This document discusses ablation of atypical flutter. It begins with a case presentation and surface ECG of a patient with incessant tachycardia. It then provides an overview of typical and atypical flutter mechanisms, including CTI-dependent typical flutter and various non-CTI dependent circuits. It describes challenges ablating non-CTI dependent flutters and mapping algorithms. The document concludes with examples of ablation of different atypical flutter circuits, including incisional flutters.

1. Ablation of Atypical Flutter
Alireza Ghorbani Sharif, MD
Interventional Electrophysiologist
Tehran Arrhythmia Clinic
September 2016

2. 76 yrs. Old
Incessant tachycardia
Tachycardia-induced cardiomyopathy

3. Surface ECG, Incessant Tachycardia

4. Surface ECG at onset

5. Tachycardia

6. RA Anatomy

7. RA Anatomy

8. Entrainment at CTI

9. Entrainment at CTI

10. Entrainment at CTI, Burn

11. Change in pattern, slowing down and
termination during burn at CTI

12. Still no CTI block

13. CTI block with more burns

14. Easy induction again

15. Tachy 2, Slower and different pattern

16. Tachy 2, Surface

17. Entrainment at Septum

18. Lines from SVC to scarred septum

19. Termination during lines from SVC to Septum

20. Non-inducible

21. Non-inducible

22. Final Lines

23. Macroreentrant Atrial Tachycardia
(MRT)
MRT (Flutter) is conventionally defined as a circuit with a
diameter of greater than 2 cm in diameter and frequently occurs
around a central obstacle.

24. Typical Atrial Flutter
• The first description of Typical Atrial Flutter was
presented by Sir Thomas Lewis in 1912.
• The ECG was characteristic of this arrhythmia showing
a ‘saw tooth’ pattern in leads II, III, and/or aVF .
• In lead V1 a positive deflection is usually seen but a
biphasic deflection may also be detected.

25. Typical Atrial Flutter
• Puech in the early sixties, showed the mechanism of this
arrhythmia is a large re-entrant right atrial circuit bounded
anteriorly by the tricuspid annulus and posteriorly by orifices of
the IVC and SVC and the Eustachian ridge and the crista
terminalis.
• Activation is usually counterclockwise, descending the anterior
and lateral walls and ascending the septal and posterior wall of
the right atrium.
• Activation is dependent on the cavotricuspid isthmus (CTI).

26. Typical Atrial Flutter
Atrial rates usually 250-350 bpm.
Saw tooth appearance

27. Typical Atrial Flutter

28. Activation on Halo Catheter

29. Mechanisms of Atrial Flutters
• Some tachycardias show a typical ECG pattern of
Flutters may not be CTI dependent and conversely an
atypical ECG can be CT dependent.
• Term Typical Flutters refers to CTI dependent
regardless of the ECG pattern.
• Term Atypical Flutters refers to a non-CTI
dependent Flutters.

30. Typical Flutters with Unusual
ECG Pattern
• Reverse Typical Atrial Flutter:
– In 10% of the cases, a reverse direction of rotation
(clockwise re-entry) has been observed.
– Reverse Typical Atrial Flutter can be induced in the EP
lab in about 50% of the patients presenting only clinically
counterclockwise Flutter.
Europace, Vol. 4, July 2002

31. Reverse Typical Atrial Flutter

32. Reverse Typical Atrial Flutter
Rev Esp Cardiol. 2006;59(8):816-31

33. Reversed Atrial Flutter

34. Atypical Atrial Flutters
• Non-incisional Atypical Right Atrial
Flutter
• Left Atrial Flutter
• Scar – Related or Incisional Arial
Tachycardia
Europace, Vol. 4, July 2002

35. Non-Incisional Atypical Right
Atrial Flutters
• Upper loop re-entry tachycardia (ULR)
• Lower loop re-entry tachycardia (LLR)
• Fossa ovalis Flutter, superior vena cava
Flutter.

36. Right Atypical Atrial Flutter's circuits

37. Upper loop re-entry tachycardia
(ULR)
• Upper loop re-entry tachycardia (ULR) is a non-CTI
dependent tachycardia involving the upper portion of
the RA and a clockwise rotation, isthmus was
identified between the superior vena cava and the
fossa ovalis.
Europace, Vol. 4, July 2002

38. Upper Loop Reentry

39. Lower loop re-entry tachycardia
(LLR)
• LLR can alternate with Typical Flutter, passing
through the CTI the activation goes up towards the
IAS, short circuits the crista terminalis and
descends along the lower part of the right lateral
wall while simultaneously activating the rest of the
lateral wall in an ascending direction.
• The mean cycle length is usually from 170 to 250
ms, positive forces in inferior leads and V1
Europace, Vol. 4, July 2002

40. Lower loop re-entry tachycardia
Rev Esp Cardiol. 2006;59(8):816-31

41. Left Atrial Flutter
• The most frequent left Atrial Flutters are
perimitral, peripulmonary veins, septal, roof
and posterior wall,
• Usually seen after AF ablation.
Europace, Vol. 4, July 2002

42. Left Atrial Flutters
Rev Esp Cardiol. 2006;59(8):816-31

43. Post AF Ablation AT
• It is common to need more than one ablation
procedure
• ATs (ERAT) account for up to 50%
of arrhythmias post AF ablation
• Most will be left atrial in origin
• Often less well tolerated than AF
• Rhythm control usually difficult with AADs
HRS/EHRA/ECAS Expert Consensus on Catheter and Surgical Ablation of AF Heart Rhythm Vol 9 No 4 April2012

44. Mechanisms
• Focal
• Micro-reentry
• Macro-reentry (Flutter) Larger circuit
-‐cavo-tricuspid isthmus dependent
-‐roof dependent
-‐mitral isthmus dependent (peri-mitral)
• Maps to a single area of early activation

45. Focal or Micro Re-‐entry
Maps to a single area of
early activation
More common:
Post PVI
Post CAFEs
Heck, Rosso & Kistler JCE 2011; 22: 832-‐8

46. Perimitral Flutter

47. Mitral isthmus line to interrupt perimitral flutter

48. Roof Dependent Flutter

49. Roof line interrupts roof dependent flutter

50. Stevenson et al Mapping Algorithm
of Atrial Tachycardias
Heart Rhythm, Vol 7, No 5, May 2010

51. Michel Haïssaguerre

52. A: AT with a left
lateral origin and no
pre-existing lines of
block
B: AT with a left lateral
origin and pre-existing
CTI block resulting in a
high-to-low RA
activation
C: Simultaneous LA and
RA activation in case
of a roof-dependent LA
AT the RA, being
activation via the
Bachmann bundle
Heart Rhythm, Vol 7, No 5, May 2010

53. A: AT with
CTI-dependant RA
flutter
B: Septal/roof-
dependant AT without
pre-existing lines of
block in the atria
C: AT with the same
origin but pre-existing
CTI block resulting in a
high-to-low RA
activation
D: AT with a
left lateral origin and a
pre-existing conduction
block in the lateral mitral
isthmus
Heart Rhythm, Vol 7, No 5, May 2010

54. • 52 yrs. Old
Post PVI, AF ablaton

55. Onset

56. Tachycardia

57. Tachycardia

58. Far from distal Halo

59. Entrainment from CS

60. Entrainment from CS

61. Entrainment from ant Mitral annulus

62. Abrupt slowing down during burn
in Mitral annulus

63. Termination

64. Pacing from LAA and Mitral
Isthmus Block

65. Non-Inducible

66. Sinus Rhythm

67. Line

68. Scar – Related or
Incisional Atrial Tachycardia
• Incisional Flutters which includes those
where the circuit uses previous surgery
related scars.
• Frequently seen in patients with history of
surgical correction of CHD.
Europace, Vol. 4, July 2002

69. Incisional Atrial Tachycardia
• 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

70. Incisional Atrial Tachycardia
Rev Esp Cardiol. 2006;59(8):816-31

71. Incisional Atrial Tachycardia

72. Incisional Atrial Tachycardia

73. Incisional Atrial Tachycardia

74. • 72 yrs. Old
H/O Myxoma Surgery

75. Tachycardia

76. Intracardiac Recordings

77. No Entrainment at Isthmus

78. Entrainment at Lateral RA

79. Double Potentials at Lateral RA

80. Closer Double Potentials

81. Loss of Double Potentials, Lower RA

82. Termination, Line from Scar to IVC

83. Block at Posterior Isthmus

84. Sinus Rhythm

85. Conclusion
• Atypical atrial flutter represents a large variety of
supraventricular tachycardias and refers to any non-
CTI dependent tachycardia.
• Ablation of non–CTI-dependent flutter can be
substantially more difficult than for CTI-dependent
ones.
• The underlying circuit(s) can be located in either the
right or left atrium.
Akar JG, Kok LC, Haines DE, DiMarco JP, Mounsey JP. J Am Coll Cardiol 2001;38:377-84.

86. Conclusion
• Recurrence and complications vary depending on the
underlying substrate, location of the tachycardia circuit
and extent of ablation.
• The most notable complications are diaphragmatic
paralysis caused by phrenic nerve injury and
thromboembolism after conversion from atrial flutter.
Nakagawa H, Shah N, Matsudaira K, et al. Circulation 2001;103:699-709.

87. Where is the target ?
• Localizing the circuit and creating a line of
block that includes an electrically inert
anatomic structure
Conclusion

88. Tehran Arrhythmia Center
WWW.IranEP.org
info@IranEP.org

89. MORE CASES

90. Incessant Tachycardia, Post-ASD Repair

91. Incessant AFL, LV Dysfunction
Tehran Arrhythmia Center

92. Atypical AFL
Tehran Arrhythmia Center

93. Very Far from Posterior Isthmus
Tehran Arrhythmia Center

94. Activation Pattern
Tehran Arrhythmia Center

95. Activation Pattern
Tehran Arrhythmia Center

96. Closer at Proximal CS
Tehran Arrhythmia Center

97. Entrainment from Left Isthmus
Tehran Arrhythmia Center

98. Termination during RFA
Tehran Arrhythmia Center

99. Final Rhythm
Tehran Arrhythmia Center

100. No Inducibility
Tehran Arrhythmia Center

101. Incisional AT

102. RA 3D Map

103. Scar and Double Potentials at Lateral RA

104. Scar and Double Potentials at Lateral RA

105. Entrainment close to Scar

106. Entrainment close to Scar

107. Linear Ablation, Lateral RA