DDx Narrow Complex Tachycardia:
- Sinus tachycardia
- SVT (AVNRT)
- A Flutter with 2:1 conduction (hint: if rate 150 +/- 20 bpm then a flutter till proven otherwise)
The way to differentiate is to look at what the Atrium is doing. Look for P waves in all the leads. Granted V1 is still your go to, but look closer in all the leads. If you're not sure flip the ECG upside down to help your mind recognize inverted p waves for what they are.