Up until now, we have posted basic rhythm strips in this area of the ECG Guru for those of you who are teachers of beginning students. Today, we offer a "normal" 12-Lead ECG for those desiring to introduce students to the 12-Lead format. It is always best to become familiar with normal before venturing into the realm of "abnormal". Encourage your students to find what they know to be normal, then add to their knowledge. Examples of findings which are within normal limits are: rate, rhythm, P wave morphology, QRS morphology, intervals, axis, R wave progression, ST segments, and T wave direction.
While advanced practitioners can almost always find something that is not "normal", we must remember that that can be said about almost any human body. This ECG was taken from a healthy volunteer with no medical complaints.
A nice, normal ECG for your collection. It always helps to have a normal ECG for your students to compare to the abnormal examples you show them. It pays to teach the characteristics of "normal" to your students so that they might readily recognize "abnormal". One could argue that the voltage in this ECG is rather low, but that can be explained by body habitus. Whether you are teaching basic rhythm interpretation, axis determination, R wave progression, or intervals, this ECG can be of help to you. Remember, if you are teaching students who have not yet learned 12-lead interpretation, the bottom line of a four-channel ECG is usually a rhythm strip - most often Lead II. It is easy to download this image, then crop it using any photo management program to include only the rhythm strip. At the ECG Guru, we use Irfanview for the Instructors' Collection ECGs.
Sometimes, when teaching a class, it can actually be a challenge to find a good example of "normal" for your students. We all tend to collect the ECGs that are "interesting" or unusual. It is very important for students to fully recognize "normal" before they can appreciate "abnormal". Here is a nice example of a normal 12-Lead for you. It was obtained by a portable machine, like those used by EMS or on crash carts, so it does not include a fourth channel rhythm strip. Challenge your students to find the "normal" characteristics of this ECG: normal sinus rhythm; Lead II has the tallest QRS of the limb leads, indicating a normal axis; Lead V1 is primarily negative and the chest leads progress in an orderly fashion to a positive QRS in V6; no ST segment elevation or depression; no T wave inversions; no pathological Q waves; no abnormally tall or wide QRS complexes; and all intervals are normal. Challenge your students to pick out the normal features of this ECG.
