Significant ECG u-waves suggest possible hypokalemia, which varies from person to person. Typical ECG changes in hyperkalemia are S-T segment depression, low and flat T waves, and increased u waves. A serum potassium concentration of less than 3.5 mmol/L is called hypokalemia. Acute hyperkalemia leads to manifestations such as lethargy, weakness, and even delayed paralysis. Hypokalemia can lead to increased excitability, increased autoregulation and decreased conductivity of cardiomyocytes, and various cardiac arrhythmias such as sinus tachycardia, intraventricular block and atrioventricular block can occur. In order to prevent the effects of hypokalemia on the organism, the primary disease should be prevented and treated, and diet and renal function should be restored. Appropriate potassium supplementation should be performed to correct water and electrolyte metabolic disorders. If abnormalities are found in ECG, go to the hospital in time and take treatment under doctor’s guidance. If low blood potassium is found, please consult a doctor in time, do not supplement potassium on your own to avoid insufficient or excessive potassium supplementation, which may cause adverse consequences.