- AV node re-entry or
- AV re-entry (av node + accessory pathway)- WPW syndrome
In WPW, there's the Delta wave- slurred upstroke of the QRS with a short PR interval bcos the signal evades the normal AV node delay and rather passes thru the accessory pathway.
Initial: vagal maneouvres (vasalva, carotid massage)
Drug Tmt :
Adenosine to block AV node except for Wolff-Parkinson-White (AV blockers r contraindicated in WPW becos it'll only promote passage thru accessory pathway.) Amiodarone for WPW
2nd line drugs include verapamil, diltiazem, metoprolol, digoxin
Cardioversion for unstable patients or those not responsive to medications.