An overview of supraventricular tachycardias

	example (lead II)	regularity	atrial frequency	ventricular frequency	origin (SVT/VT)	p-wave	effect of adenosine
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

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

• 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

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.

• Cyclophosphamide
• interferon alfacon-1
• Ixabepilone
• Rasburicase

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1. ESCnarrowQRS pmid=14563598

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