No, because-

1. AV dissociation is not present in many VTs- due to retrograde conduction of ventricular tachycardia through the AV node to cause atrial activation.

2. It may not be always possible to identify P waves on top of the VT. This is more common than appreciated.

3. There may not be P waves- patient may be in atrial fibrillation along with VT!

4. Sometimes junctional tachyarrhythmias may conduct down with aberrancy, but may not conduct up into the atria. So dissociated P waves will be present.