Editor’s note: We asked columnist Tom Bouthillet to pick a winner to this month’s contest, and he wrote: “We had dozens of great responses to the original ‘Not so fast’ presentation — and with each month’s column, the reader who I believe offers the best diagnosis and treatment plan wins an EMS1 T-shirt and bottle opener.
For this month’s column, I’ve picked Vince DiGiulio. He correctly identified the rhythm as VT and even picked up on some findings that I missed (like the fusion complex and excessive discordance in leads V2-V4). He also factored in the patient’s history to support the diagnosis. While you could support sedation and cardioversion for this patient, I think 150 mg of amiodarone was a reasonable course of action. I’ve seen a lot of cases of VT with rates in the 130s and 140s lately, especially in patients with pacemakers and ICDs, so be careful when excluding VT from your list of differentials. It’s not set in stone that the rate has to be above 150!”
Haven’t read the initial case presentation? Read: Not so fast...
Let’s look at the 12-lead ECG again.
Wide complex rhythms, fast and slow, should be considered ventricular until proven otherwise.
Because the rate here is less than 140 and the patient’s blood pressure is 150/96 it’s prudent to consider the possibility that the rhythm is sinus tachycardia with some kind of intraventricular conduction defect or paced but this 12-lead ECG shows no evidence of either.
In fact, everything about this ECG screams “ventricular tachycardia!”
- The QRS duration is > 140 ms
- The frontal plane axis is in the right superior quadrant (extreme axis deviation)
- There is a monophasic R-wave in lead V1
- Retrograde P-waves (VA conduction) is visible in leads aVF and V4
- The patient has a history of MI
If you’ve been reading my blog for any length of time, you know how I feel about using QRS morphology for the differential diagnosis of wide complex tachycardia.
When Wellens’ or Brugada’s criteria are used to “rule-in” VT they can be quite useful.
However, when these and other criteria, either through errors or inter-observer disagreement, are used to misclassify VT as SVT with aberrancy it puts patients at risk and leads to clinical misadventure including death.
There is no “safe” way to use QRS morphology to “rule-out” VT.
In this case the paramedics gave the patient 150 mg amiodarone over 10 minutes via piggyback infusion (not a bad choice if you’re going the med route).
No change was noted on the monitor.
A few minutes later the ambulance arrived at the hospital.
The patient was admitted with a presumed diagnosis of ventricular tachycardia.
The patient was given 5 mg of metropolol and an additional 150 mg of amiodarone over 10 minutes.
The rhythm converted to a paced rhythm at a rate of 80 and the patient was admitted for observation.
