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.
12 Lead ECG â Lead Placement Diagrams. Iâm an EMT-B that just found your blog. My agency allows EMT-Bs to perform 12-leads prehospital, so that doctors and paramedics at the hospital have a printout to look at. Also, if our monitor sees an Acute MI or something critical going on with the heart, we know to hurry it up.