2. Atrial Flutter A macro-reentrant atrial arrhythmia that is
very regular with rates typically between 240 and 350 bpm1. There
are several recognized variations of atrial flutter. 1. Schamroth,
L. The Disorders of Cardiac Rhythm. Oxford, UK, Blackwell Ltd,
1971, p 49.2
3. Proposed Classification of Atrial Flutter A NASPE position
paper proposed an open classification Typical AFL (CCW) Reverse
Typical AFL (CW) Saoudi, N, Cosio, F, Waldo, A, et. al. JCE Vol.
12, No. 7, pp.852-866, July, 20013
4. Cardiac Anatomy TA ER/EV ISTHMUSNetter, F. Clinical
Symposia. Novartis Pharmaceuticals Corporation, Summit, NJ,
1997.Atrial Flutter is a reentrant tachycardia in which the
reentrantcircuit is contained in the right atrium. The isthmus is
formed bythe IVC and Eustachian ridge/valve (ER/EV) on one side and
theTA on the other. Conduction during fast rates cannot
transversethe ER/EV. 4
5. Atrial Flutter5
6. Typical Atrial Flutter (CCW) In typical AF the reentrant
circuit revolves around6 the tricuspid annulus in a
counterclockwise pattern
7. Reverse Typical Atrial Flutter (CW) In reverse typical the
reentrant circuit revolves7 around the tricuspid annulus in a
clockwise pattern.
8. Electrogram Recognition Rate P wave morphology 12 Lead On
the surface ECG it may often be very difficult to see the flutter
waves. This may be overcome with vagal maneuvers or Adenosine
administration.8
9. P wave Morphology cont Adenosine9
10. Electrogram Recognition Isthmus dependent Typical Atrial
Flutter (CCW) Atrial rhythm: regular and very stable (240-340 bpm)
P wave:Characteristic sawtooth pattern with a negative deflection
in, II and III, and/or aVf (inferior axis) and positive in V1 (but
may be negative or biphasic). Leads I and aVL show low-voltage
deflections Ventricular rate: usually 2:1 in both typical and
reverse typical aflutter (higher degrees of AV block can occur in
patients with AV nodal block disease or increased vagal
tone)10
12. Electrogram : Reverse Typical AFL On the surface ECG
typical atrial flutter looks similar to reverse typical flutter,
however in Reverse Typical Aflutter (CW), the p-waves appear to be
mostly positive in the inferior leads (II, III, aVf). P waves
display an superior axis. Wide, negative deflections in V1 (may be
most specific diagnostic sign) May demonstrate atypical p -wave
morphologies12
13. Reverse Typical Atrial Flutter13
14. Catheter Positions Catheter position varies from lab to lab
Quadripolar at the His (to define septum/HBE) Multipolar in the CS
(to define CS ostium, and perform septal pacing) Multipole
(Duo-Decapolar) at the RA (to define activation anterior/lateral to
CT and isthmus). This may eliminate the HRA and CS catheters
Quadripolar at the RVA (safety pacing) optional Exploring/Rove
(mapping/RFA)14
15. Catheter Positions15
16. Isthmus Mapping Catheters16
17. Typical Atrial Flutter Typical AFL Reverse Typical AFL A 20
pole catheter placed around the TA with the distal pair of
electrodes near the posterior free wall and proximal pair, the
anterior septum, reveals counterclockwise activation around the TA
in typical AF, and clockwise in reverse typical AF.17
18. Pre Ablation Methods and Strategies Induction Conduction
barriers Diagnosis Mapping Entrainment Pacing maneuvers Strategy
Pacing maneuvers in SR Base line measurements (Pre and post
comparison)18
19. Atrial Flutter Induction Induction methods for flutter
include: Extrastimulas testing Atrial burst pacing Isoproterenol
Induction or termination using rapid atrial pacing may also induce
atrial fibrillation (due to short cycle lengths)19
20. Intracardiac Electrogram Recognition CCW Mapping Sequential
activation around the right atrium20
21. Intracardiac Electrogram Recognition CW Mapping Sequential
activation around the right atrium21
22. Conduction Barriers in AFL22
23. Concealed Entrainment PPI :Post pacing interval FCL:
Flutter cycle length Post pacing intervals PPI=TCL23 15. Lesh et
al. JCE Vol.7,No 4, April 1996
24. Entrainment Mapping24 Olgin et al. J of Cardiovasc
Electrophysiology Vol.7,No.11,Nov 96
25. Double Potential Crista terminalis is an important
anatomical and functional barrier in atrial flutter Atriotomy sites
and the eustachian ridge are25 examples of fixed lines of
block
26. Double Potentials26
27. Management of Typical and Reverse Typical AFL Medication
Control the ventricular response Convert to sinus rhythm
Anticoagulation Atrial overdrive pacing Cardioversion AV node
ablation Isthmus RF ablation27
28. AV Node Ablation In some situations medical therapy and
ablation attempts are unsuccessful. In circumstances it may be
necessary to ablate the AV node and implant a permanent
pacemaker.28
29. Goal of RF Ablation of Atrial Flutter The goal of RF
ablation is the elimination of conduction within the critical zone
of the reentrant circuit necessary to sustain atrial flutter.
Tachycardia may be terminated by one lesion point along the Isthmus
however this method is associated with a high recurrence rate In
any of the targeted ablation areas, the key to success is a
contiguous, transmural lesion from one anatomic barrier to
another29
30. Ablation Methods and Strategies Methods Point by point Drag
(Linear lesion) Strategy During SR No acute end point During SR
with CS pacing Shift in activation During tachycardia Termination
of tachycardia30
31. Orientation During RF Ablation Atrial flutter ablation is
anatomically guided along with electrogram verification of the LAO
location between the: Tricuspid annulus (TA) and CSos (septal
isthmus: 5 oclock ) TA and inferior vena cava (IVC) (posterior
isthmus: 6 oclock) TA and IVC (lateral isthmus 7 oclock) No matter
whether it is typical or reverse typical AF, the ablation sites are
always either the septal or posterior isthmuses. However, ablation
can be performed anywhere along the isthmus, from the entrance to
the exit of the 31isthmus.
32. Ablation Sites TV CS Long distance IVC Short distance but
more 0 but many smooth septal isthmus valleys 700 lateral isthmus
600 posterior isthmus LAO32Nakagawa. H., et al., Role of the
Tricuspid Annulus and the Eustachian Valve/Ridge on Atrial Flutter:
Relevance to Catheter Ablation of theSeptal Isthmus and a New
Technique for Rapid Identification of Ablation Success.
Circulation. 1996;94:407-424.
33. Ablation Challenges: Variability of Trabeculated Isthmus
Blood pool Non-uniformity of the Posterior Isthmus highly variable
trabeculated patterns found inferior to the Cs ostium as well as at
the inferior rim of the Cs ostium within the flutter isthmus
Eustachian valve and ridge 5. Nakagawa. H., et al., Role of the
Tricuspid Annulus and the EustachianWaki, K. et.al. JCE Vol 11. No
1 January 2000 pg 92 Valve/Ridge on Atrial Flutter: Relevance to
Catheter Ablation of the Septal Isthmus and a New Technique for
Rapid Identification of Ablation Success. . 33 Circulation.
1996;94:407-424.
34. RAMPTM Sheath for Access to the sub- Eustachian
recess34
37. Catheter ablation of the Posterior Isthmus RAO LAO ablation
catheter ablation catheter SVC SVC CSo IVC37 IVC
38. Ablation technique Catheter Normally an 8mm tip ablation
catheters is used, but for very thick or problematic isthmuses, an
irrigated ablation catheter can be used. Some doctors may even use
a 4mm tip, but it will be a longer procedure and recurrence may be
higher Electrogram criteria Initial lesion point should show big V
small A. Electrogram should be evaluated after each point ablation.
(Point by point ablation) Observe for a decrease in the electrogram
amplitude and keep ablating spots with significant A waves Use
pacing maneuvers to assess the creation of complete isthmus
conduction block38
39. Fluoroscopic Orientation During RF Ablation Ablation of the
isthmus in either the RAO or LAO projection LAO projection allows
identification of the position in a clockface relative to the
location of the TVA (point to point) LAO projection allows
visualization of the RF catheter as it is withdrawn into the IVC
RAO projection allows discrimination of the Anterior (TVA), initial
position, to Inferior (IVC), final position, during creation of the
lesion in the isthmus39
40. Further Considerations during AFL Ablation RF Power
considerations With 4mm tip ablation catheters, 30-50 Watts will be
adequate, but 8mm tip catheters often require more than 50 Watts
Anatomical considerations Convective effects of blood pooling and
variable, complex anatomy may require higher power applications
Patient discomfort in region of IVC due to stimulation of nerve
plexus 40
41. Ablation End Point Termination of the clinical arrhythmia
With this criteria alone there is a high recurrence rate Inability
to re-induce atrial flutter; Confirmation of Bi-Directional block.
Pre and post timing Block indicated by a multipolar catheter41
42. Termination During Ablation42
43. CS Pacing Pre Ablation (in sinus rhythm)43
44. LRA Pacing Pre Ablation (in sinus rhythm)44
45. Bi-directional Block Proven by pacing both lateral and
medial to the ablation line Block is demonstrated by a linear
activation sequence at both sites45
46. CS Pacing Post Ablation with Isthmus Block 46
47. CS Pacing During Ablation with the occurrence of Isthmus
Block 47
48. LRA Pacing Post Ablation with Isthmus Block48
49. Summary of Complete Bi-Directional Block 19-20 Ablation CT
LLRA 1-2 CS Pre Post 19-20 19-20 CS Pacing Site 1-2 1-2 19-20 19-20
LLRA 1-2 1-249
50. Other Methods to Confirm Bi-directional Block Vector
Mapping with the BDB Catheter Searching for Gaps in the Blockline
Differential Pacing50
51. Vector Mapping with the BDB CatheterBDBIsthmus ABL Catheter
51 Electrogram Polarity and Cavotricuspid Isthmus Block During
Ablation of Typical Atrial Flutter.Tada,H. Oral, H. et al. Journal
of Cardiovascular Electrophysiology. Volume12, No. 4, April 2001.
P.394.
52. Vector Mapping with the BDB Catheter Vector mapping to
confirm the blockline52 (Electrogram Polarity and Cavotricuspid
Isthmus Block During Ablation of Typical Atrial Flutter
53. Searching for Gaps in the BlocklineWhen you pace on one
side of the blockline and you will notedouble potentials along the
line where you have made acomplete line. However, where there is a
gap as you slowlymove the catheter, you will note that the double
potentialsdisappear meaning that you are on the Gap. You might
alsofind fractionated potentials. You can also look for the sites
withlarge electrograms meaning they have not yet been ablatedand
ablate at those site.53
54. Searching for Gaps in the Blockline 110 ms msTada et al.*
reported that the interval separating the twocomponents of a double
potential was useful to distinguishcomplete (>110 ms) from
incomplete isthmus block (