Before scrolling down, try to think of the possible diagnoses for this ECG.

This ECG shows a regular narrow complex tachycardia at a rate of 140/min.

It is a long RP tachycardia with superior P axis.

The possibilities are-

• Fast-slow AVNRT (slow retrograde conduction in an AVNRT)
• PJRT (slow retrograde conduction in an AVRT)
• Ectopic atrial tachycardia (focus near AV node)