by Ashifa

what methods do you use to decipher whether or not a beat or a run, is aberrantly conducted or whether it is definitely ventricular?

The only way to definitly diagnose v-tach vs. abberrancy is with a 12 lead EKG! When it comes down to brass tacks is the patietn symptomatic?

Remember a wide complex tachycardia is always considered VT unless proven otherwise.
An EP study is the only definitive way to dx the rhythm, sometimes 12 lead EKGs are inconclusive. I agree with the other person.
Treat the patient not the monitor.

Always treat the patient and not the monitor. If you have a 12-lead EKG, there are some clues you can use, they are not 100%, nothing is. If the QRS complexes in the V leads are concordant (either all positive or all negative) that favors v-tach. A left axis or a left bundle branch block pattern that was not there before the ectopy favors v-tach. Wide complex tachycardia in patients in atrial fibrillation favor ashmons phenomenon, not v-tach. You cannot diagnose ectopy from watching lead II, if you monitor in V1 or MCL1 there are certain morphologies that favor ventricular ectopics, but in lead II things that look like PVC'S clearly are not when seen on a twelve-lead.