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Do you have a simple failsafe approach to arrhythmias?
You must have your own simple approach. Members can go to the ‘Narrow Complex Tachycardias’ section to view my simple algorithm approach to the fast and slow rhythms.
An old boss of mine used to have what he called ‘The 2am in the morning’ approach to airway drug doses, so that it was simplified and minimised errors, when you were called in at that time.
It’s important to have a similar simple approach to arrhythmias.
Here is my approach.

It comes back to some simple questions.
If the rhythm is fast (>100 bpm) there are some critical questions to ask.
Is it Narrow? If Yes:

  • Is it regular?

If it’s narrow and regular then, what are the differentials?

  • Sinus tachycardia
  • SVT
  • If it’s irregular make sure it is irregularly irregular as we don’t want to miss sinus arrhythmia. If it is irregularly think of:
    • Atrial fibrillation- irregularly irregular
    • Multifocal atrial tachycardia- very irregular as 3 different atrial foci

Is it wide? If Yes:
What are the causes of wide complex tachycardia:

  1. Ventricular Tachycardia
  2. SVT with Bundle Branch Block
  3. Ischaemia
  4. Na channel blockade
  5. Hyperkalaemia
  6. Pacing

That’s about it. Sure, we can have some WPW abnormalities, like AF with WPW, but for most cases, these are the diagnoses.
Given that 80% of wide complex rhythms are Ventricular Tachycardia(VT), we can settle on that for most patients. However there are a few things to remember about VT:

  • Monomorphic VT is exquisitely regular, so if you have an irregular wide complex tachycardia, it’s isn’t monomorphic VT.
  • It really must be faster than 120bpm to be VT
    • If it’s not faster than 120bpm check:
      • The potassium as it could be hyperkalaemia
      • Ensure there is no Na channel blocker overdose
      • That is not a reperfusion accelerated idioventricular rhythm

Below is the fast portion of the algorithm and a couple of examples from the course to try.

What does the ecg below show?
This is WPW with Atrial Fibrillation. The rate in some areas is 300 bpm. If you have any rate faster than 250bpm in an adult, there must be an accessory pathway. It is irregularly irregular. Some complexes are wide and others are narrow, as some pass through the AV node and others via the accessory pathway. See below:

How do we manage this condition?
If we used Procainamide, that would be fine, as it preferentially blocks the accessory pathway. What we cannot use, is an AV nodal blocker, such as a beta or calcium channel blocker, or Amiodarone. If we did this all the impulses would be conducted down the accessory pathway and the heart would go into ventricular fibrillation.

What if we applied the simple algorithm approach?
We don’t need to know what the diagnosis is…. that’s the benefit of having an approach like this. Just follow the flow….

Let’s try one more, then you can go to the course and do a bundle of examples.
What is the diagnosis of the ECG below?
It is a fast, narrow complex tachycardia. It is AVN re-entry tachycardia. What if you weren’t sure of what to do? What would the algorithm say?

Remember to develop your own approach or just use mine. It’s very satisfying when you have a simple approach. You can then add all the other learnings to this.

​Join me for an a fun approach to really understanding  arrhythmias, when I cover ‘Rule the Arrhythmia’  at the Cardiac Bootcamp on the Gold Coast  on January 18 2022,

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