NPY and cardiac arrhythmia: Exogenous NPY can also act as an independent arrhythmic trigger during ST-elevation ischaemia reperfusion and, consistent with these observations, a combination of metoprolol and Y1 receptor blockade prevents the changes in intracellular calcium handling and decrease in VFT during stellate ganglia stimulation, or the triggered arrhythmias during ST-elevation ischaemia/reperfusion.