ECG features of WPW in sinus rhythm are:
PR interval <120ms
Delta wave – slurring slow rise of initial portion of the QRS
QRS prolongation >110ms
ST Segment and T wave discordant changes – i.e. in the opposite direction to the major component of the QRS complex
Pseudo-infarction pattern can be seen in up to 70% of patients – due to negatively deflected delta waves in the inferior / anterior leads (“pseudo-Q waves”), or as a prominent R wave in V1-3 (mimicking posterior infarction).
