the term WPW alternans is used. The accessory pathway that is exists is refractory on an alternating basis creating this appearance. This is a relatively rare ECG finding.

Patients with Wolff-Parkinson-White syndrome have an “accessory ... and results in a shortened PR interval on the ECG. The combination of WPW and atrial fibrillation can potentially be fatal ...

In another case, a conventional ECG device did not detect Wolff-Parkinson-White (WPW) syndrome, which can be lethal under a general anesthetic. The AiTiA ECG Center detected an atypical beat and ...