The heart’s electrical activity is sometimes prevented from reaching the ECG electrodes. This interference, called artifact, can hinder the correct recording of actual impulses from the heart. Artifacts can be caused by muscle tremors, shivering, patient movement, loose electrodes, or electrical signals from other devices inside the room (see Figure 2.6).

Figure 2.8 Artifact Caused by Shivering

ECG of Hypothermic Patient