A limb lead low voltage ECG is characterized by a relatively low waveform on the limb leads, with a QRS wave cluster voltage amplitude of less than 0.5mV. Limb lead low voltage is a term described on the ECG report that represents the arithmetic sum of the QRS wave cluster voltages R+S or Q+R of less than 0.5mV on leads I, II, III, avR, avL, and avF at the time of the ECG. Low voltage in the limb leads may be physiologic or may be a manifestation of a pathologic disease. If the person does not have other abnormalities or any discomfort, there is no need to deal with it; if it is combined with specific discomfort such as chest tightness, panic, chest pain, etc., it is necessary to consider whether there is pericardial effusion, myocarditis, constrictive pericarditis, pleural effusion, pneumothorax, and other conditions. If low voltage in limb leads is found, it is recommended to consult a specialized physician for evaluation and guidance in the cardiology outpatient clinic.