AbstractObjectiveWe present the results obtained in 40 patients with chronic atrial fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation surgery.MethodsBetween April 1995 and June 2002, 40 patients underwent surgery for atrial fibrillation using radiofrequency ablation and cardiac surgery at the Department of Cardiovascular Surgery of the University of Bologna. There were 8 men and 32 women with a mean age of 62 ± 11.6 years (range: 20 to 80 years).ResultsConcomitant surgical procedures were: mitral valve replacement (n = 13), mitral valve replacement plus tricuspid valvuloplasty (n = 11), combined mitral and aortic valve replacement (n = 8), and combined mitral and aortic valve replacement plus tricuspid valvuloplasty (n = 5). Moreover, 1 patient underwent tricuspid valvuloplasty plus atrial septal defect repair, another required aortic valve replacement plus coronary artery bypass graft, and a third underwent aortic valve replacement. After the mean follow-up time of 16.5 ± 2.5 months survival was 92.8% and the overall cumulative rate of sinus rhythm was 88.5%.ConclusionsWe conclude that the radiofrequency ablation procedure is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of our study population)

Chiappini, B

Di Bartolomeo, R

Loforte, A

Marinelli, G.

Martìn-Suàrez, S

English

Institutional Research Information System University of Turin

CardiopulmonarySupport andPhysiologySurgery for atrial fibrillation using radiofrequency catheterablationBruno Chiappini, MDSofia Martı̀n-Suàrez, MDAntonino LoForte, MDRoberto Di Bartolomeo, MDGiuseppe Marinelli, MDObjective: We present the results obtained in 40 patients with chronic atrialfibrillation using direct intraoperative radiofrequency to perform atrial fibrillationsurgery.Methods: Between April 1995 and June 2002, 40 patients underwent surgery foratrial fibrillation using radiofrequency ablation and cardiac surgery at the Depart-ment of Cardiovascular Surgery of the University of Bologna. There were 8 men and32 women with a mean age of 62  11.6 years (range: 20 to 80 years).Results: Concomitant surgical procedures were: mitral valve replacement (n  13),mitral valve replacement plus tricuspid valvuloplasty (n  11), combined mitral andaortic valve replacement (n  8), and combined mitral and aortic valve replacementplus tricuspid valvuloplasty (n  5). Moreover, 1 patient underwent tricuspidvalvuloplasty plus atrial septal defect repair, another required aortic valve replace-ment plus coronary artery bypass graft, and a third underwent aortic valve replace-ment. After the mean follow-up time of 16.5  2.5 months survival was 92.8% andthe overall cumulative rate of sinus rhythm was 88.5%.Conclusions: We conclude that the radiofrequency ablation procedure is a safe andeffective means of curing atrial fibrillation with negligible technical and timerequirements, allowing recovery of the sinus rhythm and atrial function in the greatmajority of patients with atrial fibrillation who underwent cardiac surgery (88.5% ofour study population).Atrial fibrillation (AF) is a common arrhythmia present in 0.4% ofthe general population and in more than 1% of the population over60 years of age. About 40% to 60% of patients undergoing mitralvalve surgery have AF, thus compromising the clinical outcome.The detrimental sequelae of AF are irregular heartbeat, compro-mised hemodynamics due to the absence of a synchronous atrio-ventricular contraction, and the risk of systemic thromboembolic events.Restoration of the sinus rhythm (SR) with atrioventricular resynchronization maybe difficult in patients with lone or chronic AF. The procedure consists of thesurgical approach described by James Cox, namely making linear lesions in the rightand left atria to prevent the occurrence of multiple reentering circuits. This surgicalFrom the Department of CardiovascularSurgery, Policlinico S. Orsola-Malpighi,University of Bologna, Bologna, Italy.Received for publication Jan 30, 2003; re-visions requested March 24, 2003; revi-sions received May 21, 2003; accepted forpublication June 18, 2003.Address for reprints: Bruno Chiappini, MD,Department of Cardiovascular Surgery,Policlinico S. Orsola-Malpighi, via Massa-renti 9-40138, Bologna, Italy (E-mail:bruno_chiappini@hotmail.com).J Thorac Cardiovasc Surg 2003;126:1788-91Copyright © 2003 by The American Asso-ciation for Thoracic Surgery0022-5223/2003 $30.00  0doi:10.1016/S0022-5223(03)01045-61788 The Journal of Thoracic and Cardiovascular Surgery ● December 2003CSPprocedure is extensive and time-consuming and requiresgreat surgical skill. More recently, Haissaguerre and col-leagues1 have demonstrated that radiofrequency (RF) abla-tion is able to confine the origin of paroxysmal AF to therapidly firing foci in the pulmonary veins. The efficacy ofRF ablation in patients with chronic AF undergoing cardiacsurgery has been evaluated and the clinical outcome ispresented here.MethodsOperative TechniqueBetween April 1995 and June 2002, 40 patients with chronic AFunderwent cardiac surgery and surgery to treat AF at the Depart-ment of Cardiovascular Surgery of the University of Bologna. Thepreoperative characteristics of the patients are shown in Table 1.All patients underwent cardiopulmonary bypass with bicaval andaortic cannulation under moderate hypothermia (32°C); myocar-dial protection was assured by antegrade crystalloid cardioplegia.The lesions were made by a Cobra Flex catheter (Boston Scientific,San Jose, Calif) at a temperature of 70°C to 80°C for a period of2 minutes in the left atrium and 90 seconds in the right atrium.After a standard lateral left atriotomy, the probe was placed on theleft atrial endocardium 5 to 10 mm medially from the right pul-monary vein orifices. The ablation probe was then used to create acircumferential lesion around the left pulmonary veins, at least 5mm from their orifices. Connecting lesions were created from theleft atrial appendage to the ablation line around the left pulmonaryveins and from this lesion to the anteromedial commissure of themitral valve. A final lesion connecting the 2 lesions encircling thepulmonary vein was created. The left atrial appendage was thenexcised and the stump of the left atrial appendage was closed withrunning polypropylene suture. We also performed the ablation inthe right atrium to prevent the early postoperative onset of atrialflutter: a single lesion was created along the crista terminalis fromthe superior vena cava to the inferior vena cava. A connectinglesion was then created from the lower end of this lesion onto theatrioventricular groove, low down and opposite the orifice of thecoronary sinus, to create a block in the cavotricuspid isthmus area(Figure 1). Two patients underwent aortic valve replacement andthe probe was applied on the epicardium of the dome of the leftatrium, connecting the pulmonary veins, which had previouslybeen isolated.Antiarrhythmic prophylactic treatment was carried out on aroutine basis. Amiodarone was the drug of choice. Its administra-tion was begun after induction of anesthesia: 300 mg intravenousbolus, followed by 1200 mg/24 hours intravenously until the endof the first postoperative day; beginning with the second postop-erative day, oral administration of 200 mg/24 hours was begun.After discharge, a maintenance regimen of 200 mg/24 hours wascontinued. The pharmacological treatment was discontinued 6months after the operation.Follow-upThe mean follow-up time was 15.5 months (range: 2-74 months).Clinical history and 12-lead electrocardiogram (ECG) were takenduring each follow-up visit. Sinus rhythm was defined as a su-praventricular rhythm with P waves on the standard 12-lead ECG.Six months after surgery, echocardiography was performed, in-cluding transmitral and transtricuspid Doppler echocardiography.E and A waves were detected to evaluate the atrial contraction. Atleast 1 Holter monitoring of rhythm was performed in each patient6 months after hospital discharge.Statistical AnalysisContinuous variables are expressed as the mean  SD. Student ttest for paired data was used to assess the statistical significance ofdifferences between pre- and postoperative parameters. A P value.05 was considered significant. The following preoperative vari-ables were considered for any possible relationship with surgicalresults: AF duration, age, and left atrial diameters. Survival wascalculated according to the Kaplan-Meier method.ResultsAs a consequence of the ablation there were no local orgeneral complications, namely atrial wounds. Concomitantsurgical procedures were: mitral valve replacement (n 13), mitral valve replacement plus tricuspid valvuloplasty (n 11), combined mitral and aortic valve replacement (n 8), and combined mitral and aortic valve replacement plustricuspid valvuloplasty (n  5). Moreover, 1 patient under-went tricuspid valvuloplasty plus atrial septal defect repairand 2 patients required aortic valve replacement, 1 of whomalso required coronary artery bypass graft. The mean car-diopulmonary bypass time was 126.3  33.4 minutes andthe crossclamp time was 104.8  31.5 minutes. The meanintensive care unit stay was 2.4 days. The cumulative in-hospital mortality was 7.5%: 1 patient died of sepsis, 1 ofsevere hepatic cirrhosis (of 20 years), and 1 of left ventric-ular disruption. Three patients (7%) needed permanentTABLE 1. Preoperative characteristics and surgical proce-duresVariable n  40 P valueAge (years) 62  11.6 NSSex (male) 8 NSSex (female) 32 NSLA dimension (mm) 56.05  7.6 NSAF duration (months) 61.9 NSEjection fraction (%) 56.8  13.3 NSNYHA class 2.8  0.5 NSMVR 13MVR  TVP 11MVR  AVR 8MVR  AVR  TVP 5TVP  ASD and VSD repair —TVP  ASD repair 1AVR 1AVR  CABG 1Redo 6 (15%) NSAF, Atrial fibrillation; ASD, atrial septal defect; AVR, aortic valve replace-ment; CABG, coronary artery bypass graft; LA, left atrial; MVR, mitral valvereplacement; NYHA, New York Heart Association; TVP, tricuspid valve-plasty; VSD, ventricular septal defect.Chiappini et al Cardiopulmonary Support and PhysiologyThe Journal of Thoracic and Cardiovascular Surgery ● Volume 126, Number 6 1789CSPpacemakers implanted because of postoperative bradycar-dia. No patient had transitory neurologic symptoms after thesurgical procedure. The cumulative rates of SR at dischargewas 85%.Follow-upAll 40 patients completed at least 6 months of follow-up.The duration of the follow-up ranged from 7 to 22 months(mean 16.5  2.5). Cumulative survival was 92.8%. At the12-lead ECG, the cumulative rate of SR was 88.5%. Biatrialcontraction was documented during transthoracic Dopplerechocardiography in 76.5% of the patients. Twenty-ninepatients (72.5%) were under treatment with warfarin so-dium and 9 patients (22.5%) were undergoing antiarrhyth-mic therapy (sotalol or amiodarone). We noted a significantimprovement of the New York Heart Association (NYHA)functional class after surgery: 20 patients (50%) were inNYHA class I and 20 (50%) in NYHA class II.DiscussionIn 1991, Cox and colleagues2-6 described a new procedurefor the radical surgical treatment of atrial fibrillation: themaze procedure. Initially it was performed as an isolatedcardiac procedure. However, as experience with this tech-nique has grown, it has been performed concomitantly withother cardiac procedures.7,8 It has been noted that the cor-rection of the underlying cardiac pathology alone usuallyfails to abolish AF.9 Kosakai and colleagues10 have shownthe advantage of the maze procedure for atrial fibrillation inpatients undergoing simultaneous cardiac surgery. The neg-ative effects of AF are widely known, particularly in com-bination with valve diseases. Therefore, a specific surgicalintervention is needed to eliminate AF. Excellent resultshave been described for the surgical treatment of chronicAF associated with organic heart disease at the expense,however, of extensive atrial incisions and suturing andgreater blood loss, as well as longer cardiac arrest.11,12In an attempt to reduce the procedure time and to sim-plify the surgical technique, modifications of the originalmaze procedure have been developed,13 including the ap-plication of RF energy.14 Heat propagation is based onresistive and passive mechanisms. In the immediate prox-imity of the probe, tissue is heated to 50°C to 60°C withconsequent coagulation and irreversible destruction of celland collagen structures. Further away from the probe, theresistance offered by tissue decreases exponentially and theheart rate rapidly decreases. Thus, ablation of the peripheralportion of the lesion results from passive heating with thesame effect of irreversible damage being reached over alonger period of time. Both resistive and passive heatingpropagate in all of the directions so that the tissue lesion issimilar in depth and width. Once transmurality is achieved,the effects of RF lesions are the same as those of the othermajor techniques with effective ablation of atrial muscle, anantiarrhythmic effect, and no significant proarrhythmic ac-tivity from the scar tissue.15The treatment of AF by the application of RF ablation inthe atria is based on the concept of preventing functionalmacro-reentrant circuits16 or eliminating anatomically de-termined circuits.17 All the lesions are made in the endo-cardium and replace most of the surgical incisions of theFigure 1. The surgical scheme of the RF ablation in the left and right atrium.Cardiopulmonary Support and Physiology Chiappini et al1790 The Journal of Thoracic and Cardiovascular Surgery ● December 2003CSPprevious techniques. The RF ablation procedure requires 15to 20 minutes of elective cardiac arrest time in contrast to atleast 50 to 60 minutes of the Cox maze III procedure.16,18The importance of interrupting conduction along the coro-nary sinus to avoid the development of postsurgical atrialflutter has been recognized.19 Therefore, we also performedRF ablation in the isthmus, between the tricuspid valveannulus and the inferior vena cava. In our study, patientshad a long duration of AF (61.9 months) and large left atrialdimensions (56.05  6 mm) but we did not find anystatistically significant relationship between these preoper-ative data and the surgical results. Restoration of SR wasdemonstrated in 88.5% of patients at follow-up.These data are comparable to the results documented bydifferent groups,20-25 who found restoration of SR between70% and 98%, depending on patient preoperative charac-teristics (lone AF, concomitant heart diseases) and the sur-gical techniques. All our patients had chronic AF; 12.5% ofthe patients underwent combined mitral and aortic valvereplacement plus tricuspid valvuloplasty and 15% (6 pa-tients) of the previous patients were reoperations. Therefore,we believe that RF ablation should also be considered a safeand effective procedure in eliminating AF in patients suf-fering from a multiple valve disease and in those undergo-ing a reoperation.An important aim of restoring SR is to produce thecontraction of both atria, restoring an adequate electrome-chanical synchrony and decreasing the risk of thromboem-bolism. In our study, biatrial contraction was restored in76.5% of the patients. Our data are equivalent to the data ofother groups, reporting the occurrence of biatrial contrac-tion in 66.7% to 99% of patients depending on the baselinecharacteristics.26 RF ablation usually prolongs the cross-clamp time only of 10 to 15 minutes. This is a significantadvantage in older patients with poor ventricular functionand/or multiple valve disease, making it possible to enlargethe indications to restore sinus rhythm surgically.In conclusion, we believe that the use of RF energy issafe and effective and simplifies the Cox maze III procedurein patients undergoing cardiac surgery, by restoring SR andatrial contraction in the majority of patients and also byreducing operating time.References1. SAS Institute Inc. SAS/STAT user’s guide. Release 6.10 ed. Cary, NC:SAS Institute Inc; 1995.2. Cox JL, Schuessler RB, Boineau JP. The surgical treatment of atrialfibrillation. I. Summary of the current concepts of the mechanisms ofatrial flutter and atrial fibrillation. J Thorac Cardiovasc Surg. 1991;101:402-5.3. Cox JL, Canavan TE, Schuessler RB, et al. The surgical treatment ofatrial fibrillation. II. Intraoperative electrophysiologic mapping anddescription of the electrophysiologic basis of atrial flutter and atrialfibrillation. J Thorac Cardiovasc Surg. 1991;101:406-26.4. Cox JL, Schuessler RB, D’Agostino HJ, et al. The surgical treatmentof atrial fibrillation. III. Development of a definitive surgical proce-dure. J Thorac Cardiovasc Surg. 1991;101:569-83.5. Cox JL. The surgical treatment of atrial fibrillation. IV. Surgicaltechnique. J Thorac Cardiovasc Surg. 1991;101:584-92.6. Cox JL, Boineau JP, Schuessler RB, et al. Successful surgical treat-ment of atrial fibrillation. Review and clinical update. JAMA. 1991;266:1976-80.7. Bonchek LI, Burlingame MW, Worley SJ, Vazales BE, Lundy EF.Cox/Maze procedure for atrial septal defect with atrial fibrillation:management strategies. Ann Thorac Surg. 1993;55:607-10.8. Kosakai Y, Kawaguchi AT, Isobe F, et al. Cox maze procedure forchronic atrial fibrillation associated with mitral valve disease. J ThoracCardiovasc Surg. 1994;108:1049-55.9. Sato S, Kawashima Y, Hirose H, Nakano S, Matsuda H, Shirakawa R.Long-term results of direct current cardioversion after open commis-surotomy for mitral stenosis. Am J Cardiol. 1986;57:629-33.10. Kosakai Y, Kawaguchi AT, Isobe F, et al. Modified maze procedurefor patients with atrial fibrillation undergoing simultaneous open heartsurgery. Circulation. 1995;92(Suppl 2):359-64.11. Kawaguchi AT, Kosakai Y, Sasako Y, Eishi K, Nakano K, KawashimaY. Risks and benefits of combined maze procedure for atrial fibrilla-tion associated with organic heart disease. J Am Coll Cardiol. 1996;28:985-90.12. Hioki M, Ikeshita M, Iedekoro Y, et al. Successful combined operationfor mitral stenosis and atrial fibrillation. Ann Thorac Surg. 1993;55:776-8.13. Cox JL, Jaquiss RDB, Schuessler RB, Boineau JP. Modifications ofthe maze procedure for atrial flutter and fibrillation. II. Surgical tech-nique of the maze III procedure. J Thorac Cardiovasc Surg. 1995;110:485-95.14. Wellens HJ, Sie HT, Smeets JL, et al. Surgical treatment of atrialfibrillation. J Cardiovasc Electrophysiol. 1998;9:S151-4.15. Viola N, Williams MR, Mehmet CO, Ad N. The technology in use forthe surgical ablation of atrial fibrillation. Semin Thorac CardiovascSurg. 2002;14:198-205.16. Patwardhan AM, Dave HH, Tamhane AA, et al. Intraoperative radio-frequency microbipolar coagulation to replace incisions of maze IIIprocedure for correcting atrial fibrillation in patients with rheumaticvalvular disease. Eur J Cardiothorac Surg. 1997;12:627-33.17. Hindriks G, Mohr FW, Autschbach R, Kottkamp H. Antiarrhythmicsurgery for treatment of atrial fibrillation: new concepts. Thorac Car-diovasc Surg. 1999;47(Suppl):365-9.18. Handa N, Schaff HV, Morris JJ, Anderson BJ, Kopecky SL, EnriquezSarano M. Outcome of valve repair and the Cox maze procedure formitral regurgitation and associated atrial fibrillation. J Thorac Cardio-vasc Surg. 1999;118:628-35.19. Cox JL, Ad N. The importance of cryoablation of the coronary sinusduring the maze procedure. Semin Thorac Cardiovasc Surg. 2000;12:20-4.20. Cox JL, Schuessler RB, Lappas DG, Boineau JP. An 81/2-year clinicalexperience with surgery for atrial fibrillation. Ann Surg. 1996;224:267-75.21. Isobe F, Kawashima Y. The outcome and indications of the Cox MazeIII procedure for chronic atrial fibrillation with mitral valve disease.J Thorac Cardiovasc Surg. 1998;116:220-7.22. Melo J, Adragao P, Neves J, et al. Surgery for atrial fibrillation usingradiofrequency catheter ablation: assessment of results at one year. EurJ Cardiothorac Surg. 1999;15:851-5.23. Melo J, Adragao P, Neves J, et al. Endocardial and epicardial radio-frequency ablation in the treatment of atrial fibrillation with a newintra-operative device. Eur J Cardiothorac Surg. 2000;18:182-6.24. Izumoto H, Kawazoe K, Eishi K, Kamata J. Medium-term results afterthe modified Cox/Maze procedure combined with other cardiac sur-gery. Eur J Cardiothorac Surg. 2000;17:25-9.25. Melo JQ, Neves J, Adragao P, et al. When and how to report the resultsof surgery on atrial fibrillation. Eur J Cardiothorac Surg. 1997;12:739-45.26. Deneke T, Khargi K, Grewe PH, et al. Left atrial versus bi-atrial Mazeoperation using intraoperative cooled-tip radiofrequency ablation inpatients undergoing open-heart surgery. Safety and efficacy. J Am CollCardiol. 2002;39:1644-50.Chiappini et al Cardiopulmonary Support and PhysiologyThe Journal of Thoracic and Cardiovascular Surgery ● Volume 126, Number 6 1791CSP

Surgery for atrial fibrillation using radiofrequency catheter ablation

Chiappini, Bruno

Martìn-Suàrez, Sofia

LoForte, Antonino

Di Bartolomeo, Roberto

Marinelli, Giuseppe

Elsevier - Publisher Connector 

Cardiopulmonary
Support and
Physiology
Surgery for atrial fibrillation using radiofrequency catheter
ablation
Bruno Chiappini, MD
Sofia Martı`n-Sua`rez, MD
Antonino LoForte, MD
Roberto Di Bartolomeo, MD
Giuseppe Marinelli, MD
Objective: We present the results obtained in 40 patients with chronic atrial
fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation
surgery.
Methods: Between April 1995 and June 2002, 40 patients underwent surgery for
atrial fibrillation using radiofrequency ablation and cardiac surgery at the Depart-
ment of Cardiovascular Surgery of the University of Bologna. There were 8 men and
32 women with a mean age of 62  11.6 years (range: 20 to 80 years).
Results: Concomitant surgical procedures were: mitral valve replacement (n  13),
mitral valve replacement plus tricuspid valvuloplasty (n 11), combined mitral and
aortic valve replacement (n 8), and combined mitral and aortic valve replacement
plus tricuspid valvuloplasty (n  5). Moreover, 1 patient underwent tricuspid
valvuloplasty plus atrial septal defect repair, another required aortic valve replace-
ment plus coronary artery bypass graft, and a third underwent aortic valve replace-
ment. After the mean follow-up time of 16.5  2.5 months survival was 92.8% and
the overall cumulative rate of sinus rhythm was 88.5%.
Conclusions: We conclude that the radiofrequency ablation procedure is a safe and
effective means of curing atrial fibrillation with negligible technical and time
requirements, allowing recovery of the sinus rhythm and atrial function in the great
majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of
our study population).
Atrial fibrillation (AF) is a common arrhythmia present in 0.4% ofthe general population and in more than 1% of the population over60 years of age. About 40% to 60% of patients undergoing mitralvalve surgery have AF, thus compromising the clinical outcome.The detrimental sequelae of AF are irregular heartbeat, compro-mised hemodynamics due to the absence of a synchronous atrio-
ventricular contraction, and the risk of systemic thromboembolic events.
Restoration of the sinus rhythm (SR) with atrioventricular resynchronization may
be difficult in patients with lone or chronic AF. The procedure consists of the
surgical approach described by James Cox, namely making linear lesions in the right
and left atria to prevent the occurrence of multiple reentering circuits. This surgical
From the Department of Cardiovascular
Surgery, Policlinico S. Orsola-Malpighi,
University of Bologna, Bologna, Italy.
Received for publication Jan 30, 2003; re-
visions requested March 24, 2003; revi-
sions received May 21, 2003; accepted for
publication June 18, 2003.
Address for reprints: Bruno Chiappini, MD,
Department of Cardiovascular Surgery,
Policlinico S. Orsola-Malpighi, via Massa-
renti 9-40138, Bologna, Italy (E-mail:
bruno_chiappini@hotmail.com).
J Thorac Cardiovasc Surg 2003;126:
1788-91
Copyright © 2003 by The American Asso-
ciation for Thoracic Surgery
0022-5223/2003 $30.00  0
doi:10.1016/S0022-5223(03)01045-6
1788 The Journal of Thoracic and Cardiovascular Surgery ● December 2003
CSP
procedure is extensive and time-consuming and requires
great surgical skill. More recently, Haissaguerre and col-
leagues1 have demonstrated that radiofrequency (RF) abla-
tion is able to confine the origin of paroxysmal AF to the
rapidly firing foci in the pulmonary veins. The efficacy of
RF ablation in patients with chronic AF undergoing cardiac
surgery has been evaluated and the clinical outcome is
presented here.
Methods
Operative Technique
Between April 1995 and June 2002, 40 patients with chronic AF
underwent cardiac surgery and surgery to treat AF at the Depart-
ment of Cardiovascular Surgery of the University of Bologna. The
preoperative characteristics of the patients are shown in Table 1.
All patients underwent cardiopulmonary bypass with bicaval and
aortic cannulation under moderate hypothermia (32°C); myocar-
dial protection was assured by antegrade crystalloid cardioplegia.
The lesions were made by a Cobra Flex catheter (Boston Scientific,
San Jose, Calif) at a temperature of 70°C to 80°C for a period of
2 minutes in the left atrium and 90 seconds in the right atrium.
After a standard lateral left atriotomy, the probe was placed on the
left atrial endocardium 5 to 10 mm medially from the right pul-
monary vein orifices. The ablation probe was then used to create a
circumferential lesion around the left pulmonary veins, at least 5
mm from their orifices. Connecting lesions were created from the
left atrial appendage to the ablation line around the left pulmonary
veins and from this lesion to the anteromedial commissure of the
mitral valve. A final lesion connecting the 2 lesions encircling the
pulmonary vein was created. The left atrial appendage was then
excised and the stump of the left atrial appendage was closed with
running polypropylene suture. We also performed the ablation in
the right atrium to prevent the early postoperative onset of atrial
flutter: a single lesion was created along the crista terminalis from
the superior vena cava to the inferior vena cava. A connecting
lesion was then created from the lower end of this lesion onto the
atrioventricular groove, low down and opposite the orifice of the
coronary sinus, to create a block in the cavotricuspid isthmus area
(Figure 1). Two patients underwent aortic valve replacement and
the probe was applied on the epicardium of the dome of the left
atrium, connecting the pulmonary veins, which had previously
been isolated.
Antiarrhythmic prophylactic treatment was carried out on a
routine basis. Amiodarone was the drug of choice. Its administra-
tion was begun after induction of anesthesia: 300 mg intravenous
bolus, followed by 1200 mg/24 hours intravenously until the end
of the first postoperative day; beginning with the second postop-
erative day, oral administration of 200 mg/24 hours was begun.
After discharge, a maintenance regimen of 200 mg/24 hours was
continued. The pharmacological treatment was discontinued 6
months after the operation.
Follow-up
The mean follow-up time was 15.5 months (range: 2-74 months).
Clinical history and 12-lead electrocardiogram (ECG) were taken
during each follow-up visit. Sinus rhythm was defined as a su-
praventricular rhythm with P waves on the standard 12-lead ECG.
Six months after surgery, echocardiography was performed, in-
cluding transmitral and transtricuspid Doppler echocardiography.
E and A waves were detected to evaluate the atrial contraction. At
least 1 Holter monitoring of rhythm was performed in each patient
6 months after hospital discharge.
Statistical Analysis
Continuous variables are expressed as the mean  SD. Student t
test for paired data was used to assess the statistical significance of
differences between pre- and postoperative parameters. A P value
.05 was considered significant. The following preoperative vari-
ables were considered for any possible relationship with surgical
results: AF duration, age, and left atrial diameters. Survival was
calculated according to the Kaplan-Meier method.
Results
As a consequence of the ablation there were no local or
general complications, namely atrial wounds. Concomitant
surgical procedures were: mitral valve replacement (n 
13), mitral valve replacement plus tricuspid valvuloplasty (n
 11), combined mitral and aortic valve replacement (n 
8), and combined mitral and aortic valve replacement plus
tricuspid valvuloplasty (n  5). Moreover, 1 patient under-
went tricuspid valvuloplasty plus atrial septal defect repair
and 2 patients required aortic valve replacement, 1 of whom
also required coronary artery bypass graft. The mean car-
diopulmonary bypass time was 126.3  33.4 minutes and
the crossclamp time was 104.8  31.5 minutes. The mean
intensive care unit stay was 2.4 days. The cumulative in-
hospital mortality was 7.5%: 1 patient died of sepsis, 1 of
severe hepatic cirrhosis (of 20 years), and 1 of left ventric-
ular disruption. Three patients (7%) needed permanent
TABLE 1. Preoperative characteristics and surgical proce-
dures
Variable n  40 P value
Age (years) 62 11.6 NS
Sex (male) 8 NS
Sex (female) 32 NS
LA dimension (mm) 56.05 7.6 NS
AF duration (months) 61.9 NS
Ejection fraction (%) 56.8 13.3 NS
NYHA class 2.8 0.5 NS
MVR 13
MVR  TVP 11
MVR  AVR 8
MVR  AVR  TVP 5
TVP  ASD and VSD repair —
TVP  ASD repair 1
AVR 1
AVR  CABG 1
Redo 6 (15%) NS
AF, Atrial fibrillation; ASD, atrial septal defect; AVR, aortic valve replace-
ment; CABG, coronary artery bypass graft; LA, left atrial; MVR, mitral valve
replacement; NYHA, New York Heart Association; TVP, tricuspid valve-
plasty; VSD, ventricular septal defect.
Chiappini et al Cardiopulmonary Support and Physiology
The Journal of Thoracic and Cardiovascular Surgery ● Volume 126, Number 6 1789
CS
P
pacemakers implanted because of postoperative bradycar-
dia. No patient had transitory neurologic symptoms after the
surgical procedure. The cumulative rates of SR at discharge
was 85%.
Follow-up
All 40 patients completed at least 6 months of follow-up.
The duration of the follow-up ranged from 7 to 22 months
(mean 16.5  2.5). Cumulative survival was 92.8%. At the
12-lead ECG, the cumulative rate of SR was 88.5%. Biatrial
contraction was documented during transthoracic Doppler
echocardiography in 76.5% of the patients. Twenty-nine
patients (72.5%) were under treatment with warfarin so-
dium and 9 patients (22.5%) were undergoing antiarrhyth-
mic therapy (sotalol or amiodarone). We noted a significant
improvement of the New York Heart Association (NYHA)
functional class after surgery: 20 patients (50%) were in
NYHA class I and 20 (50%) in NYHA class II.
Discussion
In 1991, Cox and colleagues2-6 described a new procedure
for the radical surgical treatment of atrial fibrillation: the
maze procedure. Initially it was performed as an isolated
cardiac procedure. However, as experience with this tech-
nique has grown, it has been performed concomitantly with
other cardiac procedures.7,8 It has been noted that the cor-
rection of the underlying cardiac pathology alone usually
fails to abolish AF.9 Kosakai and colleagues10 have shown
the advantage of the maze procedure for atrial fibrillation in
patients undergoing simultaneous cardiac surgery. The neg-
ative effects of AF are widely known, particularly in com-
bination with valve diseases. Therefore, a specific surgical
intervention is needed to eliminate AF. Excellent results
have been described for the surgical treatment of chronic
AF associated with organic heart disease at the expense,
however, of extensive atrial incisions and suturing and
greater blood loss, as well as longer cardiac arrest.11,12
In an attempt to reduce the procedure time and to sim-
plify the surgical technique, modifications of the original
maze procedure have been developed,13 including the ap-
plication of RF energy.14 Heat propagation is based on
resistive and passive mechanisms. In the immediate prox-
imity of the probe, tissue is heated to 50°C to 60°C with
consequent coagulation and irreversible destruction of cell
and collagen structures. Further away from the probe, the
resistance offered by tissue decreases exponentially and the
heart rate rapidly decreases. Thus, ablation of the peripheral
portion of the lesion results from passive heating with the
same effect of irreversible damage being reached over a
longer period of time. Both resistive and passive heating
propagate in all of the directions so that the tissue lesion is
similar in depth and width. Once transmurality is achieved,
the effects of RF lesions are the same as those of the other
major techniques with effective ablation of atrial muscle, an
antiarrhythmic effect, and no significant proarrhythmic ac-
tivity from the scar tissue.15
The treatment of AF by the application of RF ablation in
the atria is based on the concept of preventing functional
macro-reentrant circuits16 or eliminating anatomically de-
termined circuits.17 All the lesions are made in the endo-
cardium and replace most of the surgical incisions of the
Figure 1. The surgical scheme of the RF ablation in the left and right atrium.
Cardiopulmonary Support and Physiology Chiappini et al
1790 The Journal of Thoracic and Cardiovascular Surgery ● December 2003
CSP
previous techniques. The RF ablation procedure requires 15
to 20 minutes of elective cardiac arrest time in contrast to at
least 50 to 60 minutes of the Cox maze III procedure.16,18
The importance of interrupting conduction along the coro-
nary sinus to avoid the development of postsurgical atrial
flutter has been recognized.19 Therefore, we also performed
RF ablation in the isthmus, between the tricuspid valve
annulus and the inferior vena cava. In our study, patients
had a long duration of AF (61.9 months) and large left atrial
dimensions (56.05  6 mm) but we did not find any
statistically significant relationship between these preoper-
ative data and the surgical results. Restoration of SR was
demonstrated in 88.5% of patients at follow-up.
These data are comparable to the results documented by
different groups,20-25 who found restoration of SR between
70% and 98%, depending on patient preoperative charac-
teristics (lone AF, concomitant heart diseases) and the sur-
gical techniques. All our patients had chronic AF; 12.5% of
the patients underwent combined mitral and aortic valve
replacement plus tricuspid valvuloplasty and 15% (6 pa-
tients) of the previous patients were reoperations. Therefore,
we believe that RF ablation should also be considered a safe
and effective procedure in eliminating AF in patients suf-
fering from a multiple valve disease and in those undergo-
ing a reoperation.
An important aim of restoring SR is to produce the
contraction of both atria, restoring an adequate electrome-
chanical synchrony and decreasing the risk of thromboem-
bolism. In our study, biatrial contraction was restored in
76.5% of the patients. Our data are equivalent to the data of
other groups, reporting the occurrence of biatrial contrac-
tion in 66.7% to 99% of patients depending on the baseline
characteristics.26 RF ablation usually prolongs the cross-
clamp time only of 10 to 15 minutes. This is a significant
advantage in older patients with poor ventricular function
and/or multiple valve disease, making it possible to enlarge
the indications to restore sinus rhythm surgically.
In conclusion, we believe that the use of RF energy is
safe and effective and simplifies the Cox maze III procedure
in patients undergoing cardiac surgery, by restoring SR and
atrial contraction in the majority of patients and also by
reducing operating time.
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Chiappini et al Cardiopulmonary Support and Physiology
The Journal of Thoracic and Cardiovascular Surgery ● Volume 126, Number 6 1791
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Surgery for atrial fibrillation using radiofrequency catheter ablation 

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Surgery for atrial fibrillation using radiofrequency catheter ablation

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