A curious tachycardia

This is a case from Galle, Sri Lanka which shows a very unusual case of a 32 yo lady 3 days post partum who presents with palpitations. What’s unusual is that she can transmit AF and flutter at 1:1 to her ventricles…implying an abnormal connection to her ventricle, not her AV node. Usually a WPW Accessory pathway will lead to at least a few broad complexes as the pre-excitation leads to early ventricular depolarisation and a delta wave /broad complex.  I have seen a patient in the past with a paranodal bypass tract who had a very subtle delta wave. This lady never made it to sinus rhythm as long as I followed her up so I didn’t get to check for a subtle finding of WPW.

I suspect she had a sick sinus syndrome withAF/flutter and SVT- but I have no idea why the AV block would undo and her rate would wind up paroxysmally.

Any suggestions gratefully received.