IL6 and cardiac arrhythmia: In the acute phase of FM, it is widely acknowledged that CS may induce or exacerbate arrhythmia through three primary mechanisms.208,209 Firstly, cytokines directly disrupt Ca2+ homeostasis, with various cytokines including TNF, IL-1β, and IL-6 impacting Ca2+ handling through alterations to ryanodine receptors and the L-type voltage-gated calcium channel Cav1.2.210 Given the critical role of Ca2+ in action potential generation and excitation-contraction coupling, disturbances in Ca2+ signaling are known to promote arrhythmia.