Catecholamine, an important neurotransmitter, is derived from tyrosine synthesis and four enzymes are involved in the synthesis process. Tyrosine hydroxylase is the first reported enzyme in tyrosine synthesis, which serves as the speed limit enzymes and plays a role in catalyst. The positive staining of immunohistochemistry indicates the sympathetic nerve distribution. Latest studies suggest that the increased incidence of arrhythmia is closely related to sympathetic reconstruction in the heart. The increase in nerve fibers leads to an elevated catecholamine level and sympathetic activity, resulting in imbalance of parasympathetic activity. Therefore, the detection of positive distribution of tyrosine hydroxylase in patients with cardiac arrhythmias can help to make a judgement whether the sympathetic reconstruction plays a major role in the occurrence of arrhythmia.