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.
For 11 patients (4.7%) with equivocal clinical and ECG findings, a baseline ECG (if it was available) might have been useful in avoiding an unnecessary hospitalization. There was no patient for whom a baseline ECG would have aided in avoiding an inappropriate discharge. The routine ECG has little value as a baseline for emergency comparison when patients later experience acute cardiac symptoms. Routine ECGs as baselines for future comparison should be reconsidered.