This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chan, D. P. Articles by Waldo, A. L. Search for Related Content PubMed PubMed Citation Articles by Chan, D. P. Articles by Waldo, A. L. Related Collections Electrophysiology Ablation/ICD/surgery Pediatric and congenital heart disease, including cardiovascular surgery Arrhythmias, clinical electrophysiology, drugs

(Circulation. 2000;102:1283.)
© 2000 American Heart Association, Inc.

Clinical Investigation and Reports

Importance of Atrial Flutter Isthmus in Postoperative Intra-Atrial Reentrant Tachycardia

David P. Chan, MD; George F. Van Hare, MD; Judith A. Mackall; MD Mark D. Carlson, MD; Albert L. Waldo, MD

From the Division of Pediatric Cardiology, Department of Pediatrics (D.P.C., G.F.V.H.), and the Division of Cardiology, Department of Medicine (J.A.M., M.D.C., A.L.W.), Case Western Reserve University, Cleveland, Ohio.

Correspondence to George F. Van Hare, MD, Pediatric Cardiology, Stanford University, 750 Welch Rd, #305, Palo Alto, CA 94304. E-mail vanhare{at}leland.stanford.edu

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Background—In survivors of congenital heart surgery, intra-atrial reentrant tachycardia (IART) often develops. Previous reports have emphasized the atriotomy scar as the central barrier around which a reentrant circuit may rotate but have not systematically evaluated the atrial flutter isthmus in such patients. We sought to determine the role of the atrial flutter isthmus in supporting IART in a group of postoperative patients with congenital heart disease.

Methods and Results—Nineteen postoperative patients with IART underwent electrophysiological studies with entrainment mapping of the atrial flutter isthmus for determining postpacing intervals. Radiofrequency ablation was performed at the identified isthmus in an effort to create a complete line of block. Twenty-one IARTs were identified in 19 patients, with a mean tachycardia cycle length of 293±73 ms. The atrial flutter isthmus was part of the circuit in 15 of 21 (71.4%). In the remaining 6 of 21, the ablation target zone was at sites near atrial incisions or suture lines. Ablation was successful in 19 of 21 (90.4%) IARTs and in 14 of 15 (93.3%) cases at the atrial flutter isthmus.

Conclusions—In most of our postoperative patients, the atrial flutter isthmus was part of the reentrant circuit. The fact that the atrial flutter isthmus is vulnerable to ablation suggests that whenever IART occurs late after repair of a congenital heart defect, the atrial flutter isthmus should be evaluated. These data support the theory that some form of conduction block between the vena cava is essential for the establishment of a stable substrate for the atrial flutter reentrant circuit.

Key Words: catheter ablation • atrial flutter • heart defects, congenital • reentry

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
In survivors of congenital heart surgery, intra-atrial reentrant tachycardia (IART) often develops.^{1 2 3} This tachyarrhythmia, which has also been called atrial flutter, can be difficult to manage and represents a significant cause for morbidity and mortality in postoperative patients with congenital heart disease.¹ There has been much interest in using radiofrequency ablation (RFA) to cure IART because it is often difficult to control with antiarrhythmic drug therapy⁴ and may be poorly tolerated hemodynamically. Previous reports have emphasized the atriotomy scar as the central barrier around which a reentrant circuit could rotate.^{5 6 7}

The reentrant circuit in typical and reverse typical atrial flutter is now well understood.^{8 9 10 11 12 13 14} The critical isthmus that supports the reentrant circuit in typical and reverse typical atrial flutter is between the tricuspid annulus, the coronary sinus os, and the Eustachian ridge adjacent to the inferior vena cava. In typical atrial flutter, reentry proceeds in a counterclockwise fashion when the tricuspid annulus is viewed in the left anterior oblique view, whereas in reverse typical atrial flutter, it proceeds in a clockwise fashion.¹⁵ This isthmus has been referred to as the atrial flutter isthmus, and targeting this isthmus with radiofrequency energy has been associated with a high success rate in ablating typical and reverse typical atrial flutter.^{10 11 14 16 17 18}

Previous reports have indicated that successful RFA can be achieved in postoperative patients with congenital heart disease who have IART.^{5 6 7 19} Ablation therapy has focused on extending a line of block from the surgical incision to an appropriate boundary, such as the atrioventricular (AV) groove, the inferior vena cava, or the superior vena cava. For example, Kalman et al⁷ placed ablative lesions between an atriotomy scar or suture lines and another boundary, usually the AV groove, in all but 1 patient. However, we hypothesized, on the basis of a series of studies of atrial flutter in animal models, that the right atriotomy in such patients could serve as the needed posterior boundary of the IART reentrant circuit such that the resulting IART could use the typical and reverse typical atrial flutter isthmus as part of the reentrant circuit.²⁰ If this is correct, the atrial flutter isthmus could be targeted for ablation of the clinical tachyarrhythmia, just as it is in typical and reverse typical atrial flutter. Previous reports have not systematically evaluated the atrial flutter isthmus in such patients. We therefore sought first to determine the role of the atrial flutter isthmus in supporting IART in a group of postoperative patients with congenital heart disease in whom entrainment mapping techniques were used during electrophysiological study. Second, we sought to determine whether the atrial flutter isthmus could be a potential target site for successful RFA to cure the IART when it has been determined to be part of the reentrant circuit in this patient population.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Patient Selection
From 1994 to 1998, there were 35 postoperative patients with congenital heart disease who were examined at University Hospitals of Cleveland with findings of IART. Of these, 19 underwent electrophysiological studies that included careful entrainment mapping of the atrial flutter isthmus as part of evaluation for RFA therapy. This latter group of patients comprises our cohort for the present retrospective study. The procedures followed were in accordance with institutional guidelines, and patients or their parents or guardians gave informed consent for the procedures.

Electrophysiological Study
Each patient underwent standard electrophysiological testing in a laboratory with either biplane fluoroscopy or single-plane fluoroscopy that allowed rapid movement of the fluoroscopy arm from right anterior to left anterior oblique projections. Electrode catheters were placed to record from the coronary sinus, the bundle of His, and the right ventricle. In addition, when possible, a 20-pole halo electrode catheter was placed in the right atrium such that it encircled the tricuspid valve, with the distal pair of electrodes near the os of the coronary sinus. All intracardiac electrograms were recorded (bandpass 50 to 300 Hz) simultaneously with surface ECG leads V₁, 1, II, III, and aVF (bandpass 0.05 to 300 Hz) on a commercially available computer amplifier system (Quinton Electrophysiology) in a digital format. After measurements of intervals and assessment of AV node function, IART was initiated with standard programmed stimulation techniques. Entrainment mapping was performed, as previously described,^{6 7} during IART for assessment of postpacing intervals (PPI). This was performed by both pacing and recording from the distal electrode pair of a mapping catheter that was initially placed at the atrial flutter isthmus. Pacing was performed at cycle lengths 20 to 30 ms shorter than the tachycardia cycle length. The PPI and the tachycardia cycle length (TCL) were compared. The pacing site was considered to be part of the reentrant circuit if the PPI minus the TCL was <10 ms. If the atrial flutter isthmus was not found to be part of the reentrant circuit, alternative atrial sites were mapped by entrainment, particularly near the atriotomy incision. Particular attention was paid to sites where double potentials were recorded because these were considered to represent sites where conduction block existed along the line of an atriotomy or suture line.^{21 22}

After determination of the location of the critical isthmus of the IART, multiple radiofrequency lesions were made in an effort to create a complete line of block in this isthmus. The targeted temperature was 60°C for 30 to 60 seconds for each lesion. Each lesion was placed individually, after which the catheter was moved by 2 to 3 mm and another lesion was placed. Success was defined as termination of IART with subsequent lack of inducibility of the original tachycardia. Later in the series, bidirectional conduction block through the atrial flutter isthmus was also used as a criterion for success.¹⁷ This was judged both in the clockwise direction, observing a change in the order or atrial activation of the lateral atrial wall during proximal coronary sinus pacing, as well as the counterclockwise direction, observing a change in the order of atrial activation at the coronary sinus versus the site where the His bundle was recorded. A change in P-wave morphology with low lateral right atrial pacing from inverted to upright in lead aVF was also used as a criterion of counterclockwise isthmus block.¹⁸

	Results

Top Abstract Introduction Methods Results Discussion References

 
Patients
The mean age of our cohort of 19 patients at the time of the electrophysiological study was 22.8±12.9 years (Table 1). Ten of the patients were male. In most cases, the clinical tachycardia had developed at a remote time from the congenital heart surgical repair (mean time from surgery to ablation, 16.9 years; range, 2 to 37 years).

View this table: [in this window] [in a new window]   Table 1. Patient Characteristics

In our cohort of 19 patients, 21 distinct IARTs were identified (Table 2). The mean tachycardia cycle length was 293±73 ms. At the electrophysiological study, 10 of the 21 tachycardias were either incessant or developed spontaneously at the time of catheter manipulation. Using entrainment mapping techniques, a target isthmus was identified in each tachycardia. The atrial flutter isthmus was found to be part of the circuit by entrainment criteria in 15 (71.4%) of the tachycardias and therefore was targeted for ablation. In the remaining 6 tachycardias, the target zone for ablation of the reentrant circuit was localized to sites near atrial incisions and/or suture lines rather than the atrial flutter isthmus. Only 2 of the tachycardias with the classic atrial flutter circuit circulated in a clockwise direction (as in reverse typical atrial flutter) by visualization of the tricuspid valve as a clock face in the left anterior oblique (Figures 1 and 2). In 1 of these patients, both clockwise and counterclockwise rotation were observed at different times. The PPI-TCL interval was 2.6±3.9 ms when pacing was performed at the chosen target isthmus. Initial success of ablation was achieved in 19 of the 21 (90.4%) IARTs. When the atrial flutter isthmus was identified as the target isthmus, successful ablation was achieved in 14 of 15 (93.3%) of cases. The success rate of RFA at other sites was 5 of 6 (83.3%) IARTs. At last follow-up, 7 of the 19 successfully ablated tachycardias had recurred. It is notable that only 4 of 14 (28.7%) ablated tachycardias involving the atrial flutter isthmus recurred, whereas 3 of the 5 ablated tachycardias not involving the atrial flutter isthmus recurred (60%). It is also notable that of the 6 typical or reverse typical atrial flutters for which bidirectional isthmus block could be demonstrated, only 1 recurred, whereas of the 2 flutters for which bidirectional block could not be demonstrated, both recurred (Table 2). Five patients had attempted repeat ablation that was successful in 4 and unsuccessful in 1. No complications were noted in association with either the electrophysiological study or the ablation procedures.

View this table: [in this window] [in a new window]   Table 2. Tachycardia Characteristics

View larger version (18K): [in this window] [in a new window]   Figure 1. Rhythm strip with 4 leads in patient 9, who had repair of total anomalous pulmonary venous connection. Tracing shows IART with 2:1 AV conduction. Note that P waves are upright in all 4 leads and there are discrete P waves rather than more typical sawtooth flutter waves seen in patients with typical atrial flutter. Tracing is recorded at 100 mm/s.

View larger version (41K): [in this window] [in a new window]   Figure 2. Intracardiac electrograms in patient 9 showing entrainment pacing during IART from proximal coronary sinus electrodes positioned at mouth of coronary sinus. Halo catheter demonstrates clockwise rotation. Note that at termination of pacing, atrial electrogram recorded by the proximal electrode pair of the mapping catheter demonstrates PPI equivalent to TCL. Tracing is recorded at 200 mm/s. CS indicates coronary sinus; Dis, distal electrode pair; prx, proximal electrode pair; Halo, 20-electrode Halo catheter in right atrium (1 is distal, 6 is proximal); HBE1, His bundle electrogram.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
IART in long-term survivors of surgical repair of congenital heart disease is an important clinical problem. Ablation therapy has proven to be effective in managing this particularly difficult problem in patients who have had relatively simple atrial surgery⁷ as well as those with Mustard and Senning procedures for transposition⁶ but has had a lower long-term success rate with patients who have undergone the Fontan procedure.^{5 23} Previous reports have concentrated on the use of ablative techniques to create block in the isthmus between the atriotomy incision and the AV groove in an attempt to eliminate the IART reentrant circuit.^{5 6 7 19 23} The present report has demonstrated that despite the presence of an atriotomy scar, the atrial flutter isthmus is a part of the reentrant circuit IART in many patients with a variety of types of congenital heart disease anatomy and can be targeted for ablation with a good rate of success. Alternatively, when the atrial flutter isthmus was not part of the reentrant circuit and other areas of the right atrium were targeted for ablation, the results of ablation were not as good. We suggest that this improved result relates to the well-defined atrial anatomy and the relative ease of localizing the band of tissue of interest at the atrial flutter isthmus. This is in comparison to the somewhat variable locations of the atriotomy scar and suture lines among patients. Thus, it may be technically more difficult to establish a line of block at other atrial sites, especially sites that include pectinate muscles. Furthermore, the techniques for documenting successful creation of a complete line of block are well developed in classic (typical and reverse typical) atrial flutter and involve the observation of the pattern of right atrial lateral wall activation during coronary sinus pacing, P-wave morphology during lateral wall pacing, and order of coronary sinus os versus low septal right atrial activation during lateral wall activation.¹⁷ The adoption of these criteria for proof of bidirectional block of the atrial flutter isthmus has been responsible for a dramatic improvement in long-term success rate for ablation of classic atrial flutter, and this point is borne out in our results, in which the demonstration of bidirectional block was predictive of long-term success. Such methods and criteria are as yet undeveloped in IART that does not involve the atrial flutter isthmus.

Value of Entrainment Mapping
The concept of entrainment^{24 25} has been adapted to mapping studies of various tachyarrhythmias, including IARTs.^{6 7 26} It is a particularly powerful technique in identifying components of the reentrant circuit, including a target isthmus for ablation. It should be noted that patients with IART often have much slower TCLs than those seen in patients with typical atrial flutter and usually lack the classic sawtooth atrial flutter waves on the surface ECG (Figure 1). Prior studies of postoperative atrial arrhythmias have never carefully assessed the tricuspid valve–Eustachian ridge isthmus in an organized, careful, and prospective fashion to determine whether it is in or out of the circuit. Having done this in this study, we have found that a surprisingly large number of patients who might otherwise have been classified as having incisional reentry in fact have IART involving the typical atrial flutter isthmus. Despite the fact that the typical appearance of atrial flutter was lacking in many of these patients, our series demonstrates that patients who are considered to have IART may still be approached in the same way for ablation as those with typical and reverse typical atrial flutter, provided that the atrial flutter isthmus is demonstrated to be part of the circuit by entrainment mapping.

Why Does Late Postoperative Atrial Flutter Develop?
There is a relatively high incidence of IART among patients who are survivors of congenital heart surgery.¹ Atrial flutter as a primary arrhythmia is rare in children without structural heart disease but is seen relatively more frequently in adults without structural heart disease. It is now understood that for atrial flutter to occur, a stable line of block between the vena cavae must be present or must develop.²⁰ Olgin et al¹⁶ have proposed that in patients with typical or reverse typical atrial flutter, a line of block along the crista terminalis forms the posterior barrier for the atrial flutter circuit, and both Nakagawa et al¹⁰ and Kalman et al¹¹ have demonstrated that the tricuspid annulus forms the anterior barrier. Clearly, not all adults are prone to atrial flutter, and this suggests that block in the region of the crista terminalis is likely related to tissue abnormalities associated with atrial dilation, aging, or other factors. We suggest that the presence of 1 or more atriotomy scars or suture lines in young patients who have undergone surgical repair of a congenital heart lesion may serve to provide the posterior barrier needed to support a stable reentrant circuit. Indeed, as summarized recently,²⁰ this is consistent with the findings in several canine models of atrial flutter, including those of Frame et al.²⁷ In these models, a line of block between the superior vena cava and inferior vena cava has been demonstrated to be necessary to support sustained atrial flutter. Further mapping studies are needed in patients with tachycardia involving the atrial flutter isthmus to better delineate the remainder of the tachycardia circuit.

Implications for Nomenclature
These findings have implications for the nomenclature in use for describing atrial macroreentrant tachycardias in patients who have had atriotomies. The term "incisional reentry" was coined by Kalman et al⁷ and was used to describe a reentrant atrial tachycardia in patients in whom the reentrant circuit traveled around an atriotomy and in which an isthmus existed between the atriotomy and the AV groove (ie, between 2 anatomic barriers). Our data suggest that there are 2 groups of patients that may be described: those whose tachycardia involves the atrial flutter isthmus and those whose tachycardia circuit is distant from this isthmus. In the second group, the evidence for involvement of an atrial incision is fairly good, whereas in the first group, involvement of the atrial incision is currently speculative. We favor continued use of the term "incisional reentry" to apply only to those tachycardias in which the atrial flutter isthmus has been shown by entrainment mapping to not be a part of the circuit. We suggest the use of the term "postoperative atrial flutter" for those tachycardias that involve the atrial flutter isthmus in postoperative patients. Finally, the term "intra-atrial reentrant tachycardia" probably should be used to refer to both types, particularly those not yet differentiated by diagnostic electrophysiology study.

Study Limitations
The present study was retrospective in its data collection. However, the objective of the study was to determine the role of the atrial flutter isthmus in supporting the reentrant circuit in congenital heart surgery survivors. In this respect, these patients were approached prospectively, as evaluation of the atrial flutter was part of the plan at the time of the diagnostic electrophysiologic study. Other sites were evaluated only when the atrial flutter isthmus had been excluded as the critical isthmus by entrainment mapping. Thus, although we know the role of the atrial flutter isthmus in each of these patients, we do not know the role of other portions of the atrium (eg, the superior vena cava–right atrial junction), except in those patients who had the atrial flutter isthmus excluded by entrainment mapping. Therefore, this study does not rule out the potential for successful ablation directed at alternative sites even in patients whose circuits involve the atrial flutter isthmus. However, the important point remains that a large percentage of patients with IART after surgical repair of congenital heart disease have a reentrant circuit that uses the atrial flutter isthmus.

Our patients were not randomized to 2 distinct approaches of either mapping the atrial flutter isthmus first or evaluating the atriotomy sites initially. This prevents a head-to-head comparison of the two approaches. However, as with the prior series, our study included consecutive patients with stable tachyarrhythmias undergoing attempted RFA. This should have limited possible bias in the selection of patients for ablation.

Conclusions
We have shown that in the majority of postoperative patients in our study, the atrial flutter isthmus was part of the reentrant circuit. The fact that the atrial flutter isthmus is a vulnerable target for successful ablation suggests that whenever IART occurs late after repair of a congenital heart defect, one should evaluate the involvement of the atrial flutter isthmus in the reentrant circuit. This does not mean that true incisional reentry does not occur, nor that more than 1 potential reentrant circuit cannot be present, nor that other approaches to cure IART may not be useful or appropriate. However, with recent advances in both our understanding of the nature of the atrial flutter isthmus and in the assessment of successful isthmus ablation, a reasonably high likelihood of long-term successful ablation in such patients should be expected. Furthermore, recognition of the importance of the atrial flutter isthmus for maintenance of IART in these patients invites consideration of intra-operative methods to prevent postoperative occurrence of IART. The most obvious consideration would be to place a lesion in the atrial flutter isthmus prophylactically at the time of surgery. Other potential considerations relate to placement of the atriotomy incision in such a way that it cannot act as a stable line of block between the vena cavae. Finally, these data lend still more support to the theoretical concept that some form of conduction block between the vena cavae is essential for the establishment of a stable substrate for the classic atrial flutter reentrant circuit.

	Acknowledgments

 
This study was supported in part by grant HL-38408 from the National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, Md.

Received January 21, 2000; revision received March 30, 2000; accepted April 10, 2000.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Garson AJ, Bink BM, Hesslein PS, et al. Atrial flutter in the young: a collaborative study of 380 cases. J Am Coll Cardiol. 1985;6:871–878.[Abstract]
   
2. Driscoll DJ, Offord KP, Feldt RH, et al. Five- to 15-year follow-up after Fontan operation. Circulation. 1992;85:469–496.[Abstract/Free Full Text]
   
3. Flinn CJ, Wolff GS, Dick MD, et al. Cardiac rhythm after the Mustard operation for complete transposition of the great arteries. N Engl J Med. 1984;310:1635–1638.[Abstract]
   
4. Saul JP, Walsh EP, Triedman JK. Mechanisms and therapy of complex arrhythmias in pediatric patients. J Cardiovasc Electrophysiol. 1995;6:1129–1148.[Medline] [Order article via Infotrieve]
   
5. Triedman JK, Saul JP, Weindling SN, et al. Radiofrequency ablation of intra-atrial reentrant tachycardia after surgical palliation of congenital heart disease. Circulation. 1995;91:707–714.[Abstract/Free Full Text]
   
6. Van Hare GF, Lesh MD, Ross BA, et al. Mapping and radiofrequency ablation of intraatrial reentrant tachycardia after the Senning or Mustard procedure for transposition of the great arteries. Am J Cardiol. 1996;77:985–991.[Medline] [Order article via Infotrieve]
   
7. Kalman JM, Van Hare GF, Olgin JE, et al. Ablation of "incisional" reentrant atrial tachycardia complicating surgery for congenital heart disease: use of entrainment to define a critical isthmus of slow conduction. Circulation. 1996;93:502–512.[Abstract/Free Full Text]
   
8. Cosio FC. Endocardial mapping of atrial flutter. In: Touboul P, Waldo AL, eds. Atrial Arrhythmias. St Louis, Mo: Mosby Year Book; 1990:229–240.
   
9. Olshansky B, Okumura K, Hess PG, et al. Demonstration of an area of slow conduction in human atrial flutter. J Am Coll Cardiol. 1990;16:1634–1648.
   
10. Nakagawa H, Lazzara R, Khastgir T, et al. Role of the tricuspid annulus and the eustachian valve/ridge on atrial flutter: relevance to catheter ablation of the septal isthmus and a new technique for rapid identification of ablation success. Circulation. 1996;94:407–424.[Abstract/Free Full Text]
    
11. Kalman JM, Olgin JE, Saxon LA, et al. Activation and entrainment mapping defines the tricuspid annulus as the anterior barrier in typical atrial flutter. Circulation. 1996;94:398–406.[Abstract/Free Full Text]
    
12. Shah DC, Jais P, Haissaguerre M, et al. Three-dimensional mapping of the common atrial flutter circuit in the right atrium. Circulation. 1997;96:3904–3912.[Abstract/Free Full Text]
    
13. Cosio FG, Goicolea A, Lopez-Gil M, et al. Atrial endocardial mapping in the rare form of atrial flutter. Am J Cardiol. 1990;66:715–720.[Medline] [Order article via Infotrieve]
    
14. Saoudi N, Nair M, Abdelazziz A, et al. Electrocardiographic patterns and results of radiofrequency catheter ablation of clockwise type I atrial flutter. J Cardiovasc Electrophysiol. 1996;7:931–942.[Medline] [Order article via Infotrieve]
    
15. Saoudi N, Cosio F, Waldo A, et al. A new classification of atrial tachycardias based on electrophysiologic mechanisms. Eur Heart J. In press.
    
16. Olgin JE, Kalman JM, Fitzpatrick AP, et al. Role of right atrial endocardial structures as barriers to conduction during human type I atrial flutter: activation and entrainment mapping guided by intracardiac echocardiography. Circulation. 1995;92:1839–1848.[Abstract/Free Full Text]
    
17. Cauchemez B, Haissaguerre M, Fischer B, et al. Electrophysiological effects of catheter ablation of inferior vena cava- tricuspid annulus isthmus in common atrial flutter. Circulation. 1996;93:284–294.[Abstract/Free Full Text]
    
18. Hamdan MH, Kalman JM, Barron HV, et al. P-wave morphology during right atrial pacing before and after atrial flutter ablation: a new marker for success. Am J Cardiol. 1997;79:1417–1420.[Medline] [Order article via Infotrieve]
    
19. Baker BM, Lindsay BD, Bromberg BI, et al. Catheter ablation of clinical intraatrial reentrant tachycardias resulting from previous atrial surgery: localizing and transecting the critical isthmus. J Am Coll Cardiol. 1996;28:411–417.[Abstract]
    
20. Waldo AL. Pathogenesis of atrial flutter. J Cardiovasc Electrophysiol. 1998;9:S18–S25.[Medline] [Order article via Infotrieve]
    
21. Feld GK, Shahandeh-Rad F. Mechanism of double potentials recorded during sustained atrial flutter in the canine right atrial crush-injury model. Circulation. 1992;86:628–641.[Abstract/Free Full Text]
    
22. Shimizu A, Nozaki A, Rudy Y, et al. Characterization of double potentials in a functionally determined reentrant circuit: multiplexing studies during interruption of atrial flutter in the canine pericarditis model. J Am Coll Cardiol. 1993;22:2022–2032.[Abstract]
    
23. Van Hare GF, Lesh MD, Stanger P. Radiofrequency catheter ablation of supraventricular arrhythmias in patients with congenital heart disease: results and technical considerations. J Am Coll Cardiol. 1993;22:883–890.[Abstract]
    
24. Waldo AL, MacLean WA, Karp RB, et al. Entrainment and interruption of atrial flutter with atrial pacing: studies in man following open heart surgery. Circulation. 1977;56:737–745.[Abstract/Free Full Text]
    
25. Waldo AL. Atrial flutter: entrainment characteristics. J Cardiovasc Electrophysiol. 1997;8:337–352.[Medline] [Order article via Infotrieve]
    
26. Stevenson WG, Sager PT, Friedman PL. Entrainment techniques for mapping atrial and ventricular tachycardias. J Cardiovasc Electrophysiol. 1995;6:201–216.[Medline] [Order article via Infotrieve]
    
27. Frame LH, Page RL, Boyden PA, et al. Circus movement in the canine atrium around the tricuspid ring during experimental atrial flutter and during reentry in vitro. Circulation. 1987;76:1155–1175.[Abstract/Free Full Text]
    

This article has been cited by other articles:

				A. L. Waldo and G. K. Feld Inter-Relationships of Atrial Fibrillation and Atrial Flutter: Mechanisms and Clinical Implications J. Am. Coll. Cardiol., February 26, 2008; 51(8): 779 - 786. [Abstract] [Full Text] [PDF]

				F. Onorati, A. Esposito, G. Messina, A. di Virgilio, and A. Renzulli Right Isthmus Ablation Reduces Supraventricular Arrhythmias After Surgery for Chronic Atrial Fibrillation Ann. Thorac. Surg., January 1, 2008; 85(1): 39 - 48. [Abstract] [Full Text] [PDF]

				A. di Virgilio, F. Onorati, P. Mastroroberto, and A. Renzulli Beating-heart ablation of the cavo-tricuspid isthmus Interactive CardioVascular and Thoracic Surgery, April 1, 2006; 5(2): 85 - 87. [Abstract] [Full Text] [PDF]

				P. Lukac, V. E. Hjortdal, A. K. Pedersen, P. T. Mortensen, H. K. Jensen, and P. S. Hansen Atrial Incision Affects the Incidence of Atrial Tachycardia After Mitral Valve Surgery Ann. Thorac. Surg., February 1, 2006; 81(2): 509 - 513. [Abstract] [Full Text] [PDF]

				G. Golovchiner, A. Mazur, A. Kogan, B. Strasberg, Y. Shapira, M. Fridman, J. Kuzniec, B. A. Vidne, and E. Raanani Atrial Flutter After Surgical Radiofrequency Ablation of the Left Atrium for Atrial Fibrillation Ann. Thorac. Surg., January 1, 2005; 79(1): 108 - 112. [Abstract] [Full Text] [PDF]

				A. Nabar, C. Timmermans, A. Medeiros, K. Polymeropoulous, H.J.G.M. Crijns, and L.M. Rodriguez Radiofrequency ablation of atrial arrhythmias after previous open-heart surgery Europace, January 1, 2005; 7(1): 40 - 49. [Abstract] [Full Text] [PDF]

				A. Verma, N. F. Marrouche, N. Seshadri, R. A. Schweikert, M. Bhargava, J. D. Burkhardt, F. Kilicaslan, J. Cummings, W. Saliba, and A. Natale Importance of ablating all potential right atrial flutter circuits in postcardiac surgery patients J. Am. Coll. Cardiol., July 21, 2004; 44(2): 409 - 414. [Abstract] [Full Text] [PDF]

				S. Zhang, G. Younis, R. Hariharan, J. Ho, Y. Yang, J. Ip, R. K. Thakur, J. Seger, M. M. Scheinman, and J. Cheng Lower Loop Reentry as a Mechanism of Clockwise Right Atrial Flutter Circulation, April 6, 2004; 109(13): 1630 - 1635. [Abstract] [Full Text] [PDF]

				J. Weipert, C. Noebauer, C. Schreiber, M. Kostolny, B. Zrenner, A. Wacker, J. Hess, and R. Lange Occurrence and management of atrial arrhythmia after long-term Fontan circulation J. Thorac. Cardiovasc. Surg., February 1, 2004; 127(2): 457 - 464. [Abstract] [Full Text] [PDF]

				Committee Members, C. Blomstrom-Lundqvist, M. M. Scheinman, E. M. Aliot, J. S. Alpert, H. Calkins, A. J. Camm, W. B. Campbell, D. E. Haines, K. H. Kuck, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias --executive summary: a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) Developed in Collaboration with NASPE-Heart Rhythm Society J. Am. Coll. Cardiol., October 15, 2003; 42(8): 1493 - 1531. [Full Text] [PDF]

				C. Blomstrom-Lundqvist, M. M. Scheinman, E. M. Aliot, J. S. Alpert, H. Calkins, A. J. Camm, W. B. Campbell, D. E. Haines, K. H. Kuck, B. B. Lerman, et al. ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias*--Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias) Circulation, October 14, 2003; 108(15): 1871 - 1909. [Full Text] [PDF]

				Committee Members, C. Blomstrom-Lundqvist, M. M Scheinman, E. M Aliot, J. S Alpert, H. Calkins, A.J. Camm, W.B. Campbell, D. E Haines, K. H Kuck, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary: A Report of the American College of Cardiology/American HeartAssociation Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines(Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias)Developed in collaboration with NASPE-Heart Rhythm Society Eur. Heart J., October 2, 2003; 24(20): 1857 - 1897. [Full Text] [PDF]

				W. Anne, H. van Rensburg, J. Adams, H. Ector, F. Van de Werf, and H. Heidbuchel Ablation of post-surgical intra-atrial reentrant tachycardia. Predilection target sites and mapping approach Eur. Heart J., October 2, 2002; 23(20): 1609 - 1616. [Abstract] [Full Text] [PDF]

				B. J. Deal, C. Mavroudis, C. L. Backer, S. H. Buck, and C. Johnsrude Comparison of Anatomic Isthmus Block With the Modified Right Atrial Maze Procedure for Late Atrial Tachycardia in Fontan Patients Circulation, July 30, 2002; 106(5): 575 - 579. [Abstract] [Full Text] [PDF]

				J. K Triedman Arrhythmias in adults with congenital heart disease Heart, April 1, 2002; 87(4): 383 - 389. [Full Text] [PDF]

				N Saoudi, F Cosio, A Waldo, S.A Chen, Y Iesaka, M Lesh, S Saksena, J Salerno, and W Schoels A classification of atrial flutter and regular atrial tachycardia according to electrophysiological mechanisms and anatomical bases. A Statement from a Joint Expert Group from the Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology Eur. Heart J., July 2, 2001; 22(14): 1162 - 1182. [PDF]

				J. K. Triedman, M. E. Alexander, C. I. Berul, L. M. Bevilacqua, and E. P. Walsh Electroanatomic Mapping of Entrained and Exit Zones in Patients With Repaired Congenital Heart Disease and Intra-Atrial Reentrant Tachycardia Circulation, April 24, 2001; 103(16): 2060 - 2065. [Abstract] [Full Text] [PDF]

				A Nabar, L M Rodriguez, C Timmermans, R van Mechelen, and H J J Wellens Class IC antiarrhythmic drug induced atrial flutter: electrocardiographic and electrophysiological findings and their importance for long term outcome after right atrial isthmus ablation Heart, April 1, 2001; 85(4): 424 - 429. [Abstract] [Full Text]

				Y. Tomita, K. Matsuo, J. Sahadevan, C. M. Khrestian, and A. L. Waldo Role of Functional Block Extension in Lesion-Related Atrial Flutter Circulation, February 20, 2001; 103(7): 1025 - 1030. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chan, D. P. Articles by Waldo, A. L. Search for Related Content PubMed PubMed Citation Articles by Chan, D. P. Articles by Waldo, A. L. Related Collections Electrophysiology Ablation/ICD/surgery Pediatric and congenital heart disease, including cardiovascular surgery Arrhythmias, clinical electrophysiology, drugs