ECG of the week 27

I wonder how many of you thought this was a junctional tachycardia with two PVCs.

Sometimes PVCs are good things!  Here, the pause following the PVC uncovers the 'p' wave (vide infra) and reveals a first degree AVB; most of the 'p' waves are concealed in the preceding 'T' wave, with a PR interval somewhere around 280ms.

So it's really a sinus tachycardia with 1° AV block.