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Background The Cox-maze procedure is the standard to which other surgical treatments of atrial fibrillation (AF) are compared. However, evaluation of new devices and lesion sets is difficult because of variable methods of reporting success in eliminating AF. We analyzed 10-year outcome with the "cut and sew" Cox-maze procedure and present rhythm at last follow-up, interval contact, and actuarial AF freedom. Methods Between March 1993 and December 2002, 335 patients (211 men) underwent the Cox-maze procedure (age, 22 to 83 years; median, 62 years). Atrial fibrillation was chronic (CAF) in 175 patients and paroxysmal (PAF) in 160. Results Concomitant mitral valve procedures were performed in 59%, coronary artery bypass grafting in 19%, and tricuspid valve repairs in 7%. Early mortality was 0.9%. During hospitalization, transient AF occurred in 29% of patients and 10% required implantation of a new permanent pacemaker (PPM). Dismissal electrocardiogram was normal sinus rhythm in 64%, junctional rhythm in 18%, AF in 11%, and PPM in 7%. At last follow-up (mean 42 ± 6 months), 88% of patients were free of AF. However, when analyzed by the Kaplan-Meier method, freedom from AF was lower for patients with preoperative lone PAF (5 years, 90%; 10 years, 64%), preoperative lone CAF (5 years, 80%; 10 years, 62%), and patients undergoing combined maze-mitral valve surgery (5 years, 68%; 10 years, 41%). Conclusions Ten-year results with the standard Cox-maze procedure confirm high effectiveness, but reporting methods should be standardized to account for patients who have transient atrial arrhythmias during long-term follow-up.

Objective: The aim of this study was to evaluate the effects of the modified maze procedure using cryoablation for treating chronic atrial fibrillation (AF) associated with rheumatic mitral valve disease and to assess the risk factors for late failure of sinus rhythm restoration. Methods: Between March 2000 and June 2004, 170 consecutive patients, who underwent the modified maze procedure using cryoablation concomitant with mitral valve surgery for atrial fibrillation associated with rheumatic mitral valve disease, were divided into two groups based on the type of right-sided maze: the modified Cox-maze III (CM group, n = 93) and modified Kosakai-maze (KM group, n = 77) procedures. The postoperative and midterm follow-up results were analyzed and compared between the two groups. Both univariate and multivariate analyses were used to assess the risk factors for late recurrence of atrial fibrillation. Results: There were three in-hospital deaths, including two in the CM group (2.2%) and one in the KM group (1.3%), and there were no significant differences in the incidence of postoperative complications between the two groups. The cardiopulmonary bypass and aortic cross-clamp times were significantly shorter in the KM group than the CM group. At discharge, the sinus rhythm rate was 70% in the CM group and 74% in the KM group (p = 0.55). Follow-up was completed in 97% of the patients, with a mean time of 26.6 ± 15.2 months. At the latest follow-up, one death occurred in the CM group (0.6%). Sinus rhythm was documented in 141 (84%) out of all the patients, including 76 (84%) in the CM group and 65 (86%) in the KM group (p = 0.72). The 4-year actuarial survival free from stroke was 90.3 ± 5.9% for the CM group and 96.4 ± 3.5% for the KM group (p = 0.68), and 4-year event-free survival was 81.2 ± 7.4% for the CM group and 96.4 ± 3.5% for the KM group (p = 0.078). Using a multivariate analysis, a left atrial dimension >65 mm (p= 0.011) and repair for rheumatic mitral valve disease (p = 0.038) were independent risk factors for a late recurrence of AF. Conclusions: The modified maze procedures using cryoablation are safe and effective in treating chronic atrial fibrillation associated with rheumatic mitral valve disease.

The radiofrequency Maze procedure can effectively restore sinus rhythm in most patients with atrial fibrillation (AF) and mitral valve disease. AF after cardiac surgery is associated with increased morbidity and mortality. However, clinical determinants of long-term postoperative AF after the radiofrequency Maze procedure and concomitant mitral valve surgery are poorly defined. This study comprised 99 consecutive patients with persistent AF and mitral valve disease who underwent radiofrequency Maze procedures and concomitant mitral valvular operations. The predictive values of clinical variables for postoperative AF were examined. After a mean follow-up period of 46.1+/-24.6 months, 83 patients (83.8%) had sinus conversion after the Maze procedure, and 16 patients remained in persistent or paroxysmal AF. Multiple logistic regression analysis determined that predictors of sinus conversion were preoperative left atrial diameter (odds ratio [OR] 1.127 per 1-mm increment in left atrial diameter, 95% confidence interval [CI] 1.045 to 1.215, p0.002) and the duration of AF (OR 1.022 per 1-month increment in duration of AF, 95% CI 1.009 to 1.035, p0.001). Discriminant analysis showed that the sinus conversion rate was significantly lower in patients with preoperative left atrial diameters56.8 mm (p0.001) or AF duration66 months (p0.001) than in patients with preoperative left atrial diameters56.8 mm or AF duration66 months. In conclusion, the preoperative left atrial size and duration of AF are primary predictors of sinus conversion by the radiofrequency Maze procedure for patients with persistent AF and mitral valve disease.

Objectives The Cox maze procedure is the gold standard for ablation of atrial fibrillation in patients undergoing mitral valve surgery, and new approaches to atrial fibrillation ablation must be compared with it. Therefore, we sought to determine the time-related prevalence of atrial fibrillation and its risk factors after combined Cox maze and mitral valve surgery. Methods From November 1991 through January 2004, 263 patients (mean left atrial diameter, 5.8 ± 1.2 cm) underwent combined mitral valve surgery (repair in 71%) and a cut-and-sew Cox maze procedure for atrial fibrillation (permanent, 74%; persistent, 7%; paroxysmal, 16%). Rhythm documented on 2367 postoperative electrocardiograms was used to estimate the prevalence of atrial fibrillation across time. Results Hospital mortality was 1.9%. Postoperative atrial fibrillation prevalence peaked at 36% at 2 weeks, decreasing to 21% at 5 years. Risk factors for higher postoperative atrial fibrillation prevalence varied with time and included longer duration of preoperative atrial fibrillation ( P = .003), larger left atrial diameter ( P = .01), older age ( P = .0002), and higher left ventricular mass index ( P = .02). Conclusions In some patients undergoing mitral valve surgery and a Cox maze procedure, atrial fibrillation recurs over time, mandating close, long-term follow-up of heart rhythm. Earlier operation and left atrial size reduction should be considered to improve results in selected patients.

Background— The Maze procedure restores normal sinus rhythm in the majority of patients. However, atrial tachyarrhythmias (ATA) are a common early complication after the operation. The purpose of this study was to define the incidence and natural history of ATA after the Maze procedure. Methods— Complete medical records from 200 patients who underwent the Maze procedures (I, II, and III) from 1987 to 2002 were examined for all episodes of early postoperative ATA that occurred during the first 30 days after the procedure. Two electrophysiologists independently reviewed all postoperative 12-lead electrocardiograms. Results— ATA occurred in 86 patients (43%) after the Maze procedure. Of the patients with ATA, 59% had atrial fibrillation (AF), 14% had atrial flutter (AFL), and 27% had both AF and AFL. Of the patients with AF or AFL, 20% and 5%, respectively, also had episodes of atrial tachycardia and supraventricular tachyarrhythmia. The peak incidence of early postoperative ATA was on postoperative day 8. The average duration of ATA was 5.7±5.0 days. Late recurrence of AF (>1 year postoperatively) occurred in 7.0% of patients who had early postoperative ATA and 8.8% of patients without early postoperative ATA ( P =0.8). Conclusions— ATA occurred in 43% of patients after the Maze procedure. The tachyarrhythmias occurred primarily within 8 days after surgery and resolved within 3 weeks in almost all patients. There was no relationship between the incidence of early postoperative ATA and the late recurrence of AF.

Objective: The utilization of diathermy (electrocautery) as an energy source in the treatment of chronic atrial fibrillation has generated positive early clinical results. Although this technology is available and affordable, it has not been well studied for this indication. The objectives of this study were: (1) to characterize atrial lesions created by diathermy, (2) to determine relationships between power setting, tissue contact time, and lesion depth and (3) to histologically compare diathermy and unipolar radiofrequency lesions. Methods: Fresh bovine atrial tissue samples were used to create endocardial lesions using a unipolar diathermy system with a blade tip. A total of 120 lesions were created at varying power settings and tissue contact times. Subendocardial temperatures were recorded. All lesions were examined grossly, then fixed, sectioned and evaluated histologically by a blinded pathologist. Comparisons were made with saline irrigated unipolar radiofrequency lesions. Results: Gross examination revealed extensive tissue destruction of the endocardial surface at the point of contact. Histological examination showed minimal penetrance of the lesions beyond the destroyed tissue margin of the endocardium. This was corroborated by the finding of minimal thermal penetration beyond the endocardium and superficial myocardium. There was a linear relationship between the power setting (15‐55 watts), depth of penetrance (2‐15 mm) at varying contact times (1‐5 s/cm). Conclusions: In this in vitro model, lesions created by diathermy were not transmural, even with high power settings and prolonged contact times. At these settings, significant tissue destruction was observed that may predispose to atrial perforation without achieving penetration. Diathermy did not constitute an effective energy source in the creation of transmural lesions for atrial fibrillation ablation. q 2004 Published by Elsevier B.V.

Irrigated bipolar radiofrequency ablation has been used to replicate Cox maze surgical scars in pig hearts ex vivo. Impedance monitoring accurately predicted complete transmurality for all lesions. This study aimed to assess the feasibility and reliability of irrigated radiofrequency ablation and impedance monitoring to produce electrically isolating Cox maze lesions in vivo.A modified Cox maze procedure was performed in 8 adult sheep during cardiopulmonary bypass using irrigated bipolar and unipolar radiofrequency ablation. For bipolar radiofrequency ablation, atrial tissues were clamped between opposing electrodes; ablation was terminated at the plateau in impedance decline. Unipolar radiofrequency ablation lesions were painted on the endocardium, and transmurality was assessed visually. Animals survived 30 days.Bipolar lesions (n = 48) were thinner (7.4 +/- 2.4 mm versus 12.7 +/- 3.2 mm) and required less time (14.1 +/- 3.4 seconds versus 41.4 +/- 21.8 seconds) and energy (377.5 +/- 99.2 W.s versus 995.1 +/- 547.1 W.s) to create despite being longer (31.7 +/- 8.6 mm versus 19.2 +/- 5.6 mm) than unipolar lesions (n = 26). The left atrial pacing threshold across selected bipolar lesions increased at least fivefold above baseline (1.6 +/- 0.2 mA) at 1 hour (18.4 +/- 4.6 mA; n = 8; p0.001) and 30 days (17.2 +/- 5.2 mA; n = 6; p0.001), indicating functional conduction block. Bipolar lesions had no adherent thrombus or endocardial defects. Cross-section examination confirmed transmurality in 100% of bipolar lesions and 98.7% of unipolar lesions.Irrigated bipolar radiofrequency ablation with impedance monitoring safely and reliably produces electrically isolating, transmural Cox maze lesions in vivo.

Background The Cox maze procedure is considered an effective surgical treatment of atrial fibrillation in patients with and without organic heart disease. Radiofrequency energy offers an alternative to the complex surgical maze procedure. We used the radiofrequency modified maze III procedure in patients with atrial fibrillation undergoing elective concomitant cardiac surgery. This study evaluated the long-term results of the irrigated radiofrequency ablation to create linear lines of conduction block endocardially. Methods Between November 1995 and June 2001, 200 patients with mainly structural heart disease and chronic atrial fibrillation underwent intraoperative radiofrequency linear ablation in both atria with concomitant cardiac surgery. Results The in-hospital mortality rate was 3.5% (7 patients) and during the mean follow-up of 40 months (range, 12 to 80) 27 patients (13.5%) died. Eight patients (4%) were lost from follow-up and complete data were available in 158 survivors. Sinus or atrial rhythm was present in 116 patients (73.4%) and an atrial driven rhythm in 10 patients (6.3%) with an atrioventricular pacemaker. Atrial fibrillation or flutter was documented in 32 patients (20.3%). Antiarrhythmic drugs were used in 49% of survivors who were free of atrial fibrillation or flutter. Conclusions Intraoperative radiofrequency endocardial ablation is an effective technique to eliminate atrial fibrillation with promising long-term results.

Antiarrhythmic surgical procedures to cure atrial fibrillation (AF) are widely used in cardiac surgery. Whereas the Cox maze procedure remains the highly effective gold-standard a variety of different antiarrhythmic procedures aim at reducing the extent and duration of the procedure. Antiarrhythmic procedures are especially effective in patients undergoing mitral valve surgery. In 110 patients with permanent AF undergoing various surgical procedures sinus rhythm was re-established in 75%. Subgroup analyses revealed no significant differences in rhythm or survival after antiarrhythmic intraoperative ablation indicating the usefulness and feasibility of this procedure in patients with a wide range of characteristics. Because conversion usually occurs spontaneously within the first 6 months and antiarrhythmic medication does not increase the incidence of conversion it seems reasonable to wait for spontaneous occurrence of sinus rhythm after antiarrhythmic intraoperative ablation. In patients with permanent AF undergoing open heart surgery additional antiarrhythmic procedures have been shown to be safe and effective.

Right atrial (RA) maze procedures using linear catheter ablation have had limited efficacy in paroxysmal atrial fibrillation (AF). We hypothesized that “hybrid” therapy using overdrive atrial pacing and antiarrhythmic drugs can improve efficacy of catheter RA maze and expand its role to persistent or permanent AF. Catheter RA maze procedures were performed in 26 patients with persistent or permanent AF refractory to 4.5 ± 2.1 antiarrhythmic drugs. Overdrive dual-site RA pacing (21 patients) or high RA pacing (5 patients) was continued (n = 11) or instituted periablation (n = 15). All patients continued receiving previously ineffective antiarrhythmic drugs. Freedom from permanent AF (rhythm control), symptomatic and/or asymptomatic AF recurrences, the safety of hybrid therapy, and overall survival were assessed. There was no procedure-related mortality or stroke. Rhythm control was achieved in 24 patients (92%) within 3 months. During long-term follow-up (6 to 49 months, mean 17 ± 10), rhythm control was maintained in 20 patients (77%). Nine patients (35%) had no AF recurrences, whereas 11 patients maintained rhythm control with infrequent AF recurrences. Device datalogs at the study cut-off point demonstrated no AF events in 6 patients, nonsustained atrial tachycardia in 2 patients, and brief asymptomatic paroxysmal AF in 12 patients. Actuarial patient survival was 95% at 1 year and 74% at 2 years of follow-up. Thus, hybrid therapy utilizing catheter RA maze procedures with overdrive atrial pacing and antiarrhythmic drugs can be performed safely and can reestablish rhythm control in selected patients with refractory persistent or permanent AF.

Comment Development of new operative procedures has caused a resurgence in the surgical treatment of atrial fibrillation. Like the Cox maze procedure, these new operations generally include isolation of the pulmonary veins and excision of the left atrial appendage. Exposure of these structures, particularly in a large left atrium, is challenging. A series of new atrial retractor blades (Kapp Surgical Inc, Cleveland, Ohio) provides exposure of the posterior left atrium and pulmonary vein orifices. These blades, which are malleable and universally adjustable, attach to a standard mitral valve retractor. This system provides excellent and consistent exposure of the posterior left atrium and pulmonary veins without the need for surgical assistance, facilitating operations for atrial fibrillation.

Clinical results of the Maze procedure for treatment of atrial fibrillation (AF) are excellent, suggesting improved ventricular function after restoring sinus rhythm. However, long-term corresponding effects on the release of cardiac natriuretic peptides and other vasoactive hormones are incompletely investigated after isolated Maze surgery.Plasma levels of brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP), antidiuretic hormone, aldosterone, and angiotensin II were measured in 15 patients (mean age, 52 +/- 11 years) undergoing isolated surgical Maze (III) procedures for medically refractory AF, preoperatively and 6 months postoperatively. At the time of blood sampling, hemodynamic correlates were obtained at baseline and after 6 and 12 minutes of rapid ventricular pacing at 150 stimulations/minute.All patients were free of AF at 6-month follow-up. The measured plasma levels of BNP, ANP, and angiotensin II were all significantly lower (p = 0.03) late after the isolated Maze procedure. Cardiac output was significantly higher postoperatively (p0.01). Other hemodynamic values and left atrial size were unchanged after surgery. Ventricular pacing caused almost identical hemodynamic changes in atrial pressures before and late after surgery, but the associated plasma ANP response was significantly attenuated postoperatively (p0.001).Levels of cardiac natriuretic peptides and angiotensin II as markers of ventricular function are improved in the long term after clinically successful isolated Maze procedures. ANP response to hemodynamic challenge by ventricular pacing was attenuated postoperatively, possibly due to atrial scarring.

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SCHNEIDER, M.A.E., et al.: Application of Right Atrial Contiguous Linear Lesions: An In Vivo Efficacy Validation of Multipolar Ablation Catheters in an Animal Model. Catheter ablation of atrial flutter and catheter Maze procedures require the creation of linear lesions. The efficacy of different multipolar catheters to create linear contiguous transmural lesions was studied in a sheep model. In 19 sheep a multipolar ablation catheter was inserted into the right atrium. In nine sheep a steerable 7 Fr catheter (C1) with six 6-mm electrodes and in five sheep a steerable 7 Fr catheter (C2) with four 5-mm electrodes were placed. In five sheep a 3.7 Fr catheter (C3) with eight electrodes of 6-mm length was deployed (steerable sheath). A total of 72 linear lesions were created and evaluated. Catheter types C1, C2, and C3 produced continuous lesions with at least two adjacent electrodes in 45%, 79%, and 87% of the lesions. The mean lesion length achieved by C3 was longer compared to C1 and C2 (27 ± 14 vs 10 ± 5 and 11 ± 6 mm; P < 0.05). The ability to produce contiguous lesions by all available electrodes was low: C1, 5%; C2, 5%; and C3, 6%. C3 was most effective in exerting transmural lesions (93% vs C1 75% and C2 57%; P < 0.0001). Microscopic endocardial fibrinous adhesions and macroscopic mild electrode carbonizations were caused by all catheter types. In conclusion, (1) all three catheter types do not create contiguous lesions along all electrodes. Gaps of viable tissue remain in most instances; (2) lesion depths and transmurality varies with different catheters; and (3) potentially hazardous thrombotic material was observed during radiofrequency ablation with all three catheters.

Objective – To assess the occurrence of late thromboembolism after surgical repair of chronic atrial fibrillation (AF) simultaneously with repair of mitral valve using the Cox-Maze procedure. Methods – 69 patients underwent Cox 3 procedure, with no cryoablation simultaneously with mitral valvuloplasty or prosthesis. Mean age was 49.9±13.2 years. Mean follow-up was of 31.7±19 months. Types of lesion were as follows: 33 (48%) stenoses, 23 (33%) insufficiencies, and 13 (19%) double lesions. Procedures were: 64 (93%) valvuloplasties, 3 (4%) biological and 2 ( 3%) mechanical prosthesis placement. There were 9 (13%) patients with previous systemic embolism and 2 ( 3%) had left atrial thrombi. Results – Early mortality was 7% and late 1%. 2 patients ( 3%) were reoperated for mitral placement. At last evaluation, 10 patients (15%), were in AF. The remaining 59 (85%) were either in sinus / atrial rythm (74%) or under pacing (12%). There were no occurrence of early or late, systemic or pulmonary embolism. Permanent anticoagulation was employed in 16 cases, 10 in regular rythm and 6 in AF. The remaining 47 (75%), 2 in AF and 45 in regular rythm, did not receive anticoagulants. Conclusions – These results are in accordance with others series, where the occurrence of embolism was rare after maze procedure. Permanent systemic anticoagulation seems to be unnecessary in those cases.

Cox and colleagues devised the Maze procedure in 1991, in which both atria and all pulmonary veins were incised and sutured, in addition to excision of both atrial appendages [1,2]. The idea behind the Maze procedure was to separate all possible areas for macroreentry and restore atrial contractility [3]. Although the Maze procedure was devised as a procedure for idiopathic atrial fibrillation (AF), it has been used for surgical ablation of chronic AF associated with mitral valve disease and proved effective in curing chronic AF as well as idiopathic AF [4]. In Japan, more than 2500 Maze procedures have performed to cure chronic or paroxysmal AF. The original Maze II and Maze III procedures have been modified and simplified in recent years. I have performed several procedures to eliminate AF in over 100 patients and simplified the procedure from the original Cox Maze III procedure to sole isolation of the pulmonary vein orifice. In this study, I investigated the results of different procedures in Japan and give new insights into surgical procedures for AF.

Stroke is one of the leading causes of mortality and morbidity today. In the majority of the cases, stroke results from cardiac emboli predominantly in patients with atrial fibrillation. Theoretically, the most likely site for generation of thrombus formations as a prerequisite for emboli and stroke is the left atrial appendage (LAA). Here, the three characteristics of Virchow's triad are realized, especially flow abnormalities, besides those of the vessel wall and constituents in blood [1]. Therefore, it makes theoretical sense to exclude the LAA in order to prevent stroke as recommended in the ACC/AHA Guidelines [2] during mitral valve surgery and MAZE procedures, although some authors argue that LAA exclusion is not the whole story [3] of stroke prevention and that strokes occur also after LAA occlusion, related to unsuccessful exclusion [4] or other sources. In this issue, Hernandez-Estefania report on a special technique for LAA occlusion including invagination and double-suture technique [5]. A purse-string suture is used to delineate the rim of the orifice which is facilitated by the invagination of the LAA. Although this might help to better define the borders of the os of the LAA, a clearly defined ridge is not present at the anterior and inferior borders of the LAA os [6]. Furthermore, the rim of the os is smooth [6]. Thus, there may be few firm tissues to anchor securely the sutures for occlusion. In addition, the oval area of the os is tugged together by the sutures, potentially creating tension forces in the tissue tending to reset the oval shape of the os. These are the factors that might cause some kind of re-opening of the LAA orifice years after the operation [4]. Whether this occurs with the proposed LAA occlusion technique remains to be seen. Therefore, long-term follow-up is needed to decide whether this is an effective technique for LAA occlusion. A more definite approach would be the complete excision of the LAA. Since our negative results years after direct suture closure of the LAA [7], we switched our technique to complete excision of LAA. The LAA atriotomy is closed between two 4–5 mm wide strips of Teflon felt to reinforce the fragile tissue, using a mattress suture followed by a continuous over and over suture to definitely close the resection line. The excision technique was reported to yield the most successful results compared with exclusion by suture or stapling [4]. In that report, 27% of patients in the excision group showed a residual stump of >1 cm, but the author did not find thrombus material in the residual stump at follow-up investigation, indicating that this residual stump at the base may not generate thrombus formation. Taken together, it would be appropriate for the proposed occlusion technique to stand the test of time for final judgment of its effectiveness. The most successful technique still remains the excision of the LAA.

Since the description of initial surgical treatment of atrial fibrillation (AF) by Cox et al, the original cut-and-sew technique underwent several revisions, culminating in the Cox Maze III procedure, which has been reported to effectively restore sinus rhythm and decrease thromboembolic events in patients with AF.1,2 Article see p 262 After the seminal observation that reported initiation of AF by pulmonary vein arrhythmogenicity3 and subsequent contributions on pulmonary vein (PV) and non–PV-dependent mechanisms in the genesis of AF, percutaneous catheter ablation has rapidly evolved to eliminate both paroxysmal and persistent AF over the last decade. Numerous reports from registries and randomized clinical trials demonstrated the efficacy, safety, and feasibility of catheter ablation to eliminate AF in appropriately selected patients through the use of well-defined clinical and ECG end points with rigorous long-term follow-up. Given the complexity of the classic cut-and-sew Cox Maze procedure and the skill it requires, surgical treatment of AF has also evolved with an emphasis on (1) less invasive approaches that eliminate the need for a sternotomy and cardiopulmonary bypass, (2) tissue ablation using energy sources similar to those commonly used during percutaneous catheter ablation procedures as an alternative to the challenging and more invasive cut-and-sew technique, and (3) ablation strategies that more or less replicate the lesion sets targeted during percutaneous catheter ablation procedures, primarily on the basis of recent advances in the understanding of the mechanisms of AF.4–9 Although commonly referred as “mini-Maze,” most of the currently used surgical approaches utilize energy sources similar to those used in percutaneous catheter ablation procedures and attempt to create lesion sets to isolate the PVs with additional …

Reduced levels of atrial natriuretic peptide (ANP) has been suggested as a cause of fluid retention after combined Maze and valvular surgery. This study aimed to assess hormonal activation in the perioperative setting of isolated Maze procedures.Changes in ANP, brain natriuretic peptide (BNP), antidiuretic hormone (ADH), aldosterone, and angiotensin II were measured in 16 patients (mean age 53+/-9 years) without concomitant heart disease undergoing the Maze (III) procedure. Ten matched patients (mean age 56+/-9 years) undergoing multivessel coronary artery bypass grafting served as controls. Measurements with hemodynamic correlates were obtained at baseline and after ventricular pacing (100 stimulations/minute), directly preoperatively, postoperatively and the first postoperative day. Weight gain and diuretic requirements were recorded.The major differences in hormonal response were significantly higher plasma levels of ADH (Maze preoperative 1.1+/-0.4, postoperative 24.9+/-16.7 pmol/L; controls preoperative 1.1+/-0.1, postoperative 3.7+/-3.5 pmol/L) and aldosterone (Maze preoperative 106+/-94, postoperative 678+/-343 pmol/L; controls preoperative 124+/-79, postoperative 171+/-93 pmol/L) in the Maze group on the first postoperative day (p0.001). Preoperative baseline plasma levels of ANP and pulmonary capillary wedge pressures (PCWP) were higher in the Maze group but this difference was abolished by pacing, and postoperatively, ANP levels changed in parallel to the PCWP in both groups. Diuretic requirements were significantly higher in the Maze group.Substantial increases in ADH and aldosterone were observed after the Maze procedure, indicating these hormones as important determinants in postoperative fluid retention. The role for ANP in this setting may be a less prominent than previously reported.

Objective: To evaluate the results of the maze procedure combined with mitral valve (MV) surgery in patients with chronic atrial fibrillation (AF). Methods: From 1994‐1999, 47 patients with chronic AF underwent the maze procedure combined with MV surgery (maze group). They were compared to 47 patients matched for age, sex, left ventricular function and type of MV surgery (non-maze group). The maze group had less severe symptoms but larger left atrium, and AF of longer duration than the non-maze group. One surgeon performed all operations in both groups of patients. Results: There were two early deaths in the maze group (4.5%) and one (2.2%) in the non-maze group. The duration of cardiopulmonary bypass (Pa 0:0001) and aortic crossclamping (Pa 0:0001) were greater in the maze group. Mean follow-up was 26 ^ 3 months in the maze group and 32 ^ 4 months in the non-maze group, and was 100% complete. Three-year survival was 96 ^ 3% for the maze group compared to 85 ^ 7% for the non-maze group (Pa 0:16). At the latest follow-up, 75% of the maze patients were in sinus rhythm compared to 36% of the non-maze patients (Pa 0:0004); 38% of the maze group were on coumadin postoperatively, compared to 69% in the non-maze group (Pa 0:003); and patients in the maze group were on fewer antiarrhythmic medications (Pa 0:0002). Three-year freedom from thromboembolic complications was 100% for the maze group compared to 83 ^ 7% for the nonmaze group (Pa 0:03). Conclusions: In this retrospective study the maze procedure did not seem to increase operative mortality of MV surgery, was effective in eliminating atrial fibrillation, and reduced the risk of thromboembolic complications and the need for long-term anticoagulation after mitral valve repair or replacement with a bioprosthesis. q 2001 Elsevier Science B.V. All rights reserved.

Objective: Sinus rhythm gained after the Cox/maze procedure concomitant with mitral valve operation has demonstrated long-term attrition during the follow-up, no information exists on whether the type of mitral valve operation—(repair vs. replacement)—affects this sinus rhythm maintenance rate. We retrospectively studied patients undergoing concomitant mitral valve operation and Cox/maze procedure to answer this question.Methods: Between April 1993 and August 1995, 87 consecutive patients—35 men and 52 women (mean age: 59.3 years)—with chronic atrial fibrillation and mitral valve disease underwent the modified Cox/maze procedure and concomitant mitral valve operation, with 56 having mitral valve repair (repair group) and 31 mitral valve replacement (replacement group). Patients were followed up and changes in rhythm studied retrospectively.Results: Follow-up for a mean 51.3±11.6 months was completed in 82 of 83 long-term survivors (99%). Repair group surgery survival was 98.1±1.9% at 1 year and 94.2±3.2% at 5 based on the Kaplan-Meier method. Replacement group surgery survival was 85.7±5.9% at 1 year and 82.9 ±6.4% at 5. Probability in sinus rhythm maintenance for the repair group at 1 year was 88.6±5.4% and at 5 years was 67.6±9.1%. Probability in sinus rhythm maintenance for the replacement group at 1 year was 95.7±4.3% and at 5 years was 65.0±11.1%.Conclusions: Medium-term results after the Cox/maze III procedure concomitant with mitral valve operation are good. The attrition of sinus rhythm maintenance appears similar by the completion of 5-year follw-up.

The Cox-Maze procedure was designed to address the consequences of atrial fibrillation, tachycardia, hemodynamic impairment, and thromboembolism. From 1991 until June 1999, 100 patients underwent the Maze operation at the Cleveland Clinic Foundation. The group included 72 men with a mean age of 58 +/- 11 years (range, 23 to 78 years). Initially, the Maze-I procedure was performed primarily for patients with lone atrial fibrillation. However, since 1995, the Maze-III procedure has been performed exclusively, and it is typically combined with mitral valve repair. Twenty-three patients had only a Maze procedure, 60 patients had the Maze procedure/mitral valve repair, 10 patients had Maze procedure/coronary artery bypass, 6 had Maze procedure/mitral valve replacement, and 1 had Maze procedure/atrial septal defect repair. Chronic atrial fibrillation was present in 78% of patients for a mean of 8 +/- 9 years. There was a 1% perioperative mortality and 5% late mortality rate. Median hospital stay was 9 +/- 5 days. Six patients required new early permanent pacemaker insertion. With a mean follow-up of 3 years, 90.4% of patients are in sinus rhythm (or atrial pacing). Preoperative symptoms were reduced: 24% had preoperative syncope; none had syncope in follow-up; 14% of patients preoperatively had cerebral or systemic emboli; and there were no perioperative or late embolic events. The Maze procedure effectively addressed the major complications of atrial fibrillation and was associated with low perioperative and late morbidity rates.

Since the first patient underwent the Maze procedure on September 25, 1987, 346 patients have undergone this operation for the treatment of atrial fibrillation. The procedure was designed as an open-heart operation performed through a median sternotomy. It underwent 2 major modifications relatively early in the series, evolving into the so-called Maze-III procedure, which has been used exclusively since April 16, 1992. Since that time, the Maze-III procedure has been adapted to allow it to be done by minimally invasive techniques. In addition, we recently performed the entire procedure in 2 patients without the use of cardiopulmonary bypass. The operative mortality rate has remained at 2% to 3%. This includes patients undergoing concomitant high-risk cardiac surgical procedures and all re-do cases. The overall success rate in curing atrial fibrillation has been 99%. The procedure itself has been shown to cause no permanent damage to the sinus node. The left atrium has been documented to function long-term postoperatively in 93% of patients and the right atrium functions in 99% of patients. The Maze-III procedure remains the surgical procedure of choice for the treatment of medically refractory atrial fibrillation.

The Cox-Maze procedure corrects atrial fibrillation in 90% of patients, and successful operation restores sinus rhythm, thereby reducing risks of thromboembolism and anticoagulant-associated hemorrhage. Symptoms such as palpitation and fatigability also improve with restoration of atrioventricular synchrony. At the Mayo Clinic, 221 Cox-Maze procedures were performed from March 1993 through March 1999. Over 75% of patients had associated cardiac disease and concomitant operations. Overall, early mortality was 1.4%, and the incidence of postoperative pacemaker implantation was 3.2%. Limiting incisions to the right atrium simplifies the operation for patients who primarily have tricuspid valve disease, and in early follow-up, outcome appeared to be as good as that achieved with biatrial incisions. The Cox-Maze procedure has proved particularly useful for patients with preoperative atrial fibrillation who require valvuloplasty for acquired mitral valve regurgitation; 87 patients have had this combined procedure, and there have been no early deaths. Further, our experience indicates that ventricular dysfunction is not a contraindication for operation and that restoration of sinus rhythm after the Cox-Maze procedure improves left ventricular ejection fraction in most patients.

Objective: The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure. Patients and methods: Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n=12). Results: The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function. Conclusion: Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system. (J Thorac Cardiovasc Surg 1999;118:287-96)

Background . The maze circuit lengthens the period of atrial depolarization and may lead to small or absent P waves, which may not be readily apparent in a standard 12-lead electrocardiogram. In this prospective study, we investigate if the right precordial leads V3R through V6R can improve detection of P waves and identification of atrial electrical activity. Methods . Standard 12-lead electrocardiograms (with leads I through III, aVR, aVL, aVF, and V1 through V6) and right precordial electrocardiograms (V3R through V6R) were recorded in 30 consecutive patients during the first 5 postoperative days and 1, 3, 6, 12, and 24 months after combined Cox-maze III procedure and mitral valve surgery. The P wave identification as an indication of atrial electrical activity and atrial contraction was proved by transesophageal echocardiographic identification of atrial contractions. Results . Despite echocardiographically identifiable atrial contractions, the P waves were not visible on standard 12-lead electrocardiograms in 7 (23%) patients after 1 and 3 months, and in 4 patients after 6 months. In contrast, right precordial electrocardiograms showed P waves in all of these patients that were best seen in lead V4R. Twelve and 24 months postoperatively, only 2 patients had no visible P waves in the standard leads that were still present in the right precordial leads. However, if P waves were easily identifiable in standard 12-lead electrocardiograms (23 patients at 1 and 3 months after surgery), the right precordial leads showed P waves only in 15 patients. Conclusions . Right precordial electrocardiogram with leads V3R through V6R is a helpful tool for visualizing P waves after the Cox-maze procedure. Standard 12-lead electrocardiogram should be combined with right precordial electrocardiogram in all patients after the Cox-maze procedure.

Objectives:The Cox maze procedure has been confirmed to be effective in curing atrial fibrillation. Some authors have reported severe fluid retention after the Cox maze procedure and have suggested decreased secretion of atrial natriuretic peptide as a possible mechanism. This study was designed (1) to examine the serial changes in atrial natriuretic peptide after the Cox maze procedure as compared with changes occurring after coronary artery bypass grafting and (2) to elucidate any differences in atrial natriuretic peptide levels between patients with transient recurrence of atrial fibrillation after the Cox maze procedure and those without recurrence of atrial fibrillation. Methods:Blood samples were drawn from the right and left atria in patients undergoing the Cox maze procedure (n = 19) and from the right atrium in patients undergoing coronary artery bypass grafting (n = 6) before and 1, 2, and 3 days after the operation. In six patients undergoing the Cox maze procedure, samples were also drawn from the radial artery before and 1, 2, 3, 5, and 7 days after the operation. The plasma samples were prepared by refrigerated centrifugation and stored until radioimmunoassay. In the Cox maze procedure group, atrial natriuretic peptide levels in the right atrium were 629 ± 366, 154 ± 112, 162 ± 112, and 183 ± 97 pg/ml and those in the left atrium were 276 ± 168, 152 ± 91, 162 ± 111, and 145 ± 80 pg/ml before and 1, 2, and 3 days after the operation, respectively. A marked decrease in atrial natriuretic peptide levels was evident after the Cox maze procedure (p < 0.001). There was no significant correlation between atrial natriuretic peptide levels and atrial pressures after the Cox maze procedure, which suggests that secretion of atrial natriuretic peptide by the atria was impaired. There was a significant correlation between the atrial natriuretic peptide levels in the left atrium and those in the peripheral radial artery, and the decreased levels of atrial natriuretic peptide in the radial artery continued for 7 days after the Cox maze procedure. There were no differences in the atrial natriuretic peptide levels between the patients with transient recurrence of atrial fibrillation (n = 6) and those without recurrence (n = 13) after the Cox maze procedure. In the coronary artery bypass grafting group, the atrial natriuretic peptide levels in the right atrium were 115 ± 37, 124 ± 48, 154 ± 54, and 156 ± 36 pg/ml before and 1, 2, and 3 days after the operation, respectively. No change was seen after the operation. Conclusions: We observed a significant decrease in atrial natriuretic peptide levels after the Cox maze procedure. This may be one of the possible causes of fluid retention after this procedure. These decreased atrial natriuretic peptide levels after the Cox maze procedure may result from the multiple atriotomy incisions and excision of both atrial auricles performed during the procedure, rather than from the conversion of atrial fibrillation to normal sinus rhythm. (J Thorac Cardiovasc Surg 1998;115:139–47

Ablation has become an important and, in some cases, the first-line therapy for a number of tachyarrhythmias. The feasibility of treating arrhythmias with ablation was initially demonstrated with surgical ablation techniques. Recently, catheter ablation techniques have replaced the surgical approach in nearly all cases. Catheter ablation is highly effective for the Wolff-Parkinson-White syndrome, atrioventricular nodal reentry, and atrial ectopic tachycardia. It is effective for atrial flutter, although approximately one quarter of patients treated with catheter ablation continue to require therapy for concomitant atrial fibrillation. The surgical maze procedure has proved to be feasible for preventing atrial fibrillation. The risks and long-term efficacy of catheter ablation maze procedures for atrial fibrillation need to be defined. The efficacy of ablation for ventricular tachycardia varies with the type of tachycardia. Catheter ablation is very effective for the rare idiopathic ventricular tachycardias that occur in structurally normal hearts and for bundle-branch reentry ventricular tachycardia, which occurs most frequently in patients with dilated cardiomyopathy. When performed at an experienced center, surgical ablation is an excellent option for selected patients with ventricular tachycardia due to prior myocardial infarction who have a discrete aneurysm but otherwise well-preserved ventricular function. Catheter ablation shows promise for this arrhythmia, but it can be offered only to those patients who have relatively slow tachycardias that allow catheter mapping. Substantial advances in mapping and ablation technology will continue to occur, allowing nonpharmacologic control of cardiac arrhythmias to be achieved in an ever greater number of patients.

Atrial fibrillation (AF) is generally associated with rheumatic valve disease and atrial septal defects (ASD) in young adults. Surgical correction of both disorders fails to convert to sinus rhythm or prevent further episodes of paroxysmal or chronic AF in most patients. The role and efficacy of combining mitral valve surgery or ASD correction with AF surgery in this setting has not been widely addressed and remains to be established. The present study prospectively assessed the recovery of sinus rhythm, functional status, and atrial function in 21 patients (mean age 42 ± 9.2 years) who underwent a modified Cox-maze procedure concomitant with mitral valve or ASD surgery at our institution between March 1993 and February 1995. Seventeen (81%) had chronic AF, and 4 (19%) had paroxysmal AF, with a mean AF duration of 3.5 ± 3.6 years (range 0.6 to 15.3). Concomitant surgery was performed in 9 patients (42.9%) with mitral stenosis, 5 (23.8%) with mitral regurgitation, 1 (4.8%) with mitral and aortic regurgitation, and 3 (14.3%) with ASD. Eighteen patients (86%) were in New York Heart Association class II to IV before operation. Doppler echocardiography was performed in all patients before surgery, and 1 week, and 3 and 6 months after surgery in patients maintaining sinus rhythm. One parient with severe mitral stenosis and depressed ventricular function died in the immediate postoperative period. Sinus rhythm was restored in the immediate postoperative period in 7 patients (35%), and in another 10 patients (50%) before discharge (mean 5.8 ± 2 days). Overall, sinus rhythm was restored before discharge in 17 patients (85%); 3 (15%) patients required antiarrhythmic therapy. Doppler echocardiography performed 3 months after surgery documented atrial contractility (A and E waves) in 12 patients (71%). After a mean follow-up period of 8 months (range 3 to 23), 18 (90%) remained in sinus rhythm. Sinus rhythm was successfully restored and maintained in most patients with drug refractory AF undergoing a concomitant Cox-maze procedure with mitral valve or ASD surgery improving atrial function and New York Heart Association class.

Objective Since the introduction of the cut-and-sew Cox maze procedure for atrial fibrillation, there has been substantial innovation in techniques for ablation. Use of alternative energy sources for ablation simplified the procedure and has resulted in dramatic increase in the number of patients with atrial fibrillation treated by surgical ablation. Despite its increasingly widespread adoption, there is lack of rigorous clinical evidence to establish this procedure as an effective clinical therapy. Methods This article describes a comparative effectiveness randomized trial, supported by the Cardiothoracic Surgical Clinical Trials Network, of surgical ablation with left atrial appendage closure versus left atrial appendage closure alone in patients with persistent and long-standing persistent atrial fibrillation undergoing mitral valve surgery. Nested within this trial is a further randomized comparison of 2 different lesions sets: pulmonary vein isolation and the full maze lesion set. Results This article addresses trial design challenges, including how best to characterize the target population, operationalize freedom from atrial fibrillation as a primary end point, account for the impact of antiarrhythmic drugs, and measure and analyze secondary end points, such as postoperative atrial fibrillation load. Conclusions This article concludes by discussing how insights that emerge from this trial may affect surgical practice and guide future research in this area.

Atrial fibrillation (AF) is a complex arrhythmia in which the interplay between initiating events and subsequent maintenance of the rhythm has resulted in a multitude of approaches to the cure. Ablation has traveled full circle from substrate focused catheter based analogs of the Cox Maze procedure to initiating event focused strategies targeting the pulmonary veins and once again back to substrate based ablation. The myriad pathologies leading to and resulting from AF have led to many theories regarding how substrate should be defined and how to reconcile substrate ablation with trigger ablation. The identification of spatiotemporally stable areas of very low amplitude short cycle length complex fractionated atrial electrograms (CFAE) in a sea of otherwise discrete normal amplitude and relatively longer cycle length electrograms led to use CFAE with a much shorter cycle length as a marker of abnormal substrate and target sites for AF ablation. This pure substrate based ablation strategy has resulted in reasonably success, even in high risk patients with very long standing persistent AF. In this review, I will discuss in details the prevailing mechanisms underlying CFAE, how to map and ablate CFAE sites, correlation of CFAE areas to those of ganglionic plexi and controversy of clinical outcomes of the approach.

Atrial fibrillation is found at late follow-up in approximately half of all adults who have had correction of atrial septal defect, even if it was not present preoperatively. These patients are thus exposed to the risks of stroke and chronic drug therapy even after a successful operation. Simultaneous surgical correction of atrial septal defect and atrial fibrillation was accomplished in a 52-year-old man by means of the Cox/maze procedure. The small added risk and the substantial benefit of eliminating atrial fibrillation suggest that this approach is warranted in selected adults with atrial septal defect.

A 52-year-old man presented with atrial flutter and was found to have an atrial septal defect (ASD). The paper describes an effective surgical approach for the treatment of this atrial arrhythmia utilizing a right sided Cox-maze III procedure concomitant with ASD closure. Review of the literature and clinical implications are discussed.

Objective The effects of the Cox maze procedure on atrial function remain poorly defined. The purpose of this study was to investigate the effects of a modified Cox maze procedure on left and right atrial function in a porcine model. Methods After cardiac magnetic resonance imaging, 6 pigs underwent pericardiotomy (sham group), and 6 pigs underwent a modified Cox maze procedure (maze group) with bipolar radiofrequency ablation. The maze group had preablation and immediate postablation left and right atrial pressure–volume relations measured with conductance catheters. All pigs survived for 30 days. Magnetic resonance imaging was then repeated for both groups, and conductance catheter measurements were repeated for the right atrium in the maze group. Results Both groups had significantly higher left atrial volumes postoperatively. Magnetic resonance imaging–derived reservoir and booster pump functional parameters were reduced postoperatively for both groups, but there was no difference in these parameters between the groups. The maze group had significantly higher reduction in the medial and lateral left atrial wall contraction postoperatively. There was no change in immediate left atrial elastance or in the early and 30-day right atrial elastance after the Cox maze procedure. Although the initial left atrial stiffness increased after ablation, right atrial diastolic stiffness did not change initially or at 30 days. Conclusions Performing a pericardiotomy alone had a significant effect on atrial function that can be quantified by means of magnetic resonance imaging. The effects of the Cox maze procedure on left atrial function could only be detected by analyzing segmental wall motion. Understanding the precise physiologic effects of the Cox maze procedure on atrial function will help in developing less-damaging lesion sets for the surgical treatment of atrial fibrillation.

Background A simplified alternative to the Cox maze procedure to treat atrial fibrillation with epicardial high-intensity focused ultrasound was evaluated clinically, and the initial clinical results were assessed at the 6-month follow-up visit. Methods From September 2002 through February 2004, 103 patients were prospectively enrolled in a multicenter study. Atrial fibrillation duration ranged from 6 to 240 months (mean, 44 months) and was permanent in 76 (74%) patients, paroxysmal in 22 (21%) patients, and persistent in 5 (5%) patients. All patients had concomitant operations, and ablation was performed epicardially on the beating heart before the concomitant procedure. The device automatically created a circumferential left atrial ablation around the pulmonary veins in an average of 10 minutes, and an additional mitral line was created epicardially in 35 (34%) patients with a handheld device by using the same technology. Results No complications or deaths were device or procedure related. There were 4 (3.8%) early deaths and 2 late extracardiac deaths. The 6-month follow-up was complete in all survivors. At the 6-month visit, freedom from atrial fibrillation was 85% in the entire study group (80% in patients with permanent atrial fibrillation, 88% in the 35 patients who had the additional mitral line, and 100% in patients with paroxysmal atrial fibrillation). A pacemaker was implanted in 8 patients. Only the duration and type of atrial fibrillation significantly increased the risk of recurrence. Conclusion Epicardial, off-pump, beating-heart ablation with acoustic energy is safe and cures 80% of patients with permanent atrial fibrillation associated with long-standing structural heart disease.

The search for alternative epicardial energy sources in the treatment of nonvalvular atrial fibrillation (AF) is a relatively new aspect of the evolving spectrum of Maze operations. We tested the hypothesis that epicardial microwave ablation produces identical results to those of the standard cryosurgical Maze. Fourteen consecutive patients with chronic AF underwent on-pump epicardial Maze procedures after routine cardiac surgery. The results were compared with those of 14 control patients selected from our Maze database of 280 patients. There were no differences in age, sex, cardiothoracic ratio, duration of AF, pump time, intensive care unit or hospital stays. The aortic cross clamp time with epicardial microwave was, however, shortened from 110 to 65 minutes (p=0.011). The recurrence rate of AF after discharge showed no significant difference between the two groups (14% vs. 15%, p=0.841). Epicardial microwave ablation might be a valuable alternative to the conventional cryosurgical Maze procedure, especially for those patients without associated mitral valve disease.