Ecg Artifact

Good morning, I have a problem with artifacts on the ecg trace. We have tried to replace the patient cable, adapters, electrodes and to work on battery, excluding problems from the electrical network. The patient is regularly shaved and properly prepared before the application of the electrodes but I continue to have the trace, especially with the peripheral leads, which oscillates with respect to the baseline. I also opened the tool to clean the contacts and found no anomalies. I enclose some examples in the hope that someone can give me some suggestions to solve the anomaly. https://ibb.co/TrnZ3n5 https://ibb.co/djdXf0S https://ibb.co/tLbw7NS https://ibb.co/9brTpL6