Novel ECG parameters are strongly associated with inflammatory 18F-FDG PET findings in patients with suspected cardiac sarcoidosis

Abstract

Background: ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a feasible method to investigate the inflammatory activity of the myocardium in cardiac sarcoidosis. However, PET is costly and not as widely available as standard electrocardiogram (ECG). Current ECG findings related to cardiac sarcoidosis are highly non-specific. In this study, our aim was to determine whether novel ECG parameters are associated with pathological PET findings in patients with suspected cardiac sarcoidosis.

Methods: A total of 133 patients underwent cardiac FDG PET examination in Tampere University Hospital between August 2012 and September 2015. The left ventricular FDG uptake was categorized as either normal or pathological. Additionally, in-depth analyses of resting ECG were performed. Among other parameters, the presence of septal and inferolateral remodelling was assessed. These are novel ECG parameters related to local structural changes in the myocardium.

Results: In the ECG, septal and inferolateral remodelling, as well as widespread QRS fragmentation were significantly associated with pathological left ventricular FDG uptake even if adjusted for age, sex, body mass index, underlying cardiovascular disease and cardiac medication (p<0.05 for all). When all these ECG parameters were combined in a logistic regression model, only septal remodelling remained independently associated with abnormal left ventricular uptake (p<0.05).

Conclusions: Our findings show that novel ECG parameters septal and inferolateral remodelling, as well as diffuse QRS fragmentation, are strongly associated with pathological cardiac findings in FDG PET. Thus, the presence of these ECG findings may warrant the clinician to consider the possibility of cardiac sarcoidosis.

Keywords: Cardiac sarcoidosis; Electrocardiogram; FDG-pet.