Atrial Flutter 2:1 block can present as broad complex tachycardia at rate 150 if bundle branch block exists.
Be wary of rates that are perfectly regular with rates of 75, 100, 150, 200 – they may represent atrial flutter with a 4:1 or 3:1, 2:1 or 3:2 block.
Look for the p waves embedded in t waves.
Also remember Brugada criteria for VT (92-96% sensitive):
If no RS complex in V leads —— diagnose VT
If R to S nadir time is > 100ms ——— diagnose VT
If av dissociation ———————diagnose VT
If V1 and V6 morphology suggest VT – diagnose VT
If none of above ——— diagnose SVT with aberrancy.