RGS4 and atrial fibrillation: Investigations of RGS4 expression levels in human EAT and of potential alterations in epicardial fat RGS4 levels in heart disease (e.g., heart failure, AFib) are certainly worth pursuing, since RGS4 levels may very well correlate (in an inverse proportional manner) with levels of SNS and PNS activities in EAT of cardiovascular patients.