2. AVNRT: Dual AV node physiology
AVNRT Normal Sinus Rhythm
During sinus beats
• conduction occurs via fast pathway
• conduction via slow pathway is blocked
What happens with AVNRT is that patients have two conduction pathways through the AV node
a fast pathway and a slow pathway
and normally the fast pathway wins out

3. AVNRT: Initiation of tachycardia
And as this circuit spins around the AV node, it sends impulses up the atrium and down the ventricule
since the A and V are activated simultaneously, and getting that P wave, right after the QRS is virtually diagnostic for AVNRT

4. 58 yo male who presents to ED with light headness after Mitral Valve Replacement
Often though, you will just see a regular NCT with no clear P waves, as the P waves are literally barried in this QRS complex

5. AVNRT: Catheter ablation
AVNRT can be cured permanently with catheter ablation, using radio frequency to heat and destroy the cells in the slow pathway, creating a permanent line of block.
To treat the arrhtymia, you can try to use medications such as beta blockers or Ca channel blockers to suppress the connection through the AV node.
But if the pt has symptoms, I usually move on to catheter ablation,
Where we ablate the slow pathway, leave the fast pathway alone
and this is really a simple and curative procedure
and in my opinion, a couple of hours to have this done on an outpaient basis is better than a lifetime of medications