HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

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 Add to Personal Folders Download to citation manager Author home page(s): Jai S. Raman Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Raman, J. S. Articles by Power, J. M. Search for Related Content PubMed PubMed Citation Articles by Raman, J. S. Articles by Power, J. M. Related Collections Electrophysiology - arrhythmias

Ann Thorac Surg 2001;72:S1096-S1099
© 2001 The Society of Thoracic Surgeons

---

Supplement: Cardiothoracic techniques and technologies

Combined endocardial and epicardial radiofrequency ablation of right and left atria in the treatment of atrial fibrillation

^a Department of Cardiac Surgery, Austin & Repatriation Medical Centre, and Baker Institute of Medical Research, Prahran, Victoria, Australia

Address reprint requests to Dr Raman, Department of Cardiac Surgery, Austin & Repatriation Medical Centre, Studley Rd, Heidelberg, Melbourne, Victoria 3084, Australia
e-mail: jai.raman{at}armc.org.au

Presented at the Seventh Annual Cardiothoracic Techniques and Technologies Meeting 2001, New Orleans, LA, Jan 24–27, 2001.

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. The maze procedure and its modifications have been successful in treating atrial fibrillation (AF), at the expense of longer procedure times and increased morbidity. This study evaluated the early results of using radiofrequency ablation as a surgical adjunct in treating AF.

Methods. Twenty-six patients, with established or frequent intermittent AF, who were undergoing various cardiac surgical procedures, were enrolled. During their operations, the patients underwent intraoperative left and right atrial radiofrequency ablation lesions using a handheld flexible probe. Patients were followed up with echocardiography and Holter monitoring.

Results. All 26 patients were weaned off cardiopulmonary bypass in sinus rhythm. There were 2 early noncardiac deaths in high-risk patients; 23 surviving patients (95%) remained in sinus rhythm at a mean follow-up of 175 days (range 96 to 400 days). Three patients were defibrillated into sinus rhythm 30, 40, and 60 days after their operation. Test epicardial lesions on the right atrial appendage in 12 patients showed full-thickness coagulation of tissue in 10 (83%).

Conclusions. A combined endocardial and epicardial set of radiofrequency lesions in both atria abolished AF in most patients at 6 months and facilitated easy conversion of recurrent AF into sinus rhythm. The transmural nature of the epicardial lesions has implications for further development.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Surgical attitudes toward the treatment of atrial fibrillation (AF) range from a hands-off approach to the use of invasive treatments such as the maze procedure. The maze procedure was proposed by Cox in 1991 [1]. Along with a number of similar procedures, the maze procedure has had varying degrees of success in abolishing AF [2, 3]. However, the long procedure times and increased risk of morbid complications associated with the procedure have prevented widespread acceptance of this approach to treating AF [4]. Therefore, despite the increased risk of thromboembolic complications and the risks associated with long-term anticoagulation, to date most surgeons have limited their treatment of AF to the use of drug therapy.

The purpose of this study was to assess the early results of using radiofrequency ablation (RFA) as a surgical adjunct in treating AF. We evaluated an RFA catheter that was malleable and had seven electrodes (Cobra, EPT; Boston Scientific, San Jose, CA) initially in animals. Thereafter, based on favorable preliminary human data [5], we used the Cobra probe and the EPT system to create lines of electrical block in the atria using RFA in an attempt to abolish AF. This report describes our initial clinical experience.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Twenty-six patients undergoing a range of conventional cardiac surgical procedures between March 2000 and February 2001 were treated for established AF or frequent, intermittent AF using RFA. The mean left atrial diameter was 5.8 cm preoperatively. Twenty patients were in established AF and 6 had frequent episodic AF at the time of their operation. Mean duration of preoperative AF was 20 months (range 9 months to 8 years). Frequent episodic AF was defined as more than three episodes a week.

The breakdown of the primary surgical procedures was as follows: 10 patients underwent mitral valve repair/replacement; 3 had an aortic valve replacement; 5 had a combination of aortic valve replacement and mitral valve procedure; 4 underwent coronary artery bypass grafting (CABG); 1 underwent an Ebstein’s repair; and the remaining 3 cases each underwent CABG in conjunction with an aortic and mitral valve procedure, a mitral valve repair, and closure of an atrial septal defect, respectively.

All surviving patients were followed up at a mean of 175 days after operation with a clinical examination, echocardiogram, and a Holter monitor.

Surgical technique
The surgical technique varied depending on whether the left atrium was opened. We chose to use a combination of radiofrequency lesions based on the bilateral isolation of pulmonary veins proposed by Melo and colleagues [6] and the radial procedure proposed by Nitta and colleagues [3]. As our familiarity with the procedure in mitral valve patients grew, we adapted the salient features of this lesion set for a predominantly epicardial approach for patients undergoing aortic valve operation and coronary artery operation.

All lesions were created using radiofrequency energy delivered by the Cobra catheter at a minimum temperature of 80° to 85°C for a period of 2 minutes. In 12 of the patients, test epicardial lesions were created using the same time and temperature settings. However, these lesions were created in the trabeculated portion of the right atrial appendage with the heart beating on cardiopulmonary bypass (CPB). Biopsies were then taken of these lesions and were sent for a histopathologic check of the transmurality of the radiofrequency burn. The aim of this exercise was to establish the extent of epicardial lesions using RFA in the beating-heart situation.

Mitral operation
Patients undergoing a mitral operation usually had the mitral valve approached by the superior biatrial transseptal route. The sequence of steps before the valvular procedure was as follows: evacuation of the left atrial appendage followed by linear obliteration of its orifice from within; creation of a superior linear lesion above both superior pulmonary veins; administration of encircling lesions around left sided and right sided pulmonary vein orifices; and, finally, the creation of a lesion from the septal region down to the mitral valve annulus (Fig 1).

View larger version (46K): [in this window] [in a new window]   Fig 1. Left atrial lesions: endocardial application in mitral procedures.

View larger version (76K): [in this window] [in a new window]   Fig 2. Right atrial lesions: epicardial application. (SA = sinoatrial.)

View larger version (46K): [in this window] [in a new window]   Fig 3. Left atrium: epicardial lesions in aortic valve of patients undergoing coronary artery bypass grafting.

	Results

Top Abstract Introduction Patients and methods Results Comment References

There were 2 early deaths. One was due to a remote descending thoracic aortic dissection that caused gut ischemia in a patient who had undergone replacement of the ascending aorta and aortic valve. The other was due to a profound systemic inflammatory response syndrome and coagulopathy in a patient who required an urgent double-valve procedure and CABG operation. Both these patients had postmortem examinations, which confirmed full-thickness lesions in the atria.

Follow-up was complete in all other patients at a mean of 175 days (range 96 to 400 days). Twenty-one patients (95.4%) were in a regular sinus rhythm or regular paced rhythm, confirmed by clinical examination and Holter monitoring. Despite 4 patients being in established atrial flutter and fibrillation preoperatively, none of these patients have had problems with postoperative flutter.

Three patients required defibrillation at 30, 40, and 60 days postoperatively. These patients have since stayed in sinus rhythm. The first few patients were not started on any antiarrhythmic medications. However, over the course of the study, the protocol was changed to discharging all patients on low-dose amiodarone (200 mg/day) and maintaining this dose for 6 months. As a consequence, the latter 20 patients have been on low-dose amiodarone for 6 months.

Two patients required pacemakers. The first was a 50-year-old woman who developed viral cardiomyopathy 10 weeks postoperatively and required extracorporeal life support for 9 days. She had a permanent pacemaker to speed up her slow sinus rate, after being successfully weaned off life support. The second patient was a 54-year-old woman who underwent a modified Danielson’s repair of Ebstein’s anomaly and had a dual-chamber pacemaker inserted for complete heart block. Left atrial function was normal in this patient.

Echocardiography performed postoperatively showed reasonable atrial contraction in all patients in sinus rhythm.

Histopathology of the epicardial lesions revealed full-thickness alteration of atrial tissue in 10 of 12 patients (Fig 4). Although the thermal injury was not transmural on histopathology in 2 of the patients, the deepest part of the atrial tissue appeared abnormal and there was macroscopic evidence of blanching of the endocardial surface of the atrium.

View larger version (165K): [in this window] [in a new window]   Fig 4. Demonstration of full-thickness alteration of atrial tissue on histopathology.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

In contrast, RFA is relatively quick to perform. Radiofrequency ablation creates lesions in the myocardium through resistive heating, thereby creating scars that cause electrical block. Selective ablation of ectopic electrical foci has been effective in the treatment of focal AF [8] and other supraventricular tachycardias [9]. However, all of these techniques have been endocardial and have relied on invasive approaches whereas the lesions created have not been easily visualized.

At our center we first applied RFA endocardially in the left atrium as part of mitral valve procedures along with epicardial application on the right atrium. However, eventually, as we grew more confident of the transmural nature of the epicardial lesions, we proceeded to perform more epicardial lesions in patients undergoing aortic valve and CABG procedures.

Intraoperatively, with the heart arrested and an empty atrium, endocardial lesions can be created easily. Surgical use of this technique is simple and can easily facilitate the creation of long linear lesions in any configuration or shape, because of the malleability of the Cobra probe with its multiple electrodes. The potential therefore exists to create multiple electrically inactive scars within a short period of time without the disadvantage of making multiple incisions.

These principles have been used effectively by various groups to create lesions in the left atrium to treat AF [6, 10]. Benussi and colleagues [11] recently showed that similar results could be achieved by creating epicardial lesions around the pulmonary veins. Melo and associates [12] have also shown epicardial lesions in "off-pump" procedures to be reasonably effective. Electrophysiologists would argue that the epicardial approach does not create full-thickness lesions capable of causing persistent electrical block. However, our histologic studies suggest that RFA applied epicardially at a temperature of about 85°C for 2 minutes has the capability of consistently creating transmural lesions in atrial tissue ranging from 1 to 3 mm in thickness.

Atrial flutter has been a consistent late complication in some of these series [6]. Surprisingly, none of the groups above focused on the right atrium, which is usually where the flutter originates [13]. In contrast, in this study we used an epicardial approach to create a line of block along the region of the isthmus between the inferior vena caval orifice and the tricuspid annulus.

All the patients in this series had large atria with a mean left atrial diameter of more than 5.8 cm. We therefore chose not to focus heavily on left atrial volume. Melo and colleagues [6] pointed out that the long-term results of ablation are not too favorable in patients with larger atria. Long-term follow-up of the patients in our series is needed to show whether the modification in lesion set and temperature adopted at our center produces results consistently better than those of other groups.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

1. Cox J.L. The surgical treatment of atrial fibrillation. IV. Surgical technique. J Thorac Cardiovasc Surg 1991;101:584-592.[Abstract]
2. Cox J.L., Jaquiss R.D., Schuessler R.B., Boineau J.P. Modification of maze procedure for atrial flutter and atrial fibrillation. II. Surgical technique of the maze III procedure. J Thorac Cardiovasc Surg 1995;110:485-495.[Abstract/Free Full Text]
3. Nitta T., Lee R., Schuessler R.B., Boineau J.P., Cox J.L. Radial approach: a new concept in surgical treatment for atrial fibrillation. I. Concept, anatomic and physiologic bases and development of a procedure. Ann Thorac Surg 1999;67:27-35.[Abstract/Free Full Text]
4. Melo J.Q., Neves J.P., Abecasis L.M., Adragao P., Ribeiras R., Seabra-Gomes R. Operative risks of the maze procedure associated with mitral valve surgery. Cardiovasc Surg 1997;5:112-116.[Medline]
5. Melo J.Q., Adragao P., Neves J., et al. Surgery for atrial fibrillation using intra-operative radiofrequency ablation. Rev Port Cardiol 1998;17:377-379.[Medline]
6. Melo J.Q., Adragao P., Neves J., et al. Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year. Eur J Cardiothorac Surg 1999;15:851-855.[Abstract/Free Full Text]
7. American Heart Association policy document on atrial fibrillation. 1998. http://www.americanheart.org/arrhythmia/patient/about_atria.html
8. Haissaguerre M., Jais P., Shah D.C., et al. Right and left atrial radiofrequency catheter therapy of paroxysmal atrial fibrillation. J Cardiovasc Electrophysiol 1996;7:1132-1144.[Medline]
9. Jackman W.M., Beckman K.J., McClelland J.H., et al. Treatment of supraventricular tachycardia due to atrioventricular nodal reentry, by radiofrequency catheter ablation of slow-pathway conduction. N Engl J Med 1992;327:313-318.[Medline]
10. Kottkamp H., Hindricks G., Hammel D., et al. Intraoperative radiofrequency ablation of chronic atrial fibrillation: a left atrial curative approach by elimination of anatomic "anchor" reentrant circuits. J Cardiovasc Electrophysiol 1999;10:772-780.[Medline]
11. Benussi S., Pappone C., Nascimbene S., et al. A simple way to treat chronic atrial fibrillation during mitral valve surgery: the epicardial radiofrequency approach. Eur J Cardiothorac Surg 2000;17:524-529.[Abstract/Free Full Text]
12. Melo J., Adragao P., Neves J., et al. Endocardial and epicardial radiofrequency ablation in the treatment of atrial fibrillation with a new intra-operative device. Eur J Cardiothorac Surg 2000;18:182-186.[Abstract/Free Full Text]
13. Cosio F.G., Lopez-Gil M., Goicolea A., Arribas F., Barroso J.L. Radiofrequency catheter ablation of inferior vena cava-tricuspid valve isthmus in common atrial flutter. Am J Cardiol 1993;71:705-709.[Medline]

This article has been cited by other articles:

				R. Krakor, M. Chares, J. Schneider, H. Bernau, and I. Eichler Mid-term results of endoscopic mitral valve repair in combination with endocardial or epicardial ablation Eur J Cardiothorac Surg, September 1, 2011; 40(3): e125 - e129. [Abstract] [Full Text] [PDF]

				W. Wisser, G. Seebacher, T. Fleck, C. Aigner, C. Khazen, G. Stix, D. Hutschala, and E. Wolner Permanent Chronic Atrial Fibrillation: Is Pulmonary Vein Isolation Alone Enough? Ann. Thorac. Surg., October 1, 2007; 84(4): 1151 - 1157. [Abstract] [Full Text] [PDF]

				S. D. Barnett and N. Ad Surgical ablation as treatment for the elimination of atrial fibrillation: A meta-analysis J. Thorac. Cardiovasc. Surg., May 1, 2006; 131(5): 1029 - 1035. [Abstract] [Full Text] [PDF]

				M. Chaput, D. Bouchard, P. Demers, L. P. Perrault, R. Cartier, M. Carrier, P. Page, and M. Pellerin Conversion to sinus rhythm does not improve long-term survival after valve surgery: insights from a 20-year follow-up study Eur J Cardiothorac Surg, August 1, 2005; 28(2): 206 - 210. [Abstract] [Full Text] [PDF]

				S. Benussi and O. Alfieri Concomitant ablation of atrial fibrillation during mitral surgery MMCTS, January 1, 2005; 2005(1129): mmcts.2005.001081 - mmcts.2005.001081. [Abstract] [Full Text] [PDF]

				W. Wisser, C. Khazen, E. Deviatko, G. Stix, T. Binder, R. Seitelberger, H. Schmidinger, and E. Wolner Microwave and radiofrequency ablation yield similar success rates for treatment of chronic atrial fibrillation Eur J Cardiothorac Surg, June 1, 2004; 25(6): 1011 - 1017. [Abstract] [Full Text] [PDF]

				J. Raman, S. Ishikawa, M. M. Storer, and J. M. Power Surgical radiofrequency ablation of both atria for atrial fibrillation: results of a multicenter trial J. Thorac. Cardiovasc. Surg., November 1, 2003; 126(5): 1357 - 1365. [Abstract] [Full Text] [PDF]

				H. T Sie, W. P Beukema, A. Elvan, and A. R Ramdat Misier New strategies in the surgical treatment of atrial fibrillation Cardiovasc Res, June 1, 2003; 58(3): 501 - 509. [Abstract] [Full Text] [PDF]

				V. Vijay and J. P. Gold Late Complications of Cardiac Surgery Card. Surg. Adult, January 1, 2003; 2(2003): 521 - 537. [Full Text]

				J. S. Raman, S. Ishikawa, and J. M. Power Epicardial radiofrequency ablation of both atria in the treatment of atrial fibrillation: experience in patients Ann. Thorac. Surg., November 1, 2002; 74(5): 1506 - 1509. [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 Add to Personal Folders Download to citation manager Author home page(s): Jai S. Raman Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Raman, J. S. Articles by Power, J. M. Search for Related Content PubMed PubMed Citation Articles by Raman, J. S. Articles by Power, J. M. Related Collections Electrophysiology - arrhythmias