Many apologies for the delay, your author worked a 48 over the weekend and was unable to get time to type up this article!
This is the conclusion to 78 year old male CC: Dizziness.
There were so many great comments on this case, including some great discussion on classifying wide complex tachycardias!
The first rhythm strip clearly shows a wide complex tachycardia. An important point to note is the rate is well above the predictive maximal sinus rate for our patient’s age. This rules out sinus tachycardia with a bundle branch block. At this point, providers may ask themselves if this is Ventricular Tachycardia or SVT with aberrancy.
If we take a look at the 12-Lead ECG, we can look for signs which rule-in Ventricular Tachycardia.
We have a QRS duration of ≥140 ms, amplitude of R > R’ in V1, a non-specific IVCD, and an R wave in aVR; all of these point to Ventricular Tachycardia. Additionally, the patient has a significant cardiac history. Some readers noted the normal axis and what potentially are P- or F-waves. I would offer that these points are moot: from this ECG alone we cannot rule-out Ventricular Tachycardia.
Wide and fast is Ventricular Tachycardia until proven otherwise.
Besides, our patient is unstable and needs immediate synchronized cardioversion.
Which is just what the crew did! Given the potential for atrial flutter, the initial cardioversion setting was 50 J. With no conversion they increased the energy to 100 J.
No change was noted. A supervisor on scene mixed up 150 mg of amiodarone and began a 10 minute infusion. After no change with two cardioversions, the decision was made to move the patient to the unit.
In the back of the truck a sudden change of responsiveness was noted. The energy setting was increased to 150 J.
At 150 J the cardioversion was successful!
The post-cardioversion 12-Lead showed diffuse ischemia and the patient ended up receiving an Automatic Implantable Cardioverter-Defibrillator. Great job by the responding crew!
UPDATED 12 APRIL 2011
Jeremy asked how the QRSd was measured in this case. Usually I try and find the earliest onset and match that with the latest end in a grouping of leads, then use the largest value to map each grouping. The following image may help illustrate this point.
I first saw this visualization on Dr. Smith’s ECG Blog, where he uses it for more than just determining the QRS duration in “Cardiac Arrest, Wide Complex, Is it STEMI?” and “Wide Complex Tachycardia; It’s really sinus, RBBB + LAFB, and massive ST elevation”.
Differential diagnosis of wide complex tachycardias – Part I
Differential diagnosis of wide complex tachycardias – Part II
Differential diagnosis of wide complex tachycardias – Part III
Differential diagnosis of wide complex tachycardias – Part IV
Differential diagnosis of wide complex tachycardias – Part V
Differential diagnosis of wide complex tachycardias – Part VI