AVNRT electrocardiogram: Difference between revisions
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==Overview== | |||
An [[electrocardiogram]] performed during the occurrence of symptoms may confirm the diagnosis of AVNRT. | |||
==Slow-Fast AVNRT (Common AVNRT)== | |||
*This form of AVNRT accounts for 80% to 90% of cases of AVNRT. | |||
*The [[retrograde P wave]] that is conducted retrograde up the fast pathway is usually burried within the QRS but less frequently may be observed at the end of the [[QRS complex]] as a pseudo r’ wave in lead V1 or an [[S wave]] in leads II, III or aVF. | |||
==Fast-Slow AVNRT (Uncommon AVNRT)== | |||
[[File:Fast slow AVNRT.JPG]] | |||
*This form of AVNRT Accounts for 10% of cases of AVNRT | |||
*In this form of AVNRT, the impulse is first conducted antegrade down the Fast AV nodal pathway and is then conducted retrograde up the Slow AV nodal pathway. | |||
*In contrast to Common AVNRT, a [[retrograde P wave]] may be observed after the [[QRS complex]] before the [[T wave]] | |||
==Slow-Slow AVNRT (Atypical AVNRT)== | |||
* This form of AVNRT accounts for 1-5% of cases of AVNRT | |||
* In this form of AVNRT, the impulse is first conducted antegrade down the Slow AV nodal pathway and retrograde up the Slow left atrial fibres approaching the AV node. | |||
* The [[p wave]] may appear just before the [[QRS complex]], and this makes it hard to distinguish the rhythm from [[sinus tachycardia]]. | |||
==Aberrant Conduction== | |||
It is not uncommon for there to be a wide [[QRS complex]] due to aberrant conduction due to underlying conduction system disease. This can make it difficult to distinguish AVNRT from VT. The distinguishing features include: | |||
*AVNRT is associated with a [[QRS complex]] morphology resembles a typical [[bundle branch block]] | |||
*AVNRT is not associated with [[AV dissociation]] where there is variable coupling of the [[p wave]] and the [[QRS complex]] | |||
*AVNRT is associated with [[Cannon a waves]] | |||
*AVNRT is not associated with [[capture beats]] or [[fusion beats]] | |||
*AVNRT may convert with [[adenosine]] or [[vagal maneuvers]] | |||
An electrophysiologic study may be needed to confirm AVNRT prior to ablation. | |||
==Holter Monitor / Event Recorder== | |||
If the patient complains of recurrent [[palpitations]] and no arrhythmia is present on the resting EKG, then a [[Holter Monitor]] or [[Cardiac Event Monitor]] should be considered. | |||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} |
Revision as of 15:43, 9 September 2012
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
An electrocardiogram performed during the occurrence of symptoms may confirm the diagnosis of AVNRT.
Slow-Fast AVNRT (Common AVNRT)
- This form of AVNRT accounts for 80% to 90% of cases of AVNRT.
- The retrograde P wave that is conducted retrograde up the fast pathway is usually burried within the QRS but less frequently may be observed at the end of the QRS complex as a pseudo r’ wave in lead V1 or an S wave in leads II, III or aVF.
Fast-Slow AVNRT (Uncommon AVNRT)
- This form of AVNRT Accounts for 10% of cases of AVNRT
- In this form of AVNRT, the impulse is first conducted antegrade down the Fast AV nodal pathway and is then conducted retrograde up the Slow AV nodal pathway.
- In contrast to Common AVNRT, a retrograde P wave may be observed after the QRS complex before the T wave
Slow-Slow AVNRT (Atypical AVNRT)
- This form of AVNRT accounts for 1-5% of cases of AVNRT
- In this form of AVNRT, the impulse is first conducted antegrade down the Slow AV nodal pathway and retrograde up the Slow left atrial fibres approaching the AV node.
- The p wave may appear just before the QRS complex, and this makes it hard to distinguish the rhythm from sinus tachycardia.
Aberrant Conduction
It is not uncommon for there to be a wide QRS complex due to aberrant conduction due to underlying conduction system disease. This can make it difficult to distinguish AVNRT from VT. The distinguishing features include:
- AVNRT is associated with a QRS complex morphology resembles a typical bundle branch block
- AVNRT is not associated with AV dissociation where there is variable coupling of the p wave and the QRS complex
- AVNRT is associated with Cannon a waves
- AVNRT is not associated with capture beats or fusion beats
- AVNRT may convert with adenosine or vagal maneuvers
An electrophysiologic study may be needed to confirm AVNRT prior to ablation.
Holter Monitor / Event Recorder
If the patient complains of recurrent palpitations and no arrhythmia is present on the resting EKG, then a Holter Monitor or Cardiac Event Monitor should be considered.