Lead II showing normal sinus rhythm with sinus arrhythmia in a healthy 26 year-old woman. Note the marked variation in the P-P intervals induced by respiration.
Courtesy of Morton Arnsdorf, MD.
Graphic 65949 Version 3.0
Normal rhythm strip
Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright.