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Eur J Cardiothorac Surg 2008;33:596-599. doi:10.1016/j.ejcts.2007.12.043
Copyright © 2008, European Association for Cardio-thoracic Surgery. Published by Elsevier. All rights reserved.
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Restoring sinus rhythm in patients with previous pacemaker implantation submitted to cardiac surgery and concomitant surgical ablation of atrial fibrillation

Marta P. Marquesa, João Q. Meloa,*, Michel Knautb, Ottavio Alfieric, Stefano Benussic, Mathew R. Williamsd, Fernando Horneroe

a Santa Cruz Hospital, Carnaxide, Portugal
b Heart Center, Dresden University Hospital, Dresden, Germany
c San Raffaele Hospital, Milano, Italy
d Columbia University Medical Center, New York, United States
e Valencia University General Hospital, Valencia, Spain

Received 5 September 2007; received in revised form 20 December 2007; accepted 21 December 2007.

* Corresponding author. Tel.: +351 210433160; fax: +351 210433159. (Email: joaomelo100{at}hotmail.com).


   Abstract
Top
 Abstract
1. Introduction
 2. Materials and methods
 3. Results
 4. Discussion
 Appendix A
 References
 
Objective: Some patients submitted to cardiac surgery have concomitant atrial fibrillation and a previously implanted pacemaker. Because it is unknown if there is any potential for these patients to reassume a regular rate sinus rhythm after ablation of atrial fibrillation, we reviewed the results of all patients with pacemaker enrolled in the Registry of Atrial Fibrillation. Materials: Thirty-six patients were included in this study. Twenty-six had valve disease, seven had coronary disease and three had congenital heart disease. They were submitted concomitantly to ablation of atrial fibrillation using biatrial approaches (seven patients), left sided (27), or right sided (three patients). Thirty-three hospital survivors had a mean follow-up of 18 months, and a maximum of 25 months. Results: At 1 year (n = 21), patients’ rhythm was sinus non-pacing dependent (52%), sinus pacing-dependent (14%), and atrial fibrillation (14%). At 2 years (n = 14), patients’ rhythm was sinus non-pacing dependent (57%) and atrial fibrillation (43%). The only factor that may have had impact on the recovery of sinus rhythm at 1 year was the small size of the left atrium (p = 0.05). Conclusions: We conclude that in a significant number of patients, having a pacemaker before surgery does not preclude sinus rhythm recovery after a cardiac operation and ablation for concomitant atrial fibrillation.

Key Words: Atrial fibrillation • Ablation • Pacemaker


   1. Introduction
Top
 Abstract
 1. Introduction
2. Materials and methods
 3. Results
 4. Discussion
 Appendix A
 References
 
It is now common practice to treat concomitant atrial fibrillation surgically in patients submitted to the correction of a cardiac condition [1]. The results of this approach appear to increase survival and improve postoperative outcome [2]. Some patients submitted to AF surgery have a previously implanted pacemaker due to bradyarrhythmic atrial fibrillation. To the best of our knowledge there is no published information on whether it is worthwhile correcting atrial fibrillation in this subset of patients. It is unknown whether there is any potential for these patients to reassume a regular rate sinus rhythm and thus making the pacemaker useless. Also it is unclear if the long-term benefit of recovering sinus rhythm is similar to the one obtained by the patients that have not had a pacemaker before surgery [3–6]. From the database of the Registry of Atrial Fibrillation Surgery we selected the patients under the above conditions for this report.


   2. Materials and methods
Top
 Abstract
 1. Introduction
 2. Materials and methods
3. Results
 4. Discussion
 Appendix A
 References
 
2.1 Study population
Out of 2140 patients enrolled in the registry of AF surgery, 36 patients had a pacemaker (PM) implanted before surgery. Thirty-three patients are hospital survivors. Eighteen patients were female and their mean age was 66 ± 12 years

All patients had a previous pacemaker implanted for bradyarrhythmia. Fifteen patients were taking class I or III antiarrhythmic agents. Three patients had undergone unsuccessful cardioversions. Three patients had a history of systemic embolism and two patients have been submitted to percutaneous ablation or atrial fibrillation.

The most significant clinical characteristics of the group are described in Table 1 .


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  		Table 1 Patients’ baseline characteristics
 
All patients were operated under cardiopulmonary bypass using standard techniques.

The main operative procedures are described in Table 2 . Fifteen patients had multiple operative procedures.


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  		Table 2 Concomitant surgical procedures
 
All lesions were completed after cardiopulmonary bypass was established.

Ablation methods were performed according to surgeons’ choice. Energies used were either microwave (24 patients), or radio frequency (RF). Unipolar RF in 10 and bipolar in two patients.

The ablation procedures were biatrial in seven patients, left atrial in 27 patients, and right atrial in two patients. One patient had a maze III procedure.

Different ablation patterns are described in Table 3 .


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  		Table 3 Ablation patterns
 
Left atrial appendage was removed in 25 patients.

All patients received anticoagulation therapy under a protocol with coumadin for a period of at least 3 months after surgery to attain INR values between 2.0 and 3.5. Patients with prostheses were kept under anticoagulation therapy. Class I and III antiarrhythmic agents were used selectively in patients who had postoperative AF with rapid ventricular response.

After hospital discharge, patients were evaluated at 1, 6, 12 and 24 months after surgery. Rhythm was described on the basis of surface EKG.

2.2 Statistical analysis
Continuous data are expressed as mean and standard deviation or median and IQ range in the case of non-normally distributed data. Comparison between groups was made using Fisher's exact test for categorical data and t-test for continuous data. Non-normally distributed data were compared using the Wilcoxon rank sum test.


   3. Results
Top
 Abstract
 1. Introduction
 2. Materials and methods
 3. Results
4. Discussion
 Appendix A
 References
 
Hospital mortality (n = 3) was 8% (90% CI: 3–19%).

Follow-up varies from 3 to 26 months. Median follow-up was 18 months (range 3–26). During follow-up there were no deaths or embolic events. There were no device-related complications.

Table 4 describes heart rhythm of the 33 survivors at various points in time during follow-up.


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  		Table 4 Rhythm at follow-up
 
Table 5 compares the characteristics of patients that recovered SR at 1 year versus the others.


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  		Table 5 Comparison of patients in SR versus others at 1 year
 

   4. Discussion
Top
 Abstract
 1. Introduction
 2. Materials and methods
 3. Results
 4. Discussion
Appendix A
 References
 
Surgeons often have to decide if it is appropriate to treat atrial fibrillation in patients that have a pacemaker already implanted and are due for a cardiac procedure. Currently there is no information available on whether it is worthwhile treating atrial fibrillation in this context. It might even be assumed that bradyarrhythmia represents a more severe degree of the disease process and, if this assumption is true, then the expected success rate would be very low.

The analysis of our group of patients was surprising because of the unexpected high number of patients that recovered sinus rhythm. In fact, two thirds of our patients have regained sinus rhythm at 1 year, and of these only 14% were pacing dependent. These results are similar to the ones reported previously from the Registry in 1723 mitral patients [2]. Interestingly the results were similar in the various institutions participating in the study.

We have searched for predictors of sinus rhythm recovery at 1 year. Because of the uncertainties of the clinical consequences for patients that recovered sinus rhythm but were still bradycardic and pacing dependent, we included these patients in the same group of those remaining in atrial fibrillation. With this assumption we have created the worst-case scenario that may have contributed for not finding predictors of success with statistical significance. Yet patients that have small left atria and those with paroxysmal or persistent atrial fibrillation have better recovery as expected from the experience of treating patients with atrial fibrillation and not pacing dependent [3,4].

The groups of patients that recovered sinus rhythm and were still pacing dependent are a very puzzling group. It is important to know if they will benefit from treating atrial fibrillation. Is it logical to assume that by using physiological pacing they will have a similar outcome to the patients who recovered sinus rhythm? Only with larger experience will this knowledge become available.

Because of the small sample size it is not appropriate to draw definitive conclusions from this study but it appears very promising given the lack of late complications.

One major limitation of our study is the lack of Holter monitoring as a more precise tool to define patients’ rhythm.

Also it is very important for the future to establish if the long-term benefit of this approach will be sustained.

The question remains if it is reasonable/useful for patients with a history of AF and pacing-dependent bradycardia to ablate atrial fibrillation when they are submitted to a concomitant procedure.

Our results are very encouraging, but deserve further evaluation.

In the meantime it appears that patients with permanent atrial fibrillation who will benefit more from the procedure are those with small left atria. Also if patients have paroxysmal or persistent atrial fibrillation and are submitted to ablation the results will likely be better.

We conclude that in a significant number of patients the presence of a pacemaker before surgery does not preclude sinus rhythm recovery after cardiac surgery and ablation for concomitant atrial fibrillation.


   Appendix A
Top
 Abstract
 1. Introduction
 2. Materials and methods
 3. Results
 4. Discussion
 Appendix A
References
 
Conference discussion

Dr J. Bonatti (Innsbruck, Austria): The question that the multicenter study group asks in this paper is unique and the results are highly interesting for the heart surgery community. Few patients, however, are affected by the problem which the group addresses. It is 1.6% of the patients in your large database of more than 2000 people.

The main strength of the study is that it was derived from a large multicenter registry which was established by surgeons with extensive experience in surgical electrophysiology. The fact that different energy sources were used, that procedure conduct was inhomogeneous, and that ablation therapy was carried out in a variety of open heart procedures hampers results to a certain extent, and future studies should look at more homogeneous patient cohorts.

Whether surface ECGs taken at 1, 6, 12 and 24 months postop are enough to assess the real percentage of patients in sinus rhythm can be discussed. You mention this yourself in the paper. In addition, one has to be aware of the fact that a significant number of patients regained sinus rhythm but required pacing for bradycardia. At 24 month there was a trend towards more patients in A-fib and less patients in pacing-dependent sinus rhythm. An intense look at long-term follow-up is definitely necessary. Results concerning prediction of sinus rhythm recovery in your study are plausible. I have three questions.

Is there any paper showing similar results after catheter-based ablation in A-fib in patients with previous pacemaker implantation? Second, was pacemaker explantation in some patients discussed or even carried out? And third, what was the impact of procedure success on medical treatment of the patients?

Dr Melo: Of course when we started looking at this issue, we were aware that this is a rare condition. We performed extensive search in the literature and could not find any previous reports on this topic, and that is why we decided to analyze it.

Out of these 36 patients, we are aware of two patients where the pacemakers were explanted for local reasons, and one of the patients demanded it because it was bothering him, and it was explanted. I have data showing that he really was not pacing dependent. But I think at this moment and at this point of knowledge, if the pacemaker is there, it should be kept in place, because this papers shows that it is possible to lose sinus rhythm. Of course, this is a basic question, and with such small sample we cannot go much further. Our conclusion is that it is possible to regain sinus rhythm, especially if patients have small atria.

Regarding your last question, impact of medication of those patients, I cannot tell you. We don’t have that data in our database.


   Acknowledgments
 
The authors would like to thank António Ferreira MD and Teresa Santiago MSc for their help with statistical analysis and manuscript revision.


   Footnotes
 
{star} Presented at the 21st Annual Meeting of the European Association for Cardio-thoracic Surgery, Geneva, Switzerland, September 16–19, 2007.


   References
Top
 Abstract
 1. Introduction
 2. Materials and methods
 3. Results
 4. Discussion
 Appendix A
 References
 

  1. Melo J, Adragão PR, Neves J, Ferreira M, Pinto M, Rebocho M, Parreira L, Ramos T. 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]
  2. Melo J, Santiago T, Aguiar C, Berglin E, Knaut M, Alfieri O, Benussi S, Sie H, Williams M, Hornero F, Marinelli G, Ridley P, Fulquet-Carreras E, Ferreira A. Surgery for atrial fibrillation in patients with mitral valve disease. Results at five years from the International Registry of Atrial Fibrillation Surgery. J Thorac Cardiovasc Surg 2008, in press.
  3. Scott D, Barnett, Niv Ad. Surgical ablation as treatment for the elimination of atrial fibrillation: a meta-analysis. J Thorac Cardiovasc Surg 2006;131:1029-1035.[Abstract/Free Full Text]
  4. Krishna K, Barbara AH, Bernd L, Thomas D. Surgical ablation as treatment for the elimination of atrial fibrillation: a meta-analysis. J Thorac Cardiovasc Surg 2006;131:1029-1035.[Abstract/Free Full Text]
  5. Jessurun ER, van Hemel NM, Defauw JJ, Brutel De La Rivière A, Stofmeel MA, Kelder JC, Kingma JH, Ernst JM. A randomized study of combining the maze surgery for atrial fibrillation with mitral valve surgery. J Cardiovasc Surg 2003;44(1):9-18.[Medline]
  6. Geidel S, Ostermeyer J, Lass M, Geisler M, Kotetishvili N, Aslan H, Boczor S, Kuck KH. Permanent atrial fibrillation ablation surgery in CABG and aortic valve patients is at least as effective as in mitral valve disease. Thorac Cardiovasc Surg 2006;54(2):91-95.[CrossRef][Medline]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
João Q. Melo
Ottavio Alfieri
Stefano Benussi
Mathew R. Williams
Fernando Hornero
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Marques, M. P.
Right arrow Articles by Hornero, F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Marques, M. P.
Right arrow Articles by Hornero, F.
Related Collections
Right arrow Cardiac - other
Right arrow Electrophysiology - arrhythmias

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