Original Articles |
From the Massachusetts General Hospital, Boston (A.M.P., A.d., T.M., J.P.S., J.N.R., V.Y.R.); Homolka Hospital, Prague, Czech Republic (P.N.); and St. Jude Medical, Minneapolis, Minn (S.J.K.).
Correspondence to Vivek Y. Reddy, MD, Cardiac Arrhythmia Service, Massachusetts General Hospital, 55 Fruit St, GRB-109, Boston, MA 02114. E-mail vreddy{at}partners.org
Received November 5, 2007; accepted January 29, 2008.
| Abstract |
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Methods and Results— All study patients developed AT after ablation for atrial fibrillation. The approach to AT ablation consisted of 4 steps: use of a 20-pole penta-array catheter to map the chamber rapidly during the rhythm of interest, analysis of the patterns of atrial activation to identify wave fronts of electric propagation, targeted entrainment at putative channels, and catheter ablation at these "isthmuses." All ablations were performed with irrigated radiofrequency ablation catheters. Forty-one ATs were identified in 17 patients (2.4±1.6 ATs per patient). Using the multielectrode catheter in conjunction with the Ensite NavX system, we created activation maps of 33 of 41 ATs (81%) (mean cycle length, 284±71 seconds) with a mean of 365±108 points per map and an average mapping time of 8±3 minutes. Of the 33 mapped ATs, 7 terminated either spontaneously or during entrainment maneuvers. Radiofrequency energy was used to attempt ablation of 26 ATs; 25 of 26 of the ATs (96%) were terminated successfully by ablation or catheter pressure.
Conclusions— This study demonstrates a strategy for rapidly defining and eliminating the scar-related ATs typically encountered after ablation of atrial fibrillation.
Key Words: arrhythmia ablation fibrillation mapping tachycardia
| Introduction |
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Clinical Perspective p 22
The mechanism of these ATs is typically macroreentry but also sometimes microreentry involving preexisting or iatrogenic ablation-related scar tissue. They typically are challenging to map and ablate because of the unpredictable location and extent of these combined idiopathic/iatrogenic scars. In an effort to efficiently identify the critical isthmuses sustaining postablation ATs, this study evaluated a systematic approach combining rapid high-density activation mapping with a penta-array mapping catheter coupled to an electrical impedance-based electroanatomic mapping system (Ensite NavX, St. Jude Medical, Minneapolis, Minn) and targeted entrainment. This strategy was assessed in a consecutive series of patients who presented with ATs after prior extensive ablation of persistent AF.
| Methods |
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Electrophysiology Study for AT
For all patients, antiarrhythmic drugs and warfarin sodium were continued up to the day of the ablation. The international normalized ratio was therapeutic (INR 2–3) at the time of the procedure. The surface ECG and bipolar endocardial electrograms were monitored continuously and stored on a computer-based digital amplifier/recorder system (GE Cardiolab, Waukesha, Wis). Intracardiac electrograms were filtered from 30 to 500 Hz and measured at a sweep speed of 100 to 200 mm/s.
A standard decapolar catheter was placed in the CS. A quadripolar reference electrode also was placed in the CS, RA appendage, or aortic root to serve as a location reference for the Ensite NavX mapping system.15 Transseptal access was obtained with contrast, fluoroscopy, and intracardiac echocardiography to place both an Agilis steerable sheath and a Daig SL-1 sheath (St. Jude Medical, St Paul, Minn) in the LA. A circular mapping catheter and either a 3.5-mm-tip Celsius Thermo-Cool (Biosense-Webster, Inc, Diamond Bar, Calif) or Chili (Boston Scientific, Inc, Natick, Mass) ablation catheter were placed through these sheaths into the LA.
In all patients, AT was present at baseline or was induced with rapid atrial pacing from the CS. First, the patients were evaluated for CTI-dependent atrial flutter by entrainment from the distal and proximal CS electrodes and, if suggestive, from the CTI itself.
Using the Ensite NavX system, we acquired separate multicomponent geometries of the LA appendage, left superior PV, left inferior PV, right superior PV, right inferior PV, and LA body with the circular mapping catheter. These were combined into 1 structure as the electroanatomic map of the LA and PVs and then compared alongside a 3-dimensional computed tomography or magnetic resonance of the LA. When ablation was performed in the RA, a separate geometry of the RA was created.
PV Isolation
All of the PVs were evaluated for electric disconnection with a multipolar circular mapping catheter (Lasso or Optima catheters; Biosense-Webster, Inc, and St Jude Medical, Inc, respectively). If any reconnection was found, the veins were reisolated, typically requiring only a single ablation lesion at the point of breakthrough. Electric PV isolation was then confirmed with the circular mapping catheter.
Activation Mapping
The penta-array catheter is a 20-pole steerable mapping catheter arranged in 5 soft radiating spines (1-mm electrodes separated by 4-, 4-, and 4-mm interelectrode spacing) covering a diameter of 3.5 cm (PentaRay, Biosense-Webster, Inc). The penta-array catheter often was manipulated through the steerable sheath to facilitate mapping. Each electrode of this penta-array catheter can be localized by the Ensite NavX system so that the catheter is ultimately visualized as 5 radiating quadripolar splines (Figure 1). After introduction into the LA, activation mapping of the AT was performed. Fifteen bipolar electrograms are acquired simultaneously at each location, thereby allowing rapid creation of activation maps. Potential critical isthmuses were identified as areas of constrained activation (resulting from the idiopathic or iatrogenic scars and anatomic barriers), often also containing fractionated electrograms (Figure 2).
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10% Ohm impedance drop (Figure 4). If the AT terminated during radiofrequency ablation, rapid atrial pacing was performed to reinduce the arrhythmia. If it remained noninducible, the ablation was considered successful. If another AT was induced, it was then targeted for ablation. When linear ablation was used across an isthmus, activation mapping and/or differential pacing on either side of the ablation line was used to confirm block.
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The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.
| Results |
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AT Characteristics
All patients had AT documented on 12-lead ECG (Table 1). The mean cycle length of the clinical ATs was 266±47 ms (range, 210 to 380 ms). A total of 41 ATs were identified at the electrophysiology study in 17 patients, 1 of whom underwent 2 AT ablation procedures. The mean AT cycle length was 288±76.5 ms (range, 175 to 550 ms). The number of ATs per patient averaged 2.4±1.6 (range, 1 to 6).
Activation Mapping
Using the Ensite NavX-tracked penta-array mapping catheter, we performed activation maps in 33 of 41 ATs (81%). The characteristics of all ATs for which activation maps were created are summarized in Table 2. Eight ATs were not mapped because they stopped spontaneously before any mapping and did not recur. The mean cycle length of the mapped ATs was 284±71 ms (range, 175 to 550 ms). For 3 of the mapped ATs, detailed mapping data were not available for posthoc analysis. For the other 30 ATs, the activation maps included a mean of 365±108 points, each of which required a mean of 34±14 separate acquisitions with the penta-array catheter. For the macroreentrant ATs, these maps constituted, on average, 96±1% of the TCL. For 14 of the mapped ATs, the time to create an activation map was recorded; the mean time was 8±3 minutes.
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Follow-Up
There were no complications in any of the patients undergoing AT ablation, including hematomas, pericardial tamponade, or conduction system damage requiring a permanent pacemaker. After 1.1 procedures per patient and a mean follow-up of 7.0±3.5 months (range, 2 to 14 months), 13 (76%) of 17 patients were free of AT (and AF) recurrences. After electric cardioversion, 3 of the patients have had no further clinical recurrences on antiarrhythmic medications. The final patient had recurrent AT even after cardioversion and is awaiting another ablation procedure.
| Discussion |
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The mechanisms of postablation ATs depend to a large extent on the ablation performed in the index procedure. A segmental approach to PV isolation, confirmed with a circular mapping catheter, resulted in most postablation ATs being of a focal mechanism from reconnected PV ostia.10,12 Anatomic approaches have been associated with a much higher prevalence of macroreentrant tachycardias around the mitral isthmus or PV ostia.13,16,17 After a complex fractionated electrogram approach to AF ablation, Nadamanee et al18 reported that 36% of patients had AT, with half having macroreentrant circuits and half having focal mechanisms. It stands to reason that the mechanisms of postablation AT are particularly variable in cases in which multiple strategies are used, as in the present series. The extent of ablation could even be unknown because either the initial strategy was surgical or several ablation procedures had previously been performed.
Haïssaguerre et al19 reported a 40% prevalence of postablation ATs in patients who had undergone catheter ablation of long-lasting persistent AF. Their initial AF ablation strategy included PV isolation, isolation of the superior vena cava, complex fractionated electrogram ablation, LA roof line, mitral isthmus line, CTI line, and CS isolation. The mechanisms of the ATs observed in this series were varied and included focal mechanisms in the anterior LA, CS, LA appendage, and septum.19 The same group reported anterior left AT in patients who had undergone PV isolation combined with LA roof and mitral isthmus lines but no previous anterior LA ablation.20
Catheter ablation of left-sided ATs can be technically challenging. Previous studies evaluating left-sided ATs without prior LA ablation have used a combination of magnetic electroanatomic and entrainment mapping with reasonable success.21,22 Similar approaches have been reported in series of post–AF ablation ATs.10–14,16–18 The usual strategy involves confirmation that the CTI is not part of the circuit and assurance of PV isolation, followed by entrainment mapping at the sites most commonly involved in ATs (septum, LA appendage, mitral isthmus, roof). Activation mapping can then be used as an adjunct when the above strategy is not successful. However, the most commonly used type of activation mapping (with magnetic electroanatomic mapping) is limited by a point-by-point acquisition process that is not always systematic, can be time consuming, and may miss small areas critical to the circuit. Detailed magnetic electroanatomic mapping may require >100 to 200 points, and each flutter circuit can be complex, involving multiple loops and figure-of-8 reentrant circuits. Noncontact mapping of left ATs, in association with AF, also has been described23; however, the accuracy of this mapping system is limited by both the frequently dilated nature of the atrial chamber and the low electrogram voltage amplitudes.
The penta-array catheter has been used to map postablation AT and to identify sources maintaining AF.19,24,25 However, the present series is the first to report its use in activation mapping using an electroanatomic mapping system. This allowed us to perform multielectrode activation mapping and to rapidly create detailed activation maps with relative ease. Almost every map was created in <10 minutes, with some completed in <5 minutes. In particular, when the AT location or cycle length changed in the middle of the procedure, remapping could be repeated expediently. This stands in stark contrast to the point-to-point electroanatomic mapping typically performed with a standard mapping catheter.
The other important advantage of activation mapping with this approach is the opportunity to identify critical isthmuses for these ATs, particularly for the macroreentrant variety. Shah and colleagues26 reported a series of 16 post–AF ablation ATs in which 73% involved a narrow, slowly conducting isthmus in the LA, usually involving the ridge between the left PVs and the LA appendage. When this isthmus was found, the AT usually could be terminated with 1 radiofreqency lesion; otherwise, long linear lesions (mitral isthmus or LA roof) lines had to be performed. With our technique, similar isthmuses can be identified. Figures 4 and 5
show mitral isthmus ATs for which activation mapping identified other areas of activation percolating through scars that could be targeted more easily for ablation. When they are found, a single ablation lesion can terminate the AT, thereby obviating the need for a linear lesion set. When so much ablation has already been performed as part of the previous ablation procedure(s), the ability to substantively limit the extent of ablation may reduce any chance of harm (eg, arterial injury or electric isolation of the LA appendage) and may reduce the potential for additional iatrogenic scar formation.19,27
Our series had a 96% acute success rate; 25 of 26 postablation ATs were terminated with radiofrequency ablation or catheter pressure during the first procedure. Other series have reported similar success rates ranging from 88% to 100%.10,12,13,16,19 Our recurrence rate (5 of 17; 29%) also was similar to other published studies. Recurrence rates in these series ranged from 0% to 47% with mean follow-up ranging from 2 to 16 months.10,12,13,16,19 A higher rate of recurrence tended to occur in series with longer follow-up.
The usefulness of this technique can extend beyond post– AF ablation AT to any tachyarrhythmia in which the circuit is difficult to identify. During a staged ablation procedure to treat persistent AF, it is common for the rhythm to eventually organize to an AT percolating through areas that had been incompletely ablated or areas of chronic scarring. In these cases, the approach described in this study can be used similarly to rapidly identify and ablate isthmuses critical to the tachycardia circuits (Figure 7). In addition, although not specifically evaluated in this study, another approach to consider is multielectrode activation mapping during sinus rhythm to identify putative channels of activation. As previously demonstrated for ATs in the setting of surgically corrected congenital heart disease, systematic ablation of these channels can effectively eliminate clinical ATs.28
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Conclusions
We report a technique to rapidly identify and eliminate postablation ATs with a high degree of success. In addition, the identification of critical isthmuses may reduce the extent and time needed for radiofrequency ablation. Future studies are needed to fully assess whether this technique may be applied to other scar-related ATs, including those in the setting of prior surgery for congenital heart disease and those in the presence of idiopathic atrial scar.
| Acknowledgments |
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This work was supported in part by the Deane Institute for Integrative Research in Atrial Fibrillation and Stroke.
Disclosures
Drs Reddy and Neuzil have received grant support from and served as consultants to Biosense-Webster, Inc, and St. Jude Medical, Inc. Dr dAvila has served as a consultant to St. Jude Medical, Inc. S. Kim is an employee of St. Jude Medical, Inc. The remaining authors report no potential conflicts.
| References |
|---|
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2. Haissaguerre M, Jais P, Shah DC, Takahashi A, Hocini M, Quiniou G, Garrigue S, Le Mouroux A, Le Metayer P, Clementy J. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med. 1998; 339: 659–666.
3. Haïssaguerre M, Shah DC, Jaïs P, Hocini M, Yamane T, Deisenhofer I, Chauvin M, Garrigue S, Clémenty J. Electrophysiologic breakthroughs from the left atrium to the pulmonary veins. Circulation. 2000; 102: 2463–2465.
4. Haïssaguerre M, Jaïs P, Shah DC, Garrigue S, Takahashi A, Lavergne T, Hocini M, Peng JT, Roudaut R, Clémenty J. Electrophysiological end point for catheter ablation of atrial fibrillation initiated from multiple pulmonary venous foci. Circulation. 2000; 101: 1409–1417.
5. Pappone C, Rosanio S, Oreto G, Tocchi M, Gugliotta F, Vicedomini G, Salvati A, Dicandia C, Mazzone P, Santinelli V, Gulletta S, Chierchia S. Circumferential radiofrequency ablation of pulmonary vein ostia: a new anatomic approach for curing atrial fibrillation. Circulation. 2000; 102: 2619–2628.
6. Oral H, Scharf C, Chugh A, Hall B, Cheung P, Good E, Veerareddy S, Pelosi F Jr, Morady F. Catheter ablation for paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation. Circulation. 2003; 108: 2355–2360.
7. Usui A, Inden Y, Mizutani S, Takagi Y, Akita T, Ueda Y. Repetitive atrial flutter as a complication of the left-sided simple maze procedure. Ann Thorac Surg. 2002; 73: 1457–1459.
8. Villacastín J, Pérez-Castellano N, Moreno J, González R. Left atrial flutter after radiofrequency catheter ablation of focal atrial fibrillation. J Cardiovasc Electrophysiol. 2003; 14: 417–421.[CrossRef][Medline]
9. Oral H, Knight BP, Morady F. Left atrial flutter after segmental ostial radiofrequency catheter ablation for pulmonary vein isolation. Pacing Clin Electrophysiol. 2003; 26: 1417–1419.[CrossRef][Medline]
10. Gerstenfeld EP, Callans DJ, Dixit S, Russo AM, Nayak H, Lin D, Pulliam W, Siddique S, Marchlinski FE. Mechanisms of organized left atrial tachycardias occurring after pulmonary vein isolation. Circulation. 2004; 110: 1351–1357.
11. Kobza R, Hindricks G, Tanner H, Schirdewahn P, Dorszewski A, Piorkowski C, Gerds-Li JH, Kottkamp H. Late recurrent arrhythmias after ablation of atrial fibrillation: incidence, mechanisms, and treatment. Heart Rhythm. 2004; 1: 676–683.[CrossRef][Medline]
12. Chugh A, Oral H, Lemola K, Hall B, Cheung P, Good E, Tamirisa K, Han J, Bogun F, Pelosi F, Morady F. Prevalence, mechanisms, and clinical significance of macroreentrant atrial tachycardia during and following left atrial ablation for atrial fibrillation. Heart Rhythm. 2005; 2: 464–471.[CrossRef][Medline]
13. Deisenhofer I, Estner H, Zrenner B, Schreieck J, Weyerbrock S, Hessling G, Scharf K, Karch MR, Schmitt C. Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: incidence, electrophysiological characteristics, and results of radiofrequency ablation. Europace. 2006; 8: 573–582.
14. Haissaguerre M, Jais P, Hocini M, Sanders P, Hsu L-F, Scavee C, Weerasooriya R, Shah DC, Garrigue S, Clementy J. Macro-reentrant atrial flutter following ablation of pulmonary veins, tricuspid and mitral isthmuses. Pacing Clin Electrophysiol. 2003; 26: 970. Abstract.
15. Sra J, Hauck J, Krum D, Schweitzer J. Three-dimensional right atrial geometry construction and catheter tracking using cutaneous patches. J Cardiovasc Electrophysiol. 2003; 14: 897.[CrossRef][Medline]
16. Mesas CE, Pappone C, Lang CC, Gugliotta F, Tomita T, Vicedomini G, Sala S, Paglino G, Gulletta S, Ferro A, Santinelli V. Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: electroanatomic characterization and treatment. J Am Coll Cardiol. 2004; 44: 1071–1079.
17. Pappone C, Manguso F, Vicedomini G, Gugliotta F, Santinelli O, Ferro A, Gulletta S, Sala S, Sora N, Paglino G, Augello G, Agricola E, Zangrillo A, Alfieri O, Santinelli V. Prevention of iatrogenic atrial tachycardia after ablation of atrial fibrillation: a prospective randomized study comparing conventional pulmonary vein ablation with a modified approach. Circulation. 2004; 110: 3036–3042.
18. Nademanee K, McKenzie J, Kosar E, Schwab M, Sunsaneewitayakul B, Vasavakul T, Khunnawat C, Ngarmukos T. A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate. J Am Coll Cardiol. 2004; 43: 2044–2053.
19. Haïssaguerre M, Hocini M, Sanders P, Sacher F, Rotter M, Takahashi Y, Rostock T, Hsu LF, Bordachar P, Reuter S, Roudaut R, Clémenty J, Jaïs P. Catheter ablation of long-lasting persistent atrial fibrillation: clinical outcome and mechanisms of subsequent arrhythmias. J Cardiovasc Electrophysiol. 2005; 16: 1138–1147.[CrossRef][Medline]
20. Jaïs P, Sanders P, Hsu LF, Hocini M, Sacher F, Takahashi Y, Rotter M, Rostock T, Bordachar P, Reuter S, Laborderie J, Clémenty J, Haïssaguerre M. Flutter localized to the anterior left atrium after catheter ablation of atrial fibrillation. J Cardiovasc Electrophysiol. 2006; 17: 279–285.[CrossRef][Medline]
21. Jais P, Shah DC, Haissaguerre M, Hocini M, Peng JT, Takahashi A, Garrigue S, Le Metayer P, Clementy J. Mapping and ablation of left atrial flutters. Circulation. 2000; 101: 2928–2934.
22. Ouyang F, Ernst S, Vogtmann T, Goya M, Volkmer M, Schaumann A, Bänsch D, Antz M, Kuck KH. Characterization of reentrant circuits in left atrial macroreentrant tachycardia: critical isthmus block can prevent atrial tachycardia recurrence. Circulation. 2002; 105: 1934–1942.
23. Saksena S, Skadsberg ND, Rao HB, Filipecki A. Biatrial and three-dimensional mapping of spontaneous atrial arrhythmias in patients with refractory atrial fibrillation. J Cardiovasc Electrophysiol. 2005; 16: 505–507.[CrossRef][Medline]
24. Haissaguerre M, Hocini M, Sanders P, Takahashi Y, Rotter M, Sacher F, Rostock T, Hsu LF, Jonsson A, O_Neill MD, Bordachar P, Reuter S, Rouda R, Clementy J, Jais P. Localized sources maintaining atrial fibrillation organized by prior ablation. Circulation. 2006; 113: 616–625.
25. Sanders P, Hsu LF, Jais P, Hocini M, Scavee C, Pasquie JL, Takahashi Y, Rotter M, Sacher F, Garrigue S, Clementy J, Haissaguerre M. Novel insights in focal atrial tachycardia using high density localized mapping [abstract]. Heart Rhythm. 2004; 1: S18.[CrossRef]
26. Shah D, Sunthorn H, Burri H, Gentil-Baron P, Pruvot E, Schlaepfer J, Fromer M. Narrow, slow-conducting isthmus dependent left atrial reentry developing after ablation for atrial fibrillation: ECG characterization and elimination by focal RF ablation. J Cardiovasc Electrophysiol. 2006; 17: 508–515.[CrossRef][Medline]
27. Takahashi Y, Jais P, Hocini M, Sanders P, Rotter M, Rostock T, Sacher F, Jais C, Clementy J, Haissaguerre M. Acute occlusion of the left circumflex coronary artery during mitral isthmus linear ablation. J Cardiovasc Electrophysiol. 2005; 16: 1104–1107.[CrossRef][Medline]
28. Nakagawa H, Shah N, Matsudaira K, Overholt E, Chandrasekaran K, Beckman KJ, Spector P, Calame JD, Rao A, Hasdemir C, Otomo K, Wang Z, Lazzara R, Jackman WM. Characterization of reentrant circuit in macroreentrant right atrial tachycardia after surgical repair of congenital heart disease: isolated channels between scars allow "focal" ablation. Circulation. 2001; 103: 699–709.
| Footnotes |
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The online Data Supplement can be found with this article at http://circep.ahajournals.org/cgi/content/full/1/1/14/DC1.
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