Introduction to Arrhythmias

Author(s)	J.S.S.G. de Jong
Moderator	J.S.S.G. de jong
Supervisor
some notes about authorship

Morphologic criteria to differentiate between SVT vs. VT in a wide complex tachycardia. This is part of the wide complex tachycardia flowchart

Arrhythmias (non-normal heart rhythms) can be a challenge to the person who tries to understand them. But with a systematical approach, diagnosis is often less difficult than it seems at the beginning.

Interpretation of the heart rhythm

A good stepwise approach to interprete the heart rhythm is to follow these steps:

• Cherchez le P, French for find the P waves.
  • Do you see P waves? Leads II and V1 are often most suitable to find P waves.
  • What is the rate of the P waves?
  • What is the P wave morphology?
• What is the relationship between P waves and QRS complexes?
  • Is every P wave followed by a QRS complex? And every QRS preceded by a P wave? In short: is there a 1:1 relation between P waves and QRS complexes?
  • What is the PR interval and does it change?
• What is the ventricular heart rate?
  • >100 bpm = tachycardia
  • <60 bpm = bradycardia
  • are there extra beats? -> Ectopic Beats
• What is the QRS morphology?
• What is the clinical setting?

Secondly it is important to assess the origin of the arrhythmia:

• If the QRS < 120ms (i.e. a narrow complex), then it is either a sinus arrhythmia, supraventricular rhythm or a junctional tachycardia. In tachycardias, this flowchart will lead to the right diagnosis.[1]
• If the QRS > 120ms it is either a ventricular tachycardia or a supraventricular rhythm with additional bundle branch block. This is a challenging difficulty in arrhythmia diagnosis, therefore a flowchart might help, which incoporates the Brugada criteria for VT.[2] Another method to discriminate VT from SVT has been proposed by Vereckei et al.[3] In the editorial on that paper an excellent review is given on the subject by Dendi and Josephson.[4]

References

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