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ercutaneous Catheter Ablation Treatment ofecurring Atrial Arrhythmias After Surgicalblation

inda Henry, PhD, RN, Sarfraz Durrani, MD, Sharon Hunt, MBA, Ted Friehling, MD,enry Tran, MD, Marc Wish, MD, Albert Del Negro, MD, Margaret Bell, MD, andiv Ad, MD

nova Heart and Vascular Institute, Falls Church, Virginia

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Background. Surgical ablation for atrial fibrillation isssociated with early and late recurrence of atrial ar-hythmias. Although early arrhythmias may be con-rolled with conventional treatment, late arrhythmias areften highly symptomatic and relatively hard to manageith antiarrhythmic drugs and electrical cardioversion.his study explores a single-center experience with cath-ter ablation to treat late failures (>3 months) afterurgery.

Methods. This is a prospective longitudinally designedtudy assessing all patients who underwent surgicalreatment for atrial fibrillation as a standalone or con-omitant with other procedures by multiple surgeons. Allatients were monitored according to the Heart Rhythmociety guidelines.Results. From January 2005 to present, 400 consecutive

atients operated on by multiple surgeons were enrolled.he overall success rate per the Heart Rhythm Societyuidelines was 87% and 84% (off antiarrhythmic drugs,8% and 73%) at 12 and 24 months, respectively. Sixteenatients (4%) were referred for electrophysiology studyfter the surgical procedure (15 Cox-maze III or IV, 1ulmonary vein isolation). The average age was 61.1 �

5.2 years; the mean left atrium size was 5.1 � 0.7 cm; and

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2010 by The Society of Thoracic Surgeonsublished by Elsevier Inc

he mean time to ablation was 16.9 � 10 months. In 16atients radiofrequency ablation was applied to treat theollowing atrial arrhythmias: 7 right atrial flutter orachycardia, 3 left atrial flutter, 1 biatrial flutter, and 5 lefttrial tachycardia. Six patients required a subsequentadiofrequency ablation intervention including 4 pa-ients who required atrioventricular nodal ablations. Theong-term success rate for the subsequent catheter abla-ion in these 16 patients (follow-up of 42.9 � 9.8 months)etermined by the rate of sinus rhythm as captured bylectrocardiography was 94%. Fifty-three percent of theatients (n � 8) in sinus rhythm were still taking antiar-hythmic drugs; 8 patients remained on warfarin. Thereas 1 late noncardiac death and no late strokes.Conclusions. In a certain subset of patients, unsuccess-

ul surgical ablation of atrial fibrillation may result inymptomatic atrial arrhythmia. If indicated, catheter ab-ation is a safe and effective intervention with a relativelyigh success rate. The combination of the two treatmentodalities, catheter and surgical ablation, can improve

he outcome even in complex patients.

(Ann Thorac Surg 2010;89:1227–32)

© 2010 by The Society of Thoracic Surgeons

he number of surgical procedures to ablate atrialfibrillation has dramatically increased. The majority

f the procedures performed are done using an alterna-ive energy source to replace the cut-and-sew Cox mazerocedure; this includes the application of the full Coxaze III lesions or a limited modified lesion set [1, 2].The success rate reported after the cut-and-sew Coxaze procedure is considered to be the gold standard, and

ome reports document a success rate as high as 90% [3],lthough other studies suggest a different success rate [4, 5].

Unlike the cut-and-sew techniques, the application ofurgical ablation devices may result in an incomplete con-

ccepted for publication Jan 18, 2010.

resented at the Fifty-sixth Annual Meeting of the Southern Thoracicurgical Association, Marco Island, FL, Nov 4–7, 2009.

ddress correspondence to Dr Ad, Inova Heart and Vascular Institute,

uction block and thus recurrence of the atrial arrhythmia6]. Previous studies have focused mainly on sinus nodeunction [7]; however, new mapping devices allow a moreomplete intraatrial mapping in symptomatic patients suchhat recurrence of atrial arrhythmia was documented. As aesult, new information related to the electrophysiologicharacteristics is available, and another treatment option tomprove success is available to us [8].

In this study we describe our clinical experience withatients after surgical ablation; the clinical and electro-hysiologic characteristics and management of postsur-ical ablation atrial arrhythmia is described andiscussed.

aterial and Methods

his study was a substudy for which data were extracted

rom the main parent longitudinal follow-up study in

0003-4975/10/$36.00doi:10.1016/j.athoracsur.2010.01.042

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1228 HENRY ET AL Ann Thorac SurgCATHETER ABLATION OF ATRIAL ARRHYTHMIAS 2010;89:1227–32

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hich patients who were found to be highly symptomaticespite maximal medical treatment (n � 16) after theurgical ablation procedure were referred for an electro-hysiologic study and catheter ablation. The study waspproved by our local institutional review board, tonclude a waiver for patient consent.

The parent study is a prospective longitudinal study inhich all patients undergoing surgical ablation for atrialbrillation by multiple surgeons either as a standalonerocedure or concomitantly with other surgical proce-ures are enrolled. All patients are longitudinally fol-

owed according to the Heart Rhythm Society guidelines9] as well as a clinical protocol for recurrent atrialrrhythmias. The follow-up times occur at 6, 12, and 24onths. The clinical data obtained includes (1) rhythm as

er electrocardiography, 24-hour Holter, or long-termonitoring, (2) incidence of stroke in the interim be-

ween follow-up times, (3) bleeding related to warfarin,nd (4) all current medications to include antiarrhythmicedications. In addition to the clinical data collected,

ealth-related quality of life using the Short Form 12uestionnaire (SF-12v2; Medical Outcomes Trust anduality Metrics, Lincoln, RI) was also obtained at base-

ine and at respective times.The following describes the surgical ablation tech-

iques used for the subgroup of patients having subse-uent radiofrequency catheter ablation procedures (RFAroup):Fifteen patients who underwent a complete Cox maze

II or IV procedure had the procedure carried out usingne of the following procedures:

. A combination (n � 12) of bipolar radiofrequencyclamps (AtriCure Inc, West Chester, OH) and cryo-thermal probes (AtriCure) was used. The cryo-probes were used to ablate across the right and leftatrioventricular (AV) grooves and the coronary si-nus epicardially (Cox maze IV). When ablatingacross the pulmonary veins, multiple applications(between three and five) were used at the time ofstudy. The cryothermal application across the rightand left AV grooves was carried out for 120 secondsafter detection of a stable ice ball. The epicardialcryothermal lesion across the coronary sinus wasapplied for 120 seconds after detection of the iceball endocardially.

. Three patients had the Cryo Cox maze III using acryothermal-only approach in which all lesionswere performed using argon-based cryosystem(ATS Medical, Inc, Minneapolis, MN). The princi-ples of cryoablation were followed as describedabove. The interatrial septal lesion was applied inpatients having the Cox maze III and IV.

The pulmonary vein isolation (n � 1) was performedsing bipolar radiofrequency (AtriCure). In all patientsaving pulmonary vein isolation only, to include the one

n the study, exit block was tested and confirmed. How-ver, conduction block was not routinely assessed in the

ox maze III or IV patients at the time of the surgical m

rocedure. This has, however, changed and our currentractice is to test for an exit block across the pulmonaryeins in patients having this part of the surgery per-ormed with bipolar radiofrequency technology. It isnclear yet whether acute conduction block can bechieved for cryoablation, and therefore an assessment ofonduction block for these patients is not being per-ormed routinely.

The following paragraphs describe the radiofrequencyatheter ablation approach for the RFA group:

The procedure was initiated by placing three quadri-olar catheters (Biosense Webster, Inc, Diamond Bar,A) in the right atrium, the bundle of His area, and the

ight ventricular apex. Through the left subclavian vein, aecapolar catheter (Biosense Webster) with a lumen waslaced in the coronary sinus. Overall, mapping andblation was performed with a 4-, 8- (Biosense Webster),r a 3.5-mm irrigated-tip Navistar catheter (Thermo-cool,iosense Webster). CARTO three-dimensional mapping

Biosense Webster) was used for navigation, mapping,nd ablation.Specifically, the suspected atrial tachycardias were

nitially mapped in the right atrium using CARTO three-imensional mapping, and in the majority of instances,ntrainment was performed from the right atrial isthmuss well as through the distal coronary sinus. If entrain-ent or right atrial mapping indicated a left atrial origin

f the tachycardia, transseptal catheterization was per-ormed for left atrial mapping and ablation. Transseptalatheterization was performed using fluoroscopic guid-nce, pressure monitoring, and on occasion, intracardiacltrasound. Intravenous heparin was given with the goalf maintaining activated clotting time at more than 350econd. Because all tachycardias studied were eitheracro reentrant or focal tachycardia, no attempts wereade at pulmonary vein isolation.If a focal atrial tachycardia was suspected, it wasapped using the CARTO three-dimensional mapping

nd ablated at the site of earliest activation. For macroeentrant tachycardia, the critical isthmus was identifiedith the help of entrainment mapping, and ablative

esions were delivered across the isthmus with the goal oferminating the tachycardia.

esults

rom January 2005 to present, 400 consecutive patientsperated on by multiple surgeons were enrolled. Patientsad either a Cox maze III or IV (n � 350; 2% with bipolarnd unipolar radiofrequency, 35% cryothermia only, and3% combination of radiofrequency and cryothermia) oreft atrial surgical ablation, which was only performed on0 patients (67% bipolar radiofrequency, 34% cryother-ia only, and 10% combination of cryothermia and

adiofrequency).Two hundred five patients were available for analysis

t 12 months, and 130, at 24 months. The overall return toinus rhythm rate by electrocardiography and Holter

onitoring at 12 months was 87% (78% off antiarrhyth-

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ic drugs) and 84% (73% off antiarrhythmic drugs) at 24onths.Perioperative mortality was 3% (n � 12), with an

dditional 23 (6%) patient deaths during a mean fol-ow-up of 24.1 months (5 cardiac-related, 10 noncardiac,nd in 8 patients the cause is unknown).Sixteen patients (4%) were referred for a subsequent

ercutaneous RFA for intractable atrial arrhythmias. In-erestingly, an additional 4 patients were found to haveecurrent atrial tachycardia with very minimal symptomsnd were managed medically.The group of patients referred for catheter ablation is a

nique group that may be considered by some as aigh-risk group for recurrence of atrial arrhythmia afterurgical ablation, in which 25% (n � 4) of the patients hadpacemaker with or without AV nodal ablation before

urgery, 31% (n � 5) had a previous cardiac surgery tonclude 3 with complex congenital anomalies, and 38%n � 6) had at least one catheter ablation before surgery.

The average age at time of surgery for this group was1.2 � 14.7 years. Before surgery, 11 patients (69%) hadongstanding persistent atrial fibrillation, and 5 patients31%) had persistent atrial fibrillation. The mean lefttrium size was 4.7 � 0.6 cm. There were no subsequenteported thromboembolic events for this group with aean time to follow-up of 42.87 � 9.8 months. The

verage time to ablation was 16.9 � 10 months.A total of 24 RFA catheter procedures were performed

Fig 1), in which only 10 patients required a singlentervention.

The first electrophysiology study yielded the followingtrial arrhythmias that were subsequently ablated: 7 righttrial flutters or atrial tachycardias, 3 left atrial flutters, 1iatrial flutter, and 5 left atrial tachycardias.After the first RFA intervention, 6 patients continued to

ave significant symptoms related to atrial arrhythmias,ndicating the need for a subsequent electrophysiologytudy and ablation. Of these 6 patients, 2 patients werereviously ablated for atypical left atrial flutter after the

urgical ablation, and both continued to experience sig-ificant events of atypical flutter necessitating an ablationf the AV node. Two patients who had typical right atrialutter ablation underwent a subsequent ablation foright atrial tachycardia.

Of the 2 remaining patients in the group that requiredsecond catheter ablation, 1 patient with previous bia-

rial ablation for biatrial tachycardia continued to beymptomatic, and 1:1 conduction of atrial tachycardiaas diagnosed, leading to AV nodal ablation. An addi-

ional patient who initially had ablation to treat righttrial tachycardia underwent a subsequent ablation forecurrence of right atrial typical flutter.

One patient did require a third electrophysiologytudy and ablation for recurrent right atrial tachycardiand underwent an AV nodal ablation and pacemakerlacement (Fig 1).Interestingly, during the repeated catheter interven-

ions none of the patients mapped were found to have aulmonary vein source for the arrhythmia, and all veinsapped were found to be electrically silent. We are

ntrigued by these findings in light of not acutely testingor conduction block in these patients. Therefore, itould be impossible for us to comment on the impor-

ance of such acute testing and its predictive value forong-term success.

The success rate for the 16 patients who underwentatheter ablation as captured by electrocardiography atheir last known follow-up was 94% with a mean time toollow-up of 42.87 � 9.8 months. At last follow-up, 53% ofhe patients (n � 8) in sinus rhythm were still takingntiarrhythmic drugs, with 47% of patients remaining onarfarin. One patient (6%) died owing to a noncardiac

ause, and there were no reported thromboembolicvents (mean time of follow-up, 42.87 � 9.8 months). Inddition, 4 other patients required a pacemaker: 1 in themmediate postoperative period for severe bradycardiand 3 in the later postoperative period for tachy-bradyyndrome. All patients labeled as successes in this spe-

Fig 1. Ablations for recurrence of atrial ar-rhythmias after surgical ablation for atrialfibrillation. (AT � atrial tachycardia; AV �atrioventricular; Lt � left; PM � pacemaker;Rt � right; SR � sinus rhythm.)

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1230 HENRY ET AL Ann Thorac SurgCATHETER ABLATION OF ATRIAL ARRHYTHMIAS 2010;89:1227–32

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ial subgroup of patients are still to be considered as aailed surgical ablation per the Heart Rhythm Societyuidelines [9]; however, the study shows a reasonableuccess rate after the subsequent intervention when theajority of the patients present a significant challenge.Because the average time to first ablation was 16.9 � 10onths, the first reported assessment of the health-

elated quality of life for the RFA group was at 24 monthsfter surgery (n � 10), and it showed no statisticalifference in their scores for physical functioning (CPS),ental state (CMS), and perception of their overall

eneral health (GH) when compared with the patientsfter surgical ablation who did not have a catheterblation and were in sinus rhythm (n � 117). For both theblation and nonablation groups the average CMS (55.56 �.57; 54.56 � 7.34) and GH (51.21 � 5.6; 51.35 � 9.59)cores were greater than the norm-based mean of 50.here was no statistical difference between groups for

heir CPS (44.62 � 10.87; 47.87 � 10.15); however, neitherroup reached the norm-based mean of 50.This same pattern held for reporting of their health-

elated quality of life at 36 months. For both groups (n �and n � 80) their GH (50.13 � 11.73; 52.11 � 10.80) andMS (57.36 � 8.7; 54.38 � 9.18) remained higher than theorm-based mean of 50, but were not statistically differ-nt from each other. The CPS was documented to belightly below the norm-based mean of 50, but nottatistically different, with no difference between groupslthough incrementally both groups improved (47.24 �.42; 49.52 � 9.19).

omment

here are only few reports discussing catheter ablation toreat atrial arrhythmia recurrences after surgical ablationor atrial fibrillation. The reports in the literature wereesigned to address mainly the electrophysiologic find-

ngs and the mode of atrial arrhythmias in patientsresenting with recurrent tachyarrhythmia after the sur-ical procedure [8, 10]. The current study reports the typef atrial arrhythmia, but also focuses on the longer termuccess of the catheter intervention with a comprehen-ive follow-up that includes the use of antiarrhythmicrugs and anticoagulation and assesses quality of life.Our findings suggest that in a certain subset of patients

he surgical treatment of atrial fibrillation may result inighly symptomatic atrial arrhythmia, which can beafely and effectively addressed with catheter ablation. Aelatively high success rate should be expected whenombining the two modalities of treatment, catheter andurgical ablation, for atrial fibrillation, especially in aore challenging subset of patients such as reported in

his study and more specifically patients with previousurgical treatment for congenital heart disease.

The long-term success of surgical ablation to includehe Cox maze III procedure varies. Previous reports [11,2] demonstrated that the extent of the ablation as well aspecific lesion pattern may have a significant impact onhe results. The reported success rate is also dependent

n the type of follow-up and its duration. Significant g

umbers of publications deal with a relatively smallumber of patients and with a relatively short follow-upf several months to 1 year. We believe that despite the

mportance of longer follow-up, the shorter periods ofollow-up represent the significant challenges of main-aining a longer period of follow-up [13–15]. In ourrogram, we have established a comprehensive protocol

hat allows us a detailed and complete follow-up on aarge scale of patients [16].

In this report we describe a very interesting group ofatients in which we were able to address recurrence oftrial arrhythmia with catheter ablation. When takingnto consideration the traditional risk factors for failedurgical ablation [17–19], this group of patients comprisesatients with a lower risk to have a recurrence; however,3% (n � 10) of the patients had either undergonerevious open heart surgery or catheter interventionefore the surgical ablation procedure. Although it is stillnclear what the real impact of previous interventions on

he success rate of the surgical ablation is, it makes senseo assume in some of these patients that excessive scar-ing may lead to late atrial arrhythmias. In fact when weompared this group with our total surgical ablationroup, we found that this group had significantly more

nterventions before their surgical ablation than the totalroup: 37% had had a least one prior ablation comparedith only 15% in the total group (p � 0.0161), 63% hadndergone at least one cardioversion as compared withnly 31% in the total group (p � 0.0078), and 50% had arevious cardiac surgery interventions as compared withnly 24% in the total group (p � 0.0177). It is of impor-ance to mention that none of the patients mapped wereound to have the source of the arrhythmia within theulmonary veins. These findings are unique and differ-nt from some of the reports in the literature and shouldead us to study atrial tissue scarring and remodeling in

ore depth [20, 21].In our series, the success rate at 1 and 2 years suggest

hat about 15% of the patients have documented atrialrrhythmias. Catheter ablation was offered to symptom-tic patients who failed medical treatment. In 4 patientsn AV nodal ablation and a pacemaker was offered afterostsurgery catheter ablation failed to control atrial

achycardia and rapid ventricular response rate. Interest-ngly, 3 of the 4 patients having AV nodal ablation wereound to be in sinus rhythm as determined by electro-ardiography. No major complications were reported,nd in longer-term follow-up there was one death re-orted to be noncardiac-related. For the 16 patients,lectrocardiographic assessment revealed significantuccess; however, about 50% of the patients are still beingontrolled with antiarrhythmic drugs and being kept onarfarin. However, we believe that the success is signif-

cant mainly because all the patients in this group expe-ienced significant symptomatic atrial arrhythmias be-ore the catheter intervention. Although the number ofatients is small, we are encouraged by the relatively

ood reports on their respective quality-of-life surveys.

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imitations of the Studyn this study we report the success rate after catheterblation (n � 16) based on electrocardiography only. It islear to us that the use of longer-term monitoring mayhow a higher rate of atrial arrhythmia [22]. However, its important to keep in mind that these patients treatedere all highly symptomatic with their atrial arrhythmias

fter the surgical procedure, and after the ablation theirlinical status was improved significantly. Pacemakernterrogation (n � 10) showed that 63% of the patients

ere indeed in stable sinus rhythm; however, pacemakernterrogation interpretation is complicated when atrial

ode switching is occurring.In addition, the surgical procedure was performed

sing different combinations of energy sources. It may bemportant to study the potential differences in outcomesetween the two techniques; however, this was not thecope of this study, and the number of patients may beoo small to draw a scientifically sound conclusion.

onclusionsn a certain subset of patients unsuccessful surgicalblation of atrial fibrillation may result in symptomatictrial arrhythmias. We believe that when indicated, sub-equent catheter ablation should be considered. Weound that this modality of intervention was safe andffective with a relatively high success rate. The combi-ation of the two treatment modalities, catheter andurgical ablation, can improve the outcome even in a veryomplex subset of patients.

eferences

1. Lall SC, Melby SJ, Voeller RK, et al. The effect of ablationtechnology on surgical outcomes after the Cox-maze proce-dure: a propensity analysis. J Thorac Cardiovasc Surg 2007;133:389–96.

2. Wolf RK, Schneeberger EW, Osterday R, et al. Video-assisted bilateral pulmonary vein isolation and left atrialappendage exclusion for atrial fibrillation. J Thorac Cardio-vasc Surg 2005;130:797–802.

3. Gaynor SL, Schuessler RB, Bailey MS, et al. Surgical treat-ment of atrial fibrillation: predictors of late recurrence.J Thorac Cardiovasc Surg 2005;129:104–11.

4. Deneke T, Khargi K, Voss D, et al. Long-term sinus rhythmstability after intraoperative ablation of permanent atrialfibrillation. Pacing Clin Electrophysiol 2009;32:653–9.

5. Melo J, Santiago T, Aguiar C, et al. Surgery for atrialfibrillation in patients with mitral valve disease: results atfive years from the International Registry of Atrial Fibrilla-tion Surgery. J Thorac Cardiovasc Surg 2008;135:863–9.

6. Sakamoto S, Voeller RK, Melby SJ, et al. Surgical ablation for

atrial fibrillation: the efficacy of a novel bipolar pen device in

essons about the long-term consequences of some of the

attgfi

the cardioplegically arrested and beating heart. J ThoracCardiovasc Surg 2008;136:1295–301.

7. Tuinenburg AE, Van Gelder IC, Van Den Berg MP, et al.Sinus node function after cardiac surgery: is impairmentspecific for the maze procedure? Int J Cardiol 2004;95:101–8.

8. Wazni OM, Saliba W, Fahmy T, et al. Atrial arrhythmiasafter surgical maze: findings during catheter ablation. J AmColl Cardiol 2006;48:1405–9.

9. Calkins H, Brugada J, Packer DL, et al. HRS/EHRA/ECASexpert consensus statement on catheter and surgical abla-tion of atrial fibrillation: recommendations for personnel,policy, procedures and follow-up. A report of the HeartRhythm Society (HRS) Task Force on Catheter and SurgicalAblation of Atrial Fibrillation. Europace 2007;9:335–79.

0. Ishii Y, Gleva MJ, Gamache MC, et al. Atrial tachyarrhyth-mias after the maze procedure: incidence and prognosis.Circulation 2004;110(Suppl 1):II-164–8.

1. Gillinov AM, Bhavani S, Blackstone EH, et al. Surgery forpermanent atrial fibrillation: impact of patient factors andlesion set. Ann Thorac Surg 2006;82:502–13.

2. Barnett SD, Ad N. Surgical ablation as treatment for theelimination of atrial fibrillation: a meta-analysis. J ThoracCardiovasc Surg 2006;131:1029–35.

3. Han FT, Kasirajan V, Kowalski M, et al. Results of a mini-mally invasive surgical pulmonary vein isolation and gan-glionic plexi ablation for atrial fibrillation: single-centerexperience with 12-month follow-up. Circ Arrhythm Elec-trophysiol 2009;2:370–7.

4. Miyairi T, Miura S, Kigawa I, et al. Mid-term results of aclosed biatrial procedure using bipolar radiofrequency ab-lation concomitantly performed with non-mitral cardiac op-erations. Interact Cardiovasc Thorac Surg 2009;9:169–72.

5. Iverson GL, Langlois JA, McCrea MA, Kelly JP. Challengesassociated with post-deployment screening for mild trau-matic brain injury in military personnel. Clin Neuropsychol2009;23:1299–314.

6. Hunt S, Henry L, Martin L, Ad N. Atrial fibrillation modulefor patients undergoing Cox maze procedure: how to man-age new hospital data elements and follow up beyond thirtydays. Abstract presented at The Society of Thoracic Sur-geons—Advances in Quality and Outcomes: A Data Manag-ers Annual Meeting (poster presentation). San Diego, CA,Sept 24–26, 2009.

7. Ballaux PK, Geuzebroek GS, van Hemel NM, et al. Freedomfrom atrial arrhythmias after classic maze III surgery: a 10-yearexperience. J Thorac Cardiovasc Surg 2006;132:1433–40.

8. Ad N, Barnett S, Lefrak EA, et al. Impact of follow-up on thesuccess rate of the cryosurgical maze procedure in patientswith rheumatic heart disease and enlarged atria. J ThoracCardiovasc Surg 2006;131:1073–9.

9. Gillinov AM, Sirak J, Blackstone EH, et al. The Cox mazeprocedure in mitral valve disease: predictors of recurrentatrial fibrillation. J Thorac Cardiovasc Surg 2005;130:1653–60.

0. Burstein B, Nattel S. Atrial structural remodeling as anantiarrhythmic target. J Cardiovasc Pharmacol 2008;52:4–10.

1. Burstein B, Nattel S. Atrial fibrosis: mechanisms and clinicalrelevance in atrial fibrillation. J Am Coll Cardiol 2008;51:802–9.

2. Ad N, Henry L, Hunt S, Barnett S, Stone L. The Cox-maze IIIprocedure success rate: comparison by electrocardiogram,24-hour Holter monitoring and long-term monitoring. Ann

Thorac Surg 2009;88:101–5.

ISCUSSION

R MARK A. GROH (Asheville, NC): Niv, let me congratulateou on a nice presentation and thanks for sending me theanuscript in advance. Through the comprehensive follow-up

f your large group of patients, we are learning important

blation techniques and technologies that we are using inreating patients with atrial fibrillation. Postablation atrial reen-rant tachycardias represent both good and bad. It can be seen asood because the rhythm is more organized than the original

brillation and as shown in this report will frequently be

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menable to catheter ablation. On the other hand because ofetronomic conduction from the atria to the ventricles fre-

uently seen in these patients, the patients are frequently muchore symptomatic from the reentrant tachycardia than from the

riginal fibrillation that was being treated. Therefore, theseachycardias will frequently require some form of intervention.

Interestingly enough, in Circulation 2 years ago, there was aice report on postablation tachycardias from the cath lab, 16atients, much like yours. All of those patients were found to beeentrant tachycardias from the left side; none of them wereight-sided reentrant tachycardias. Most of the tachycardiasentered on the mitral isthmus. In your group of patients, overalf the tachycardias originated from the right side. All theseatients had right-sided lesions except for 1, which was a patientho underwent pulmonary vein isolation. So my question is, doe know that the right-sided lesion set is actually favorable inatients with atrial fibrillation? If patients with right atrial lesionets have an increased risk of reentrant tachycardia from theight-sided ablation as well as an increased risk of pacemakermplantation over patients with left-sided lesion set alone,hould we be performing right-sided ablation? When one con-iders the additional risks of right-sided ablation and a recentandomized trial showing no difference in efficacy betweeniatrial and left atrial ablation reported in the European Journal ofardiothoracic Surgery by Dr Wang et al, there seems to be a case

or avoiding the biatrial approach.My second question is in reference to your thoughts regarding

he hybrid approach for treating atrial fibrillation. We are seeingncreased interest in the hybrid approach where an epicardialurgical ablation is performed and then at the same procedurendocardial catheter-based ablation is also performed. Since aumber of these reentrant tachycardias, representing gaps andacroreentry around those gaps, that you have described will

ecome evident after the scar from the ablation has matured, ist not better to separate the two ablation procedures by someime to allow these gaps and reentrant tachycardias to become

appable and then able to be taken care of in the EP (electro-hysiology) lab at the time of an initial catheter-based proce-ure? It just seems to me that the current single epicardial andndocardial ablation sequence will result in additional catheter-ased procedures to take care of late reentrant tachycardias.I would like to thank the Society for the invitation to discuss

his paper.

R AD: Thank you, Mark. As usual, excellent questions. Well,he focus of the study is not on the type of arrhythmia; it is on thepproach. I can tell you that the 400 patients were done by

ultiple surgeons initially. There were some relevant differ- a

nces between surgeons, and we are trying to solidify thepproach to treat our A-fib (atrial fibrillation) patients, withoutajor deviations, but yet only 7 out of 400 had a right-sided

ssue, which is very little. Interestingly enough of those patients,e had 3 patients with complex congenital anomalies, all of

hem had right atrial issues, and the only patient who had PVIpulmonary vein isolation) had right atrial issues. So 4 out of thewith right atrial arrhythmias can be well explained. The otherI think that we can explain by using a lower dosage of

ryothermal energy. When we moved from the Frigitronics tohe argon-based CryoCath, we were recommended to freezenly for 1 minute, and 2 out of the 3 patients with the right-sidedrrhythmias were treated with an underdosage of cryo. So Ielieve that this may explain better your concerns and youroint is well taken. But as mentioned this was not the focus of

he study. The focus is that these arrhythmias are highly symp-omatic and need to be addressed aggressively and not justith an AV (atrioventricular) node ablation and pacemakerlacement.The other comment is actually very important, and I am

ctually going back and forth on the hybrid approach. However,e have to keep in mind that we have to work together with the

lectrophysiologists on this issue. Otherwise we are going to betaying by ourselves doing 5 to 10 cases a year and help feweratients. Therefore we have to be able to develop some protocolsnd look at this problem prospectively in a very serious way,hether to space the procedures, whether to do it together, what

ype of protocol to use, et cetera, et cetera. My personal thoughts that we should move forward and participate in all thoseollaborations provided we can use sound techniques andeliable devices to create transmural lesions that as you knowone of the RF (radiofrequency) devices is a good fit.

R DWIGHT E. HAND (Cincinnati, OH): Was there any at-empt at the time of the ablations in the cath lab to actually maphe site of the failure? Can we say with any assurance that it washe site of the cryolesions and not the site of the bipolaradiofrequency lesions?

R AD: That is an excellent point. That is a question I ask.xcept for 2 patients with a redo operation that was certainlyelated to some scar from a previous cannulation site, I can’teally comment on that. The one very interesting point in myind was that none of the patients were mapped to have any

ssues within the pulmonary vein, which is a little different thanhe big series from Italy, from the Cleveland Clinic, and others.hat is a very good point and we don’t really have a good

nswer.