Organized Atrial Tachycardias

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• Organized Atrial Tachycardias
• Focal ectopic atrial tachycardia
• Typical isthmus - dependent flutter
• dependent on the isthmus between
• tricuspid annulus - inferior vena cava
• - clockwise flutter
• - counterclockwise flutter
• - lower loop reentry
• Macroreentry non-isthmus dependent flutter
• - prior atrial surgery or scarring
• - left atrial flutter

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Common Flutter Isthmus - dependent
broad reentry paths outside the
isthmus interpatient variability - path
anterior /- posterior to SVC -
areas of block along crista
terminalis - 17 of patients have
partial block (double potentials) in
isthmus
SVC
FO
CS
IVC
Kalman et al
Shah Circ 963904, 1997 Olgin Circ 921365,
1995 Cosio Pace 19841, 1996 Kalman Circ
94398, 1996 Nakagawa Circ 94407, 1996
Takahashi JACC 331996, 1999 Arenal et al
Circulation 992771, 1999
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Counterclockwise Atrial Flutter
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Confirming right atrial location of reentry with
entrainment
s
s
s
s
In the circuit post- pacing interval AFl
cycle length
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Termination of A Flutter
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Conduction block in the IVC - Tricuspid
IsthmusSchwartzman et al J Am Coll Cardiol 1996
281519Shah et al J Am Coll Cardiol 2000 35
1478

• After RF terminates atrial flutter conduction
  through the isthmus often persists
• Conduction slowing often occurs before isthmus
  block
• conduction slowing can be rate dependent
• Recovery of conduction after initial isthmus
  block is common

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Methods of confirming conduction block depend
on assessing conduction of stimulated
wavefronts from one side of the ablation
line to the opposite side of the line
No block
Block
cs pacing
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Assessing isthmus block during CS pacing
Double potentials gt 100 ms
No block
Block
reversal of electrogram polarity opposite to the
pacing site
Tada et al JACC 200138750
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Markers of Conduction Block

• increase in trans-isthmus conduction time
• differential pacing
• double potentials
• 100 - 110 ms interval between potentials
• along entire ablation line
• differential pacing
• reversal of electrogram polarity on the opposite
  side of the ablation line from the pacing site
• change in p-wave morphology pacing lateral to the
  ablation line

Tada JACC 200138750. Tai JICE 2002777.
Chen JICE 2002767. Tada JCE 200112393. Shah
JCE 199910662. Circ 1997962505. Nakagawa
Circ 1996943204. Poty Circ 1996943204
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During CS pacing conduction across the
posterior right atrium through the crista
terminalis can falsely suggest conduction through
the isthmus when block is present
Crista shunt
Scaglione et al J Cardiovasc Electrophysiol
2000 11387 Anselme et al Circulation
20011031434
cs pacing
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Pacing from lateral RA
Gap in the RF line
s
s
s
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Large Tip electrode with high power generator
Creating Bigger Ablation Lesions
RF ablation with internal saline cooling
RF ablation with Saline Irrigation
Compared to standard 4 mm electrode
irrigated/cooled electrodes - decrease number
of lesions required for block - decrease
fluoroscopy time 8 mm electrode has similar
efficacy to cooled electrode
Tsai Circulation 1999 Jais Circulation 2000
Schreieck J Cardiovasc Electrophy 2002
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• Septal Line vs Lateral Line
• Similar efficacy
• Increased risk for septal line
• impairment of AV node conduction
• in 5 / 36 patients with septal line
• - RF in CS with cooled tip or large electrode
  catheters can occlude the distal right coronary
  artery

septal
TV
CS
lateral
IVC
Anselme et al Am J Cardiol 2000 Ouali et al J
Cardiovasc Electrophys 2002 Tai et al Circulation
20011041501
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Drug therapy vs first-line ablation for atrial
flutter Natale et al J Am Coll Cardiol 2000
61 patients gt 1 episode of atrial flutter no
prior antiarrhythmic drug therapy
Antiarrhythmic Drug Therapy sotalol,
amiodarone flecainide, procainamide, propafenone
RF Ablation gt 90 reduction in electrogram
amplitude along ablation line
Atrial Flutter Recurrence Atrial
Fibrillation Sinus rhythm last f/u
93 60 36
6 29 80
mean follow-up 22 months
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Atrial Fibrillation after Catheter Ablation of
Atrial Flutter Hsieh et al J Interv Card
Electrophysiol 20027225
n 212 n 121
Recurrent atrial flutter 9
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Is it atrial flutter?
Clockwise Flutter
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• Organized Atrial Tachycardia
• p-waves not typical for isthmus
• dependent flutter
• isthmus - dependent flutter
• - prior atrial surgery / scar
• - cardiac transplantation
• Macroreentry non-isthmus dependent flutter
• - prior atrial surgery or scarring
• - left atrial flutter
• Focal atrial tachycardia

ectopic AT
Flutter
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Late after ASD repair Is it atrial flutter?
Palpitations late after ASD repair
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Atrial Reentry Circuits After Surgery
for Congenital Heart Disease Delacretaz et al 2000
47 circuits in 20 patients Common Flutter -
18 Lateral Wall Circuit - 19 Septal
Circuit - 8 Undefined - 2 Successful
ablation (free from AFl recurrence) - 80
follow-up 3 - 46 mo
SVC
ASD patch
FO
CS
IVC
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Left Atrial Mapping for Tachycardias After Mitral
Surgery Markowitz et al JACC 2002 391973
Left atrial macroreentry
Focal
Right Atrial Tachycardia
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Left Atrial Flutter Jais
et al Circulation 2000- positive p wave in
V1- atypical for common flutter in II, III, AVF
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Scar related (Incisional) Macroreentrant Atrial
Tachycardias

• Non-isthmus dependent atrial tachycardia can not
  be reliably predicted from the ECG
• Ablation is often more difficult
• multiple circuits are common
• difficult to define critical isthmus
• difficult to achieve block across an isthmus
• Mapping is facilitated by an advanced mapping
  system
• Successful ablation 50 88
• Akar, et al.2001,Chan, et al.2000,Delacretaz, et
  al.2001, Nakagawa, et al.2001,Triedman, et
  al.1997 Jais, et al.2000,Saoudi, et al.2001,Tai,
  et al.2001,Thomas, et al.2000

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Catheter Ablation of Atrial Flutter

• First line therapy for recurrent, typical flutter
• Excellent efficacy, low risk
• Subsequent atrial fibrillation occurs in
  gt20-30 of patients
• Non-isthmus dependent flutter is occasionally
  encountered, particularly in patients with prior
  atrial surgery
• efficacy is less predictable