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.