I want to take a couple of minutes to follow up on my tachycardia post from the other day. I left off on wide complex tachycardias, and I feel like this is a follow up that needs to be done.
As I said in the other post, we assume that all wide complex tachycardias are VT unless proven otherwise. The first question that we need to know is: does this wide complex tachycardia have a pulse? If the answer is no, then we work the patient as if it was a VF/VT code. If there is anything that a person with an ACLS card in his pocket should know how to do, it is work a VF/VT code. For crying out loud, they train cashiers at WalMart how to do most of this, and if you can’t, then maybe you should turn in that ACLS card and throw in an application to WalMart.
Anyway, if the patient has a pulse with this tachycardia, the next question we should ask ourselves is whether or not this patient is critically unstable as a result. There is only one thing that counts: Are we perfusing the brain? There are two fairly reliable indicators that we can use to determine this: mental status and blood pressure.
If the patient has altered mental status, or has a systolic blood pressure of less than 90mm Hg, then this patient is critically unstable and needs immediate intervention. Synchronized cardioversion is the way to go here. Time is tissue. Going with drugs at this point is costing you brain tissue: time to get the IV, time to drip amiodarone over 10 minutes, or time to push the lidocaine is going to cost the patient brain tissue.
If the patient is not critically unstable, then we have time to find out what we are dealing with: Is this VT or is it SVT with an aberrancy? We can tell by running a 12 lead. Run a 12 lead EKG, and if leads aVF and I are both showing negative deflection, then your QRS axis is in the upper left quadrant, meaning XAD or Indeterminate axis. This is an indicator that your patients heart is experiencing retrograde conduction. The foci, or pacemaker, in this heart is in the ventricles, and you are dealing with VT. Otherwise, it is SVT with an aberrant conduction.
Hope this helps. Good luck out there!