Wolff-Parkinson-White Alternans (WPW Alternans) ECG
2. Wolff-Parkinson-White Syndrome with Alternans
When every other beat conducts through an accessory pathway causing a short PR interval and a delta wave, 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.