Refers to the noise signal caused by the vibration of human muscles. This noise signal is irregular. The frequency of myoelectric interference signal is between 10-3000 Hz, and the voltage ranges from tens of microvolts to several millivolts. When doing an electrocardiogram examination, 35Hz EMG interference signals are generally common.
The main reasons for it are as follows:
1. The patient is too nervous, causing electromyographic interference;
2. The ambient temperature is too low, and the patient feels chills, causing electromyographic interference;
3. The patient's movement or the uncomfortable bed causes electromyographic interference;
4. Electrocardiograph electrode straps or electrode clamps are too tight, causing electromyographic interference.
In addition, some elderly patients are also very easy to cause electromyographic interference.
The general disposal methods are as follows:
1. Ask the patient not to be nervous and to relax mentally;
2. Instruct the patient to relax all over, do not make fists, exert force, or move. Sandbags can also be used to cushion the patient’s knees, allowing the lower limbs to bend and relax the muscles naturally;
3. The elasticity of the straps or electrode clamps for the electrodes of the electrocardiograph should be moderate;
4. Properly increase the temperature in the ward, and pay attention to keeping the patient warm. For example, after the chest electrodes are fixed, the patient's chest should be covered with clothes in time and so on. Generally, after the above processing, the EMG interference can be effectively eliminated.
