The Role of Echocardiography in the Contemporary Diagnosis and Prognosis of Cardiac Sarcoidosis: A Comprehensive Review

Abstract

Cardiac sarcoidosis (CS) is a rare inflammatory disorder characterised by the presence of non-caseating granulomas within the myocardium. Contemporary studies have revealed that 25-30% of patients with systemic sarcoidosis have cardiac involvement, with detection rates increasing in the era of advanced cardiac imaging. The use of late gadolinium enhancement cardiac magnetic resonance and ¹⁸fluorodeoxy glucose positron emission tomography (FDG-PET) imaging has superseded endomyocardial biopsy for the diagnosis of CS. Echocardiography has historically been used as a screening tool with abnormalities triggering the need for advanced imaging, and as a tool to assess cardiac function. Regional wall thinning or aneurysm formation in a noncoronary distribution may indicate granuloma infiltration. Thinning of the basal septum in the setting of extracardiac sarcoidosis carries a high specificity for cardiac involvement. Abnormal myocardial echotexture and eccentric hypertrophy may be suggestive of active myocardial inflammation. The presence of right-ventricular involvement as indicated by free-wall aneurysms can mimic arrhythmogenic right-ventricular cardiomyopathy. More recently, the use of myocardial strain has increased the sensitivity of echocardiography in diagnosing cardiac involvement. Echocardiography is limited in prognostication, with impaired left-ventricular (LV) ejection fraction and LV dilatation being the only established independent predictors of mortality. More research is required to explore how advanced echocardiographic technologies can increase both the diagnostic sensitivity and prognostic ability of this modality in CS.

Keywords: FDG-PET; cardiac imaging; cardiac magnetic resonance; cardiac sarcoidosis; echocardiography; nuclear cardiology; sarcoid.

Figure 1

Central illustration: Prevalence of echocardiographic abnormalities in cardiac sarcoidosis. The white arrows indicate multifocal RWMA (top-left image) and global pericardial effusion (bottom-right image). (MR = mitral regurgitation; PHTN = pulmonary hypertension; RWMA = regional wall motion abnormality).

Figure 2

Transthoracic echocardiogram of patient with active cardiac sarcoidosis demonstrating hypertrophied, echogenic speckled left-ventricular myocardium in regions with high ¹⁸F-FDG uptake on PET, particularly the interventricular septum. ¹⁸F-FDG = ¹⁸F-fluorodeoxyglucose; PET = positron emission tomography.

Figure 3

(A) Active cardiac sarcoidosis with FDG uptake extending from the lateral wall to involve the anterolateral papillary muscle (white arrow). (B) The same patient had moderate eccentric mitral regurgitation on transthoracic echocardiography. FDG = fluorodeoxyglucose.

Figure 4

Impairment of multi-chamber myocardial strain to predict cardiac involvement in 122 sarcoidosis patients referred for cardiac evaluation. Optimal cut-off, sensitivities, specificities, and area under the curve (AUC) figures from a study into 83/219 sarcoidosis patients diagnosed with cardiac involvement [45]. LA = left atrial; LV = left-ventricular, GLS = global longitudinal strain, RV FWS = right-ventricular free-wall strain.

Figure 5

Multi-modality imaging in a 47-year-old patient with active cardiac sarcoidosis demonstrating the value of myocardial strain analysis, incremental to LVEF. (A) TTE revealed preserved LV systolic function with LVEF of 62%. (B) However, average GLS was impaired at −14.8% with segmental strain readings showing significant impairment in the lateral, basal inferior, and mid-apical anterior regions. (C) Areas of reduced strain correlate with regions of increased FDG uptake on PET (red arrows) and the CMR (D) revealed subepicardial LGE in the basal-mid inferior wall and mid-wall LGE throughout most of the lateral wall (white arrows). CMR = cardiac magnetic resonance; FDG = fluorodeoxyglucose; GLS = global longitudinal strain; LGE = late gadolinium enhancement, LVEF = left-ventricular ejection fraction; PET = positron emission tomography.

Figure 6

Three-dimensional speckle tracking echocardiography offers additional deformation parameters such as twist and torsion. ED = end-diastolic; EDV = end-diastolic volume; EDVI = indexed end-diastolic volume; EF = ejection fraction; ESV = end-systolic volume; ESVI = indexed end-systolic volume; GCS = global circumferential strain; GLS = global longitudinal strain; SDI = strain delay index.