This tracing, from the same patient, now shows the emergence of an AV nodal rhythm that has a slightly faster rate than the sinus rate. It persists for 2 minutes and then sinus rhythm returns. The positive, delta wave like deflections, before the 5th QRS complex in the upper strip and the 3rd QRS in the lower strip are partial sinus P waves. They appear incomplete because the nodal QRS complexes are superimposed upon them