STAT4 and obesity due to melanocortin 4 receptor deficiency: HFD feeding further revealed over-activation of proinflammatory IL-6 signaling in the ventricles of these guinea pigs and was associated with a novel activation and enhanced nuclear translocation of downstream signal transducer and activator of transcription 4 (STAT4), thus providing a unique opportunity to reveal novel cellular proarrhythmic inflammatory mechanisms of obesity VT.