Supraventricular arrhythmias

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]

## Overview

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An overview of supraventricular tachycardias | example (lead II)  | regularity  | atrial frequency  | ventricular frequency  | origin (SVT/VT)  | p-wave  | effect of adenosine

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Narrow complex (QRS<0.12)
Sinus tachycardia |  | regular  | 100-180 bpm  | 100-180 bpm  | sinus node (SVT)  | precedes every QRS complex  | gradual slowing
Atrial Fibrillation |  | grossly irregular  | 400-600 bpm  | 75-175 bpm  | atria (SVT)  | absent  | slows down rate; irregularity remains
Atrial Flutter |  | regular (sometimes alternating block)  | 250-350 bpm  | 75-150 bpm (3:1 or 2:1 block is most common)  | atria (SVT)  | negative sawtooth in lead II  | temporary reduced conduction (e.g. 4:1)
AVNRT |  | regular  | 180-250 bpm  | 180-250 bpm  | AV-node (SVT)  | in QRS complex (R')  | stops
Atrial tachycardia |  | regular  | 120-250 bpm  | 75-200 bpm  | atria  | precedes QRS, p wave differs from sinus-p  | temporary AV-block
Atrio-Ventricular Reentry Tachycardia (AVRT)- orthodromic |  | regular  | 150-250 bpm  | 150-250 bpm  | circle: av-node - ventricles - bypass - atria  | RP < PR  | stops
AV junctional tachycardia |  | regular  | 60-100 bpm  | 70-130 bpm  | AV node  | RP < PR  | reduces rate
Wide complex (QRS>0.12)
Supraventricular tachycardia with block |  | (ir)regular depending on SVT  | 100-250 bpm  | 75-200 bpm  | atria (SVT)  | absent  | temporary increased AV-block (eg 4:1)
Atrio-ventricular Reentry Tachycardia (AVRT) - antidrome |  | regular  | 150-250 bpm  | 150-250 bpm  | circular: bypass - atria - av-node - ventricles  | RP < PR  | stops

### Supraventricular ectopic beats

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* Atrial Premature Complexes
* Wandering Pacemaker
* AV-nodal complexes

### Also read

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* Flowchart: Approach to the Narrow Complex Tachycardia Adapted from ESCnarrowQRS.
* Introduction to Arrhythmias
* Mechanisms of Arrhythmias
* Sinus node rhythms and arrhythmias
* Junctional Tachycardias
* Ventricular Arrhythmias

## EKG Examples

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This is an electrocardiogram from a woman in her forties who had several operations for congenital heart disease. At the time of the electrocardiogram the patient was taking flecainide and metoprolol .

This patient was being treated for ventricular tachycardia. She was initially treated with amiodarone and then was switched to a combination of flecainide and metoprolol. She was doing well. The underlying congenital heart disease was Tetralogy of Fallot. The electrocardiogram shows a supraventricular rhythm which is probably not sinus as indicated by the negative P waves in the inferior leads. The cardiogram also shows 1 PVC and a right Branch block with a left anterior hemi-block.

### Causes

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### Drug Side Effect

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* Cyclophosphamide
* interferon alfacon-1
* Ixabepilone
* Rasburicase

## References

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<biblio>

1. ESCnarrowQRS pmid=14563598

</biblio>