According to the speed of action produced by cardiomyocytes after being stimulated, and its different mechanisms of action production, cardiomyocytes can be categorized into fast-responsive cells and slow-responsive cells. Slow-responsive cells are stimulated by ECG signals to produce slow action and small amplitude of action, i.e., slow-responsive cardiomyocytes receive stimulation, the contraction speed is slow and the contraction amplitude is small, and slow-responsive cells further transmit the electrical signals to the next cardiomyocyte, so that the next cardiomyocyte contraction of the conduction speed is also slow. The formation of the contractile state of slow-responsive cells is mainly dependent on the inward flow of calcium ions into the cytoplasm, which is greatly influenced by the intracellular and extracellular concentrations of calcium ions, and their contractile process can be blocked by calcium channel blockers. Slow-responsive cells are a type of cardiomyocytes with slow contraction and conduction velocities and small contraction amplitudes, including sinoatrial node cells and atrioventricular node cells, and fast-responsive cells and slow-responsive cells can be transformed under certain pathologic conditions and experimental conditions.