Modified maze procedure for patients with atrial fibrillation undergoing simultaneous open heart surgery

Outcomes of Atrial Arrhythmia Surgery in Patients With Congenital Heart Disease: A Systematic Review

Background The improved life expectancy of patients with congenital heart disease is often accompanied by the development of atrial tachyarrhythmias. Similarly, the number of patients requiring redo operations is expected to continue to rise as these patients are aging. Consequently, the role of arrhythmia surgery in the treatment of atrial arrhythmias is likely to become more important in this population. Although atrial arrhythmia surgery is a well-established part of Fontan conversion procedures, evidence-based recommendations for arrhythmia surgery for macroreentrant atrial tachycardia and atrial fibrillation in other patients with congenital heart disease are still lacking. Methods and Results Twenty-eight studies were included in this systematic review. The median reported arrhythmia recurrence was 13% (interquartile range, 4%-26%) during follow-up ranging from 3 months to 15.2 years. A large variation in surgical techniques was observed. Based on the acquired data, biatrial lesions are more effective in the treatment of atrial fibrillation than exclusive right-sided lesions. Right-sided lesions may be more appropriate in the treatment of macroreentrant atrial tachycardia; evidence for the superiority of additional left-sided lesions is lacking. There are not enough data to support the use of exclusive left-sided lesions. Theoretically, prophylactic atrial arrhythmia surgery may be beneficial in this population, but evidence is currently limited. Conclusions To be able to provide recommendations for arrhythmia surgery in patients with congenital heart disease, future studies should report outcomes according to the type of preoperative arrhythmia, underlying congenital heart disease, lesion set, and energy source. This is essential for determining which surgical techniques should ideally be applied under which circumstances.

Treatment of Chronic Atrial Fibrillation During Surgery for Rheumatic Mitral Valve Disease

Introduction

The result of surgical ablation of atrial fibrillation remains controversial, although prospective and randomized studies have shown significant differences in the return to sinus rhythm in patients treated with ablation versus control group. Surgery of the Labyrinth, proposed by Cox and colleagues, is complex and increases the morbidity rate. Therefore, studies are needed to confirm the impact on clinical outcomes and quality of life of these patients.

Objective

To analyze the results obtained in the treatment of atrial fibrillation by surgical approach, by Gomes procedure, for mitral valve surgery in patients with rheumatic heart disease associated with chronic atrial fibrillation.

Methods

We studied 20 patients with mitral valve dysfunction of rheumatic etiology, evolving with chronic atrial fibrillation, submitted to surgical treatment of valvular dysfunction and atrial fibrillation by Gomes procedure.

Results

The mean duration of infusion ranged from 65.8±11.22 and aortic clamping of 40.8±7.87 minutes. Of 20 patients operated, 19 (95%) patients were discharged with normal atrial heart rhythm. One (5%) patient required permanent endocardial pacing. In the postoperative follow-up of six months, 18 (90%) patients continued with regular atrial rhythm, one (5%) patient returned to atrial fibrillation and one (5%) patient continued to require endocardial pacemaker to maintain regular rhythm.

Conclusion

Gomes procedure associated with surgical correction of mitral dysfunction simplified the surgical ablation of atrial fibrillation in patients with rheumatic mitral valve disease and persistent atrial fibrillation. The results showed that it is a safe and effective procedure.

Preoperative study of the surface ECG for the prognosis of atrial fibrillation maze surgery outcome at discharge

The Cox-maze surgery is an effective procedure for terminating atrial fibrillation (AF) in patients requiring open-heart surgery associated with another heart disease. After the intervention, regardless of the patient's rhythm, all are treated with oral anticoagulants and antiarrhythmic drugs prior to discharge. Furthermore, patients maintaining AF before discharge could also be treated with electrical cardioversion (ECV). In view of this, a preoperative prognosis of the patient's rhythm at discharge would be helpful for optimizing drug therapy planning as well as for advancing ECV therapy. This work analyzes 30 preoperative electrocardiograms (ECGs) from patients suffering from AF in order to predict the Cox-maze surgery outcome at discharge. Two different characteristics of the AF pattern have been studied. On the one hand, the atrial activity (AA) organization, which provides information about the number of propagating wavelets in the atria, was investigated. AA organization has been successfully used in previous studies related to spontaneous reversion of paroxysmal AF and to the outcome of ECV. To assess organization, the dominant atrial frequency (DAF) and sample entropy (SampEn) have been computed. On the other hand, the second characteristic studied was the fibrillatory wave (f-wave) amplitude, which has been demonstrated to be a valuable indicator of the Cox-maze surgery outcome in previous studies. Moreover, this parameter has been obtained through a new methodology, based on computing the f-wave average power (fWP). Finally, all the computed indices were combined in a decision tree in order to improve prediction capability. Results for the DAF yielded a sensitivity (Se), a specificity (Sp) and an accuracy (Acc) of 61.54%, 82.35% and 73.33%, respectively. For SampEn the values were 69.23%, 76.00% and 73.33%, respectively, and for fWP they were 92.31%, 82.35% and 86.67%, respectively. Finally, the decision tree combining the three parameters analyzed improved the preoperative prognosis of the Cox-maze outcome with values of Se, Sp and Acc of 100%, 82.35% and 90%, respectively. As a consequence, the analysis of parameters related to the f-wave pattern, extracted from the preoperative ECG, has provided a considerable ability to predict the outcome of AF Cox-maze surgery at discharge.

Impact of epicardial ablation of concomitant atrial fibrillation on atrial natriuretic peptide levels and atrial function in 6 months follow-up: does preoperative ANP level predict outcome of ablation?

Background

Epicardial ablation concomitant to cardiac surgery is an easy and safe approach to treat atrial fibrillation (AF), but its efficacy in longstanding persistent (LsPe) AF remains intermediate. Although larger left atrial size has been associated with worse outcome after ablation, biochemical predictors of success are not well established. The aim of this study was to evaluate relationship between biochemical marker, echo-characteristic and cardiac rhythm in 6 months follow-up after epicardial ultrasound (HIFU) ablation.

Methods

We included 78 consecutive patients, who underwent elective cardiac surgery. 42 patients with AF (11.9% paroxysmal, 23.8% persistent, 64.3% LsPeAF) underwent concomitant HIFU ablation (AF ablation group), 16 with AF underwent cardiac surgery without ablation (AF control) and 20 had preoperatively normal sinus rhythm (SR control). We measured plasma ANP secretion before, on postoperative day (POD) 1, POD 7 as well as 3 and 6 months after surgery. Moreover, we estimated cardiac rhythm and atrial mechanical function by Atrial Filling Fraction (AFF) and A-wave velocity in follow-up.

Results

Baseline ANP levels were higher in patients with LsPeAF, as compared to the paroxysmal and permanent AF and to the SR control group. Patients with LsPeAF (n = 27) who converted to SR had preoperatively smaller left atrial diameter (LAD) and LA area (p < 0.05) and higher ANP level (p = 0.009) than those who remained in AF at 6 months after ablation. Multivariate regression analysis revealed that only preoperative ANP level was an independent predictor of cardiac rhythm after ablation. Patients with LsPeAF and preoperative ANP >7.5 nmol/l presented with SR in 80%, in contrast to those with ANP <7.5 nmol/l who converted to SR in 20%. We detected gradual increase of AFF and A-velocity at 6 months after ablation (p < 0.05) solely in AF ablation group. ANP levels were increased on POD 1 in ablation group (p < 0.05), without changes in further follow-up.

Conclusion

Our results indicate that preoperative ANP levels may be a new biochemical predictor of successful epicardial ablation in patients with concomitant LsPeAF. HIFU ablation caused a significant improvement of atrial mechanical function and gradual increase of AFF and did not associate with alteration of atrial endocrine secretion at 6 months follow-up.

Guideline for the surgical treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and its prevalence is ∼1-2% of the general population, but higher with increasing age and in patients with concomitant heart disease. The Cox-maze III procedure was a groundbreaking development and remains the surgical intervention with the highest cure rate, but due to its technical difficulty alternative techniques have been developed to create the lesions sets. The field is fast moving and there are now multiple energy sources, multiple potential lesion sets and even multiple guidelines addressing the issues surrounding the surgical treatment of AF both for patients undergoing this concomitantly with other cardiac surgical procedures and also as stand-alone procedures either via sternotomy or via videothoracoscopic techniques. The aim of this document is to bring together all major guidelines in this area into one resource for clinicians interested in surgery for AF. Where we felt that guidance was lacking, we also reviewed the evidence and provided summaries in those areas. We conclude that AF surgery is an effective intervention for patients with all types of AF undergoing concomitant cardiac surgery to reduce the incidence of AF, as demonstrated in multiple randomized studies. There is some evidence that this translates into reduced stroke risk, reduced heart failure risk and longer survival. In addition, symptomatic patients with AF may be considered for surgery after failed catheter intervention or even as an alternative to catheter intervention where either catheter ablation is contraindicated or by patient choice.

Cardioscopic Trans-septal Cryoablation of Left Atrium in Nonmitral Cases

BACKGROUND

: A modified maze procedure in which trans-septal cardioscopy was used for cryoablation in the left atrium is described.

METHODS

: The technique was used in 11 consecutive patients (9 men and 2 women, 56.5 ± 19.8 years) with permanent atrial fibrillation (Af) and concomitant nonmitral cardiac or aortic disease: aortic valvular disease in 4 patients, atrial septal defect (ASD) in 2 patients, tricuspid regurgitation in 2 patients, acute aortic dissection in 1 patient, arch aneurysm in 1 patient, and coronary artery disease in 1 patient. The mean Af duration detected in 7 cases was 18.5 ± 10.1 months. Partial sternotomy was used in aortic valve replacement, ASD closure, and tricuspid valve plasty, and fullsternotomy was used in aortic graft replacement and coronary artery bypass. Cardiopulmonary bypass was established, aortic cross-clamp was performed, a right atriotomy was created, a cryoablation probe and cardioscope (3 mm) were introduced into the left atrium through a 1-cm cut at the fossa ovalis or ASD, and cardioscopic left-atrial endocardial cryoablation was performed. The right-side maze procedure was conducted directly. The atrial appendages were excised in each case.

RESULTS

: Left-atrial cardioscopic cryoablation required 25.0 ± 5.5 minutes, and no deaths or procedure-related morbidities occurred. The mean follow-up period was 12 ± 8.5 months. One patient with tricuspid regurgitation died of liver failure. With the exception of coronary and acute dissection cases, all patients have maintained a sinus rhythm.

CONCLUSION

: Although experience is limited, videocardioscopic trans-septal left-atrial cryoablation is a viable method for nonmitral Af cases, and the partial sternotomy approach can be performed.

Surgical approaches for atrial fibrillation

For cardiac surgery patients presenting with atrial fibrillation (AF), surgeons offer an operation that corrects the structural heart disease and the AF. With this approach, it is estimated that surgeons will perform more than 10,000 ablation procedures in 2007. Surgeons are developing minimally invasive techniques for stand-alone, epicardial ablation of AF. This article (1) reviews the rationale for surgical ablation of AF, (2) describes the classic maze procedure and its results, (3) details new approaches to surgical ablation of AF, (4) emphasizes the importance of management of the left atrial appendage, and (5) considers challenges and future directions in the ablation of AF.

Preoperative left atrial volume index is a predictor of successful sinus rhythm restoration and maintenance after the maze operation

OBJECTIVE

The purpose of this study was to identify the relationship of preoperative and postoperative left atrial volume indices and dimensions with successful restoration of sinus rhythm after the maze operation.

METHODS

Forty-three patients who underwent the Cox-maze III procedure for permanent atrial fibrillation in conjunction with surgical intervention for various heart diseases were evaluated. Echocardiographic studies were performed preoperatively and 3 months postoperatively. Volumes and dimensions were corrected for body surface area and analyzed.

RESULTS

Sinus rhythm was restored and maintained in 36 (83.7%) of the 43 patients. The preoperative left atrial volume index of the group with successful restoration of sinus rhythm (group A) was significantly smaller than that of the group with unsuccessful restoration (group B: 76.7 +/- 16.4 vs 108.9 +/- 43.9 mL/m2, P = .047). In group A the volume index (76.7 +/- 16.4 vs 52.3 +/- 15.0 mL/m2, P < .001) and dimension index (35.8 +/- 6.2 vs 30.8 +/- 4.7 mL/m2, P < .001) decreased significantly 3 months after the operation. No such significant changes were found in group B. The duration of arrhythmia for group A was significantly shorter than that for group B (3.4 +/- 2.8 vs 13.7 +/- 8 years, P = .001).

CONCLUSIONS

The preoperative left atrial volume index, as opposed to the conventional left atrial dimension, and the duration of arrhythmia are important predictors of successful sinus rhythm restoration after the maze operation. A significant reduction of the volume index can be achieved in patients whose rhythm is successfully restored and maintained after the procedure.

Role of the Simultaneous Sequential Strategy for Failed Acute Sinus Restoration after Modified Left Maze Procedure for Persistent Atrial Fibrillation with Concomitant Mitral Surgery

BACKGROUND

We assessed whether the simultaneous sequential strategy could (1) achieve additional sinus restoration for those patients who were not in sinus rhythm while coming off bypass after modified left maze procedure and (2) attain the same long-term success rates as the bi-atrial maze procedure in patients with persistent atrial fibrillation (AF) and mitral valve disease.

MATERIALS AND METHODS

Twenty-seven consecutive patients - ten men and 17 women with a mean age of 52 +/- 13 years, all with persistent AF and mitral valve disease - underwent the modified maze procedure with the simultaneous sequential strategy. In the first phase, the modified left atrial maze operation was carried out with concomitant valvular surgery; the right side maze operation was subsequently carried out as a second phase of the sequential strategy only if AF re-appeared following the spontaneous restoration of heart beats during the operation.

RESULTS

Twenty patients (74.1%) underwent the left atrial maze procedure only, and seven patients (25.9%) required the subsequent right atrial maze procedure as part of the sequential strategy. At a mean follow-up of 15.1 +/- 7.7 months, six of the 27 patients (22.2%) who underwent additional right atrial maze procedure had restored sinus rhythm. At a mean follow-up of 17.8 +/- 7.3 months, 24 of the 27 patients (88.9%) had restored sinus rhythm and 22 patients (81.5%) had restored bi-atrial transport function (right atrial filling fraction: 40.8 +/- 11.7%; left atrial filling fraction: 22.9 +/- 8.1%) after application of the sequential strategy.

CONCLUSIONS

Compared with modified left atrial maze procedure, the application of the simultaneous sequential strategy successfully restored sinus rhythm in an additional 22.2% of patients with persistent AF. The overall sinus conversion rate of 88.9% was comparable with that of the standard bi-atrial maze procedure.

Impact of the maze operation combined with left-sided valve surgery on the change in tricuspid regurgitation over time

BACKGROUND

Atrial fibrillation (AF) has been reported to be a predisposing factor for the progression of TR in patients with previous mitral or combined mitral/aortic valve surgery. We hypothesized that the maze operation (MAZE) can prevent the progression of tricuspid regurgitation (TR) in these patients.

METHODS AND RESULTS

We analyzed 170 patients (age, 45.5+/-10.9 years) who had undergone mitral or combined mitral/aortic valve surgery. On the basis of preoperative rhythm, patients were divided into 3 groups; GrI was composed of 44 patients with sinus rhythm, GrII of 48 who had undergone MAZE, and GrIII of 78 with AF who had not undergone MAZE. Echocardiographic examinations were performed before, immediately after, and 92.2+/-17.2 (range, 50 to 131) months after surgery. Preoperative and immediate postoperative clinical and echocardiographic parameters were similar among the groups. Insignificant TR at the immediate postoperative examination worsened with time in 7.3% of GrI (3 of 41), 12.8% of GrII (6 of 47), and 38.8% of GrIII (26 of 67) patients at the final examination (P=0.63 for GrI versus GrII, P=0.001 for GrI versus GrIII, P=0.005 for GrII versus GrIII). The incidence of significant TR at the final echocardiographic examination was higher in GrIII (39.7%) compared with GrI (9.1%) and GrII (14.6%) (P=0.001 for GrI versus GrIII, P=0.005 for GrII versus GrIII), whereas GrI and GrII did not show any difference (P=0.63). By multivariate analysis, the only factor identified to prevent TR progression was the group factor (GrI and GrII versus GrIII, P=0.002 and P=0.005, respectively). In a subgroup analysis of GrII according to the presence or absence of atrial mechanical activity, the absence of atrial mechanical activity was identified as an independent parameter for the progression of TR (P=0.001).

CONCLUSIONS

AF predisposes patients undergoing mitral valve surgery to the progression of TR, which can be prevented by MAZE. This additional benefit of MAZE is largely dependent on the restoration and maintenance of atrial mechanical function.

Surface atrial frequency analysis in patients with atrial fibrillation: assessing the effects of linear left atrial ablation

INTRODUCTION

Our group has shown previously that measurements of atrial frequency can be obtained from surface 12-lead ECG recordings of patients during atrial fibrillation (AF), using a combination of principal component and Fourier transform algorithms. Such measurements are reproducible over time and change with drug manipulation of the arrhythmia.

AIMS

To determine whether linear left atrial ablation, using a combination of "roof" and "mitral isthmus" lines results in changes in surface atrial frequency during AF and to assess the contribution of each individual line when sited sequentially.

METHODS AND RESULTS

Computerized recordings from 26 patients, who had undergone linear ablation procedures for AF, were reviewed. The atrial signal was extracted from the 12-lead ECG data by principal component analysis and the main frequency component identified using Fourier analysis. Atrial frequency before and after these two standard ablation lines was compared. Atrial frequency decreased significantly after the combination of roof and mitral isthmus lines (5.66 vs 5.15 Hz) and when either roof (5.61 vs 5.13 Hz) or mitral isthmus (5.89 vs 5.75 Hz) lines were sited first. However, only the roof line led to a significant reduction in atrial frequency when sited second (5.64 vs 5.49 Hz).

CONCLUSIONS

Measurements of atrial frequency can be obtained from surface 12-lead ECG recordings during AF and change as predicted in response to linear left atrial ablation. This technique may be useful in assessing antiarrhythmic treatments for AF.

The Cox maze procedure in mitral valve disease: Predictors of recurrent atrial fibrillation

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.

Epicardial microwave application in chronic atrial fibrillation surgery

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.

Cardioscopic Trans-septal Cryoablation of Left Atrium in Nonmitral Cases

Background

A modified maze procedure in which trans-septal cardioscopy was used for cryoablation in the left atrium is described.

Methods

The technique was used in 11 consecutive patients (9 men and 2 women, 56.5 ± 19.8 years) with permanent atrial fibrillation (Af) and concomitant nonmitral cardiac or aortic disease: aortic valvular disease in 4 patients, atrial septal defect (ASD) in 2 patients, tricuspid regurgitation in 2 patients, acute aortic dissection in 1 patient, arch aneurysm in 1 patient, and coronary artery disease in 1 patient. The mean Af duration detected in 7 cases was 18.5 ± 10.1 months. Partial sternotomy was used in aortic valve replacement, ASD closure, and tricuspid valve plasty, and fullsternotomy was used in aortic graft replacement and coronary artery bypass. Cardiopulmonary bypass was established, aortic cross-clamp was performed, a right atriotomy was created, a cryoablation probe and cardioscope (3 mm) were introduced into the left atrium through a 1-cm cut at the fossa ovalis or ASD, and cardioscopic left-atrial endocardial cryoablation was performed. The right-side maze procedure was conducted directly. The atrial appendages were excised in each case.

Results

Left-atrial cardioscopic cryoablation required 25.0 ± 5.5 minutes, and no deaths or procedure-related morbidities occurred. The mean follow-up period was 12 ± 8.5 months. One patient with tricuspid regurgitation died of liver failure. With the exception of coronary and acute dissection cases, all patients have maintained a sinus rhythm.

Conclusion

Although experience is limited, videocardioscopic trans-septal left-atrial cryoablation is a viable method for nonmitral Af cases, and the partial sternotomy approach can be performed.

Endocardial Radiofrequency Ablation During Mitral Valve Surgery: Effect on Cardiac Rhythm, Atrial Size, and Function

BACKGROUND

Restoration of sinus rhythm is thought to lead to a reduction in left atrial size and to recovery of atrial contraction. We aimed to investigate changes in atrial size and function in patients undergoing radiofrequency ablation for atrial fibrillation during mitral valve surgery.

METHODS

In a prospective study, 70 patients (64 +/- 10 years) with mitral valve disease and atrial fibrillation underwent mitral surgery and left atrial endocardial radiofrequency ablation. Evaluation was achieved before surgery, at 7 days, 5 months, and 22 months after surgery. Maximal right and left atrial areas, left atrial diameter, and volume were measured. Atrial filling fraction (ventricular filling related to atrial contraction to total ventricular filling ratio) was used as an index of atrial contraction.

RESULTS

At the end of follow-up (22 +/- 10 months) most patients (91%) were in sinus rhythm. Actuarial freedom from atrial fibrillation recurrence was 62.5% after 2 years. Atrial size decreased, with a significant improvement in right (36 +/- 15 vs 10 +/- 20% preoperatively, p < 0.0001) and left (25 +/- 12 vs 7 +/- 14%, p < 0.0001) atrial filling fraction. Despite similar preoperative atrial size, at the end of follow-up atrial fibrillation recurrence was associated with a higher left atrial volume than in patients free of recurrence (41 +/- 14 vs 32 +/- 9 mL/m2, p = 0.004). Independent predictors of atrial fibrillation recurrence were previous mitral procedure (p = 0.029), left ventricular ejection fraction (p = 0.033), and mitral rheumatic lesion (p = 0.034).

CONCLUSIONS

Left atrial radiofrequency ablation for atrial fibrillation during mitral surgery is an effective procedure restoring sinus rhythm. Right and left atrial size was significantly reduced, with a recovery in atrial contraction.

Radiofrequency ablation for atrial fibrillation: different approaches

The existing literature regarding radiofrequency ablation for the surgical treatment of atrial fibrillation was reviewed, analyzing the early and late results. A MEDLINE search supplemented with a manual bibliographic review was performed for all peer-reviewed English language articles regarding the use of radiofrequency ablation for the treatment of atrial fibrillation. Six studies were identified, with a total of 451 patients. None of the studies was completely randomized. All patients underwent radiofrequency ablation as an adjunct to a variety of cardiac surgical procedures. The hospital mortality rate was 2.7%. The overall survival rate was 97.1%, and freedom from atrial fibrillation was 76.3% +/- 5.1% after a mean follow-up period of 13.8 +/- 1.9 months. It was concluded that radiofrequency ablation should be considered a safe and effective means to cure atrial fibrillation in patients undergoing open heart surgery.

Long-Term Results of Cryoablation with a New Cryoprobe to Eliminate Chronic Atrial Fibrillation Associated with Mitral Valve Disease

The purpose of this study was to examine the performance of a new cryoprobe in the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The study included 66 patients undergoing mitral valve replacement. The mean AF duration was 9.0 +/- 9.0 years and mean left atrial (LA) was diameter 57 +/- 10 mm. Cryoablation (-60 degrees C) was applied to four pulmonary vein (PV) orifices over 2-3 minute. The spherical tip (2-cm in diameter) of the cryoprobe is capable of ablating the left atrium near the PV, as well as the PV ostium with a single cryoablation. After cryoablation, mitral valve surgery or a combined surgical procedure were performed in 66 patients. There were no intraoperative complications. Sinus rhythm was restored in 60 patients (91%) immediately after the operation. Recurrent AF was treated with antiarrhythmic drugs and/or direct current cardioversion in 43 patients (72%). At discharge, 48 patients (72%) were in sinus rhythm. During a mean follow-up period of 31 +/- 16 months, 40 patients (61%) were in sinus rhythm with (29) or without antiarrhythmic drugs (11). In patients in sinus rhythm at the end of the follow-up period, the duration of preoperative AF duration was significantly shorter (P < 0.05) and the preoperative LA diameter and cardiothoracic ratio were significantly smaller than in patients who were in AF (both for P < 0.005). Using this new cryoprobe, sinus rhythm was restored and maintained in 61% of patients with chronic AF and mitral valve disease with a 12-15 minute cryoablation procedure.

Pulmonary vein isolation by microwave energy ablation in patients with permanent atrial fibrillation

BACKGROUND

Atrial fibrillation is associated with significant morbidity and mortality. Microwave energy ablation (MW) is a new option for surgical treatment of permanent atrial fibrillation (pAF). We present our experience with surgical treatment of mitral valve disease (MVD), coronary artery disease (CAD), and aortic valve disease (AVD) and microwave ablation in patients with pAF.

METHODS

In 202 consecutive patients (100 female, 102 male, age 68.3 +/- 8.1 years from 30.4 to 83.5 years, ejection fraction 25-80%, left atrial diameter 56 +/- 9.1 mm from 30 to 102 mm) with an indication for a cardiosurgical intervention, pAF was documented for 6.8 +/- 9.1 years. MW was performed using two different lesion concepts. In the first 140 patients we used an ablation line starting at the posterior mitral valve annulus and incorporated the interior of all pulmonary veins. After the first 137 patients we switched to a different ablation line concept. Starting at the posterior mitral valve the annulus ablation line additionally included the left atrial appendix. Another ablation circle around the pulmonary veins of both sides was created and both circles were connected. If opening of the right atrium was necessary additional isthmus ablation was performed.

RESULTS

Survival rate was 98.5%. There were no ablation-related complications. In the 6-month follow-up 87 patients were in sinus rhythm (65%), in the 1-year follow-up 74 patients were in SR (62.2%).

CONCLUSIONS

Microwave ablation is a safe and efficient method for surgical treatment of pAF in patients with a concomitant cardiosurgical procedure. The short duration for this additional procedure and easy application has made this procedure the method of choice in our institution for treatment of pAF in patients with cardiosurgical operations.

Preoperative Atrial Size Predicts the Success of Radiofrequency Maze Procedure for Permanent Atrial Fibrillation in Patients Undergoing Concomitant Valvular Surgery

BACKGROUND

The radiofrequency (RF) maze procedure can effectively restore sinus rhythm and atrial transport function in the majority of patients with permanent atrial fibrillation (AF) and mitral valve disease. No previous study has described a cutoff value of preoperative atrial size determined by the discriminant analysis in predicting the success of sinus conversion by the RF maze procedure for permanent AF in patients with mitral valve disease.

METHODS AND RESULTS

This study included 81 patients with permanent AF and mitral valve disease who underwent the RF maze IV procedure while undergoing concomitant valvular operations. There was one surgical death (1.2%). Another patient died of acute necrotizing pancreatitis 13 months later. Two patients (2.5%) developed sick sinus syndrome and received transvenous permanent pacemaker implantation. In the remaining 77 patients, there were 38 men and 39 women, with a mean (+/- SD) age of 51 +/- 11 years. At a mean follow-up time of 38 months, 65 patients (84.4%) had persistent sinus conversion that had been accomplished by the RF maze procedure (group 1), and 12 patients (15.6%) did not regain sinus rhythm (group 2). We evaluated the preoperative variables between the two groups. Univariate analysis demonstrated that the preoperative left atrial area and the left atrial diameter of group 1 patients were significantly smaller than those of group 2 patients. Group 1 had significantly fewer patients associated with tricuspid valve disease than did group 2. By multiple stepwise logistic regression analysis, only the preoperative left atrial area was an independent determinant of sinus conversion by the RF maze procedure (odds ratio, 0.961; 95% confidence interval, 0.935 to 0.988; p < 0.005). Linear discriminant analysis demonstrated that the sensitivity and specificity of the cutoff value of 56.25 cm(2) of the preoperative left atrial area in predicting the sinus conversion by the RF maze procedure were 50.0% and 86.2%, respectively, and the positive and negative predictive values were 40.0% and 90.3%, respectively.

CONCLUSION

The preoperative left atrial area is an independent determinant of sinus conversion by the RF maze procedure for patients with permanent AF and mitral valve disease.

Atrial reduction plasty Cox maze procedure: extended indications for atrial fibrillation surgery

BACKGROUND

The Cox maze procedure yields good results for atrial fibrillation (AF). However, patients with predictors of failure-chronic long-standing AF, low amplitude fibrillatory waves, and large left atriums-are generally thought not to benefit from a maze procedure. We report an aggressive approach for these patients, utilizing biatrial reduction plasty concomitantly with the Cox maze procedure for AF.

METHODS

A complete Cox maze procedure utilizing supplemental RF ablation was performed in 36 patients. All underwent resection of both atrial appendages and biatrial reduction plasty encompassing resection of the left atrial posterior wall from left to right pulmonary veins and from inferior pulmonary veins to the mitral annulus, as well as removal of the right atrial lateral wall. Mitral or tricuspid valve repair, or both, was performed on 32 patients.

RESULTS

These patients had a mean AF duration of 45 +/- 89 months. Their preoperative left atria measured 66 +/- 16 mm, with mean AF waves of 0.74 +/- 0.3 mm. Mean preoperative New York Heart Association class was 2.7 +/- 0.7 and left ventricular ejection fraction was 48 +/- 9. Cross clamp and bypass times were 91 +/- 35 minutes and 124 +/- 33 minutes, respectively. The average posterior left atrial tissue resected was 5.4 x 2.1 cm, and mean resected atrial weight was 10.3 +/- 2 g. There were no deaths and length of stay was 5.5 +/- 2 days. At a follow-up time of 19 +/- 16 months, 32 of the 36 patients were in normal sinus rhythm and New York Heart Association class I.

CONCLUSIONS

Aggressive biatrial reduction plasty Cox maze procedure was effective in 89% of these "low success" AF patients. This simple procedure can extend utilization of the Cox maze procedure to more patients with chronic AF.

Cox/Maze III operation versus radiofrequency ablation for the surgical treatment of atrial fibrillation: a comparative study

BACKGROUND

The purpose of this study was to evaluate the efficacy of radiofrequency (RF) ablation in the treatment of atrial fibrillation, by comparatively analyzing the outcomes of the patients who underwent RF ablation with those of patients who underwent Cox/Maze III surgery.

METHODS

Between April 1995 and June 2002, 70 patients underwent surgery for atrial fibrillation and open-heart surgery at the Department of Cardiovascular Surgery of the University of Bologna: 30 patients underwent the surgical Cox/Maze III procedure (group 1), and 40 patients underwent the RF ablation according to the Maze III configuration at least on the left atrium (group 2). There were 14 males and 56 females, with a mean age of 61.5 +/- 12.5 years (range 22 to 80 years old).

RESULTS

Groups 1 and 2 did not differ in terms of baseline characteristics. The perioperative mortality rate was not significantly different between the two groups (6.6% in group 1 vs 7.5% in group 2). The overall cumulative rates of sinus rhythm were 68.9% in group 1 and 88.5% in group 2 (not statistically significant). Biatrial contraction was assessed by transthoracic echocardiography in 70.4% of the patients in group 1 and 76.5% of the patients in group 2 (p = 0.65).

CONCLUSIONS

The RF ablation procedure offers as good results as the Cox/Maze III operation, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent open heart surgery; it is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements.

Atrial Contraction After Surgical Isolation of the Left Atrial Posterior Wall Concomitant With Mitral Valve Replacement

BACKGROUND

Surgical isolation of the left atrial posterior wall (LA-PW isolation) can terminate chronic atrial fibrillation associated with mitral valve disease. However, atrial contraction after LA-PW isolation has not been evaluated.

METHODS AND RESULTS

The study group comprised 14 patients (mean age, 63+/-14 years) with mitral valve disease who recovered and maintained regular sinus rhythm after LA-PW isolation. Before the procedure, and 2-3 weeks and 1 year after the LA-PW isolation, the patients underwent an echocardiographic study. The left atrial (LA) diameter decreased after the LA-PW isolation and the change became significant 1 year later (before: 50.1+/-5.1 mm, after 2-3 weeks: 46.0+/-4.9 mm; p<0.05, after 1 year: 44.0+/-6.1 mm; p<0.05 vs before the operation). The left ventricular (LV) end-diastolic diameter, LV ejection fraction and LV fractional shortening did not change significantly from before the LA-PW isolation and after 1 year. The time - velocity integral of the atrial wave (Ai) and atrial filling fraction significantly increased (Ai: 4.5+/-2.1 cm vs 5.8+/-2.3 cm; p<0.05; atrial filling fraction: 15.4+/-7.7% to 19.2+/-8.3%; p<0.05) during the follow-up period.

CONCLUSION

LA-PW isolation can benefit the restoration of regular sinus rhythm and, furthermore, the recovery of atrial contraction.

Surgery for atrial fibrillation using radiofrequency catheter ablation

OBJECTIVE

We present the results obtained in 40 patients with chronic atrial fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation surgery.

METHODS

Between April 2001 and June 2002, 40 patients underwent surgery for atrial fibrillation using radiofrequency ablation and cardiac surgery at the Department of Cardiovascular Surgery of the University of Bologna [corrected]. There were 8 men and 32 women with a mean age of 62 +/- 11.6 years (range: 20 to 80 years).

RESULTS

Concomitant surgical procedures were: mitral valve replacement (n = 13), mitral valve replacement plus tricuspid valvuloplasty (n = 11), combined mitral and aortic valve replacement (n = 8), and combined mitral and aortic valve replacement plus tricuspid valvuloplasty (n = 5). Moreover, 1 patient underwent tricuspid valvuloplasty plus atrial septal defect repair, another required aortic valve replacement plus coronary artery bypass graft, and a third underwent aortic valve replacement. After the mean follow-up time of 16.5 +/- 2.5 months survival was 92.8% and the overall cumulative rate of sinus rhythm was 88.5%.

CONCLUSIONS

We conclude that the radiofrequency ablation procedure is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of our study population).

Beyond Fontan conversion: Surgical therapy of arrhythmias including patients with associated complex congenital heart disease

BACKGROUND

Arrhythmia operations may be extended to patients with failed ablation procedures or associated structural defects requiring surgical intervention. The purpose of this study is to review our experience with arrhythmia operations in 29 patients who did not have Fontan conversions after the introduction of catheter ablation.

METHODS

Between July 1992 and January 2002, 29 patients had operations for refractory atrial (n = 24) or ventricular (n = 5) arrhythmias. Mechanisms of arrhythmia included atrial reentry (n = 11), atrial fibrillation (n = 5), automatic atrial (n = 3), accessory connections (n = 6), atrioventricular nodal reentry (n = 2), and ventricular tachycardia (n = 5). Median age at operation was 12.3 years (range, 6 days to 45 years). Two patients had structurally normal hearts; the remaining 27 patients underwent concomitant repair of structural heart disease, including atrioventricular valve replacement or repair (n = 8), anatomy-specific repair of Ebstein's anomaly (n = 4), tetralogy of Fallot repair or revision (n = 4), atrial septal defect closure (n = 3), ventricular septal defect repair (n = 2), Mustard takedown with arterial switch (n = 2), initial Fontan (n = 2), right ventricle-to-pulmonary artery conduit revision (n = 2), Norwood procedure (n = 1), 1 ventricular repair for Uhl's anomaly (n = 1), Mustard baffle revision (n = 1), pulmonary valve replacement with aneurysm resection (n = 1), and aortic valve replacement with complex repair (n = 1).

RESULTS

No patient developed heart block, and the surgical mortality rate was 7%. One patient died after Mustard takedown and arterial switch operation, and 1 neonate died after repair of severe Ebstein's anomaly. There was one late death after arterial switch conversion at another institution. Recurrent clinical supraventricular tachycardia was present in 2 patients (2 of 27, 7.4%) and 2 patients had new-onset tachycardias with different underlying mechanisms of arrhythmia at late follow-up (median follow-up 47 months).

CONCLUSIONS

Successful surgical therapy of arrhythmias can be performed safely at the time of repair of complex congenital heart disease or in patients with failed catheter ablation procedures. Early consideration for single-stage therapy of arrhythmia and structural heart disease is indicated.

Left atrial maze procedure: a useful addition to other corrective operations

BACKGROUND

The left atrial maze procedure is performed to treat atrial fibrillation (AF), mainly in patients with mitral valve disease. In this study, we assessed the midterm results of this procedure and clinically analyzed predicting factors for postoperative persistent AF.

METHODS

From June 1997 to May 2001, the left atrial maze procedure was performed on 31 patients (29 with mitral valve disease and 2 lone AF). For purposes of analysis, patients were divided postoperatively into those with persistent atrial fibrillation (AF) and those with sinus rhythm (SR), except 2 patients who required pacemaker implantation for sinus node dysfunction. Over a follow-up period of more than 12 months, patients were compared based on their preoperative and intraoperative variables.

RESULTS

At discharge, the success rate was 89.7%. The midterm rates (total of 94.9 patient-years of follow-up) of sinus rhythm and freedom from AF were 72.4% and 79.3%, respectively. There were significant differences in duration of AF, voltage of f-wave at first precordial lead of electrocardiogram, and cardiothoracic ratio between the SR and AF groups.

CONCLUSIONS

Our midterm results suggest that the left atrial maze procedure is an effective alternative adjunct procedure for elective open heart surgery to treat AF, depending upon the patient's clinical condition.

Surgical treatment of arrhythmias related to congenital heart diseases

BACKGROUND

Supraventricular arrhythmias complicate operated and unoperated congenital heart disease, especially when atrial dilatation coexists.

METHODS

We evaluated the results of intraoperative ablation in a group of 23 patients with chronic supraventricular tachyarrhythmias (mostly intraatrial reentry) that were unresponsive to conventional medical therapy. All procedures were performed consecutively between September 1999 and November 2001. Ablation was done during redo operations (Fontan conversion to total cavopulmonary connection in 16 patients) in 18 patients and during primary surgical correction in 5 patients. The mean age at operation was 25 +/- 12 years (2 to 50 years). Cryoablation was done in 10 patients and radiofrequency ablation in 13 patients. Nineteen patients had ablation in one atrium and 4 had ablation in both atria. A generous atrial reduction was always performed at the end of the operation.

RESULTS

The operative mortality rate was 13% (3 patients) from causes unrelated to ablation. In 20 survivors, the ablation was effective immediately. Eight patients required a permanent pacemaker. During a mean follow-up of 22 +/- 4 months, atrial arrhythmias recurred in 25% (5 patients) and were controlled with medical therapy, whereas 1 patient required pacemaker implantation.

CONCLUSIONS

Intraoperative treatment of unresponsive atrial tachyarrhythmias associated with operated or unoperated congenital heart disease is feasible and the midterm results are encouraging.

Specific linear left atrial lesions in atrial fibrillation: intraoperative radiofrequency ablation using minimally invasive surgical techniques

OBJECTIVES

A specific left atrial (LA) linear lesion concept for treatment of paroxysmal and permanent atrial fibrillation (AF) was tested using intraoperative ablation with minimally invasive surgical techniques.

BACKGROUND

Curative treatment for patients with chronic AF is among the main challenges of interventional electrophysiology.

METHODS

Seventy patients (mean age 53 +/- 10 years) with drug-refractory persistent (n = 28) or paroxysmal (n = 42) AF underwent intraoperative radiofrequency (RF) ablation using video-assisted minimally invasive techniques via a right anterolateral minithoracotomy. Contiguous lesion lines involving the mitral annulus and the orifices of the pulmonary veins were placed with RF energy application under direct vision to prevent anatomically defined LA re-entrant circuits.

RESULTS

Mean follow-up was 18 +/- 7 months in patients with permanent AF and 18 +/- 5 months in patients with paroxysmal AF. Antiarrhythmic drug treatment was instituted in patients with postoperative atrial arrhythmias to allow "reverse electrical remodeling" and was discontinued after three months. Six months following ablation, 93% of the patients were in sinus rhythm in both groups, and after 12 months, 95% and 97%, respectively. As major complications, one esophagus perforation and one circumflex coronary artery stenosis were observed.

CONCLUSIONS

A pure linear lesion line concept confined to the left atrium targeting specifically at elimination of anatomically defined LA "anchor" re-entrant circuits eliminated AF in >90% of the patients treated with intraoperative ablation using minimally invasive surgical techniques over a mean follow-up of 1.5 years.

Coexistence of sinus rhythm and segmental atrial fibrillation after maze procedure

We present the case of an 80-year-old man with chronic atrial fibrillation associated with mitral regurgitation. The atrial fibrillation was successfully treated with the maze procedure combined with mitral valve replacement. The electrophysiological data are also reported. Recordings of sinus rhythm and intraatrial activity demonstrated the coexistence of sinus rhythm and fibrillation of both atria. This finding indicates that the sinus node was protected from segmental atrial fibrillation by entrance block, and this, in turn, is evidence of the efficacy of the maze procedure.

Combined atrial fibrillation and mitral valve surgery using microwave technology

Atrial fibrillation is associated with a significant morbidity and mortality and is typically related to patients with mitral valve disease. Microwave ablation is a new option for surgical treatment of chronic atrial fibrillation. We present our experience with surgical treatment of mitral valve disease and microwave ablation in patients with chronic atrial fibrillation. In 105 patients (73 women, 32 men, 68.6 +/- 8 years of age from 45 to 83 years, ejection fraction 28% to 80%, left atrial diameter 56 +/- 9.1 mm from 35 to 97 mm) with mitral valve disease, chronic atrial fibrillation was documented for 8.6 +/- 6.8 years. Microwave ablation was performed using a continuous ablation line starting at the posterior mitral valve annulus and incorporating the interior of all pulmonary veins. In 33 patients, mitral valve reconstruction was performed. Ten patients received biologic valve replacement; 3 of them got a stentless quattro mitral valve prosthesis. Survival rate was 99.1% (n = 104). In the 6-month follow-up, 42 of 69 patients were in sinus rhythm (61%); in the 1-year follow-up, 37 of 64 patients were in sinus rhythm (57.8%). Microwave ablation is a safe and efficient method for surgical treatment of chronic atrial fibrillation in patients with mitral valve disease.

Pulmonary veins: preferred site for catheter ablation of atrial fibrillation

Atrial fibrillation (AF) is one of the most challenging arrhythmias to treat. Many patients have to accept this disorder and the medications required. Nonpharmacologic therapies have emerged as alternative methods of treatment. However, technical difficulty, low success rate, high recurrence, and complications still are obstacles. Pulmonary veins as the most common trigger foci of paroxysmal AF are now the most interesting source of curative ablation. With more knowledge, technologies, techniques, and equipment, AF ablation is likely to be more successful. This article introduces some exciting aspects of pulmonary vein ablation, including our hope to cure AF in some selected patients.