Irregular narrow complex tachycardia

Irregular narrow complex tachycardia
Treat as AF —by far the most likely diagnosis.
Control rate with either β blocker or digoxin.
If onset <48h consider cardioversion with either amiodarone, 300mg in over 20-60 min, then 900mg over 24h; or DC shock,
Consider anticoagulation with heparin and/or warfarin to reduce the risk of stroke.