10,777) and overall improved expected quality of life-years compared to the standard of care (0.77 vs 0.69).

CONCLUSION AND RELEVANCE

The findings suggest that patients with access to cardiac PET/CT are not representative of the patient population most likely to have cardiac sarcoidosis in this limited study evaluation. Universal insurance coverage should be considered for Cardiac PET imaging as same day cardiac PET and MR imaging has potential long-term cost and quality of life benefit.

Clinical features and prognosis of isolated cardiac sarcoidosis diagnosed using new guidelines with dedicated FDG PET/CT

BACKGROUND

Diagnostic guidelines for isolated cardiac sarcoidosis (iCS) were first proposed in 2016, but there are few reports on the imaging and prognosis of iCS. This study aimed to evaluate the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging in predicting iCS prognosis.

METHODS AND RESULTS

We retrospectively reviewed the clinical and imaging data of 306 consecutive patients with suspected CS who underwent FDG PET/CT with a dedicated preparation protocol and included 82 patients (55 with systemic sarcoidosis including cardiac involvement [sCS], 27 with iCS) in the study. We compared the FDG PET/CT findings between the two groups. We examined the relationship between the CS type and the rate of adverse cardiac events. The iCS group had a significantly lower target-to-background ratio than the sCS group (P = 0.0010). The event-free survival rate was significantly lower in the iCS group than the sCS group (log-rank test, P < 0.0001). iCS was identified as an independent prognostic factor for adverse events (hazard ratio 3.82, P = 0.0059).

CONCLUSION

iCS was an independent prognostic factor for adverse cardiac events in patients with CS. The clinical diagnosis of iCS based on FDG PET/CT and new guidelines may be important.

Comorbidities of sarcoidosis

Sarcoidosis is a heterogeneous disease, which can affect virtually every body organ, even though lungs and intra thoracic lymph nodes are almost universally affected. The presence of noncaseating granulomas is the histopathological hallmark of the disease, and clinical picture depends on the organs affected. Data about interaction between sarcoidosis and comorbidities, such as cardiovascular and pulmonary diseases, autoimmune disorders, malignancy and drug-related adverse events are limited. Several lung conditions can be associated with sarcoidosis, such as pulmonary hypertension and fibrosis, making it difficult sometimes the differentiation between complications and distinctive pathologies. Their coexistence may complicate the diagnosis of sarcoidosis and contribute to the highly variable and unpredictable natural history, particularly if several diseases are recognised. A thorough assessment of specific disorders that can be associated with sarcoidosis should always be carried out, and future studies will need to evaluate sarcoidosis not only as a single disorder, but also in the light of possible concomitant conditions.Key messagesComorbidities in sarcoidosis are common, especially cardiovascular and pulmonary diseases.In the diagnostic workup, a distinction must be made between sarcoidosis-related complaints and complaints caused by other separate disorders. It can be very difficult to distinguish between complications of sarcoidosis and other concomitant conditions.The coexistence of multiple conditions may complicate the diagnosis of sarcoidosis, affect its natural course and response to treatment.

Cardiac Sarcoidosis: Current Approaches to Diagnosis and Management

PURPOSE OF REVIEW

Cardiac sarcoidosis (CS) is an important cause of non-ischemic cardiomyopathy and has specific diagnostic and therapeutic considerations. With advances in imaging techniques and treatment approaches, the approach to monitoring disease progression and management of CS continues to evolve. The purpose of this review is to highlight advances in CS diagnosis and treatment and present a center's multidisciplinary approach to CS care.

RECENT FINDINGS

In this review, we highlight advances in granuloma biology along with contemporary diagnostic approaches. Moreover, we expand on current targets of immunosuppression focused on granuloma biology and concurrent advances in the cardiovascular care of CS in light of recent guideline recommendations. Here, we review advances in the understanding of the sarcoidosis granuloma along with contemporary diagnostic and therapeutic considerations for CS. Additionally, we highlight knowledge gaps and areas for future research in CS treatment.

Detection of inflammation using cardiac positron emission tomography for evaluation of ventricular arrhythmias: An institutional experience

BACKGROUND

The use of cardiac positron emission tomography-computed tomography (PET-CT) is increasingly used for the detection of underlying inflammation in patients with ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]), but the role of PET-CT remains undefined, particularly for patients who do not meet Task Force criteria for sarcoidosis.

OBJECTIVE

The purpose of this study was to determine the utility of PET-CT for clinical evaluation of VT/VF in patients with nonischemic cardiomyopathy.

METHODS

Consecutive patients with nonischemic cardiomyopathy and VT/VF who underwent cardiac PET-CT to detect inflammation between 2012 and 2019 were analyzed for baseline demographic characteristics, imaging results, and outcomes. Patients with known sarcoidosis or other conditions requiring immunosuppressive therapy were excluded.

RESULTS

PET-CT was performed in 133 patients with mean age 56.3 ± 13.5 years and left ventricular ejection fraction 43% ± 16.1%, with evidence of myocardial inflammation detected in 32 (23.5%). Patients with myocardial inflammation were managed conservatively with medical therapy including immunosuppressive agents. Ten patients with myocardial inflammation ultimately required catheter ablation for ongoing arrhythmias. There was no significant difference in arrhythmia recurrence between PET-positive and PET-negative groups (37.5% vs 32.4%; P = .43) or in time to recurrence (P = .26), in spite of the disparate management strategies. Gadolinium-enhanced cardiac magnetic resonance imaging was performed in 96 patients (72%); however, magnetic resonance imaging did not detect 31% of cases with active inflammation that were otherwise detected on PET-CT.

CONCLUSION

The use of PET-CT significantly improves the detection of underlying myocardial inflammation contributing to ventricular arrhythmias. Management of these patients with immunosuppressive medical therapy is effective for arrhythmia control and may obviate the need for invasive ablation procedures in some patients.

Evaluation and Catheter Ablation of Ventricular Arrhythmias in Cardiac Sarcoidosis

Ventricular arrhythmias are a common clinical manifestation in patients with cardiac sarcoidosis (CS) and other arrhythmogenic inflammatory cardiomyopathies (AIC). The management of sustained ventricular arrhythmias in these patients presents unique challenges. Current therapies include immunosuppressive, antiarrhythmic agents, and catheter ablation. Significant progress has been made in deciphering the importance of patient selection for ablation, systematic preablation evaluation, and optimal ablation timing, as well as ablation approaches and techniques. In this overview, we discuss the evaluation and management of ventricular arrhythmias in patients with CS, focusing on catheter ablation, which has evolved into an effective approach in reducing the burden of ventricular arrhythmias in these patients in the context of multifaceted treatment along with medical therapies.

Transcriptional and Immune Landscape of Cardiac Sarcoidosis

BACKGROUND

Cardiac involvement is an important determinant of mortality among sarcoidosis patients. Although granulomatous inflammation is a hallmark finding in cardiac sarcoidosis, the precise immune cell populations that comprise the granuloma remain unresolved. Furthermore, it is unclear how the cellular and transcriptomic landscape of cardiac sarcoidosis differs from other inflammatory heart diseases.

METHODS

We leveraged spatial transcriptomics (GeoMx digital spatial profiler) and single-nucleus RNA sequencing to elucidate the cellular and transcriptional landscape of cardiac sarcoidosis. Using GeoMX digital spatial profiler technology, we compared the transcriptomal profile of CD68+ rich immune cell infiltrates in human cardiac sarcoidosis, giant cell myocarditis, and lymphocytic myocarditis. We performed single-nucleus RNA sequencing of human cardiac sarcoidosis to identify immune cell types and examined their transcriptomic landscape and regulation. Using multichannel immunofluorescence staining, we validated immune cell populations identified by single-nucleus RNA sequencing, determined their spatial relationship, and devised an immunostaining approach to distinguish cardiac sarcoidosis from other inflammatory heart diseases.

RESULTS

Despite overlapping histological features, spatial transcriptomics identified transcriptional signatures and associated pathways that robustly differentiated cardiac sarcoidosis from giant cell myocarditis and lymphocytic myocarditis. Single-nucleus RNA sequencing revealed the presence of diverse populations of myeloid cells in cardiac sarcoidosis with distinct molecular features. We identified GPNMB (transmembrane glycoprotein NMB) as a novel marker of multinucleated giant cells and predicted that the MITF (microphthalmia-associated transcription factor) family of transcription factors regulated this cell type. We also detected additional macrophage populations in cardiac sarcoidosis including HLA-DR (human leukocyte antigen-DR)+ macrophages, SYTL3 (synaptotagmin-like protein 3)+ macrophages and CD163+ resident macrophages. HLA-DR+ macrophages were found immediately adjacent to GPMMB+ giant cells, a distinct feature compared with other inflammatory cardiac diseases. SYTL3+ macrophages were located scattered throughout the granuloma and CD163+ macrophages, CD1c+ dendritic cells, nonclassical monocytes, and T cells were located at the periphery and outside of the granuloma. Finally, we demonstrate mTOR (mammalian target of rapamycin) pathway activation is associated with proliferation and is selectively found in HLA-DR+ and SYLT3+ macrophages.

CONCLUSIONS

In this study, we identified diverse populations of immune cells with distinct molecular signatures that comprise the sarcoid granuloma. These findings provide new insights into the pathology of cardiac sarcoidosis and highlight opportunities to improve diagnostic testing.

Multicenter Registry in the Japanese Cardiac Sarcoidosis Prognostic (J-CASP) Study: Baseline Characteristics and Validation of the Non-invasive Approach Using 18F-FDG PET

Background: Recent advances in cardiac modalities contribute to the guidelines on the diagnosis of cardiac sarcoidosis (CS) updated by the Japanese Circulation Society. The multicenter registry, Japanese Cardiac Sarcoidosis Prognostic (J-CASP) study tried to reveal recent trends of diagnosis and outcomes in CS patients and to validate the non-invasive diagnostic approach, including cardiac ¹⁸F-fluorodeoxyglucose (FDG) study. Methods/results: Databases from 12 hospitals consisting of 231 CS patients (mean age, 64 years; female, 65%; LV ejection fraction, 47%) diagnosed by the guidelines with FDG positron emission tomography (PET) study were integrated to compile clinical information on the diagnostic criteria and outcomes. Cardiac ¹⁸F-FDG uptake and magnetic resonance imaging (CMR) was positive identically in the histology-proven and clinically-diagnosed groups. The histology-proven group more frequently had reduce LV ejection fraction, myocardial perfusion abnormality and low-grade electrocardiogram (ECG) abnormality (P=0.003 to 0.016) than did the clinical group. During a 45-month period, the histology-proven group more frequently underwent appropriate implantable cardioverter-defibrillator (ICD) treatment (14% versus 4%, P=0.013) and new electronic device implantation (30% versus 12%, P=0.007) than did clinical group, respectively. There, however, was no difference in all-cause or cardiac mortality or in new hospitalization due to heart failure progression between them. Conclusion: The J-CASP registry demonstrated the rationale and clinical efficacies of non-invasive approach using advanced cardiac imaging modalities in the diagnosis of CS even when histological data were available.

Successful treatment of cardiac sarcoidosis based on clinical suspicion and advanced cardiac imaging: A case report

INTRODUCTION

Confirming the diagnosis of cardiac sarcoidosis (CS) is a challenging task as we often do not count with histopathologic evidence. However, prompt initiation of treatment is sometimes necessary, and advanced cardiac imaging along with key clinical findings can play a crucial role in the diagnostic workup.

PATIENT CONCERNS

A 77-year-old male with a history of heart failure presented with chest pain and shortness of breath. He was found to have an acute drop in left ventricular ejection fraction associated with frequent premature ventricular contractions and nonsustained ventricular tachycardia. Coronary angiogram was negative for acute coronary syndrome. Advanced cardiac imaging with cardiac magnetic resonance raised suspicion of CS, and steroids were started empirically. Endomyocardial biopsy was attempted but was not successful.

DIAGNOSIS

The patient's presentation was highly suggestive of cardiac sarcoidosis.

INTERVENTIONS

Corticosteroids, diuresis, guideline-directed medical therapy for heart failure.

OUTCOMES

The patient's symptoms and ventricular arrhythmias improved on steroids. Subsequent FDG-PET revealed increased uptake in a pattern consistent with CS.

CONCLUSION

This clinical scenario highlights the importance of advanced cardiac imaging and clinical findings for the diagnosis of CS and exposes the practical need for a standardized, noninvasive strategy to the diagnosis of CS.

Predicting adverse cardiac events in sarcoidosis: deep learning from automated characterization of regional myocardial remodeling

Recognizing early cardiac sarcoidosis (CS) imaging phenotypes can help identify opportunities for effective treatment before irreversible myocardial pathology occurs. We aimed to characterize regional CS myocardial remodeling features correlating with future adverse cardiac events by coupling automated image processing and data analysis on cardiac magnetic resonance (CMR) imaging datasets. A deep convolutional neural network (DCNN) was used to process a CMR database of a 10-year cohort of 117 consecutive biopsy-proven sarcoidosis patients. The maximum relevance - minimum redundancy method was used to select the best subset of all the features-24 (from manual processing) and 232 (from automated processing) left ventricular (LV) structural/functional features. Three machine learning (ML) algorithms, logistic regression (LogR), support vector machine (SVM) and multi-layer neural networks (MLP), were used to build classifiers to categorize endpoints. Over a median follow-up of 41.8 (inter-quartile range 20.4-60.5) months, 35 sarcoidosis patients experienced a total of 43 cardiac events. After manual processing, LV ejection fraction (LVEF), late gadolinium enhancement, abnormal segmental wall motion, LV mass (LVM), LVMI index (LVMI), septal wall thickness, lateral wall thickness, relative wall thickness, and wall thickness of 9 (out of 17) individual LV segments were significantly different between patients with and without endpoints. After automated processing, LVEF, end-diastolic volume, end-systolic volume, LV mass and wall thickness of 92 (out of 216) individual LV segments were significantly different between patients with and without endpoints. To achieve the best predictive performance, ML algorithms selected lateral wall thickness, abnormal segmental wall motion, septal wall thickness, and increased wall thickness of 3 individual segments after manual image processing, and selected end-diastolic volume and 7 individual segments after automated image processing. LogR, SVM and MLP based on automated image processing consistently showed better predictive accuracies than those based on manual image processing. Automated image processing with a DCNN improves data resolution and regional CS myocardial remodeling pattern recognition, suggesting that a framework coupling automated image processing with data analysis can help clinical risk stratification.

Comparisons between biopsy-proven versus clinically diagnosed cardiac sarcoidosis

OBJECTIVES

Diagnosis of cardiac sarcoidosis (CS) without histological evidence remains controversial. This study aimed to compare characteristics and outcomes of histologically proven versus clinically diagnosed cases of CS, which were adjudicated using Heart Rhythm Society or Japanese Circulation Society criteria.

METHODS

A total of 512 patients with CS (age: 62±11 years, female: 64.3%) enrolled in the multicentre registry were studied. Histologically confirmed patients were classified as 'biopsy-proven CS', while those with the presence of strongly suggestive clinical findings of CS without histological evidence were classified as 'clinical CS'. Primary outcome was a composite of all-cause death, heart failure hospitalisation and ventricular arrhythmia event.

RESULTS

In total, 314 patients (61.3%) were classified as biopsy-proven CS, while 198 (38.7%) were classified as clinical CS. Patients classified under clinical CS were associated with higher prevalence of left ventricular dysfunction, septal thinning, and positive findings in fluorodeoxyglucose-positron emission tomography or Gallium scintigraphy than those under biopsy-proven CS. During median follow-up of 43.7 (23.3-77.3) months, risk of primary outcome was comparable between the groups (adjusted HR: 1.24, 95% CI: 0.88 to 1.75, p=0.22). Similarly, the risks of primary outcome were comparable between patients with clinical isolated CS who did not have other organ/tissue involvement, and biopsy-proven isolated CS (adjusted HR: 1.23, 95% CI: 0.56 to 2.70, p=0.61).

CONCLUSIONS

A substantial number of patients were diagnosed with clinical CS without confirmatory biopsy. Considering the worse clinical outcomes irrespective of the histological evidence, the diagnosis of clinical CS is justifiable if imaging findings suggestive of CS are observed.

High-sensitivity cardiac troponin serving as a useful marker for the early recognition of relapse of isolated cardiac sarcoidosis: a case report

Background

Isolated cardiac sarcoidosis is a relatively rare disease that is difficult to manage because of challenges in determining the progression and flare-up of cardiac lesions. Routine reduction of glucocorticoid doses may lead to treatment failure and disease relapse, which are associated with increased mortality.

Case summary

Herein, we present the case of a 49-year-old woman with isolated cardiac sarcoidosis in whom high-sensitivity cardiac troponin served as a biomarker for tailoring immunosuppressive therapy. She presented with progressive dyspnoea on exertion for 2 months and had elevated levels of high-sensitivity cardiac troponin I (hs-cTnI) at presentation. A diagnosis of isolated cardiac sarcoidosis was made based on the finding of electrocardiography, echocardiography, cardiac magnetic resonance imaging, and 18F-fluorodeoxyglucose (FDG) positron emission tomography. After the introduction of glucocorticoids, the hs-cTnI concentration immediately decreased, followed by the disappearance of FDG uptake in the heart. However, 2 months after oral prednisolone was reduced to the maintenance dose, the hs-cTnI concentration began to increase gradually, and 2 months later, worsening heart failure, progression of impaired left ventricular function, and de novo accumulation of FDG in the heart were observed, confirming the relapse of cardiac sarcoidosis. Intensified glucocorticoid therapy resulted in another immediate decrease in hs-cTnI concentration and improved heart failure management.

Discussion

This case highlights the potential of hs-cTnI to serve as a serum biomarker for monitoring disease activity and response to immunosuppressive therapy in patients with cardiac sarcoidosis. The hs-cTnI could be a highly sensitive and cost-effective biomarker reflecting the inflammatory status of cardiac sarcoidosis.