Utility of 18-Fluorodeoxyglucose positron emission tomography in the prediction of ventricular tachycardia and advanced conduction disease in patients with cardiac sarcoidosis

Background The diagnosis and management of cardiac sarcoidosis (CS) along with the recognition of high risk features remains a significant challenge. Failing to identify reliable disease prognosticators often results in fatal ventricular arrhythmia or heart failure. Aims This study sought to determine the association of regional fluorodeoxyglucose positron emission tomography ( 18 FDG PET) patterns and the presence of ventricular tachycardia (VT) storm and conduction disease in patients with CS. Methods In an observational cohort analysis, patients with a working diagnosis of CS who underwent 18 FDG PET imaging were included. Baseline clinical data and 18 FDG PET data were collected and analysed. Results A total of 57 patients with CS were studied. All had abnormal 18 FDG PET imaging consisting of inflammation, scar or combination of both. VT storm was present in 33 per cent of the cohort, while 63 per cent had high grade conduction disease. Mean inflammatory burden noted on 18 FDG PET in those with VT storm was 12 per cent. Inflammation involving ≥2 basal septal or mid septal segments (>15 per cent myocardium) was an independent predictor of VT storm (OR: 9.62, 95 per cent CI 1.97–46.9, p=0.005). The degree of inflammatory burden and regional inflammation pattern on 18 FDG PET demonstrated significant concordance with the presentation of VT storm. Inflammation in the anteroseptal segment was associated with high grade conduction disease (OR: 8.00, 95 per cent CI 0.94–68, p=0.029). Conclusion The presence of >15 per cent myocardial inflammation on 18 FDG PET imaging and regional inflammation ≥2 basal or mid septal segment significantly correlated with risk of ventricular arrhythmia specifically VT storm regardless of scar burden.