INTRODUCTION
Sarcoidosis is an inflammatory condition characterized by the presence of non-caseating granulomas in affected organs and primarily affects patients between the ages of 20 to 40 years.1,2 In the United States, the incidence of sarcoidosis ranges from 10.9 to 35.5 per 100,000 in Caucasians and African Americans, respectively.3 Based on autopsy findings, cardiac involvement has been reported to occur in 25% of patients with systemic sarcoidosis ,4 while imaging-based studies using cardiac magnetic resonance (CMR) have demonstrated that up to 50% may have cardiac lesions .2,5 While patients with cardiac sarcoidosis (CS) can be asymptomatic, others can present with symptoms due to conduction abnormalities, ventricular arrhythmias, and cardiomyopathy.6 Very rarely, cardiac involvement or even sudden cardiac death may be the first manifestation of systemic sarcoidosis.7
Currently, all patients with biopsy-proven extra-cardiac sarcoidosis routinely undergo screening for cardiac sarcoidosis with an electrocardiogram (EKG), with or without an echocardiogram.5 Advanced imaging modalities such as (CMR) and 18F-Fluorodeoxyglucose–Positron Emission Tomography (FDG-PET) are reserved for individuals suspected to have cardiac involvement based on initial screening.5,8 The sensitivity of EKG for detecting cardiac involvement is limited at 21 – 68%,6,9 while sensitivity for conventional echocardiography ranges between 27% in asymptomatic individuals and 75% in the presence of symptoms or abnormal EKG findings.9 Despite the demonstrated superiority of CMR and FDG-PET in early diagnosis of CS, their role is limited by cost and availability, making them inadequate initial screening tests.10 Speckle tracking echocardiography (STE) is a novel modality with a promising utility in predicting subclinical myocardial involvement.11,12 The region of interest (ROI) is marked with speckles that serve as stable acoustic markers to trace tissue movement, irrespective of the angle of interrogation.12 STE can evaluate cardiac function by measuring left ventricular global longitudinal strain (LVGLS) and/or global circumferential strain (GCS)10. We sought to perform a meta-analysis of studies investigating the role of STE in asymptomatic patients with proven extra-cardiac sarcoidosis and no known cardiac involvement.