1 Most episodes of acute lower back pain are caused by muscle strain, such as from lifting a heavy object, a sudden movement or a fall. 2  The low back pain can be very severe and last for several hours, several days or even a few weeks.
3. Characteristics of the Normal ECG. It is important to remember that there is a wide range of normal variability in the 12 lead ECG. The following normal ECG characteristics, therefore, are not absolute. It takes considerable ECG reading experience to discover all the normal variants.
Itâs not uncommon for 12-lead ECGâs to have some form of artifact; however, itâs important to try to reduce any interference to ensure an accurate ECG. Below is a list of guidelines that will help reduce artifact when performing ECGâs. Patient Positioning. Place the patient in a supine or semi-Fowlerâs position.