9.avnrt chang sl-0324-2

1 1

(AVNRT)

Atrioventricular Nodal reentrant Tachycardia

張世霖醫師

台北榮民總醫院

2

Basics of AVNRT Most common form of SVT treated by ablation and

accounts for 25% of all cases presenting to EP labs1

More common in females than males Otherwise healthy individuals Usually adolescent to mid-30's, but can occur at any

age, including infancy A reentrant tachycardia which utilizes distinct atrial

inputs into the AVN that make up a large portion of the circuit which makes it possible to ablate the arrhythmia without damaging the AVN

1. Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 71.

3

AVNRT Circuit

Patients with AVNRT have a Dual Pathway Physiology In 1/3 of patients with a slow pathway, it is not relevant for normal

conduction.

4

Slow and Fast Pathways

Slow Pathway – Perinodal tissue possessing conduction

properties of slow depolarization and relatively rapid repolarization inferiorly and posteriorly close to the Csos (Posteroseptal region)

Fast Pathway – Perinodal tissue possessing the conduction

properties of relatively rapid depolarization and relatively slow repolarization located anteriorly and superiorly to Koch’s triangle (Anteroseptal region)

5

Rightward and Leftward Posterior Extensions of the Compact AVN

A. The compact part of the AV node (with rightward and leftward posterior extensions) is superimposed on the RAO view of the AV septal junction. The rightward posterior extension runs in close proximity to the annular attachment of the septal tricuspid valve leaflet and extends to the level of the CSos.

B. Posterior extension types in a series of 21 random hearts. None had a blunt-ending of the posterior end of the compact node; 1 a leftward extension only; 7 a rightward extension only; and 13 both rightward and leftward extensions. Dotted line = Compact AVN/His bundle transition site.

A B

Posterior Extension

Anterior Extension

Compact AV Node Inoue,S, Becker,AE.

Posterior extensions of the human compact atrioventricular node: a neglected anatomic feature of potential clinical significance. Circulation. 1998;97:188-193.

Presenter

Presentation Notes

Rightward and Leftward Posterior Extensions of the Compact AVN: A. The compact part of the AV node (with rightward and leftward posterior extensions) is superimposed on the RAOview of the AV septal junction. The rightward posterior extension runs in close proximity to the annular attachment of the septal tricuspid valve leaflet and extends to the level of the CSos B. Schematic representation of posterior extensions of the compact AV node as encountered in this series of 21 randomly selected hearts. Note that none had a blunt-ending posterior end of the compact node. One case showed a leftward extension only; 7 showed a rightward extension only; and 13 showed both rightward and leftward extensions. The dotted lines indicate the site of transition between compact node and His bundle Inoue,S, Becker,AE. Posterior extensions of the human compact atrioventricular node: a neglected anatomic feature of potential clinical significance. Circulation. 1998;97:188-193.

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Image showing the histology of the AV node and its posterior extensions. A. The compact AV node (arrows) resting on the slope of the muscular AV septum. B. A section close to the opening of the CSos, showing the leftward (L) and rightward extensions (R) (circled). C and D. Magnifications images of the leftward and rightward extensions (arrows), respectively.

Rightward and Leftward Posterior Extensions of the Compact AVN

Inoue,S, Becker,AE. Posterior extensions of the human compact atrioventricular node: a neglected anatomic feature of potential clinical significance. Circulation. 1998;97:188-193.

Presenter

Presentation Notes

Rightward and Leftward Posterior Extensions of the Compact AVN: Image showing the histology of the AV node and its posterior extensions. A. The compact AV node (arrows) resting on the slope of the muscular AV septum. B. A section close to the opening of the CSos, showing the leftward (L) and rightward extensions (R) (circled). C and D. Magnifications images of the leftward and rightward extensions (arrows), respectively.

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Types of AVNRT

Three Main Types – Typical (common; slow-fast) AVNRT: antegrade slow,

retrograde fast (88%)* – Atypical AVNRT (uncommon; fast-slow or slow-slow)

Fast-slow AVNRT: antegrade fast, retrograde slow (10%)* Slow slow AVNRT: antegrade certain slow fibers, retrograde other

slow fibers (2%)*

*Kuck KH, Cappato R. Catheter Ablation in the Year 2000. Current Opinion in Cardiology 2000;15:29-40.

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Atypical Slow-Fast AVNRT with a Posterior Exit

The atria are activated via the posterior septum rather than the anterior septum – Earliest activation is via the

proximal CS electrodes This is still called common

AVNRT, but it has a posteriorly located fast pathway In the figure the VA interval

is very short, but the earliest atrial activation is recorded in the proximal CS

Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 83

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Regular or irregular because of varying conduction through the AV node.

Rate: 170-250 bpm Conduction ratio: usually 1:1, uncommonly 2:1 Typical:

– The retrograde P wave is seen within, or in close proximity to the terminal portion of the QRS complex (Short RP)

– Pseudo s wave – Presence of a notch in lead aVL is a sensitive and specific predictor

of a diagnosis of AVNRT*

Atypical: – The retrograde P wave occurs late, within or following the T wave

(Long RP).

AVNRT ECG Recognition

*Utility of the aVL lead in the electrocardiographic diagnosis of atrioventricular node reentrant tachycardia. Dar ́ıo Di Toro, et al. Europace (2009) 11, 944–948

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Typical AVNRT

R P

Short RP

http://en.wikipedia.org/wiki/ File:AV_nodal_reentrant_tachycardia.png

Pseudo S Waves

http://en.wikipedia.org/wiki/

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Typical AVNRT

Notch in aVL

Utility of the aVL lead in the electrocardiographic diagnosis of atrioventricular node reentrant tachycardia. Dar ́ıo Di Toro, et al. Europace (2009) 11, 944–948

Pseudo S Waves

Notch in aVL

12 Fujiki A et al. Europace 2008;10:982-987

V A A

Atypical (Fast-Slow) AVNRT EGM

R P

Long RP

Presenter

Presentation Notes

Slow pathway ablation during sinus rhythm in fast–slow type of atypical atrioventricular nodal re-entrant tachycardia. Three surface electrocardiographic leads and intra-cardiac electrograms are shown. Left panel: during atrioventricular nodal re-entrant tachycardia with the AA interval of 280 ms, the HA interval at the His-bundle electrogram was 120 ms and A(CS–His) was 0 ms. The AH interval of 160 ms suggested a fast–slow type of atypical trioventricular nodal re-entrant tachycardia. Right panel: slow pathway ablation induced junctional rhythm with ventriculoatrial block. CS, coronary sinus; HRA, high right atrial electrogram; HBE, His-bundle electrogram; ABL1, distal pair of the ablation catheter located at the posteroseptal region; and ABL2, proximal pair of the ablation catheter.

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Requirements for AVNRT

Three main requirements for AVNRT to occur: - Fast and slow pathways - Difference in refractory periods

- Slow pathway has a short refractory period - Fast pathway has a long refractory period

- Block must occur in one pathway

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Slow Pathway (SP)

Fast Pathway (FP)

FP ERP

SP ERP

15





Slow Pathway (SP)

Fast Pathway (FP)

FP ERP

SP ERP

16 1.Zipes & Jalife, Cardiac Electrophysiology: From Cell to Bedside, 2nd ed., 1995, p. 1199

Atrium

Ventricle

AV Node

Right Bundle Branch

Left Bundle Branch

Fast premature atrial beat

Inverted P Wave

Fast Pathway

Slow Pathway

Requirements for AVNRT Induction of AVNRT

- Block must occur in the fast pathway and conduction is down the slow pathway

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Sinus Rhythm with Dominant Fast Pathway Conduction

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S2 Through Fast Pathway

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S2 Through Slow Pathway

AH Jump occurs when for a 10msec decrement in the S1S2 interval you get > 50msec increase in the AH interval

20

PR Longer Than RP (Indicative of Slow Pathway)

RP Interval

PR Interval

A V V

Long PR interval indicates slow pathway conduction Short RP interval indicates fast pathway conduction

21 Zhu DWX, Maloney JD. Radiofrequency catheter ablative therapy for atrioventricular nodal reentrant tachycardia. In Singer I:

Interventional Electrophysiology. Williams & Wilkins, Baltimore, 1997, pp 310.

AVN Conduction Curve



AVN Conduction Curve con’t

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“Dual Pathway” Physiology

“JUMP”

Dual AV nodal physiology - a “jump” in the A-H interval of greater than, or equal to, 50 msec in response to a 10 msec decrement in the S1S2 interval; during atrial extra-stimulus testing as the extra-stimulus is introduced (decremented).

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Extra-Stimulus From 600-460 to 600-390

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Conduction Curve Indicative of Multiple Slow Pathways

Zhu DWX, Maloney JD. Radiofrequency catheter ablative therapy for atrioventricular nodal reentrant tachycardia. In Singer I: Interventional Electrophysiology. Williams & Wilkins, Baltimore, 1997, pp 290.

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Dual AV Nodal Physiology Antegrade dual pathways are demonstrable in 75% of AVNRT

patients2 and AVNRT may occur in the presence of continuous AV nodal conduction curves.3–5 But antegrade dual pathways can be demonstrated in subjects

without tachycardia as well.6–10 In patients with the fast–slow variety of AVNRT, antegrade

conduction curves are usually continuous.11-12 Retrograde stimulation curves may exhibit an H-A jump if the

fast pathway retrograde refractory period is longer than the slow pathway’s.

See references in notes

Presenter

Presentation Notes

1. Denes P, Wu D, Dhingra RC, Chuquimia R, Rosen KM. Demonstration of dual AV nodal pathways in patients with paroxysmal supraventricular tachycardia. Circulation 1973; 48: 549–555.[ISI][Medline] 2. Josephson ME and Kastor JA. Supraventricular tachycardia: mechanisms and management. Ann Intern Med 1977; 87: 346–358.[Medline] 3. Tai CT, Chen SA, Chiang CE, et al. Complex electrophysiological characteristics in atrioventricular nodal re-entrant tachycardia with continuous atrioventricular node function curves. Circulation 1997; 95: 2541–2547.[Medline] 4. Kuo CT, Lin KH, Cheng NJ, et al. Characterization of atrioventricular nodal reentry with continuous atrioventricular node conduction curve by double atrial extrastimulation. Circulation 1999; 99: 659–665.[Medline] 5. Sheahan RG, Klein GJ, Yee R, Le Feuvre CA, Krahn AD. Atrioventricular node reentry with ‘smooth’ AV node function curves: a different arrhythmia substrate? Circulation 1996; 93: 969–972.[Medline] 6. Denes P, Wu D, Dhingra R, Amat-y-Leon F, Wyndham C, Rosen KM. Dual atrioventricular nodal pathways: a common electrophysiological response. Br Heart J 1975; 37: 1069–1076.[Abstract/Free Full Text] 7. Levites R and Haft JI. Evidence suggesting dual AV nodal pathways in patients without supraventricular tachycardias. Chest 1975; 67: 36–42.[Abstract/Free Full Text] 8. Thapar MK and Gillette PC. Dual atrioventricular nodal pathways: a common electrophysiologic response in children. Circulation 1979; 60: 1369–1374.[Medline] 9. Casta A, Wolff GS, Mehta AV, et al. Dual atrioventricular nodal pathways: a benign finding in arrhythmia-free children with heart disease. Am J Cardiol 1980; 46: 1013–1018.[CrossRef][Medline] 10. Brugada P, Heddle B, Green M, Wellens HJ. Initiation of atrioventricular nodal reentrant tachycardia in patients with discontinuous anterograde atrioventricular nodal conduction curves with and without documented supraventricular tachycardia: observations on the role of discontinuous retrograde conduction curve. Am Heart J 1984; 107: 685–697.[CrossRef][Medline] 11. Wu D, Denes P, Amat-y-Leon F, Wyndham CR, Dhingra R, Rosen KM. An unusual variety of atrioventricular nodal re-entry due to retrograde dual atrioventricular nodal pathways. Circulation 1977; 56: 50–59.[ISI][Medline] 12. Sung RJ, Styperek JL, Myerburg RJ. Castellanos A. Initiation of two distinct forms of atrioventricular nodal reentrant tachycardia during programmed ventricular stimulation in man. Am J Cardiol 1978; 42: 404–415.[CrossRef][Medline] 13. Coumel P, Attuel P, Leclercq JF. Permanent form of junctional reciprocating tachycardia: mechanism, clinical and therapeutic implications. In Narula OS (Ed.). Cardiac Arrhythmias: Electrophysiology, Diagnosis and Management 1979; Baltimore Williams and Wilkins 347–363.

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Two for One Phenomenon Rarely the AV nodal tissue

has time to recover between the conduction of the slow and fast pathways and a single atrial impulse can result in two His and ventricular depolarizations, one from the fast pathway conduction and the other from the slow pathway conduction

Conduction travels down the fast and slow pathways simultaneously giving rise to a normal A-H-V response via the fast pathway and an echo response (H-V only) via the slow pathway.

Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 71.

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Slow Pathway

Fast pathway recovers

Slow pathway with very

slow conduction

Fast Pathway

Two for One Phenomenon Normally

conduction blocks in the

slow pathway due to retrograde conduction

from the fast pathway

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An atrial premature beat travels down the slow pathway and then retrograde up the fast pathway resulting in an atrial echo beat almost simultaneous with the ventricular beat.

AV Nodal Echo Beats

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Retrograde Dual AV Nodal Pathways Retrograde dual AV nodal pathways A jump in the retrograde VA interval may occur if

conduction in the fast pathway occurs during ventricular pacing or a PVC, allowing conduction up the slow pathway to the atrium. An atypical ventricular echo beat can occur via the fast

pathway. An H-A interval prolongation will occur.

Block in the His-Purkinje system A VA jump can occur due to an infra-His delay where block

occur in the His-Purkinje system below the AVN and this is the most common cause of VA block. The H-A interval will be normal, but the VA prolonged

(prolonged V-H).

Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 78-79

31 Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 78-79

Retrograde Dual AV Nodal Pathways

Figure A: Retrograde conduction is via the SP resulting in a retrograde jump with earliest atrial activation at PCS. By the time the retrograde beat reaches the atrium the FP is no longer refractory and an atypical ventricular echo beat (V’) occurs.

Figure B: Note the V2-H2 interval prolongs and not the H2-A2 showing jump was in the His-Purkinje system not the AVN.

A B

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Typical AVNRT In typical AVNRT,

antegrade conduction is down the slow pathway and retrograde up the fast pathway. The earliest atrial

activation is recorded in the anteroseptal region (HIS) where the fast pathway is located. Also since conduction

to the ventricle is down the slow pathway, the AH interval will be prolonged.

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Criteria for Typical AVNRT Typical AV Nodal Reentry

– Retrograde atrial activation caudocephalic with electrogram in the AV Junction (His) earliest (VA = 42-70 msec)

– Retrograde P wave within the QRS with distortion of terminal portion of the QRS. Atrium, His bundle, and ventricle not required

– Vagal manuevers slow and then terminate SVT – During ablation junctional rhythm arising from

the posterior extension of the AV node occurs with retrograde atrial conduction via the fast pathway*

Clinical Cardiac Electrophysiology: techniques and interpretations,2nd. Ed..Lea and Febiger, 1993.page224 *Fujiki A et al. Europace 2008;10:982-987

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Typical AVNRT

V A H

35

Typical AVNRT

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Atypical AVNRT In atypical AVNRT

antegrade conduction is down the fast pathway and retrograde up the slow pathway Earliest atrial

activation would be recorded in the posteroseptal region (proximal CS) where the slow pathway is located. Since conduction to

the ventricle is down the fast pathway, the AH interval will be normal.

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Atypical AVNRT Atypical AVNRT is dependent on the same perinodal reentrant

circuit as typical AVNRT – Antegrade conduction is via the fast pathway – Retrograde conduction occurs over a slow pathway.

Atypical, or uncommon, AVNRT induction is dependent on a critical HA interval during slow pathway conduction.

Retrograde atrial activation sequence caudocephalic with earliest activation at the CSos

Retrograde P wave with long R-P interval Atrium, His bundle, and ventricle not required; vagal manuevers

slow and then terminate SVT, always in the retrograde slow pathway

During ablation junctional rhythm occurs without retrograde atrial conduction via the fast pathway suggesting atypical AVNRT is not a simple reversal of the typical slow–fast type*

*Fujiki A et al. Europace 2008;10:982-987


V A A

Atypical (Fast-Slow) AVNRT EGM

R P

Long RP

Presenter

Presentation Notes

Slow pathway ablation during sinus rhythm in fast–slow type of atypical atrioventricular nodal re-entrant tachycardia. Three surface electrocardiographic leads and intra-cardiac electrograms are shown. Left panel: during atrioventricular nodal re-entrant tachycardia with the AA interval of 280 ms, the HA interval at the His-bundle electrogram was 120 ms and A(CS–His) was 0 ms. The AH interval of 160 ms suggested a fast–slow type of atypical trioventricular nodal re-entrant tachycardia. Right panel: slow pathway ablation induced junctional rhythm with ventriculoatrial block. CS, coronary sinus; HRA, high right atrial electrogram; HBE, His-bundle electrogram; ABL1, distal pair of the ablation catheter located at the posteroseptal region; and ABL2, proximal pair of the ablation catheter.

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Slow Slow AVNRT In Slow Slow AVNRT,

antegrade conduction is down some slow pathway fibers and retrograde up other slow pathway fibers. Earliest atrial activation

is recorded in the posteroseptal region (CSos) where the slow pathway is located. Since conduction to the

ventricle and back to the atrium is via slow pathways, both the AH & HA intervals may be prolonged (not always).

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Slow-Slow AVNRT Slow–fast AVNRT (slow-slow) has long VA intervals and the

earliest retrograde atrial activation near the CSos.1,2 Posterior fast pathways have been reported in up to 6% of

patients with AVNRT3,4 and care must be taken to avoid causing AV block when ablating at the site of the slow pathway. In true clinical practice, the junctional rhythm induced by the

slow pathway ablation does not show any VA conduction. After successful retrograde slow pathway ablation,

antegrade slow pathway conduction remains in patients with slow–slow AVNRT*

*Fujiki A et al. Europace 2008;10:982-987

Presenter

Presentation Notes

1. McGuire MA, Lau K-C, Johnson DC, Richards DA, Uther JB, Ross DL. Patients with two types of atrioventricular junctional (AV nodal) reentrant tachycardia: evidence that a common pathway of nodal tissue is not present above the reentrant circuit. Circulation 1991; 83: 1232–1246. 2. Ross DL, Johnson DC, Dennis AR, Cooper MJ, Richards DA, Uther JB. Curative surgery for atrioventricular junctional (‘AV nodal’) reentrant tachycardia. J Am Coll Cardiol 1985; 6: 1383–1392.[Abstract] 3. Engelstein ED, Stein KM, Markowitz SM, Lerman BB. Posterior fast atrioventricular node pathways: implications for radiofrequency catheter ablation of atrioventricular node reentrant tachycardia. J Am Coll Cardiol 1996; 27: 1098–1105.[Abstract] 4. Delise P, Bonso A, Coro L, et al. Pacemapping of the triangle of Koch: a simple method to reduce the risk of atrioventricular block during radiofrequency ablation of atrioventricular node reentrant tachycardia. Pacing Clin Electrophysiol 2001; 24: 1725–1731.


Slow-Slow AVNRT

V A A V

HA = 150ms AH = 270ms

Presenter

Presentation Notes

Slow–slow type of atypical atrioventricular nodal re-entrant tachycardia. Three surface electrocardiographic leads and intra-cardiac electrograms are shown. Left panel: during atrioventricular nodal re-entrant tachycardia with the AA interval of 420 ms, the HA interval at the His-bundle electrogram was 150 ms and A(CS–His) was 0 ms. The AH interval of 270 ms indicated slow–slow type of atrioventricular nodal re-entrant tachycardia. Right panel: during para-Hisian pacing at a cycle length of 500 ms (slightly longer than tachycardia cycle length), the second stimulus captured His-bundle and shortened QRS width and HA interval. The HA interval during stable para-Hisian pacing was 170 ms and longer than the HA interval during tachycardia suggesting the presence of the lower common pathway. HRA, high right atrial electrogram; HBE, His-bundle electrogram; ABL, ablation catheter electrogram; and CS, coronary sinus electrogram.

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Summary of AVNRT Types

Katritsis D G , Camm A J Europace 2006;8:29-36 Fujiki A et al. Europace 2008;10:982-987

43

EP study during AVNRT

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Catheter Positions

High right atrium near the sinus node (HRA)

Just across the tricuspid valve against septum for His bundle recording (HBE)

Right ventricular apex (RVA)

Coronary sinus (CS)

Mapping/Ablation catheter

45

Induction

Decremental atrial pacing

Premature atrial stimulation

Decremental ventricular pacing

Premature ventricular stimulation

Isoproterenol

46

Induction

Convover: Understanding electrocardiography pg 135

Jump Induction

47

HRA

HBE

RVA

Induction of Typical AVNRT w/ Single Extra

A H V

Slow Fast

A

48

Differentiate AVNRT from:

− AVRT

−Atrial tachycardias

− PJRT

Differential Diagnosis

Presenter

Presentation Notes

Permanent junctional reciprocating tachycardia (PJRT) An arrhythmia is any disorder of your heart rate or rhythm. It means that your heart beats too quickly, too slowly or with an irregular pattern. When the heart beats faster than normal, it is called tachycardia. When the heart beats too slowly, it is called bradycardia

49

Differential Diagnosis

PVC when His bundle is refractory Para-Hisian Pacing Adenosine Administration A-V Wenckebach periodicity or

Dissociation V-A Wenckebach periodicity or

dissociation

50

PVCs on the His

Performed during tachycardia Pace RV when AV node is refractory Look for retrograde atrial conduction V-A conduction while the AV Node is

refractory is diagnostic of an accessory pathway not AVNRT

51

Paced PVC During His Refractory Period

52

Interventional Electrophysiology, Igor Singer,m.D.1997 Pg241

RETROGADE A

PVC on His - Advancing the A

53

PVC on His – No Atrial Activation

54

Parahisian Pacing

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Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

Retrograde conduction traveling from the His to the atrium quickly via the normal conduction system during His capture resulting in a short Spike-A Interval.

Spike-A Interval

ParaHisian Pacing: Retrograde Conduction via the Normal Conduction System during His Capture

☼

56

Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

Retrograde – Conduction travels from the His region through the ventricle to the Purkinje fibers then up the bundle branches, His and finally to the atrium. Thus, the Spike-A interval is long.

☼

Parahisian Pacing: Retrograde Conduction via the Normal Conduction System during loss of His Capture

Spike-A Interval

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Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

☼

Parahisian Pacing: Retrograde Conduction via an Accessory Pathway and Normal Conduction System during His Capture

Spike-A Interval

Retrograde – Conduction travels from the His region to the atrium via the normal conduction system and simultaneously through the ventricle to atrium via the accessory pathway very quickly resulting in a short Spike-A interval.

58

Para-Hisian Pacing: Retrograde Conduction via an Accessory Pathway during loss of His Capture

Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

Retrograde conduction travels from the ventricle to the atrium via the accessory pathway and normal conduction system, but the accessory pathway conduction is faster resulting in a short Spike-A Interval.

☼ Spike-A Interval

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Para-Hisian pacing- Retro AVN conduction; no BPT

Narrow QRS Wide QRS

His and V capture

V capture only

Variable Stim -A

Zipes & Jalife, Cardiac Electrophysiology: From Cell to Bedside, 2nd ed,. 1995, p. 623

Presenter

Presentation Notes

“Retrograde conduction over an accessory pathway is identified either by an absence of change in the timing of atrial activation with the loss of His bundle capture (fig 59-9) or by a delay in atrial activation that is less than the delay in timing of His bundle activation.” pp 623 – 625 Zipes/Jackman In this example, a bypass tract has been ruled out, as there is a significant increase in Stim to A conduction time in the beat that has a wide QRS. The longer Stim - A time on the right is due to the activation reaching the His by cell to cell conduction in ventricular tissue, as opposed to the high speed transmission of signal afforded by direct stimulation of the His as seen on the left. Retrograde atrial activation occurs through the AV node as witnessed by the fixed H-A interval of 50 mSec for both beats.

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Para-Hisian pacing- Retro conduction through BPT

Narrow QRS Wide QRS

His and V capture

V capture only

Fixed Stim - A

Zipes & Jalife, Cardiac Electrophysiology: From Cell to Bedside, 2nd ed,. 1995, p. 623

Presenter

Presentation Notes

“Retrograde conduction over an accessory pathway is identified either by an absence of change in the timing of atrial activation with the loss of His bundle capture (fig 59-9) or by a delay in atrial activation that is less than the delay in timing of His bundle activation.” pp 623 – 625 Zipes/Jackman In this example, a bypass tract has been confirmed, as there is no change in Stim to A conduction time, regardless of His capture in the first beat. The stim – A time of 46 mSec is due to the fixed conduction of a bpt.

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Pharmacological block

*Glatter et al. Electrophysiologic Effects of Adenosine in Patients With Supraventricular Tachycardia. Circulation.1999;99:1034-1040

Block AV node conduction with adenosine or verapamil – Continued V-A conduction is diagnostic of an

accessory pathway during ventricular pacing Adenosine can break some non-AVRT

tachycardias There is no difference in incidence of

tachycardia termination at the AV node in AVRT versus AVNRT after giving adenosine* However with AVRT there may be an increase in

the VA interval but not with typical AVNRT, so this can be used to differentiate between them* Adenosine does not work in every patient

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Adenosine Blocks AV Conduction: Retrograde Conduction via an Accessory Pathway Results in an “A” Wave

Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

☼ Retrograde “A”

Retrograde “A” = Accessory Pathway

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Atrium

Ventricle AV Node

Right Bundle Branch

Left Bundle Branch

☼

No Retrograde “A”

No Retrograde “A” = No Accessory Pathway

Adenosine Blocks AV Conduction: No Retrograde Conduction Means No Accessory Pathway and No “A” Wave Results

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Wenckebach Periodicity or Dissociation

If A-V or VA Wenckebach periodicity or dissociation occurs, it may rule out AVRT A-V or V-A Wenckebach periodicity or

dissociation can occur during AVNRT

65

Differential Diagnoses – Absence of an AV accessory pathway is

confirmed when: Ventricular pre-excitation is absent during sinus rhythm (SR) and

atrial pacing The ventriculo-atrial (VA) interval during the tachycardia is not

lengthened by the occurrence of bundle branch block The tachycardia is not reset by ventricular extrastimuli delivered

when the His bundle is refractory Para-Hisian pacing2 during SR exhibited an exclusive retrograde

AV nodal conduction pattern The VA interval during pacing from the RV apex is shorter than

that during pacing from the RV base.

1.Josephson ME: Supraventricular tachycardias. Clinical Cardiac Electrophysiology. Techniques and Interpretations. Third edition. Philadelphia: Lippincott Williams & Wilkins, 2002, pp. 168-271.

2.Knight BP, Zivin A, Souza J, Flemming M, Pelosi F, Goyal R, Man C, Strickberger SA, Morady F: A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory. J Am Coll Cardiol. 1999;33:775-81.

Presenter

Presentation Notes

1. Josephson ME: Supraventricular tachycardias. Clinical Cardiac Electrophysiology. Techniques and Interpretations. Third edition. Philadelphia: Lippincott Williams & Wilkins, 2002, pp. 168-271. 2. Knight BP, Zivin A, Souza J, Flemming M, Pelosi F, Goyal R, Man C, Strickberger SA, Morady F: A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory. J Am Coll Cardiol. 1999;33:775-81.

66

Differential Diagnoses – Atrial tachycardia is excluded when:

A “V-A-V sequence” (not a “V-A-A-V sequence”) is

observed upon cessation of ventricular pacing associated with 1:1 VA conduction during the tachycardia2

The tachycardia is reproducibly terminated with ventricular extrastimuli not reaching the atrium.

Heidbuchel H, Jackman WM: Characterization of subforms of AV nodal reentrant tachycardia. Europace. 2004;6:316-29

Presenter

Presentation Notes

1. Heidbuchel H, Jackman WM: Characterization of subforms of AV nodal reentrant tachycardia. Europace. 2004;6:316-29.

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VAAV Response

The response to ventricular pacing with 1:1 VA conduction during an SVT in a patient with AT. The electrogram response upon cessation of ventricular pacing is an atrial-atrial-ventricle (A-A-V). Knight et al. JACC Vol. 33, No. 3, 1999. Rapid Diagnosis of Atrial Tachycardia. March 1, 1999:775–81

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VAAV Response

Note after stopping ventricular pacing the last paced V is followed by an “entrained” A, then by a spontaneous tachycardia A and V. This V-A-A-V response is diagnostic of AT.

Roberts-Thompson et al. Atrial Tachycardia: Mechanisms, Diagnosis, and Management. Curr Probl Cardiol 2005;30: 529-573.

Presenter

Presentation Notes

This shows ventricular pacing during tachycardia. Note after cessation of pacing the last paced V is followed by an “entrained” A, followed by a spontaneous tachycardia A and tachycardia V. This V-A-A-V response following the cessation of ventricular pacing with atrial entrainment is diagnostic of AT.

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VAV Response

The response to ventricular pacing with 1:1 VA conduction during tachycardia in a patient with typical AVNRT. The electrogram response upon cessation of ventricular pacing is an atrial-ventricle (A-V).

Knight et al. JACC Vol. 33, No. 3, 1999. Rapid Diagnosis of Atrial Tachycardia. March 1, 1999:775–81

Presenter

Presentation Notes

Figure 1. The response to ventricular pacing with 1:1 ventriculoatrial conduction during tachycardia in a patient with typical atrioventricular nodal reentrant tachycardia. Shown are leads V1, I, II, and III and the intracardiac electrograms recorded at the high right atrium (HRA), His-bundle electrogram (HBE) and right ventricular apex (RVA). The tachycardia cycle length is 430 msec. Ventricular pacing at a cycle length of 370 msec results in 1:1 ventriculoatrial conduction. The electrogram response upon cessation of ventricular pacing is atrial-ventricle (A-V). S 5 ventricular pacing stimuli.

70 70

Mapping and Ablation Objective Modify the slow pathway of the AV node in order

that it will no longer conduct

Slow Pathway Modification Ablation catheter is positioned “anatomically” on

the tricuspid valve annulus posterior and inferior to the His bundle at the level of the CS ostium. If unsuccessful, the catheter is moved anterior and superior in a stepwise fashion until successful.

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Triangle of Koch

Zipes :catheter ablation of arrhythmias Selective transcatheter modification of the atriovetricular node

His bundle/compact AVN are at the apex of Koch’s triangle CS ostium forms the posterior portion of Koch’s triangle Tricuspid annulus defines the third face of Koch’s triangle

Tendon of Todaro

Membranous Septum

http://www.rjmatthewsmd.com/Definitions/anatomy_ofthe_heart.htm

http://www.rjmatthewsmd.com/Definitions/anatomy_ofthe_heart.htm

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Catheter Mapping Techniques




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P1 P2

M1 M2 A1 A2

Netter, F. Clinical Symposia. Novartis Pharmaceuticals Corporation, Summit, NJ, 1997.

His Bundle Recording Site


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P1 P2 M1 M2 A1

A2

Netter, F. Clinical Symposia. Novartis Pharmaceuticals Corporation, Summit, NJ, 1997.


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LAO RAO

His

CS RV

ABL

His

RV

CS

ABL

Radiographic Positioning

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Zipes: catheter ablation of arrhythmias

Selective transcatheter modification of the

atriovetricular node pg 176 S.Deshpande, M Jazayeri, A dhala, Z Blanck, J. Sra, S.

Bremner, M. Aktar


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Slow Pathway Potentials In the region of the Triangle of Koch, potentials

separate from the local atrial potential and His potential can be recorded. These are slow pathway (SP) potentials. Near the Csos the atrial potential may be sharp, but the

SP potential may have a low frequency and amplitude. Moving slightly more anterior the SP potential may be

more discrete and the atrial potential will be less well defined. Moving even more anterior, neither an SP or His

potential can be recorded. This is the location of the AVN.

Francis Murgatroyd and Andrew Krahn. Handbook of cardiac Electrophysiology. ReMEDICA Publishing. London, 2002, pg. 80

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Slow Pathway Potentials

80

Slow pathway potential

Junctional rhythm

During ablation

Slow Pathway Potentials

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Junctional Rhythm During Ablation During ablation, thermal injury to the slow pathway

may enhance the automaticity of the posterior extension of the AV node and induce junctional rhythm that conducts to the atrium through the retrograde fast pathway Junctional beats associated with VA block during

slow pathway ablation are suggested as a marker of injury to the fast pathway, which could induce AV block Loss of VA conduction during slow pathway

ablation is not always associated with AV conduction block.

Fujiki A et al. Europace 2008;10:982-987

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Schematic diagram summarizing the distribution of NF160, Cx43, Cx45, Cx40, and HCN4 in the rabbit AV junction. TV indicates tricuspid valve; TT, tendon of Todaro. The posterior nodal extension is the slow pathway and responsible for the junctional rhythm pacemaker site.

AV Junctional Tissue

Fluorescent imaging of the AV junction showing the pacemaker area of AV Junctional Rhythm marked by the blue oval. This shows AV Junctional Rhythm breakthrough to the atrium by the fast pathway exit.

Dobrzynski, H, Nikolski, VP, Sambelashvili, AT, Greener, ID, Yamamoto, M, Boyett, MR, Efimov, IR. Site of Origin and Molecular Substrate of Atrioventricular Junctional Rhythm in the Rabbit Heart. Circulation Research. 2003;93:1102.).

Circulation Research. 2003;93:1102

Presenter

Presentation Notes

Posterior nodal extension: The posterior nodal extension (PNE) is not only responsible for junctional rhythm, but also is the slow pathway for conduction into the compact AV node.and as such, it plays an important role in AV node reentry. The slow pathway expresses NF160 (confirming that the tissue is similar to that of compact AV node), Cx45, and a low amount of Cx40, but predominately it does not express Cx43, which is present at high densities in adjacent bundles and tissue layers of the triangle of Koch. The expression of Cx45, but not Cx43, could help explain the low conduction velocity of the pathway. The lack of Na+ channels in the AVN may also contribute to the slow conduction. However, it is unlikely to be as important as connexin expression, because a reduction in the Na+ conductance can produce only a three-fold reduction in the conduction velocity, whereas a decrease in intercellular coupling can result in a 100-fold reduction. In addition, a decrease in the intercellular coupling leads to a paradoxical improvement in the safety of conduction. There are also horizontally orientated bundles of Cx43-expressing cells. However, those bundles express Cx43 and not NF160, and are distinct from the Cx43-negative tract (they run parallel to the Cx43-negative tract but superior to it). Based on the location, the Cx43-negative tract, rather than the bundles of atrial-like Cx43-expressing cells, probably comprises the slow pathway and, therefore, constitutes the PNE. However, it is still possible that the bundles of Cx43-expressing cells may play a role in AV node reentry, because a significant difference in the conduction velocity of the two adjacent bundles could be responsible for longitudinal dissociation and reentry. Position of the Leading Pacemaker Site The junctional pacemaker site in the majority of cases is located not in the compact node or nodal-His area, but in the area posterior to the compact node between the coronary sinus and tricuspid valve. It is well known that the leaflets of the tricuspid valve have pacemaker activity. However, usually the pacemaker site is located near the coronary sinus. Some studies have shown that the coronary sinus can have rhythmic activity. However, usually the pacemaker site corresponds to AVN-like cells. During premature stimulation and reentry, conduction occurs along the slow pathway (PNE), and the junctional pacemaker site corresponds to that pathway most often. This suggests that the junctional pacemaker site is a part of the PNE. This conclusion is supported by the histology in which Masson’s trichrome shows that the junctional pacemaker site corresponds to a cluster of small nodal-like cells extending from the compact node toward the coronary sinus along the tricuspid valve, which describes the PNE. In the rabbit, NF160 is known to be expressed in other parts of the conduction system, and it can be found at the junctional pacemaker site (as well as the compact node and His bundle) and this is additional evidence that the junctional pacemaker site is a part of the PNE. At the junctional pacemaker site, Cx43 is largely not expressed, whereas Cx45 is expressed just as the compact node. All 3 connexins (Cx43, Cx45, and Cx40) are expressed in variable amounts in the rabbit compact node, and in the AVN and His bundle branches in other species. The slowing of pacemaker activity by Cs+ showed that If is important in pacemaker activity, and at the junctional pacemaker site, only the nodal-like cells expressed the If channel protein, HCN4. HCN4 (the main HCN channel protein) was abundantly expressed at the junctional pacemaker site. In expressing HCN4, the cells of the junctional pacemaker site are like the cells of te compact node, and this confirms that the junctional pacemaker site is an integral part of the PNE and conduction system of the heart. The site of the origin of the pacemaker activity can originate from the area of the His bundle. However, the His bundle pacemaker activity could have been related to injury during dissection. Site of Origin and Molecular Substrate of Atrioventricular Junctional Rhythm in the Rabbit Heart Halina Dobrzynski*, Vladimir P. Nikolski*, Alexandre T. Sambelashvili, Ian D. Greener, Mitsuru Yamamoto, Mark R. Boyett, Igor R. Efimov � Circulation Research. 2003;93:1102

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Junctional Rhythm during RF application The peri-AV nodal region is highly innervated by the autonomic nervous system and may be stimulated during the AVNRT RF ablation, generating junctional tachycardia. It also may be due to the effects of the local release of norepinephrine causing an abrupt rise and fall in the rate. Junctional rhythm may result from heat injury to the slow pathway.

Fujiki A et al. Europace 2008;10:982-987


Junctional Rhythm during RF application

Tachycardia Circuits

Junctional Rhythm Mechanism during Ablation

Typical AVNRT Conducts to the atrium

Fast-Slow/Slow-Slow do not conduct to the atrium

Presenter

Presentation Notes

Schematic representation of atrioventricular nodal re-entrant tachycardia circuit (upper panels) and junctional rhythm during slow pathway ablation (lower panels). In typical atrioventricular nodal re-entrant tachycardia, radiofrequency injury to the slow pathway results in junctional rhythm conducting to the atrium through the retrograde fast pathway of the atrioventricular node (left). In either fast–slow type (middle) or slow–slow type (right) of atypical atrioventricular nodal re-entrant tachycardia, radiofrequency injury to the slow pathway results in junctional rhythm, but it does not conduct to the atrium. CS, coronary sinus; and TV, tricuspid valve. ★ = ablation site.

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Inability to reinduce tachycardia

Not favor

Loss of dual AVN physiology

Prolongation of AH interval

Complete heart block *

RF Ablation Endpoints

* Not a desirable endpoint for slow-pathway ablation.

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Post RF Stimulation

No slow pathway conduction

AVN ERP

No His or V

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Fast Pathway ERP Post Ablation

A significant shortening of the fast pathway (FP) ERP (improved conduction) after successful slow pathway (SP) ablation often occurs, possibly due to: – Increased sympathetic tone which can shorten

both the antegrade and retrograde FP ERPs – Loss of the electronic interactions between the

FP and SP

Presenter

Presentation Notes

Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common supraventricular tachycardias in childhood.1,2 The occurrence of AVNRT seems to be age related because it happens very rarely in infants and young children. Besides, previous studies had demonstrated the specific electrophysiologic characteristics and changing AV nodal recovery properties in pediatric patients.3-6 Selective radiofrequency (RF) catheter ablation of the slow pathway has afforded an ideal method to treat the patients with AVNRT.7-12 This method was demonstrated to be safe and effective in children with AVNRT.13-16 Previous studies in adults have shown a significant shortening of the fast pathway effective refractory period (ERP) after successful slow pathway ablation.17-21 However, information on AVNRT in childhood is limited.22 The purpose of this retrospective study was to investigate the effect of radiofrequency catheter ablation on the dual AV nodes in pediatric patients with AVNRT. Gillette PC. The mechanism of supraventricular tachycardia in children. Circulation 1976;54:133-139. Ko JK, Deal BJ, Strasburger JF, Benson DW Jr. Supraventricular tachycardia mechanisms and their age distribution in pediatric patients. Am J Cardiol 1992;69:1028-1032. Lee PC, Chen SA, Chiang CE, Tai CT, Yu WC, Hwang B. Clinical and Electrophysiological Characteristics in Children with Atrioventricular Nodal Reentrant Tachycardia. Ped Cardiol 2003;24:6-9. Lin MH, Young ML, Wu JM, Wolff GS. Developmental changes of atrioventricular nodal recovery properties. Am J Cardiol 1997;80:1178-1182. Kuo CT, Wu JM, Lin KH, Young ML. The effects of aging on AV nodal recovery properties. PACE 2001;24:194-198. Blaufox AD, Rhodes JF, Fishberger SB. Age related changes in dual AV nodal physiology. PACE 2000;23:477-480. Kay GN, Epstein AE, Dailey SM, Plumb VJ. Selective radiofrequency ablation of the slow pathway for the treatment of atrioventricular nodal reentrant tachycardia. Circulation 1992;85:1675-1688. Jackman WM, Beckman KJ, McClelland JH, et al. Treatment of supraventricular tachycardia due to atrioventricular nodal reentry by radiofrequency catheter ablation of slow pathway conduction. N Engl J Med 1992;327:313-318. Jazayeri MR, Hempe SL, Sra JS, Dhala AA, Blanck Z, Deshpande SS, Avitall B, Krum DP, Gilbert CJ, Akhtar M. Selective transcatheter ablation of the fast and slow pathways using radiofrequency energy in patients with atrioventricular nodal reentrant tachycardia. Circulation 1992;85:1318-1328. Haissaguerre M, Gaita F, Fischer B, Commenges D, Montserrat P, d'Ivernois C, Lemetayer P, Warin JF. Elimination of atrioventricular nodal reentrant tachycardia using discrete slow potentials to guide application of radiofrequency energy. Circulation 1992;85:2162-2175. Langberg JJ, Leon A, Borganelli M, Kalbfleisch SJ, el-Atassi R, Calkins H, Morady F. A randomized, prospective comparison of anterior and posterior approaches to radiofrequency catheter ablation of atrioventricular nodal reentry tachycardia. Circulation 1993;87:1551-1556. Chen SA, Chiang CE, Tsang WP, et al. Selective radiofrequency catheter ablation of fast and slow pathways in 100 patients with atrioventricular nodal reentrant tachycardia. Am Heart J 1993;125:1-10. Kugler JD, Danford DA, Deal BJ, Gillette PC, Perry JC, Silka MJ, Van Hare GF, Walsh EP. Radiofrequency catheter ablation for tachyarrhythmias in children and adolescents. N Engl J Med 1994;330:1481-1487. Teixeira OH, Balaji S, Case CL, Gillette PC. Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in children. PACE 1994;17:1621-1626. Silka MJ, Halperin BD, Hardy BG, McAnulty JH, Kron J. Safety and efficacy of radiofrequency modification of slow pathway conduction in children < or = 10 years of age with atrioventricular node reentrant tachycardia. Am J Cardiol 1997;80:1364-1367. Kugler JD, Danford DA, Houston KA, Felix G. Pediatric radiofrequency catheter ablation registry success, fluoroscopy time, and complication rate for supraventricular tachycardia: comparison of early and recent eras. J Cardiovasc Electrophysiol 2002;13:336-341. Natale A, Klein G, Yee R, Thakur R. Shortening of fast pathway refractoriness after slow pathway ablation. Effects of autonomic blockade. Circulation 1994;89:1103-1108. Strickberger SA, Daoud E, Niebauer M, Williamson BD, Man KC, Hummel JD, Morady F. Effects of partial and complete ablation of the slow pathway on fast pathway properties in patients with atrioventricular nodal reentrant tachycardia. J Cardiovasc Electrophysiol 1994;5:645-649. Takahashi A, Iesaka Y, Igawa M, et al. Atrioventricular nodal physiology after slow pathway ablation. PACE 1994;17:2137-2142. Basta MN, Krahn AD, Klein GJ, Rosenbaum M, Le Feuvre C, Yee R. Safety of slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a long fast pathway effective refractory period. Am J Cardiol 1997;80:155-159. Geller JC, Biblo LA, Carlson MD. New evidence that AV node slow pathway conduction directly influences fast pathway function. J Cardiovasc Electrophysiol 1998;9:1026-1035. Van Hare GF, Chiesa NA, Campbell RM, Kanter RJ, Cecchin F; Pediatric Electrophysiology Society. Atrioventricular nodal tachycardia in children: Effect of slow pathway ablation on fast pathway function. J Cardiovasc Electrophysiol 2002;13:203-209.

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Zhu DWX, Maloney JD. Radiofrequency catheter ablative therapy for atrioventricular nodal reentrant tachycardia. In Singer I: Interventional Electrophysiology. Williams & Wilkins, Baltimore, 1997, pp 310.

AVN conduction curve

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AVN Wenkebach Post RF Ablation

If the FP ERP is too long, you can get Wenkebach while at rest

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Lower Common Pathway

Hein Heidbüchel. Characterization of subforms of AV nodal reentrant tachycardia.Europace.Volume 6, Issue4P.p. 316-329

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Upper and Lower Common Pathways Upper Common Pathway (UCP) Lower Common Pathway (LCP)

Without a UCP the AH during SVT and pacing is the same (350ms), with a UCP of AVN tissue between the AVN circuit and atrium (stippled area) in SVT, the AH = 320 ms and during atrial pacing at the same CL as SVT, the AH = 380 msec or 60 msec more than SVT

Without an LCP the HA (dotted lines) during SVT and pacing is the same (50ms) up the retrograde fast pathway, with an LCP of AVN tissue between the AVN circuit and His bundle (stippled area) in SVT, the HA = 20 ms and during ventricular pacing at the same SVT CL, the HA = 80 msec or 60 msec more than SVT

Miller et al. Atrioventricular nodal reentrant tachycardia: studies on upper and lower 'common pathways‘.Circulation 75, No. 5, 930-940, 1987.

Presenter

Presentation Notes

FIGURE 1. Ladder diagram depicting the use of atrial pacing to assess a UCP. Diagrams on the left show events during SVT; those on the right show atrial pacing at the SVT cycle length. Top (no UCP), Atrium, AV nodal (AVN) tachycardia circuit and His bundle are as shown. During SVT the impulse travels antegradely down a slow AVN pathway, retrogradely up a fast pathway. The AH interval measured as shown by dotted lines is 350 msec. During atrial pacing at SVT cycle length, the impulse takes the same course antegradely as in SVT (slow pathway); the AH measured as shown is also 350 msec. Bottom, An upper common pathway of AVN tissue has been inserted between the AVN circuit and atrium (stippled area). In SVT, the AH as measured above is now 320 msec, although the time spent in the slow pathway is unchanged. During atrial pacing at the same cycle length, the AH as measured above is now 380 msec or 60 msec more than SVT. FIGURE 2. Ladder diagram depicting the use of ventricular pacing to assess a lower common AV nodal pathway (LCP). Format similar to figure 1. Top (no LCP), In SVT. the HA shown as measured by dotted lines is 50 msec. During ventricular pacing, the impulse takes the same course retrogradely (fast pathway) as during SVT; the HA measured as shown is also 50 msec. Bottom, A lower common pathway of AVN tissue has been inserted between the AVN circuit and His bundle (stippled area). In SVT, the HA as measured above is 20 msec, although the time spent in fast and slow AVN pathways is unchanged. During ventricular pacing at SVT cycle length, the HA as measured above is now 80 msec, or 60 msec more than during SVT.

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Potential Complications

3rd degree AV block

– Rare when targeting slow pathway – 10% when targeting fast pathway

Other EP study related complications

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Posterior Fast Pathway Input

The fast pathway retrograde input is usually located anteriorly close to the His bundle, but rarely it may be located in the posteroseptal RA, where the slow pathway ablation is performed. Thus, occasionally while ablating the slow pathway you could ablate the retrograde fast pathway and affect the antegrade fast pathway if the location of the antegrade and retrograde fast pathways is anatomically similar. Therefore, failure to recognize the presence of a

posterior fast pathway input may result in AV block.

Lee, Pi-Chang; Chen, Shih-Ann; Hwang, Betau. Current Opinion in Cardiology: March 2009 - Volume 24 - Issue 2 - p 105-112. Atrioventricular node anatomy and physiology: implications for ablation of atrioventricular nodal reentrant tachycardia

94

Posterior Fast Pathway Input

The retrograde conduction route is very low so transient heart block can occur To avoid the low retrograde conduction routes, RF energy (brown dots) is delivered while viewing the precise geometry

Lee, Pi-Chang; Chen, Shih-Ann; Hwang, Betau. Current Opinion in Cardiology: March 2009 - Volume 24 - Issue 2 - p 105-112. Atrioventricular node anatomy and physiology: implications for ablation of atrioventricular nodal reentrant tachycardia

Low site

Low site

Presenter

Presentation Notes

Geometric anatomy associated with the activation routes of the retrograde VA conduction is demonstrated in the left posterior oblique view. Notice that the positions of the retrograde conduction routes were both uncommonly low so that transient heart block could easily happen during the previous session of RF catheter ablation. To avoid the retrograde conduction routes, RF energy (deep brown dots) was delivered under surveillance of the precise geometric mapping in both cases. CSO, coronary sinus ostium; FO, foramen ovale; IVC, inferior vena cava; RAA, right atrial appendage; RF, radio frequency; SVC, superior vena cava; TT, tendon of Todaro; TV, tricuspid valve annulus. Adapted with permission from [25].

95

Conclusions

Easy to diagnose Easy to treat High success rate with RFA

96

QUESTIONS?

Health & Medicine

9.avnrt chang sl-0324-2