- may produce inverted P waves which can appear immediately before or just after each QRS complex in the tachycardia; 
Causes of Irregular Tachycardia: 
1) A. Fib 
2) MAT  
3) Sinus Tach w/ PACs 
4) Sinus Tach w/ PVCs 
- Look for R on T pattern  
- Multifocal PVCs 
- PVC Salvos: 3 or more in a row;  
- PVC: More than 5/min