[[File:E000779.jpg|thumb|600px|left|This recording shows a positive delta waves in I and aVL, as well as V4 to V6. The pr interval is short (<120ms.) This is suggestive of a right free wall atrio-ventricular bypass tract of the W.P.W. type.]]
[[File:E000779.jpg|thumb|600px|left|This is a recording from an elderly man with sever lung disease.]]