Review: Contrast-enhanced magnetic resonance in the diagnosis and management of cardiac sarcoidosis

Arrhythmias in Cardiac Sarcoidosis: Management and Prognostic Implications

Cardiac sarcoidosis (CS) is characterized by various arrhythmic manifestations ranging from catastrophic sudden cardiac death secondary to ventricular arrhythmia, severe conduction disease, sinus node dysfunction, and atrial fibrillation. The management of CS is complex and includes not only addressing the arrhythmia but also controlling the myocardial inflammation resultant from the autoimmune reaction. Arrhythmic manifestations of CS carry significant prognostic implications and invariably affect long-term survival in these patients. In this review, we focus on management of arrhythmic manifestation of cardiac sarcoidosis as well as risk stratification for sudden cardiac death in these patients.

Prevalence of Cardiac Sarcoidosis in Middle-Aged Adults Diagnosed with High-Grade Atrioventricular Block

INTRODUCTION

Atrioventricular block may be idiopathic or a secondary manifestation of an underlying systemic disease. Cardiac sarcoidosis is a significant underlying cause of high-grade atrioventricular block, posing diagnostic challenges and significant clinical implications. This study aimed to assess the prevalence and clinical characteristics of cardiac sarcoidosis among younger patients presenting with unexplained high-grade atrioventricular block.

METHODS

We evaluated patients aged between 18 and 65 years presenting with unexplained high-grade atrioventricular block, who were systematically referred for cardiac magnetic resonance imaging, positron emission tomography-computed tomography, or both, prior to pacemaker implantation. Subjects with suspected cardiac sarcoidosis based on imaging findings were further referred for tissue biopsy. Cardiac sarcoidosis diagnosis was confirmed based on biopsy results.

RESULTS

Overall, 30 patients with high-grade atrioventricular block were included in the analysis. The median age was 56.5 years (interquartile range 53-61.75, years). In 37%, cardiac magnetic resonance imaging, positron emission tomography-computed tomography, or both, were suggestive of cardiac sarcoidosis, and in 33% cardiac sarcoidosis was confirmed by tissue biopsy. Compared with idiopathic high-grade atrioventricular block patients, all cardiac sarcoidosis patients were males (100% vs 60%, P = .029), were more likely to present with heart failure symptoms (50% vs 10%, P = .047), had thicker inter-ventricular septum on echocardiography (12.2 ± 2.7 mm vs 9.45 ± 1.6 mm, P = .002), and were more likely to present with right ventricular dysfunction (33% vs 10%, P = .047).

CONCLUSIONS

Cardiac sarcoidosis was confirmed in one-third of patients ≤ 65 years, who presented with unexplained high-grade atrioventricular block. Cardiac sarcoidosis should be highly suspected in such patients, particularly in males who present with heart failure symptoms or exhibit thicker inter-ventricular septum and right ventricular dysfunction on echocardiography.

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.

Cardiac magnetic resonance in giant cell myocarditis: a matched comparison with cardiac sarcoidosis

AIMS

Giant cell myocarditis (GCM) is an inflammatory cardiomyopathy akin to cardiac sarcoidosis (CS). We decided to study the findings of GCM on cardiac magnetic resonance (CMR) imaging and to compare GCM with CS.

METHODS AND RESULTS

CMR studies of 18 GCM patients were analyzed and compared with 18 CS controls matched for age, sex, left ventricular (LV) ejection fraction and presenting cardiac manifestations. The analysts were blinded to clinical data. On admission, the duration of symptoms (median) was 0.2 months in GCM vs. 2.4 months in CS (P = 0.002), cardiac troponin T was elevated (>50 ng/L) in 16/17 patients with GCM and in 2/16 with CS (P < 0.001), their respective median plasma B-type natriuretic propeptides measuring 4488 ng/L and 1223 ng/L (P = 0.011). On CMR imaging, LV diastolic volume was smaller in GCM (177 ± 32 mL vs. 211 ± 58 mL, P = 0.014) without other volumetric or wall thickness measurements differing between the groups. Every GCM patient had multifocal late gadolinium enhancement (LGE) in a distribution indistinguishable from CS both longitudinally, circumferentially, and radially across the LV segments. LGE mass averaged 17.4 ± 6.3% of LV mass in GCM vs 25.0 ± 13.4% in CS (P = 0.037). Involvement of insertion points extending across the septum into the right ventricular wall, the "hook sign" of CS, was present in 53% of GCM and 50% of CS.

CONCLUSION

In GCM, CMR findings are qualitatively indistinguishable from CS despite myocardial inflammation being clinically more acute and injurious. When matched for LV dysfunction and presenting features, LV size and LGE mass are smaller in GCM.

Prognostic Value of Late Gadolinium Enhancement Detected on Cardiac Magnetic Resonance in Cardiac Sarcoidosis

BACKGROUND

Sarcoidosis is a complex multisystem inflammatory disorder, with approximately 5% of patients having overt cardiac involvement. Patients with cardiac sarcoidosis are at an increased risk of both ventricular arrhythmias and sudden cardiac death. Previous studies have shown that the presence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is associated with an increased risk of mortality and ventricular arrhythmias and may be useful in predicting prognosis.

OBJECTIVES

This systematic review and meta-analysis assessed the value of LGE on CMR imaging in predicting prognosis for patients with known or suspected cardiac sarcoidosis.

METHODS

The authors searched the Embase and MEDLINE databases from inception to March 2022 for studies reporting individuals with known or suspected cardiac sarcoidosis referred for CMR with LGE. Outcomes were defined as all-cause mortality, ventricular arrhythmia, or a composite outcome of either death or ventricular arrhythmias. The primary analysis evaluated these outcomes according to the presence of LGE. A secondary analysis evaluated outcomes specifically according to the presence of biventricular LGE.

RESULTS

Thirteen studies were included (1,318 participants) in the analysis, with an average participant age of 52.0 years and LGE prevalence of 13% to 70% over a follow-up of 3.1 years. Patients with LGE on CMR vs those without had higher odds of ventricular arrhythmias (odds ratio [OR]: 20.3; 95% CI: 8.1-51.0), all-cause mortality (OR: 3.45; 95% CI: 1.6-7.3), and the composite of both (OR: 9.2; 95% CI: 5.1-16.7). Right ventricular LGE is invariably accompanied by left ventricular LGE. Biventricular LGE is also associated with markedly increased odds of ventricular arrhythmias (OR: 43.6; 95% CI: 16.2-117.2).

CONCLUSIONS

Patients with known or suspected cardiac sarcoidosis with LGE on CMR have significantly increased odds of both ventricular arrhythmias and all-cause mortality. The presence of biventricular LGE may confer additional prognostic information regarding arrhythmogenic risk.

The role of late gadolinium enhancement in predicting arrhythmic events in cardiac sarcoidosis patients - a mini-review

Sarcoidosis is a multisystem inflammatory disorder with an unknown origin. Symptomatic cardiac involvement is rare and occurs in about 5% of patients with sarcoidosis. Fatal ventricular arrhythmias are the most severe clinical presentation of the disease. Cardiac magnetic resonance (CMR) is a useful non-invasive tool for the risk stratification of ventricular arrhythmias and sudden cardiac death (SCD) in patients with cardiac sarcoidosis (CS). More specifically, late gadolinium enhancement (LGE), a CMR tool for scar detection, has been found to be significantly associated with arrhythmic events in CS patients. This review aims to present the existing evidence regarding the association of LGE with adverse events and especially with fatal ventricular arrhythmias.

Feasibility of Hepatic T1-Mapping and Extracellular Volume Quantification on Routine Cardiac Magnetic Resonance Imaging in Patients with Infiltrative and Systemic Disorders

RATIONALE AND OBJECTIVES

Cardiac magnetic resonance imaging (CMR) is commonly obtained to evaluate for myocardial infiltrative disorders and fibrosis. Pre- and post-Gadolinium contrast T1-mapping sequences are employed to estimate interstitial expansion using extracellular volume fraction (ECV). Given the proximity of the liver to the heart, T1 and ECV quantification of the liver is feasible on CMR. The purpose of this study was to evaluate for hepatic measures of fibrosis and interstitial expansion in patients with amyloidosis or systemic disease on CMR.

MATERIALS AND METHODS

Myocardial and hepatic native T1 values were measured retrospectively using a cardiac short axis modified Look-Locker inversion recovery sequence. Myocardial and hepatic ECV were calculated using pre- and post-contrast T1 and blood pool values according to the following formula: ECV = (Δ(1/T1) myocardium or liver and/or Δ(1/T1) blood)x(1 - hematocrit). Patients were divided into three cohorts by final diagnosis: amyloidosis, systemic disease (e.g. sarcoid, scleroderma), and controls (EF > 50, no ischemia).

RESULTS

Of the 135 patients who underwent CMR, 22 had cardiac amyloidosis (age 59.9 ± 12.6 yrs, 41% female), 20 had systemic disease (age 50.9 ± 13.4 yrs, 35% female), and 93 were controls (age 49.5 ± 17.3 yrs, 50% female). Myocardial T1 and ECV values were highest for patients with amyloid, second highest for systemic disease, and least for controls (T1: 1169 ± 92 vs 1101 ± 53 vs 1027 ± 73 ms, p < 0.0001; ECV: 0.47 ± 0.11 vs 0.31 ± 0.05 vs 0.27 ± 0.04, p < 0.0001). Hepatic T1 and ECV were similarly higher in patients with amyloid and systemic disease compared to controls (T1: 646 ± 101 vs 660 ± 93 vs 595 ± 58 ms, p < 0.0001; ECV: 0.38 ± 0.08 vs 0.37 ± 0.05 vs 0.31 ± 0.03, p < 0.0001). There was a positive correlation between hepatic T1 and ECV (R² = 0.282, p < 0.0001). No patients had abnormal liver function tests or clinical liver disease.

CONCLUSION

Hepatic ECV quantification on CMR in patients with amyloidosis and systemic disorders is feasible. Further longitudinal investigation regarding detection of early or subclinical liver disease is warranted.

Histology of Cardiac Sarcoidosis with Novel Considerations Arranged upon a Pathologic Basis

Sarcoidosis is a rare disease of isolated or diffuse granulomatous inflammation. Although any organs can be affected by sarcoidosis, cardiac sarcoidosis is a fatal disorder, and it is crucial to accurately diagnose it to prevent sudden death due to dysrhythmia. Although endomyocardial biopsy is invasive and has limited sensitivity for identifying granulomas, it is the only modality that yields a definitive diagnosis of cardiac sarcoidosis. It is imperative to develop novel pathological approaches for the precise diagnosis of cardiac sarcoidosis. Here, we aimed to discuss commonly used diagnostic criteria for cardiac sarcoidosis and to summarize useful and novel histopathologic criteria of cardiac sarcoidosis. While classical histologic observations including noncaseating granulomas and multinucleated giant cells (typically Langhans type) are the most important findings, others such as microgranulomas, CD68⁺ CD163^- pro-inflammatory (M1) macrophage accumulation, CD4/CD8 T-cell ratio, Cutibacterium acnes components, lymphangiogenesis, confluent fibrosis, and fatty infiltration may help to improve the sensitivity of endomyocardial biopsy for detecting cardiac sarcoidosis. These novel histologic findings are based on the pathology of cardiac sarcoidosis. We also discussed the principal histologic differential diagnoses of cardiac sarcoidosis, such as tuberculosis myocarditis, fungal myocarditis, giant cell myocarditis, and dilated cardiomyopathy.

Cardiac Sarcoidosis: A Clinical Overview

Cardiac sarcoidosis (CS) with clinical manifestation occurs in about 5-8% of patients with sarcoidosis. CS may be clinically suspected by the presence of ventricular arrhythmia, conduction abnormalities, and heart failure (HF). However, 20%-25% of patients may present with silent CS, having asymptomatic cardiac involvement. The diagnosis of CS is based on findings from nuclear studies, cardiac magnetic resonance, and extra-cardiac tissue biopsy. Due to the inflammatory nature of the disease, immunosuppressive medications are a cornerstone of therapy. The treatment also includes recommended HF medical therapies. Since CS patients are at risk of sudden cardiac death resulting from progression of cardiac dysfunction or the presence of scar originating from fatal arrhythmias, implantable cardioverter-defibrillators should be considered, with special indication beyond accepted recommendations in HF. In CS, the extent of left ventricular dysfunction is the most important mortality predictor. Heart transplant or mechanical circulatory support may represent life saving strategies in selective CS patients.

Sarcoid Heart Disease: an Update on Diagnosis and Management

PURPOSE OF REVIEW

The purpose of this review is to provide an update on cardiac sarcoidosis (CS) and to discuss the current recommendations and progress in diagnosis and management of this disease. Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Cardiac involvement is seen in at least 25% and is associated with poor prognosis. Manifestations of cardiac sarcoidosis (CS) can vary from presence of silent myocardial granulomas, which may lead to sudden death, to symptomatic conduction abnormalities, ventricular arrhythmias, and heart failure.

RECENT FINDINGS

We discuss newer imaging modalities such as cardiac magnetic resonance imaging and positron emission tomography in conjunction with clinical criteria increasingly used for diagnosing and prognosticating patients with CS. Immunosuppression (primarily corticosteroids) is recommended for treatment of CS; however, its efficacy has never been proven in prospective randomized studies. The role of imaging to guide the use of immunotherapy is unknown. Cardiac sarcoidosis continues to challenge clinicians due to its protean presentations, lack of diagnostic standards, and data for risk stratification and treatment. There is a need for prospective, randomized controlled trials to understand how best to diagnose and treat cardiac sarcoidosis.