11.atrial flutter for basic ep.final


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11.atrial flutter for basic ep.final

  1. 1. Atrial Flutter 馬偕紀念醫院 心臟內科 李應湘 醫師1
  2. 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. 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. 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. 5. Atrial Flutter5
  6. 6. Typical Atrial Flutter (CCW)  In typical AF the reentrant circuit revolves around6 the tricuspid annulus in a counterclockwise pattern
  7. 7. Reverse Typical Atrial Flutter (CW)  In reverse typical the reentrant circuit revolves7 around the tricuspid annulus in a clockwise pattern.
  8. 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. 9. P wave Morphology con’t Adenosine9
  10. 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
  11. 11. Typical Atrial Flutter Sawtooth pattern 3:1 A-V Block11
  12. 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. 13. Reverse Typical Atrial Flutter13
  14. 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. 15. Catheter Positions15
  16. 16. Isthmus Mapping Catheters16
  17. 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. 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. 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. 20. Intracardiac Electrogram Recognition – CCW Mapping Sequential activation around the right atrium20
  21. 21. Intracardiac Electrogram Recognition – CW Mapping Sequential activation around the right atrium21
  22. 22. Conduction Barriers in AFL22
  23. 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. 24. Entrainment Mapping24 Olgin et al. J of Cardiovasc Electrophysiology Vol.7,No.11,Nov 96
  25. 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. 26. Double Potentials26
  27. 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. 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. 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. 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. 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. 32. Ablation Sites TV CS Long distance IVC Short distance but more 4:30 but many smooth septal isthmus valleys 7:00 lateral isthmus 6:00 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. 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. 34. RAMPTM Sheath for Access to the sub- Eustachian recess34
  35. 35. Catheter Position: Septal Isthmus35
  36. 36. Catheter Positions: Posterior Isthmus RAO LAO36
  37. 37. Catheter ablation of the Posterior Isthmus RAO LAO ablation catheter ablation catheter SVC SVC CSo IVC37 IVC
  38. 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. 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. 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. 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. 42. Termination During Ablation42
  43. 43. CS Pacing Pre Ablation (in sinus rhythm)43
  44. 44. LRA Pacing Pre Ablation (in sinus rhythm)44
  45. 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. 46. CS Pacing Post Ablation with Isthmus Block 46
  47. 47. CS Pacing During Ablation with the occurrence of Isthmus Block 47
  48. 48. LRA Pacing Post Ablation with Isthmus Block48
  49. 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. 50. Other Methods to Confirm Bi-directional Block  Vector Mapping with the BDB Catheter  Searching for Gaps in the Blockline  Differential Pacing50
  51. 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. 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. 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. 54. Searching for Gaps in the Blockline <90 >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 (<90 ms)in patients undergoing radiofrequency ablation of typical atrialflutter.* Tada H et al. J Am Coll Cardiol 2001; 38:750-554
  55. 55. Differential Pacing to Confirm the Bloclline <90 ms <90 ms Eustachian Eustachian Low Ridge Low Ridge Lateral CS Lateral CS right right Atrium Atrium Tricuspid Annulus Tricuspid AnnulusPre-ablation – No Blockline• CS pacing – measure the time it takes for the conduction impulse to reach the catheter located at the LLRA.• LLRA pacing - measure the time it takes for the conduction impulse to reach the proximal electrodes of the CS catheter. 55
  56. 56. Differential Pacing to Confirm the Block line >110 ms >110 ms Eustachian Eustachian Low Ridge Low Ridge Lateral CS Lateral CS right right Atrium Atrium Block line Tricuspid Annulus Tricuspid Annulus Post-ablation – Block line • CS pacing – measure the time it takes for the conduction impulse to reach the catheter located at the LLRA. • LLRA pacing - measure the time it takes for the conduction impulse to reach the proximal electrodes of the CS catheter. • A 50% increase in the transisthmus conduction time from baseline is also56 predictive of complete block.
  57. 57. THANK YOU57