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Ann Thorac Surg 2006;81:1780-1785
© 2006 The Society of Thoracic Surgeons
Division of Cardiovascular Surgery, Mayo Clinic and Foundation, Rochester, Minnesota
Accepted for publication October 31, 2005.
* Address correspondence to Dr Dearani, Division of Cardiovascular Surgery, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905 (Email: dearani.joseph{at}mayo.edu).
Presented at the Forty-first Annual Meeting of The Society of Thoracic Surgeons, Tampa, FL, Jan 24–26, 2005.
| Pediatric cardiac surgery:
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Abstract |
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METHODS: From 1993 to 2003, 99 patients with CHD and associated AFl/F underwent a concomitant right-sided maze procedure at the time of CHD repair. Ages ranged from 9 to 72 years (median, 43 years). Atrial flutter and/or fibrillation was paroxysmal in 81 and chronic in 18; duration ranged from less than 1 month to 39.5 years (median, 2.9 years). Primary cardiac diagnoses were Ebstein anomaly (n = 47), other congenital tricuspid regurgitation (n = 19), univentricular heart (n = 11), isolated atrial septal defect (ASD, n = 8), tetralogy of Fallot (n = 8), and other (n = 6).
RESULTS: Other concomitant procedures included tricuspid valve repair or replacement (n = 70), ASD closure (n = 39), and pulmonary valve procedures (n = 18). There were 6 early deaths. At hospital dismissal, 83 patients were free of AFl/F and 63 were in sinus rhythm. Follow-up in 87 of the 93 early survivors extended up to 8 years (mean, 2.7 years). There were 4 late deaths, all from noncardiac causes. Of the 83 known late survivors, 77 (93%) were free of AFl/F. Eighty-two of the 83 survivors were in New York Heart Association class I or II.
CONCLUSIONS: In patients with AFl/F associated with CHD, a concomitant right-sided maze procedure at the time of intracardiac repair is effective in reducing late recurrent AFl/F. Most patients enjoy an excellent quality of life.
Congenital heart disease (CHD) resulting in right atrial dilatation is commonly associated with atrial tachyarrhythmias, particularly atrial flutter and/or atrial fibrillation (AFl/F) [1–4]. In order to reduce the incidence of persistent late AFl/F in this patient population that already exhibits a limited physiologic reserve, we utilized a concomitant right-sided modification of the Cox-maze III procedure at the time of intracardiac repair [5]. Because many repairs for CHD are reoperations in patients with AFl/F, the right-sided maze procedure has the advantage of minimizing dissection of adhesions, thus resulting in shorter cardiopulmonary bypass time when compared with the standard biatrial maze procedure. In addition, by avoiding suture lines in the left atrium, the total number of suture lines is limited and the risk of bleeding behind the heart is minimized while also preventing a possible postoperative noncontractile left atrium and the subsequent risk of systemic embolization. We report our experience and results in patients with AFl/F who underwent a right-sided maze procedure at the time of CHD repair.
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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Fifty-two patients (53%) were female and 47 (47%) were male. Median age at operation was 43 years (range, 9 to 72 years). Documented preoperative atrial tachyarrhythmias are summarized in Table 1; this included atrial fibrillation in 77 patients and atrial flutter in 22. The duration of preoperative arrhythmias ranged from less than 1 month to 39.5 years (median, 2.9 years). Seventy-seven patients were taking cardiac medications preoperatively including digoxin (42%), beta-blockers (22%), and amiodarone (15%).
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Results |
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Early nonfatal morbidity included AFl/F (n = 26, 28% of early survivors; 16 arrhythmias were transient and 10 were present at hospital dismissal), cerebrovascular accident (n = 2) and ventricular fibrillation, myocardial infarction, and complete heart block in 1 patient each. In addition, permanent pacemakers were placed at operation in all 11 patients undergoing Fontan revisions, and 4 new transvenous pacemakers were required in other patients (sick sinus syndrome in 3 and complete heart block in 1). Cardiac rhythm of the 93 early survivors at hospital dismissal was sinus (n = 63), pacemaker (n = 12), junctional (n = 8), and AFl/F (n = 10).
Of the 93 early survivors, 6 were lost to follow-up. Late follow-up in 87 patients extended up to 8 years (mean 2.7 years, median 2 years). There were 4 late deaths a mean of 1.3 years after operation due to noncardiac causes (malignancy in 3 and pneumonia in 1). All 4 patients were in sinus rhythm before death.
Seventy-seven of the 83 known late survivors (93%) were free of AFl/F; 61 (73%) were in sinus rhythm. Of the 22 patients with preoperative atrial flutter (19 paroxysmal, 3 chronic), there were 21 known late survivors (preoperative rhythm paroxysmal in 19 and chronic in 2), all of whom were free of atrial flutter at last follow-up. This included 15 patients in sinus rhythm. Of the 77 patients with preoperative atrial fibrillation (62 paroxysmal, 15 chronic), there were 62 known late survivors (preoperative rhythm paroxysmal in 51 and chronic in 11); 56 of the 62 were free of atrial fibrillation at last follow-up with 46 patients in sinus rhythm. Analyzed according to type of preoperative atrial fibrillation, 8 of the 11 known late survivors with preoperative chronic fibrillation and 48 of the 51 known late survivors with paroxysmal fibrillation were free of atrial fibrillation at last follow-up (p = 0.15).
Those who had chronic atrial arrhythmias preoperatively did not have a longer duration of preoperative arrhythmia when compared with those who had paroxysmal arrhythmias preoperatively (p = 0.32). The patient with the longest duration of preoperative arrhythmia (39.5 years) was free of his atrial fibrillation at last follow-up. Three of the 6 patients who had late recurrence of their arrhythmia had preoperative arrhythmia duration that was greater than the median for the entire series, and 3 had arrhythmia duration that was less than the median. In addition, mean left atrial dimension did not differ significantly between patients with paroxysmal and chronic preoperative arrhythmias (39 mm vs 44 mm, respectively, p = 0.56).
Cardiac medications at last follow-up included digoxin (n = 24), beta-blockers (n = 12), amiodarone (n = 8), propafenone (n = 1), and calcium-channel blockers (n = 1). Functional classes of the 83 known late survivors were class I (n = 77), class II (n = 5), and class III (n = 1).
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Comment |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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Although surgical repair of Ebstein anomaly and other congenital heart diseases results in significant improvement in functional capacity, postoperative cardiac arrhythmias continue to be a significant source of morbidity [2, 4]. The median age in the present series was 43 years (range, 9–72 years), which is considerably older than the median age of typical patients who undergo repair of CHD. It has been shown that increasing age in this patient population is a risk factor for the development of atrial tachyarrhythmias both preoperatively and postoperatively [3, 8].
The Cox-maze operation is currently the gold standard for the surgical treatment of atrial fibrillation (primarily arising from the left atrium) that is refractory to maximal medical therapy [9, 10]. The original concept was that incisions should be made in both the left and right atria to control the arrhythmia. We investigated the possibility that AFl/F arising from the right atrium in the setting of CHD could be improved by a right-sided maze only [5]. The advantages of performing only a right-sided maze instead of the standard biatrial maze include shorter operating time, minimizing dissection of adhesions (since many operations for congenital heart disease with AFl/F are reoperations), limiting the number of suture lines, and avoiding suture lines behind the left atrium where hemostasis can be difficult. In addition, a possible postoperative noncontractile left atrium and the risk of subsequent systemic embolization are avoided. In our experience, there has been no increase in early morbidity or mortality associated with the addition of a concomitant right-sided maze procedure at the time of repair of congenital heart disease [3, 5]. Various modifications of the Cox-maze procedure employed by others for patients with AFl/F associated with congenital heart disease have also demonstrated beneficial effects [11, 12].
A potential disadvantage of a right-sided maze is that, in some patients, the left atrium may contribute an additional substrate for AFl/F. To minimize this possibility, our patients were selected on the basis of right atrial dilatation and a normal left atrial size in nearly all cases. Seven patients with associated mitral valve disease were present in this series. In all cases, stenosis and/or regurgitation were mild to moderate, and left atrial size was within the upper limit of normal (41 mm) except for 2 patients whose atria measured 44 mm and 45 mm, respectively. One of the 2 patients was free of her preoperative atrial flutter, and the other was not free of his preoperative atrial fibrillation at last follow-up. In the current era, we would consider performing a biatrial maze procedure in any patient with AFl/F and mitral valve disease, especially if the left atrium was dilated.
Although there has been concern that the left atrium may be adversely affected in patients with a longer duration of AFl/F, in this study there was no statistically significant difference between those who were free from their arrhythmia on follow-up and those who were not in terms of how long their arrhythmia was present preoperatively. There was also no significant difference in freedom from AFl/F between patients who had paroxysmal versus chronic AFl/F preoperatively; this was true for both preoperative atrial fibrillation and atrial flutter.
All patients in this series had a modified cut and sew Cox-maze III procedure with incisions limited to the right atrium and atrial septum. This included cryoablation at the anterior and inferior aspect of the tricuspid valve annulus. In 5 patients with preoperative atrial flutter, the right atrial isthmus was cryoablated, in addition to the right-sided maze procedure. In the latter part of this series, instead of an incision a line of cryolesions was generally employed on the medial aspect of the right atrium from the amputated right atrial appendage to the tricuspid valve annulus, in order to decrease the possibility of injury to arterial blood supply to the sinoatrial node. In general, we continue to prefer the standard cut and sew technique for all other atrial lesions in performing the right-sided maze procedure because the transmurality of lesions can be assured.
Protocols for the postoperative management of patients who have undergone a Cox-maze operation vary. For arrhythmia control, some centers utilize an antiarrhythmic drug such as amiodarone prophylactically in all patients and maintain it for three months. We prefer to use antiarrhythmic medications selectively in patients who experience atrial or ventricular arrhythmias during hospitalization. We monitor potassium and magnesium levels and maintain them in the high normal range. Postoperative atrial fibrillation is treated promptly with amiodarone, and electrical cardioversion is used as needed. If atrial fibrillation occurs early after operation and is treated with amiodarone, we continue the drug for 3 months. In our experience, a junctional rhythm is the most common rhythm abnormality noted after operation, so we utilize temporary atrial or atrioventricular sequential pacing in the early postoperative period until the heart rate is adequate. Only 4 of the 82 early survivors not undergoing Fontan revisions required permanent transvenous pacemaker before dismissal from the hospital. In this study, the majority of patients who received permanent pacemakers were continued on digoxin postoperatively.
It is important to use diuretics liberally early after operation. Removal of both atrial appendages during the standard Cox-maze procedure eliminates an important source of atrial natriuretic peptide and this, along with elevations of aldosterone and antidiuretic hormone early postoperatively, predisposes the patient to fluid retention. This has been a minimal problem with the right-sided maze procedure only.
We recommend systemic anticoagulation with warfarin for three months postoperatively, but there is no consensus on the need for anticoagulation beyond this interval if the patient remains free of AFl/F. Some clinicians prefer to continue warfarin believing that risk of thromboembolism is not reduced sufficiently to avoid the need for systemic anticoagulation. Others argue that if AFl/F is eliminated and ventricular function is normal, the risk of an intracardiac source of thromboemboli is very low.
With the standard biatrial maze, as reported in the original series, there was an early incidence of postoperative AFl/F in 45% to 50% of patients [9]; this compares with 28% early incidence in the present series. Even in patients with complex cardiac lesions and associated anatomic and pathophysiological changes, this 28% incidence of early arrhythmias decreased with time as postoperative changes resolved. While previous studies have shown that the freedom from AFl/F at late follow-up is modestly reduced by CHD repair which includes restoring a competent tricuspid valve combined with right reduction atrioplasty [1, 3, 5], this study demonstrates that late results are substantially improved by the addition of a concomitant right-sided maze; 93% of patients were free of AFl/F at follow-up.
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Discussion |
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DR STULAK: In the current era, we would consider performing a biatrial maze procedure in any patient with evidence of atrial arrhythmias and any pathology leading to the development of a substrate for atrial fibrillation in the left atrium.
DR CARL L. BACKER (Chicago, IL): I have a couple of questions, and most of these are based on our experience with the Fontan conversion. We have been quite systematic about dividing these patients up into those with atrial reentry tachycardia or atrial flutter versus those with atrial fibrillation. In the patients with atrial reentry tachycardia we have performed the right-sided maze procedure in a similar fashion to the technique Drs. Danielson and Dearani have outlined. If the patient has atrial fibrillation at any point prior to the Fontan conversion, we would then do a full Cox-maze III.
My first question is, do you differentiate between atrial flutter and fibrillation and are you treating these patients differently? I also have two technical questions. I noticed in your slides that you had the multiple small cryolesions, using the cryoprobe that was 10 mm in diameter. We have been using the new CryoCath Surgifrost (CryoCath Technologies Inc, Montreal, Quebec, Canada), which gives you the ability to place a long linear lesion that is 10 cm in length. You can apply the lesions in one minute, at -150°C. The question is, have you tried that new cryoprobe? My final question is what are your indications for doing the right-sided maze as a prophylactic procedure? For example, the patient having their third pulmonary valve replacement that does not currently have atrial arrhythmias but has had multiple right atrial incisions.
DR STULAK: I will answer your final question first, Dr Backer. We believe there is a role for a prophylactic maze in patients without documented atrial arrhythmias. This would most commonly include patients with a markedly dilated right and/or left atrium. We believe that these patients are at high risk for the subsequent development of atrial tachyarrhythmias. In addition, many of these patients have had multiple prior operations. Multiple prior incisions in the right atrium may also increase the late development of atrial fibrillation or "incisional" atrial tachycardias. In these patients we would perform either the standard Cox-maze III as previously described or a modified cryoablation maze similar to that described by yourself and Dr Mavroudis in your Fontan experience. Second, we have various types of Frigitronics cryoprobes (Frigitronics; CooperVision Inc, Lake Forest, CA) with an assortment of shapes, lengths, and angles that help facilitate the cryolesions for the Cox-maze III incisions.
To address you first question, there were 22 patients with preoperative atrial flutter in this series. The arrhythmia was paroxysmal in 19 and chronic in 3. None of these patients with atrial flutter preoperatively suffered late recurrence of their arrhythmia. Intraoperatively, 5 of these patients had cryoablation of the right atrial isthmus in addition to a right-sided maze procedure, which was at the discretion of the operating surgeon.
DR EZZELDIN A. MOSTAFA (Cairo, Egypt): I have two comments and two questions. My first comment about the completion of this right atrial maze, as it has been shown in the slides, I consider it incomplete. You have to go up from the SVC (superior vena cava) down to the IVC (inferior vena cava) and all around the posterior end of the coronary sinus, and at 5 o'clock to the tricuspid valve, and then lastly to the septum vertically. As I have seen in the slide, it's considered to be missing two or three steps of this complete right atrial maze.
My second point about the completion for the biatrial maze, because as the first discussant said, I mean in the ASDs and probably in the Ebstein, they need at least biatrial maze. My question is, have you used the electrocautery instead of the cryo, yes or no?
DR STULAK: To answer your question, these patients underwent a "cut and sew" Cox-maze III procedure confined to the right atrium including the septal incision. Cryolesions were placed at the anterior and inferior tricuspid valve annulus. Early in the series, some patients had electrocautery used at the level of the anterior and inferior tricuspid annulus instead of cryoablation.
In response to your comment, the right atrial maze procedure that was performed in this series were the exact incisions that were described by Dr Cox in his Cox-maze III description. In contrast to the original description by Dr Cox, we direct the septal incision toward the coronary sinus in an effort to minimize the chance for heart block. In patients with Ebstein anomaly who have a dilated right atrium and a normal-sized left atrium, it has been our practice to perform a right-sided maze. We have shown in previous studies a reduction of late atrial arrhythmias when a right-sided maze has been applied to patients with Ebstein anomaly and other congenital anomalies that result in right atrial dilatation. In patients with a dilated left atrium, we usually perform a biatrial maze. We have now gained a large experience with the biatrial maze procedure in more than 500 patients with various acquired and congenital diagnoses. Our improved experience, additional information about the role of the left atrium as a source of atrial fibrillation, and the introduction of cryoablation and radiofrequency devices has resulted in our preference for a biatrial maze when a maze is performed.
DR MOSTAFA: And my second question, what about the results instead of the cryo? I mean, the electrocautery is better or bad or the same like the cryo?
DR STULAK: We prefer cryoablation. In the early part of the series, Dr Danielson used electrocautery at these two areas adjacent to the tricuspid annulus. I am not certain if electrocautery is equivalent to cryoablation.
DR MOSTAFA: And your protocol of the Cordarone. Because I have seen many drugs, actually, the Cordarone or the amiodarone has been used as a single pre and post, or I mean intraop and post. What are you going to do if you have junctional rhythm, how can you deal with the junctional rhythm?
DR STULAK: In our experience, a junctional rhythm is common following the maze procedure. In the early postoperative period, we use temporary atrial pacing. If the heart rate remains 45 to 50 beats per minute in the early postoperative period but increases with activity, then we continue to observe and do not place a permanent pacemaker. If the heart rate remains low despite activity or if the patient has symptoms related to a low heart rate, then permanent pacing is usually recommended.
DR MOSTAFA: You haven't tried the aminophylline drip?
DR STULAK: We have not used drugs such as aminophylline to stimulate the heart rate. If a junctional rhythm is present but increases with activity, we continue to observe and avoid drugs that would slow the rate further; eg, beta-blockers, calcium channel blockers, or amiodarone.
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