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

Differentiating Cardiac Sarcoidosis from Arrhythmogenic Right Ventricular Cardiomyopathy: A Systematic Review

OBJECTIVE

Cardiac sarcoidosis (CS) and arrhythmogenic right ventricular cardiomyopathy (ARVC) are distinct disorders with different pathophysiologic pathways, but they share similar clinical presentations that could lead to misdiagnosis and inappropriate therapeutic decisions.

METHODS

We searched PubMed and Google Scholar databases and other relevant literature to retrieve comparative studies including CS and ARVC that were published before 2024. The National Heart, Lung and Blood Institute checklist was used for quality assessment and the review was conducted according to the PRISMA guidelines. Three reviewers determined study eligibility and made quality assessments.

RESULTS

A total of seven studies were included in the review. Patients with CS were older (five of seven studies) and had more comorbidities (two of two studies). PR interval (four of five studies) and QRS duration (four of four studies) were longer in CS. Most studies reported lower left ventricular ejection fraction in CS (five of six studies), and septal involvement on cardiac MRI was more common in CS (two of three studies). 18-Fluorodeoxyglucose uptake on positron emission tomography (PET) scan was seen in up to 90% of CS patients. 62.5%-100% of patients with CS fulfilled 1994 or 2010 International Task Force criteria for ARVC.

CONCLUSIONS

Available evidence suggests that atrioventricular and intraventricular conduction defects in an older (>40 years) patient with low left ventricular ejection fraction should raise suspicion for CS, especially when other supportive findings, such as 18-fluorodeoxyglucose avidity on PET, were present. Neither 1994 nor 2010 ARVC Task Force criteria should be used to discriminate CS from ARVC.

Cardiac PET Imaging for Coronary Artery Disease and Heart Failure: An Overview

Cardiac PET imaging is an important noninvasive modality for the diagnosis and management of heart failure. Cardiac PET myocardial perfusion imaging can identify coronary artery disease with high accuracy and also detect myocardial viability, offering crucial information for the treatment of ischemic cardiomyopathy. Additionally, cardiac PET can help diagnose nonischemic cardiomyopathies including sarcoidosis, amyloidosis, and myocarditis. Improved PET scanner technology combined with emerging radiotracers will, in the future, offer disease-specific molecular imaging that will further assist in the diagnosis, prognosis, and treatment selection for a variety of cardiovascular pathologies.

Characteristics and outcomes of hospitalized patients with Isolated and systemic cardiac sarcoidosis: Analysis of the Nationwide readmissions database 2016-2021

Objective

To identify any differences in the characteristics and outcomes of patients with Isolated cardiac sarcoidosis (iCS) vs systemic cardiac sarcoidosis (sCS).

Patients and methods

All inpatient encounters in the Nationwide Readmission Database from 2016 to 2021 were analyzed for the rates, predictors, costs and mortality during index and unplanned 90-days readmissions for iCS and sCS patients. Patients with ischemic heart disease were excluded.

Results

1,667 patients were identified (57.8 % male), of which, 1,013 (60.8 %) had iCS and 654 (39.2 %) had sCS. The median (IQR) age of iCS patients was slightly older [57.0 (49.0-66.0) vs 56.0 (48.0-64.0), p = 0.04]. On index admission, iCS patients had higher prevalence of ventricular tachycardia (36.9 % vs 28.8 %, p = 0.001) and catheter ablation (5.6 % vs 2.8 %, p = 0.006). The predictors for all-cause readmissions were Charlson Comorbidity Index (CCI) (HR 1.19, 95 % CI 1.01-1.40, p = 0.04), age (HR 0.98 (0.97-1.00), p = 0.01) and the use of anticoagulant therapy (HR 1.92, 95 % CI 1.35-2.72, p < 0.001). Patients with sCS were more likely to be readmitted with heart failure compared to iCS patients (SHR 3.78, 95 % CI 1.11-12.94, p = 0.03). During subsequent readmission, iCS and sCS patients had comparable rates of in-hospital mortality, median length of stay and healthcare-associated costs. No independent predictors of in-hospital mortality at readmission were ascertained.

Conclusions

Isolated CS patients, when compared to systemic CS, had a greater prevalence of ventricular tachycardia and catheter ablation. They were less likely to be re-hospitalized with heart failure within 90-days. Age, higher CCI, and use of anticoagulant therapy were predictors for all-cause readmissions.

Cardiac sarcoidosis; update for the heart failure specialist

PURPOSE OF REVIEW

This review presents contemporary data on epidemiology, common presentations, investigations and diagnostic algorithms, treatment and prognosis. It particularly focuses on topics of most relevance to heart failure specialists, including what left ventricle (LV) function changes can be expected after treatment and outcomes to all standard and advanced heart failure therapies.

RECENT FINDINGS

Around 5% of sarcoidosis patients have clinically manifest cardiac sarcoidosis (CS), presenting with significant arrhythmias (such as conduction disturbances and ventricular arrhythmias) or newly developed unexplained heart failure. These cardiac symptoms (including sudden cardiac death) may be the initial manifestations of CS. While cardiac magnetic resonance imaging (CMR) is the preferred method for identifying fibrosis in the myocardium, FDG-positron emission tomography (FDG-PET) helps in identifying active inflammation within the myocardium and aids in managing immunosuppressive treatment. The concept of isolated CS is much debated. However very importantly, recent data have shown that some patients diagnosed with 'clinically and imaging isolated CS' are subsequently found to have genetic cardiomyopathy. The management of CS involves a comprehensive approach including medications for immunosuppression, all standard heart failure medication and, in high-risk patient's implantable cardioverter defibrillators (ICDs). In CS patients with terminal heart failure who do not respond to medical and surgical interventions, heart transplantation and ventricular assist devices should be considered. Long-term results after transplantation are generally favorable and comparable to non-CS patients. The degree of left ventricular dysfunction remains a crucial prognostic factor in CS cases. Outcomes for CS have very significantly improved, over the last two decades due to earlier diagnosis, advanced heart failure treatments, and the strategic use of ICD therapy.

SUMMARY

Outcomes for CS have significantly improved, over the last two decades due to earlier diagnosis, advanced heart failure treatments, and the strategic use of ICD therapy.

Lamin AC Cardiomyopathy, the Next Masquerader: Laminopathy Mimicking Cardiac Sarcoidosis

Phenotypic expression of lamin AC-dilated cardiomyopathy (LMNA-DCM) and cardiac sarcoidosis (CS) at times presents with similar clinical findings, including arrhythmia, conduction abnormalities, and heart failure. Lamin AC-dilated cardiomyopathy is one of the most common causes of genetic DCM with an autosomal dominant inheritance pattern. Contrastingly, a smaller proportion of sarcoid cases present with isolated cardiac involvement, highlighting the intricate nature of this systemic disease. This paper presents three cases highlighting potential pitfalls in the clinical diagnosis and management of laminopathies. Also highlighted is the need for extreme caution when endomyocardial biopsies are equivocal and there is sole reliance on cardiac imaging to establish diagnostic criteria. In addition, this case series highlights the imperative role of genetic testing during the initial workup for establishing the accurate etiology in the setting of cardiomyopathy. The strikingly similar clinical characteristics of LMNA-DCM and CS underscore the necessity for a robust diagnostic approach, including early integration of genetic testing, as this approach holds great promise for improving outcomes and the quality of life for those grappling with these challenging cardiac conditions. Innovative strategies, including comprehensive advanced imaging protocols and precision medicine, promise to advance our comprehension and management of both disease entities.

Steroids Versus Immunomodulators in Cardiac Sarcoidosis: A Systematic Review

Granulomatous inflammation of the heart causes arrhythmias, heart block, and heart failure in cardiac sarcoidosis (CS), a rare but potentially deadly condition. There is increasing interest in using immunomodulators as steroid-sparing medicines, even though corticosteroids are still the usual treatment. This study compared corticosteroids and immunomodulatory treatments through a systematic review and meta-analysis. After a thorough literature search in October 2024, 11 pertinent studies were found. These included observational studies, case series, and randomized controlled trials. Based on changes in myocardial inflammation (SUVmax) and left ventricular ejection fraction (LVEF), the effectiveness of corticosteroids, methotrexate, infliximab, rituximab, and their combinations was evaluated. The analysis revealed that all treatments significantly reduced myocardial inflammation, with methotrexate showing the highest effect size (d = 1.65, p < 0.001). Infliximab in combination with corticosteroids also demonstrated a significant reduction in SUVmax (d = 1.61, p < 0.001). LVEF improved across all treatment groups, although the effect was modest, with infliximab and corticosteroids showing the most significant increase in LVEF (d = 0.4, p = 0.05). The differences between subgroups were not statistically significant (p = 0.46 for SUVmax, p = 0.36 for LVEF). Corticosteroids remain the standard first-line treatment for CS, while methotrexate has shown the highest effect size for reducing myocardial inflammation, supporting its role as a steroid-sparing agent with fewer long-term side effects. Infliximab is effective but carries risk of infection. These findings highlight the need for customized treatment regimens in the management of CS. This study underscores the urgent need for more research to enhance combination medications, pinpoint patient subgroups that may benefit most from specific therapies, and enhance treatment regimens in the field of CS.

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.

Advanced Computed Tomography and Magnetic Resonance Imaging in Ischemic and Nonischemic Cardiomyopathies

Cardiomyopathies represent a diverse group of heart diseases that can be broadly classified into ischemic and nonischemic etiologies, each requiring distinct diagnostic approaches. Noninvasive imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), play a pivotal role in the diagnosis, risk stratification, and prognosis of these conditions. This paper reviews the characteristic CT and MRI findings associated with ischemic cardiomyopathy (ICM) and nonischemic cardiomyopathy (NICM), focusing on their ability to provide detailed anatomical, functional, and tissue characterization. In ICM, CT and MRI reveal myocardial scarring, infarct size, and coronary artery disease, while MRI further distinguishes tissue viability through late gadolinium enhancement (LGE). Conversely, nonischemic cardiomyopathies demonstrate a wide array of findings, with MRI's LGE pattern analysis being particularly critical for identifying specific subtypes, such as restrictive, hypertrophic, or dilated cardiomyopathies. By comparing the strengths and limitations of these modalities, this paper highlights their complementary roles in improving diagnostic accuracy, risk stratification, prognosis, and therapeutic decision making in both ischemic and nonischemic cardiomyopathies.

Comparison of long-term outcomes in patients with cardiac sarcoidosis treated with different immunosuppressive drugs

BACKGROUND

We compared long-term clinical outcomes between patients with cardiac sarcoidosis (CS) who received no treatment (NT), steroid treatment (ST), disease-modifying anti-rheumatic drugs (DMARDs), or tumor necrosis factor alpha inhibitors (TNF).

METHODS

Patients from SSM healthcare system's data warehouse were identified using ICD codes. Inclusion criteria included at least 6 months of follow-up. Outcomes studied were heart failure (HF) admissions, ventricular tachyarrhythmias (VTA), and pacemaker/defibrillator placement. Statistical analysis included multivariate logistic regression and Kaplan-Meier curves.

RESULTS

We identified 198, 174, 66, and 19 patients in NT, ST, DMARDs, and TNF groups respectively. Mean age was 62.4, 60.2, 56, and 54.4 respectively. There was no significant difference in the rate of medical comorbidities including pulmonary sarcoidosis between the groups. Mean follow up was 92.3 months. Percent incidences of VTA were 17.5, 16.3, 12.5, and 5.6 (P 0.57) in the NT, ST, DMARDs and TNF groups respectively. DMARDs and TNF groups had a lower incidence of HF admission (43.9% and 36.8%) compared to NT and ST (59.1% and 59.2%). In the multivariate model, compared to NT group, the odds ratio for HF admission was 1.08 (CI: 0.70-1.65), 0.64 (0.36-1.14) and 0.45 (0.17-1.20) in the ST, DMARDs and TNF groups respectively. There was no significant difference in the rate of pacemaker/defibrillator placement between the groups.

CONCLUSION

In this retrospective study from a large healthcare system, CS patients treated with DMARDs or TNF had a trend for lower incidence of HF admission than those on NT or ST.

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.

Outcomes of definite vs probable/presumed cardiac sarcoidosis: a systematic review and meta-analysis

BACKGROUND

Diagnosing cardiac sarcoidosis (CS), which can be associated with arrhythmias and heart failure, remains challenging despite multiple advances over time. The 2014 Heart Rhythm Society (HRS) consensus statement recommends an endomyocardial biopsy (EMB) to establish a definite diagnosis of CS. In the absence of a positive EMB, a diagnosis of probable or presumed CS is made on the basis of clinical and imaging criteria.

OBJECTIVE

To investigate whether there is any difference in outcomes between definite vs probable/presumed CS.

METHODS

PubMed/MEDLINE, Embase, and the Cochrane Library databases were searched for relevant studies published after 2014. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using the random effects model and presented in forest plots.

RESULTS

6 studies involving 2,204 patients were identified. The cohort had a mean age of 56.8 years (SD: ±13.6 years). The median duration of follow-up was 40.5 months. No statistically significant difference was observed between definite and probable/presumed CS for reduced risk of the composite endpoint (RR: 1.80, 95% CI: 0.93 to 3.49), and all-cause death (RR: 1.01, 95% CI: 0.48 to 2.10).

CONCLUSION

This meta-analysis demonstrated the equivalence of clinical course and prognosis between definite and probable/presumed CS. This highlights the importance of a multi-disciplinary approach to CS care and emphasizes that histological confirmation should not be a prerequisite to diagnose or manage this condition.

Sarcoidosis Diagnostic Score (SDS) system: Impact of race, sex, organ involvement and duration of symptoms prior to diagnosis

BACKGROUND

The Sarcoidosis Diagnostic Score (SDS) system has been established for sarcoidosis patients based on the WASOG organ involvement criteria. We evaluated modifications of the SDS system to determine if they improved its the diagnostic accuracy.

METHODS

Biopsy-confirmed patients with sarcoidosis seen during a 7-month period at 9 sarcoidosis centers across the world. Patients with non-sarcoidosis seen at the same sites were served as control patients. Comparing the SDS-biopsy and SDS-clinical values of five groups: duration of symptoms prior to evaluation (≤1 years vs.>1 years, ≤2 years vs.>2 years), organ involvement (lung, eye, or cardiac), race, and sex.

RESULTS

A total of 990 patients with sarcoidosis and 1011 controls were included in this study. The SDS-clinical was significantly more discriminating for those undergoing assessment with symptoms for more than one year (z-statistic=2.570, p = 0.0102) or two years (z-statistic=2.546, p = 0.0109). However, the addition of two points for both >1 years and >2 years since onset of symptoms did not increase sensitivity and specificity of diagnosis with the SDS system. The SDS-clinical cut-off for patients with ocular or cardiac disease was two points higher than that for lung disease. There was no difference in SDS-clinical or biopsy AUC values based on gender or race.

CONCLUSIONS

The longer the duration of symptoms prior to diagnosis, the more likely the diagnosis of sarcoidosis was correct. For patients presenting with ocular or cardiac symptoms, evidence of multi-organ involved can improve the diagnostic accuracy of the SDS-clinical.

Case 331: Cardiac Sarcoidosis

HISTORY

A 43-year-old male patient with no known past medical history presented to the emergency department with new-onset bitemporal headache, dizziness, and bilateral lower extremity weakness for 1 day. The patient denied chest pain, shortness of breath, cough, or recent exposure to sick individuals. He was not on any medications and denied alcohol or illicit drug use. Vital signs were unremarkable. Physical examination was notable for a left-sided pronator drift and bilateral dysmetria that was more pronounced on the left. Results of routine laboratory workup, including complete blood count, metabolic panel, and high-sensitivity troponin level, were normal. An electrocardiogram revealed sinus tachycardia with a heart rate of 102 beats per minute, T-wave inversions in the inferior leads, left axis deviation, incomplete right bundle branch block, and frequent premature ventricular contractions. A radiograph of the chest was unremarkable. CT of the head without contrast enhancement demonstrated no acute intracranial abnormalities. MRI of the brain without contrast enhancement revealed multiple acute infarcts involving left posterior inferior cerebellar artery distribution, right cerebellar hemisphere, right mesial temporal lobe, and right posterior limb of the internal capsule. CT angiography of the head and neck showed an occlusion of the right posterior cerebral artery near its origin, with a trace of distal flow. Given that these findings were concerning for a cardioembolic etiology of acute ischemic stroke, transesophageal echocardiography was performed. This showed mild left ventricular systolic dysfunction with an ejection fraction of 40%, mild global hypokinesis, and an additional finding also seen at subsequent cardiac CT and MRI, disclosed herein. The patient was started on systemic anticoagulation and guideline-directed medical therapy for heart failure with reduced ejection fraction. CT of the chest showed no evidence of lymphadenopathy or abnormalities in the lung parenchyma or interstitium. Coronary CT angiography (CCTA) was performed, followed by cardiac MRI.

Cardiac sarcoidosis: diagnosis and management

Non-caseating granulomatous infiltration of the myocardium is the hallmark of cardiac sarcoidosis (CS). CS manifests clinically as conduction disturbance, ventricular arrhythmia, sudden cardiac death and/or heart failure with reduced ejection fraction. Other than confirmation through endomyocardial biopsy, a diagnosis of probable CS can be established by histological evidence of systemic sarcoidosis in addition to characteristic clinical or advanced imaging findings. Cardiac Magnetic Resonance imaging (CMR) and 18F-flurodeoxyglycose positron emission tomography (FDG-PET) are imaging modalities indispensable in the diagnosis and monitoring of CS. FDG-PET is the method of choice for identifying the active inflammatory phase of CS and in the monitoring and modifying of immunosuppressive treatment. CMR is better suited for assessing cardiac morphology and function. Both modalities are more effective in detecting CS when used in combination than either is alone. Management of CS is primarily based upon observational data of low quality due to a paucity of randomized controlled trials. Corticosteroid therapy and/or tiered-immunosuppression are the mainstays of treatment in reducing myocardial inflammation. Steroid-sparing agents aim to limit the unfavorable side-effects of a significant steroid burden. Antiarrhythmics and guideline-directed medical therapies are utilized for control of ventricular arrhythmia and left ventricular dysfunction respectively. CS necessitates multidisciplinary care in specialized centers to most effectively diagnose and manage the disease. Additional randomized trials are warranted to further our understanding of medical optimization in CS.

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.

Can FDG-PET Imaging Identify Cardiac Sarcoidosis Disease Phenotypes?

PURPOSE OF REVIEW

Despite the scarcity of data, most guidelines have advocated for the treatment of cardiac sarcoidosis with corticosteroids. However, there is heterogeneity in disease presentation and response to treatment, which can make treatment challenging. The ability to identify disease phenotypes to allow for tailored therapy is therefore highly desirable. This review will seek to outline the disease phenotypes of cardiac sarcoidosis and the role that FDG-PET imaging can play in identifying these phenotypes to optimize disease diagnosis and treatment management.

RECENT FINDINGS

FDG PET can identify cardiac sarcoidosis and is being increasingly used to monitor therapeutic response to immunosuppressive therapy, to follow treatment response after discontinuation of corticosteroid therapy, and to evaluate for disease relapse. Modern quantitative techniques using FDG PET imaging may allow for even better phenotypic disease characterization and the ability to track the response to immunosuppression more accurately. FDG PET currently plays an important role in cardiac sarcoidosis diagnosis. However, it also affords us the opportunity to offer insights into cardiac sarcoidosis disease phenotypes to better understand the underlying disease process and in the future may allows us to tailor therapies accordingly.

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.

Contemporary Diagnostics of Cardiac Sarcoidosis: The Importance of Multimodality Imaging

Sarcoidosis is an inflammatory condition that can affect multiple organ systems and is characterized by the formation of non-caseating granulomas in various organs, including the heart. Due to suboptimal diagnostic rates, the true prevalence and incidence of cardiac sarcoidosis (CS) remain to be determined. In patients with suspected CS, an initial examination should include 12-lead ECG or ambulatory ECG monitoring, and echocardiography with the estimation of LV, RV function, and strain rate. In patients with confirmed extracardiac sarcoidosis and with high clinical suspicion for CS, sophisticated imaging modalities, including cardiac MRI and PET, are indicated. Typical inflammation patterns and myocardial scarring should pose a high suspicion for CS. In patients without diagnosed extracardiac sarcoidosis and high clinical suspicion, although with low diagnostic probability, an endomyocardial biopsy should be considered to establish the diagnosis of definite isolated cardiac sarcoidosis. Timely diagnosis enables the initiation of therapy and close monitoring of adverse cardiac events that can be life-threatening, including sudden cardiac death, ventricular tachycardia, high-degree AV block, and heart failure. Implementing biomarkers in correlation to cardiac imaging can determine the disease's severity and progression but can also be helpful in following the treatment response. The formation of larger global registries can be helpful in the identification of independent predictors of adverse clinical events and the development of specific diagnostic algorithms to reduce the overall risk of this serious condition.

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.

Isolated cardiac sarcoidosis presenting as transient ischemic attack

Key clinical message

Isolated cardiac sarcoidosis may rarely present with TIA or stroke as an initial clinical manifestation. This case highlights the necessity of a broad differential and a high degree of suspicion for cardiac sarcoidosis in a patient with new neurologic symptoms and evidence of cardiac disease.

Abstract

Cardiac sarcoidosis is a rare disease with a variety of clinical manifestations including heart failure and sudden death. Stroke as the earliest sign of disease has been described in rare cases. We present a case of a 54-year-old female with recurrent transient ischemic attacks (TIAs) of unknown etiology, initially in the absence of left ventricular dysfunction. Cardiomyopathy was later identified on echocardiography after a second TIA. Cardiac MRI was remarkable for focal left ventricular wall thinning with akinesis and dyskinesis of multiple wall segments, a right ventricular aneurysm, and diffuse myocardial late gadolinium enhancement. PET/CT showed multifocal areas of myocardial FDG uptake. At follow-up, echocardiography showed a left ventricular apical thrombus, in a previously identified thinned, akinetic region, suggesting cardioembolic origin for previous TIAs. She was started on anticoagulation therapy, prednisone, methotrexate, and adalimumab, with resolution of the thrombus and improvement in cardiac function. In conclusion, this case highlights the need to consider CS as a potential cause of cerebrovascular ischemic events in patients with few stroke risk factors but findings indicative of cardiac disease. It is essential to further explore the mechanisms behind these events and develop treatments that target their causes in this patient population.

Isolated Cardiac Sarcoidosis Presenting as High-Degree Atrioventricular Block

Isolated cardiac sarcoidosis is a rare phenomenon of systemic sarcoidosis, with presentation ranging from asymptomatic to sudden cardiac death. Controversy exists on diagnostic and therapeutic options, creating an ongoing challenge for clinicians in providing patient care. A 79-year-old male presented status post looposcopy and interval ureteral stent replacement with sinus bradycardia and high-degree atrioventricular block. A comprehensive examination was performed that conclusively ruled out common etiologies of atrioventricular block, including coronary artery disease, electrolyte abnormalities, and medications. This prompted an investigation using advanced cardiac imaging modalities that demonstrated cardiac sarcoidosis. Computed tomography of the chest was negative for lymphadenopathy or infiltrates indicative of pulmonary involvement. The lack of extracardiac manifestations, in combination with imaging findings, led to a probable diagnosis of isolated cardiac sarcoidosis. The patient underwent biventricular implantable cardioverter defibrillator placement and was started on oral corticosteroids.

Diagnostic and management strategies in cardiac sarcoidosis

Cardiac sarcoidosis (CS) is increasingly recognized in the context of with otherwise unexplained electrical or structural heart disease due to improved diagnostic tools and awareness. Therefore, clinicians require improved understanding of this rare but fatal disease to care for these patients. The cardinal features of CS, include arrhythmias, atrio-ventricular conduction delay and cardiomyopathy. In addition to treatments tailored to these cardiac manifestations, immunosuppression plays a key role in active CS management. However, clinical trial and consensus guidelines are limited to guide the use of immunosuppression in these patients. This review aims to provide a practical overview to the current diagnostic challenges, treatment approach, and future opportunities in the field of CS.

Circulating Mitochondrial DNA Is Associated With High Levels of Fatigue in Two Independent Sarcoidosis Cohorts

BACKGROUND

Patients with sarcoidosis who develop severe clinical phenotypes of pulmonary fibrosis or multiorgan disease experience debilitating symptoms, with fatigue being a common chief complaint. Studies that have investigated this patient-related outcome measure (PROM) have used the Fatigue Assessment Scale (FAS), a self-reported questionnaire that reflects mental and physical domains. Despite extensive work, its cause is unknown and treatment options remain limited. Previously, we showed that the plasma of patients with sarcoidosis with extrapulmonary disease endorsing fatigue was enriched for mitochondrial DNA (mtDNA), a ligand for the innate immune receptor toll-like receptor 9 (TLR9). Through our cross-disciplinary platform, we investigated a relationship between sarcoidosis-induced fatigue and circulating mtDNA.

RESEARCH QUESTION

Is there a psychobiologic mechanism that connects sarcoidosis-induced fatigue and mtDNA-mediated TLR9 activation?

STUDY DESIGN AND METHODS

Using a local cohort of patients at Yale (discovery cohort) and the National Institutes of Health-sponsored Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis study (validation cohort), we scored the FAS and quantified in the plasma, mtDNA concentrations, TLR9 activation, and cytokine levels.

RESULTS

Although FAS scores were independent of corticosteroid use and Scadding stage, we observed a robust association between FAS scores, which included mental and physical domains, and multiorgan sarcoidosis. Subsequently, we identified a significant correlation between plasma mtDNA concentrations and all domains of fatigue. Additionally, we found that TLR9 activation is associated with all aspects of the FAS and partially mediates this PROM through mtDNA. Last, we found that TLR9-associated soluble mediators in the plasma are independent of all facets of fatigue.

INTERPRETATION

Through our cross-disciplinary translational platform, we identified a previously unrecognized psychobiologic connection between sarcoidosis-induced fatigue and circulating mtDNA concentrations. Mechanistic work that investigates the contribution of mtDNA-mediated innate immune activation in this PROM and clinical studies with prospective cohorts has the potential to catalyze novel therapeutic strategies for this patient population and those with similar conditions.

FDG-PET/CT and rest myocardial perfusion imaging to predict high-degree atrioventricular block recovery in cardiac sarcoidosis

BACKGROUNDS

High-degree atrioventricular block (AVB) recovery in CS has been shown to be highly variable despite immunosuppressive treatment, with no reliable tool available to predict odds of reversibility. This study sought to evaluate the potential of combined fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and resting myocardial perfusion imaging (rMPI) to predict reversibility of newly diagnosed high-grade AVB in cardiac sarcoidosis (CS).

METHODS

We performed a single-center, retrospective analysis of patients with CS presenting with high-grade AVB who underwent combined FDG-PET/CT and rMPI. The 2016 JCS and the 2014 HRS diagnostic criteria were used for the diagnosis of CS. Patients with a history of coronary artery disease or prior immunosuppressive treatment were excluded. Patients were divided into AVB recovery and non-recovery subgroups. CS disease staging was based on FDG-PET and rMPI findings: (Stage 0) normal FDG-PET and rMPI (Stage 1) positive FDG-PET and normal rMPI (Stage 2) positive FDG-PET with perfusion deficits on rMPI (Stage 3) normal FDG-PET with perfusion deficits on rMPI.

RESULTS

Twenty-seven patients, including 13 demonstrating AVB recovery, were identified. Eleven out of fourteen (78.6%) patients presenting with stage 1 CS demonstrated AVB recovery. Stage 1 CS was significantly more present in the recovery group compared to the non-recovery group (84.6% vs 21.4%, P = .002). Eleven presented with stage 2 CS, with only 2 (18.2%) recovering AV nodal conduction. Stage 2 CS presented more frequently in the non-recovery group (64.3% vs 15.4%, P = .020).

CONCLUSIONS

Combined FDG-PET and rMPI employed to stage CS disease presenting with high-degree AVB appears to have good performance for predicting likelihood of recovery.

Complete resolution of focal-on-diffuse myocardial activity pattern on FDG PET-CT by prolonging the dietary preparation protocol in cardiac sarcoidosis

Patient preparation is crucial for reliable interpretation of cardiac inflammation FDG PET. We share our experience of improved reporting confidence and propose a simple approach of prolonging preparation (from 24 to 48 hours) with the high-fat, no-carbohydrate, and protein-permitted diet followed by fasting in cardiac sarcoidosis in cases with diffuse or focal-on-diffuse myocardial FDG uptake.

Establishing a Diagnosis of Pulmonary Sarcoidosis

Pulmonary sarcoidosis is the most prevalent manifestation of sarcoidosis and the commonest diagnosis in clinics for ILD. Due to the lack of a simple and reliable test, making the diagnosis is often challenging. There are three criteria that must always be considered: (1) compatible clinical presentation; (2) evidence of granuloma formation (usually non-caseating); and (3) exclusion of alternative causes of granulomatous disease. There are various tools available for diagnosis, amongst which serum biomarkers like sACE and sIL-2R, HRCT, BAL, EBUS/EUS and sometimes bronchoscopic or surgical lung biopsy are most contributive. However, the degree of invasiveness of the applied test and associated risk to the patient must be weighed against management consequences. In specific situations (e.g., presentation as Löfgren's syndrome) or when there is high suspicion based on HRCT in the context of supportive clinical findings, it might be justifiable to decide on a "working diagnosis of sarcoidosis" and to refrain from further invasive procedures for the patient. This should, however, preferably be agreed upon after discussion in an experienced multidisciplinary team and requires close follow-up of the patient. In general, it is advisable to always maintain a healthy dose of skepticism when making the diagnosis of sarcoidosis, especially when the clinical course of disease gives rise to this.

Re-evaluating serum angiotensin-converting enzyme in sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology, which mainly affects the lungs and lymph nodes, as well as extrapulmonary organs. Its incidence, and prevalence rate, and disease course largely vary with regions and populations globally. The clinical manifestations of sarcoidosis depend on the affected organs and the degree of severity, and the diagnosis is mainly based on serum biomarkers, radiographic, magnetic resonance, or positron emission tomography imaging, and pathological biopsy. Noncaseating granulomas composing T cells, macrophages, epithelioid cells, and giant cells, were observed in a pathological biopsy, which was the characteristic pathological manifestation of sarcoidosis. Angiotensin-converting enzyme (ACE) was first found in the renin-angiotensin-aldosterone system. Its main function is to convert angiotensin I (Ang I) into Ang II, which plays an important role in regulating blood pressure. Also, an ACE insertion/deletion polymorphism exists in the human genome, which is involved in the occurrence and development of many diseases, including hypertension, heart failure, and sarcoidosis. The serum ACE level, most commonly used as a biomarker in diagnosing sarcoidosis, in patients with sarcoidosis increases. because of epithelioid cells and giant cells of sarcoid granuloma expressing ACE. Thus, it serves as the most commonly used biomarker in the diagnosis of sarcoidosis and also aids in analyzing its therapeutic effect and prognosis in patients with sarcoidosis.

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.

Update on cardiac sarcoidosis

Cardiac sarcoidosis is an inflammatory myocardial disease of unknown etiology. It is characterized by the deposition of non-caseating granulomas that may involve any part of the heart. Cardiac sarcoidosis is often under-diagnosed or recognized partly due to the heterogeneous clinical presentation of the disease. The three most frequent clinical manifestations of cardiac sarcoidosis are atrioventricular block, ventricular arrhythmias, and heart failure. A definitive diagnosis of cardiac sarcoidosis can be made with histology findings from an endomyocardial biopsy. However, the diagnosis in the majority of cases is based on findings from the clinical presentation and advanced imaging due to the low sensitivity of endomyocardial biopsy. The Heart Rhythm Society (HRS) 2014 expert consensus statement and the Japanese Ministry of Health and Welfare criteria are the two most commonly used diagnostic criteria sets. This review article summarizes the available evidence on cardiac sarcoidosis, focusing on the diagnostic criteria and stepwise approach to its management.

Incidence and Predictors of Relapse After Weaning Immune Suppressive Therapy in Cardiac Sarcoidosis

Cardiac sarcoidosis (CS) is a relapsing-remitting disease, and immune suppression (IS) is the mainstay of therapy. Predictors of relapse for patients with CS in remission are not well characterized. We assessed incidence of relapse in consecutive patients with CS treated with high-dose steroids and/or steroid-sparing agents (SSA) in our center from 2000 to 2020. Remission was defined as reaching maintenance therapy (no IS, SSA, and/or prednisone ≤5 mg/d) for ≥1 month. Relapse was defined as recurrence of CS syndrome requiring IS intensification: heart failure, ventricular arrhythmia, decrease in left ventricular ejection fraction, or increased disease burden on imaging. Among 68 patients, the mean age was 50.7±9.0 years; 25 (37%) were women, and 32 (47%) were Black. In total, 59 patients (87%) reached remission. Over a median follow-up of 39.5 months (interquartile range 17.6, 92.5), 28 (48%) relapsed. Greater percentage of late gadolinium enhancement (LGE) on pretreatment magnetic resonance imaging corresponded with increased likelihood of relapse (odds ratio 1.396 per 5% increase [95% confidence interval (CI) 1.04 to 1.88]; p = 0.028). LGE ≥11% predicted elevated risk of relapse (adjusted odds ratio 4.998 [1.34 to 18.64]; p = 0.017). Shorter time to relapse was observed with isolated CS (adjusted hazard ratio 4.084 [1.44,11.56]; p = 0.008) and LGE ≥11% (adjusted hazard ratio 3.007 [1.01, 8.98]; p = 0.049). Approximately 1 in 2 patients with CS in remission experienced relapse. Greater burden of LGE on cardiac magnetic resonance imaging and isolated CS are associated with greater risk of relapse. Future work is needed to refine risk stratification for relapse and to optimize surveillance strategies on the basis of the burden of disease.

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.

Prognostic Implications of Sarcoidosis Granulomas - Insights From the Multicenter Registry, the Japanese Cardiac Sarcoidosis Prognostic Study

Background: Definitions of cardiac sarcoidosis (CS) differ among guidelines. Any systemic histological finding of CS is essential for the diagnosis of CS in the 2014 Heart Rhythm Society statement, but not necessary in the Japanese Circulation Society 2016 guidelines. This study aimed to reveal the differences in outcomes by comparing 2 groups, namely CS patients with or without systemic histologically proven granuloma. Methods and Results: This study retrospectively included 231 consecutive patients with CS. CS with granulomas in ≥1 organs was diagnosed in 131 patients (Group G), whereas CS without any granulomas was diagnosed in the remaining 100 patients (Group NG). Left ventricular ejection fraction (LVEF) was significantly reduced in Group NG compared with Group G (44±13% vs. 50±16%, respectively; P=0.001). However, Kaplan-Meier curves showed that major adverse cardiovascular events (MACE)-free survival outcomes were comparable between the 2 groups (log-rank P=0.167). Univariable analyses showed that significant predictors of MACE were Groups G/NG, histological CS, LVEF, and high B-type natriuretic peptide (BNP) or N-terminal pro BNP concentrations, but none of these was significant in multivariable analyses. Conclusions: Overall risks of MACE were similar between the 2 groups despite different manifestations in cardiac dysfunction. The data not only validate the prognostic value of non-invasive diagnosis of CS, but also show the need for careful observation and therapeutic strategy in patients with CS without any granuloma.

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.

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.

Clinical Utilization of Multimodality Imaging for Myocarditis and Cardiac Sarcoidosis

Myocarditis is defined as inflammation of the myocardium according to clinical, histological, biochemical, immunohistochemical, or imaging findings. Inflammation can be categorized histologically by cell type or pattern, and many causes have been implicated, including infectious, most commonly viral, systemic autoimmune diseases, vaccine-associated processes, environmental factors, toxins, and hypersensitivity to drugs. Sarcoid myocarditis is increasingly recognized as an important cause of cardiomyopathy and has important diagnostic, prognostic, and therapeutic implications in patients with systemic sarcoidosis. The clinical presentation of myocarditis may include an asymptomatic, subacute, acute, fulminant, or chronic course and may have focal or diffuse involvement of the myocardium depending on the cause and time point of the disease. For most causes of myocarditis except sarcoidosis, myocardial biopsy is the gold standard but is limited due to risk, cost, availability, and variable sensitivity. Diagnostic criteria have been established for both myocarditis and cardiac sarcoidosis and include clinical and imaging findings particularly the use of cardiac magnetic resonance and positron emission tomography. Beyond diagnosis, imaging findings may also provide prognostic value. This case-based review focuses on the current state of multimodality imaging for the diagnosis and management of myocarditis and cardiac sarcoidosis, highlighting multimodality imaging approaches with practical clinical vignettes, with a discussion of knowledge gaps and future directions.

Sarcoid Heart Disease: Review of Current Knowledge

Sarcoidosis is a granulomatous disease with the potential of multiple organ system involvement and its etiology remains unknown. Cardiac involvement is associated with worse clinical outcome, and has been reported to be 20-30% in white and as high as 58% in Japanese populations with sarcoidosis. Clinical manifestations of cardiac sarcoidosis highly depend on the extent and location of granulomatous inflammation. The most frequent presentations include heart block, tachyarrhythmia, or heart failure. Endomyocardial biopsy is the most specific diagnostic test, but has poor sensitivity due to often patchy involvement. The diagnosis of cardiac sarcoidosis remains challenging due to nonspecific imaging findings. Both 18 F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and cardiac magnetic resonance imaging can be used to evaluate cardiac sarcoidosis, but evaluate different stages of the disease process. FDG-PET detects metabolically active inflammatory cells while cardiac magnetic resonance imaging with late gadolinium enhancement reveals areas of myocardial necrosis and fibrosis. Aggressive therapy of symptomatic cardiac sarcoidosis is often sought due to the high risk of sudden death and/or progression to heart failure. Prednisone 20-40 mg a day is the recommended initial treatment. In refractory or severe cases, higher doses of prednisone, 1-1.5 mg/kg/d (or its equivalent) and addition of a steroid-sparing agent have been utilized. Methotrexate is added most commonly. Long-term improvement has been reported with the use of a combination of weekly methotrexate and prednisone versus prednisone alone. After initiation of treatment, a cardiac FDG-PET scan may be performed 2-3 months later to assess treatment response.

Unexpected Case of Cardiac Sarcoidosis in a Caucasian Male

Cardiac sarcoidosis (CS) is an underappreciated diagnosis in healthy patients presenting with recurrent syncope. This may be particularly limited in patients who do not meet common epidemiology and manifestations of sarcoidosis, which are typically African American women and pulmonary, respectively. In our case, we have a previously healthy middle-aged Caucasian American male who presented with recurrent syncope for one week. Initial electrocardiogram showed a right bundle branch block with a normal P-R interval. A few days into the admission, the patient suffered another episode of syncope precipitated by micturition, and repeat electrocardiogram revealed evolution to complete atrioventricular block, necessitating emergent placement of a temporary permanent pacemaker. Transthoracic echocardiogram showed preserved left ventricular ejection fraction of 55%-60% with normal heart valves. Chest computerized tomography revealed few pulmonary nodules, prompting a weak concern for infiltrative disease, e.g., sarcoidosis. To evaluate for possible cardiac structural abnormalities, a cardiac magnetic resonance imaging (MRI) study was considered but precluded by the presence of MRI-incompatible temporary pacemaker. Despite low suspicion, a fluorodeoxyglucose-positron emission tomography was obtained which unexpectedly revealed hypermetabolic lymph nodes in the perihilar, supraclavicular, and mediastinal regions as well as an area along the interventricular septum, consistent with atrioventricular (AV) conduction pathways. As the patient met major criteria for CS per Japanese Circulation Society guidelines, a tentative diagnosis was made, and a Biotronik single-chamber implantable cardiac defibrillator was ultimately placed. On outpatient follow-up, endobronchial ultrasound-guided fine-needle biopsy of perihilar lymph nodes revealed only rare epithelioid histiocytes, rare alveolar macrophages, and benign bronchial cells, consistent with benign nodal tissue. Further attempts for histological confirmation were aborted due to profound calcification and location of affected lymph nodes. A decision was made to defer further biopsy, including the gold standard of diagnosis endomyocardial biopsy, due to the risks outweighing the benefits. He initiated medical therapy with prednisone and mycophenolate, as well as trimethoprim-sulfamethoxazole for Pneumocystis prophylaxis. Unlike general sarcoidosis, which is often considered a benign systemic disease, CS has high potential for severe complications including arrhythmia, systolic heart failure, and sudden cardiac death. In general, males carry a higher risk of CS than females, especially those who are of African American descent as they carry a higher incidence of nonspecific sarcoidosis. Expectations related to our patient's demographic initially delayed diagnostic workup for infiltrative disease, primarily focusing on intracranial, orthostatic, and infectious causes. This case report serves to inform clinicians on early manifestations of CS, raise awareness of its incidence in unexpected demographics, and encourage them to consider infiltrative diseases when presented with patients of similar symptoms.

Effect of Immunosuppressive Therapy and Biopsy Status in Monitoring Therapy Response in Suspected Cardiac Sarcoidosis

BACKGROUND

Patients with suspected cardiac sarcoidosis frequently undergo fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) imaging to assess disease activity at baseline and after treatment initiation.

OBJECTIVES

This study investigated the effect of immunosuppressive therapy and biopsy status to achieve complete treatment response (CTR), partial treatment response (PTR), or no response (NR) on myocardial FDG-PET/CT.

METHODS

This study analyzed 83 patients with suspected cardiac sarcoidosis (aged 53 ± 1.8 years, 71% were male, 69% were White, 61% had a history of biopsy-confirmed sarcoidosis) who were treatment naive, had evidence of myocardial FDG at baseline, and underwent repeat PET imaging after treatment initiation. CTR was graded visually, and PTR/NR were measured both visually and quantitatively using the total glycolytic activity. Patients were also evaluated for the occurrence of death, sustained ventricular arrhythmias, and heart failure admissions.

RESULTS

Overall, 59 patients (71%) achieved CTR/PTR (30%/41%) at follow-up scan (P = 0.04). Total glycolytic activity and visual estimate of PTR/NR had excellent agreement (κ = 0.86 [95% CI: 0.72-0.99]; P < 0.0001). In patients receiving prednisone only, the highest rates of CTR/PTR were observed in patients initiated on moderate or high dose (P < 0.01). In a regression model, moderate prednisone start dose (P = 0.03) was more strongly associated with achieving CTR/PTR than was high prednisone start dose. However, the latter patients were tapered faster between start dose and follow-up scan (P < 0.01). After a median follow-up of 4.7 (IQR: 3.1-7.8) years, patients who were biopsy-proven (vs non-biopsy-proven; P = 0.029) and with preserved left ventricular function (P = 002) were less likely to experience major adverse cardiac events. Outcomes based on treatment response status (CTR vs PTR vs NR; P = 0.23) were not significantly different.

CONCLUSIONS

Among patients with suspected sarcoidosis and evidence of myocardial inflammation, treatment response by serial FDG-PET was variable, but a favorable response was more common when using moderate-to-high intensity prednisone dose. Biopsy-proven individuals and those with preserved systolic function were less likely to experience adverse outcomes during follow-up.

Kardiale MRT bei nichtischämischen Kardiomyopathien

Hintergrund

Die in Deutschland angewandte Einteilung der Kardiomyopathien geht auf die Klassifikation der Europäischen Gesellschaft für Kardiologie (ESC) von 2008 zurück. Dort werden sie nach ihrem Phänotyp unterteilt, so dass die Magnetresonanztomographie (MRT) in der Lage ist, die unterschiedlichen Kardiomyopathien zu differenzieren.

Bildgebung und Differenzialdiagnostik

Die Stärke der MRT ist es, anhand der Möglichkeiten der Gewebsdifferenzierung nichtischämische Kardiomyopathien von anderen Erkrankungen mit ähnlichen morphofunktionellen Aspekten zu differenzieren. So gelingt im Fall der dilatativen Kardiomyopathie (DCM) eine Differenzierung zur inflammatorischen DCM. Im Fall der hypertrophen Kardiomyopathie (HCM) kann analog zur Echographie eine obstruktive und nichtobstruktive Form differenziert werden, aber auch die Detektion einer Amyloidose oder eines Morbus Fabry ist möglich. Die Evaluation der rechtsventrikulären Funktion gelingt im Rahmen einer arrhythmogenen rechtsventrikulären Kardiomyopathie (ARVC) zuverlässig. Außerdem ist die MRT in der Lage, die charakteristische fettige Ersatzfibrose direkt nachzuweisen. Bei den seltenen restriktiven Kardiomyopathien kann sie die Restriktion nachvollziehen und z. B. mittels T1-, T2- und T2*-Mapping die Sphingolipid-Akkumulation im Myokard bei einem Morbus Fabry oder eine Eisenüberladung bei Hämochromatose nachvollziehen.

Innovationen

Die quantitativen Verfahren des parametrischen Mappings bieten die Möglichkeit eines Therapiemonitorings; die klinische Relevanz dieses Monitorings ist aber noch Gegenstand aktueller Forschung. Die unklassifizierten Kardiomyopathien können sich klinisch mit ähnlicher Symptomatik wie ischämische oder inflammatorische Erkrankungen präsentieren, so dass im Fall eines Myokardinfarkts ohne verschlossene Koronararterien („myocardial infarction without obstructive coronary arteries“, MINOCA) in der Herzkatheteruntersuchung die MRT ein entscheidendes diagnostisches Instrument ist, um die tatsächlich zugrundeliegende Erkrankung festzustellen. Gleichermaßen kann sie bei neuen Kardiomyopathien wie der Non-compaction-Kardiomyopathie der Wegbereiter für eine morphologische Krankheitsdefinition sein.

Isolated Cardiac Sarcoidosis Presenting as Torsades de Pointes in a Patient With Non-ischemic Cardiomyopathy: A Case Report

Sarcoidosis is an immune-mediated, inflammatory, non-caseating-granulomatous disease that can virtually infiltrate any organ. Cardiac sarcoidosis is a leading cause of death in patients with sarcoidosis. Its clinical presentation is highly heterogenous and unpredictable, ranging from asymptomatic to life-threatening conduction disturbances, such as ventricular arrhythmias, and heart failure. Herein, we report a case of isolated cardiac sarcoidosis presenting as sinus bradycardia with first-degree atrioventricular block and an episode of non-sustained polymorphic ventricular tachycardia in a 42-year-old male with non-ischemic cardiomyopathy. He was diagnosed by cardiac magnetic resonance imaging and positron emission tomography with fluorodeoxyglucose and treated with oral prednisone.