Circulation. 1999;99:3206-3208
(Circulation. 1999;99:3206-3208.)
© 1999 American Heart Association, Inc.
Images in Cardiovascular Medicine |
Spot Welding the Gap in Atrial Flutter Ablation
Paul A. Friedman, MD;
Marshall S. Stanton, MD
From the Mayo Clinic, Rochester, Minn.
Correspondence to Paul A. Friedman, MD, Cardiovascular Diseases, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
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Figure 1. A, Left anterior oblique view of right atrium
(view is from right ventricle looking into right atrium with tricuspid
valve removed). Yellow curved arrow demonstrates electrical activation
around tricuspid valve annulus during atrial flutter. Isthmus catheter
has multiple electrode pairs that record electrical activation and
spans isthmus of tissue between inferior vena cava and
tricuspid valve annulus. Its poles I-1,2 (I is for isthmus catheter,
and 1 and 2 are most distal electrodes) are at coronary sinus
ostium, and poles I-19,20 are low lateral right atrium. Intervening
poles are numbered sequentially but not labeled. MEA indicates multiple
electrode array, part of Ensite 3000 noncontact mapping system, which
reconstructs endocardial electrical activation in a 3-dimensional
model. Dashed line depicts site of linear ablation for atrial flutter.
B, Right anterior oblique view of right atrium. Note that completion of
ablation line (dashed line from tricuspid valve to inferior
vena cava) will interrupt flutter circuit. Depicted in white is
tricuspid valve (which was cut away in Figure 1A ). C, Electrograms from
intracardiac catheters. Three left complexes show atrial flutter. Note
that activation proceeds from poles I-19,20, positioned at low lateral
right atrial wall, toward I-1,2, positioned near coronary
sinus. This is typical counterclockwise atrial flutter. After third
beat during delivery of radiofrequency energy (not shown), atrial
flutter terminates and sinus rhythm ensues. Note change in morphology
of P waves in lead II. afl and nsr indicate atrial flutter and normal
sinus rhythm, respectively.
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Figure 2. A, After ablation line is completed, pacing is
performed from vicinity of coronary sinus to determine whether
line is intact. Note gap in ablation line allowing conduction across
isthmus. This is depicted by electrical activation (yellow arrow)
proceeding from catheter position I-1,2 directly to I-19,20 through
gap. In this situation, there is a high risk of recurrent atrial
flutter, because flutter circuit is not fully interrupted. B, Single
"movie" frame of a 3-dimensional map generated by Ensite 3000
system. Yellow arrow has been added to show direction of electrical
activation during real-time computer display. Area of "pinched"
conduction is gap in an ablation line (which permits conduction to
"squeeze" through); this critical site is precisely localized by
system. This permits ablation catheter to be directly positioned at gap
to complete ablation line. MEA indicates multiple electrode
array.
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Figure 3. A, Pacing from coronary sinus after
successful completion of ablation line. Note that electrical activation
proceeds from coronary sinus (I-1,2) to point of ablation line,
depicted in this figure between electrodes I-7,8 and I-9,10 (not
labeled). Because wave front cannot cross barrier (completed ablation
line), remainder of isthmus is activated from opposite
direction by a wave front that starts at coronary sinus and
progresses counterclockwise to low lateral right atrium (I-19,20) and
then toward ablation line, where it must stop. It is this presence of a
complete line across isthmus of tissue that prevents typical atrial
flutter. B, Electrical activation during ablation at site of gap in
ablation line. Pacing is occurring from coronary sinus. First 2
complexes (while gap is still present) on left show electrical
activation proceeding from coronary sinus region (I-1,2)
directly across isthmus to I-19,20 at low lateral right atrium. With
third complex, line of ablation is completed and activation can proceed
only halfway across isthmus to electrode position I-5,6. Wave front
traveling around tricuspid valve annulus in counterclockwise direction
activates rest of isthmus from opposite direction. This
confirms successful isthmus block with septal pacing. A similar
maneuver with lateral pacing is then performed to confirm
lateral-to-septal block. MEA indicates multiple electrode array.
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Footnotes
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke's Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to Dr Hugh A. McAllister, Jr, St Luke's Episcopal Hospital and Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.
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P. D. Bella, A. Fraticelli, C. Tondo, S. Riva, G. Fassini, and C. Carbucicchio
Atypical atrial flutter: clinical features, electrophysiological characteristics and response to radiofrequency catheter ablation
Europace,
January 1, 2002;
4(3):
241 - 253.
[Abstract]
[PDF]
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