C5 and cardiomyopathy: C5a reacts with its receptor, leading to cytokine storm, lymphocyte apoptosis, neutrophilic innate immune function loss, cardiomyopathy, disseminated intravascular coagulation, etc. Meanwhile, C5a also affects intracellular calcium homeostasis (Fattahi et al., 2018a; Ward and Fattahi, 2019).