Cox/maze procedure for atrial septal defect with atrial fibrillation: management strategies

Surgical or interventional treatment for adult patients with atrial septal defect and atrial fibrillation: A systemic review and meta-analysis

The prevalence of atrial fibrillation (AFib) in adult patients with atrial septal defect (ASD) who did not undergo ASD repair in the childhood is higher than that in general population. The primary aim of this study is to collect various related articles published in the literature and to compare the clinical outcomes with different treatment strategies by systemic reviews and meta-analyses. Of the 1299 initially screened articles, 13 studies with 213 patients were included in this study. All the patients were adults and the mean age at presentation was 55.7 years (range 34-79 years) and 47.8% of the patients were male. Regarding the types of the AFib, there were paroxysmal AFib in 62 patients, persistent AFib in 40 patients and long-standing persistent AFib in 111 patients. For adult patients with ASD and AFib, ASD closure is beneficial for most of the patients if significant left-to-right shunt exists but risk stratification cannot be overlooked because worsening of the functional class may be experienced by some patients post-operatively, especially for the patients with advanced age (>75 years). Reduction of prevalence of AFib could be observed after ASD closure alone which is mainly effective for paroxysmal AFib but not for persistent or long-standing persistent AFib. The successful ablation rate of paroxysmal AFib by catheter ablation is similar to that of all kinds of AFib by surgical ablation. Regarding AFib recurrence, bi-atrial surgical ablation is better than right-atrial ablation for the adult patients with ASD and AFib.

Prophylactic arrhythmia surgery in association with congenital heart disease

Certain congenital heart anomalies make patients more susceptible to arrhythmia development throughout their lives. This poses the question whether prophylactic arrhythmia surgery should be incorporated into reparative open heart procedures for congenital heart disease. There is currently no consensus on what constitutes a standard prophylactic procedure, owing to the questions that remain regarding lesions to be performed; energy sources to use; proximity of energy source or incisions to coronary arteries, sinoatrial node, atrioventricular node; circumstances for right atrial, left atrial, or biatrial appendectomy; and whether to perform a right, left, or biatrial maze procedure. These considerations are important because prophylactic arrhythmia procedures are performed without knowing if the patient will actually develop an arrhythmia in his or her lifetime. By reviewing and summarizing the literature, congenital heart disease patients who are at risk for developing atrial arrhythmias can be identified and lesion sets can be suggested in an effort to standardize experimental protocols for prophylactic arrhythmia surgery.

Surgical aspects of atrial arrhythmia : Right atrial ablation and anti-arrhythmic surgery in congenital heart disease

BACKGROUND

Atrial arrhythmias are frequently described in congenital heart disease.

OBJECTIVES

To provide a surgical perspective of anti-arrhythmic procedures and strategic approaches.

METHODS

Discussion of the history of anti-arrhythmic treatments in congenital heart disease.

RESULTS

Before the advent of the Maze procedure (first published in 1991), surgery mainly focused on patients with Wolff-Parkinson-White syndrome and also on arrhythmias in Ebstein's malformation. Atrial septal defects (ASD) subsequently received more attention, i.e., in terms of atrial arrhythmia in the natural prognosis and the surgically modified course and in terms of surgical versus transcatheter approaches. Based on the background of various atrial arrhythmia mechanisms of ASD, several surgical procedures have been reported, ranging from the bilateral full Maze procedure to simple modification of right atriotomy. The so-called right atrial Maze procedure occupies a special position from the viewpoint of cardiology in acquired heart disease, especially in cases of frequently occurring right heart failure. In hearts with more complex structural abnormalities, a detailed understanding of the conditions to improve overall surgical outcome and develop future "anti-arrhythmic" strategies is necessary.

CONCLUSIONS

It is important to precisely specify factors in the individual cases, not only morphological diversity but also technical and strategic variations and their consequences. A variety of anti-arrhythmic surgical procedures are currently available. How and when to use which procedure requires professional insight and cautious clinical decision-making.

Surgical correction of atrial septal defect in the elderly

Introduction

Atrial septal defects (ASDs) are one of the most common congenital malformations in adults. Correction of ASDs in advanced age remains controversial, even though beneficial effects in this patient group were found in recent studies. In older patients, less invasive transcatheter closure of ASDs has been recommended.

Aim

The aim of this study was to analyze our advanced age ASD surgical cohort: early and late results.

Material and methods

Retrospective analysis of 32 patients operated on at an age of ≥ 60 years (i.e. age 66.13 ± 4.8, range from 60 to 78) in our center between 2001 and 2011 was carried out. We reviewed our experience of surgical ASD closure in elderly patients over a 10-year period to assess the effects of this type of treatment on early postoperative and long-term survival, early and late complications, preoperative and postoperative clinical status (New York Heart Association [NYHA] functional class), pulmonary hypertension (PH) and atrial arrhythmias. The patients were divided into two groups according to age.

Results

The frequency of comorbidities was lower in younger age group patients (11 [61%] vs. 13 [93%], p < 0.05). Atrial fibrillation/flutter was found in 21 (66%) of all patients. Late postoperative mortality was higher in the older patient group (3 [21%] vs. 1 [5.6%]). Despite this, we observed significant improvement of symptoms and functional ability in the older population after surgical ASD closure (group I, n = 10 [56%] vs. group II, n = 12 [86%]).

Conclusions

Surgical correction of clinically significant ASD is effective even in older patients with comorbidities.

Prophylactic atrial arrhythmia surgical procedures with congenital heart operations: review and recommendations

Specific congenital heart anomalies significantly increase the risk for late atrial arrhythmias, raising the question whether prophylactic arrhythmia operations should be incorporated into reparative open heart procedures. Currently no consensus exists regarding standard prophylactic arrhythmia procedures. Questions remain concerning the arrhythmia-specific lesions to perform, energy sources to use, need for atrial appendectomy, and choosing a right, left, or biatrial Maze procedure. These considerations are important because prophylactic arrhythmia procedures are performed without knowing if the patient will actually experience an arrhythmia. This review identifies congenital defects with a risk for the development of atrial arrhythmias and proposes standardizing lesion sets for prophylactic arrhythmia operations.

Operative techniques in association with arrhythmia surgery in patients with congenital heart disease

Arrhythmia surgery in patients with congenital disease is challenged by the range of anatomic variants, arrhythmia types, and intramyocardial scar location. Experimental and clinical studies have elucidated the mechanisms of arrhythmias for accessory connections, atrial fibrillation, atrial reentry tachycardia, nodal reentry tachycardia, focal or automatic atrial tachycardia, and ventricular tachycardia. The surgical and transcatheter possibilities are numerous, and the congenital heart surgeon should have a comprehensive understanding of all arrhythmia types and potential methods of ablation. The purpose of this article is to introduce resternotomy techniques for safe mediastinal reentry and to review operative techniques of arrhythmia surgery in association with congenital heart disease.

The Management of Atrial Fibrillation in a Patient with Unrepaired Atrial Septal Defect

Atrial fibrillation (AF) is a frequent comorbidity in adults with atrial septal defect (ASD), one of the most common congenital heart defects. However, there are currently limited recommendations for the management of AF associated with ASD. This article describes a case using a planned approach of catheter ablation followed by transcatheter device closure and discusses management options.

Mid- to Long-term Results of Surgical Treatment of ASD in Patients over 60 Years Old

BACKGROUND

There is controversy about the benefit of surgical correction of an atrial septal defect (ASD) in patients over 60 years old. The purpose of this study was to determine whether surgical treatment is beneficial in those 60 years of age or older.

MATERIALS AND METHODS

We reviewed the clinical course of 57 patients (mean age: 63.54±5.59 years) diagnosed with an isolated secundum ASD after the age of 60. The 24 patients (group A) who underwent surgical repair were compared with the 33 patients (group B) who were treated non-surgically. The mean follow-up period was 6.8±4.5 years.

RESULTS

One operative death, 5 late deaths (20.8%) in group A, and 9 deaths (27.3%) in group B occurred in the study period. Symptomatic improvement was noted in 18 patients (75%) of group A after surgery. However 13 patients (39.4%) of group B showed symptomatic improvement during the follow-up period (p=0.012). The incidence of new atrial arrhythmia of the two groups was significantly different (16.7% vs 36.7%, p=0.038). The actuarial 10 year survival rate was 79% in group A and 73% in group B.

CONCLUSION

Although surgical correction of ASD did not increase survival in patients over 60 years old, the surgical outcomes of ASD showed low operative mortality and resulted in symptomatic improvement in the majority of these patients. This study has shown the benefits of surgical closure of ASD even in advanced age in comparison to medical treatment.

Atrial Septal Defect and Atrial Fibrillation: The Known and Unknown

Atrial fibrillation (AF) is a common complication in patients with atrial septal defects (ASDs). The link between AF and ASD is fairly complex and entails modifications in electrophysiologic, contractile and structural properties, at the cellular and tissue level, of both atria, mainly due to chronic atrial stretch and dilation. Surgical repair or percutaneous closure of ASDs are equally effective in reducing mortality and symptoms but limited in preventing or curbing AF, unless combined with an arrhythmia-specific procedure. Transesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) have improved the safety and success of the above procedures. Finally, clearer understanding of the pathophysiology of AF in patients with ASD (and CHF, in general) has led to target-specific advances in medical management.

Combined Atrial Septal Defect Surgical Closure and Irrigated Radiofrequency Ablation in Adult Patients

BACKGROUND

Atrial arrhythmias are relatively common among patients over 40 years old with atrial septal defect (ASD) and are a precipitating cause of heart failure. Surgical closure of the ASD in these patients is feasible and is associated with a low mortality rate and a beneficial effect on the clinical status; however the occurrence of atrial arrhythmia does not decrease after surgery. We present the results of our preliminary experience with surgical ASD closure combined with intraoperative irrigated radiofrequency (IRF) ablation in adult patients.

METHODS

During a 26-month period between September 2002 and December 2004, 15 patients more than 40 years old with ASD and atrial arrhythmia underwent elective surgical closure of the defect and intraoperative IRF ablation. All patients had supraventricular arrhythmias: 8 had permanent atrial fibrillation, whereas 7 had previous episodes of atrial flutter or intra-atrial reentry tachycardia. The biatrial approach (Cox-Maze III procedure) was used in 7 patients and a right-sided Maze procedure (ablation lines on the right atrium only) was carried out in the remaining 8 patients.

RESULTS

All patients survived the procedure. Fourteen patients left the operating room in sinus rhythm and 1 had a pacemaker implanted. There were no complications resulting from the IRF ablation. All 15 patients survived over the average follow-up period of 24 months. Thirteen patients were still in sinus rhythm, 1 had pacemaker rhythm, and only 1 (1 of 15; 6.5%) suffered a recurrence of atrial fibrillation 3 months after the procedure.

CONCLUSIONS

We suggest adding intraoperative IRF ablation during surgical closure of an ASD in all adult ASD patients with arrhythmias. The IRF ablation is easy to perform, safe, and effective.

Surgery for arrhythmias in children

BACKGROUND

Transcatheter radiofrequency ablation to treat supraventricular and ventricular arrhythmias has supplanted routine surgical ablative therapy and redefined its role. A small population of arrhythmia patients now requires surgical ablation: those who have failed catheter ablation, patients with concomitant congenital heart disease in association with arrhythmias, those with atrial fibrillation and very young patients for whom transcatheter techniques are prohibitive because of small size, cyanosis or distorted anatomy.

METHODS

From July 1992 through August 2003, 133 patients underwent arrhythmia surgery at Children's Memorial Hospital, 50% (67/133) in association with Fontan conversion (FC), 22% (28/133) with concomitant initial Fontan (IF) procedure and 28% (38/133) for various arrhythmias (MISC) in patients with (36/38, 95%) or without (2/38, 5%) associated structural heart disease. Mean age at surgery in the FC group was 20+/-7.6 years (median 19 years), and in the IF group and the MISC group, mean ages were 8.1+/-8.9 (median 4.2) years and 16.4+/-10.9 (median 11.3) years, respectively.

RESULTS

There were three operative (3/133, 2.6%; 1 FC, 2 MISC) and three late deaths (2 FC, 1 MISC). Four patients in the FC group had progressive ventricular failure and underwent successful cardiac transplantation. Follow-up data are available for non-transplant, surviving patients and reveal 11 incidences of persistent arrhythmia recurrence and 2 new-onset arrhythmias. Five of the 11 recurrences occurred early in our series of FC patients, when isthmus block interruption of arrhythmia foci was performed. Four additional recurrences occurred later in the FC series, two post-maze and two post-Cox-maze III. In the MISC group, there were two recurrences. Atrial reentry tachycardia (ART) recurred in a patient with no structural heart disease and accessory connection-mediated tachycardia recurred in a child who underwent concomitant initial Fontan. Two patients had ventricular tachycardia inducible at postoperative studies (2/7, 29%), but no clinical recurrence. Two new-onset tachycardias occurred, one child developed ART post-surgical ablation of accessory connections and one patient with inducible ventricular tachycardia developed ART 5 years postoperatively.

CONCLUSION

Variations in atrial and ventricular anatomy that may limit the catheter approach can be addressed surgically. Patient size or anatomic complexity should not be limiting factors in the combined surgical arrhythmia approach. Incorporation of arrhythmia therapy into planned surgical revision should be considered.

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.

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).

Effectiveness of percutaneous device occlusion for atrial septal defect in adult patients with pulmonary hypertension

BACKGROUND

Adult patients with atrial septal defect (ASD) and pulmonary hypertension have a more advanced degree of disease, frequently having functional class deterioration and atrial arrhythmias when they are aged >40 years. Surgery at this age prolongs life expectancy and limits functional deterioration. Although percutaneous ASD device occlusion is an accepted alternative to surgery, there is limited information on the immediate and long-term effects of device occlusion in middle-aged and elderly patients with ASD and pulmonary hypertension.

METHODS

From a total of 101 patients with secundum ASD who were receiving treatment with percutaneous device occlusion, we selected for analysis 29 adult patients (mean age 56 +/- 14 years) with a baseline peak pulmonary pressure of >40 mm Hg (mean 65 +/- 23 mm Hg). Three of the patients had suprasystemic pulmonary pressure and a bidirectional shunt. Six patients were asymptomatic at treatment. The remaining 23 had different degrees of dyspnea; 14 of them had an advanced New York Heart Association functional class (III-IV). Twelve patients had chronic atrial fibrillation. At cardiac catheterization, the mean ratio of pulmonary to systemic flow was 1.8 +/- 0.5, and the pulmonary-to-systemic pressure ratio was 0.66 +/- 0.22. The mean diameter of the defect, as evaluated by the stretching balloon method, was 26 +/- 7 mm. All patients received an Amplatzer septal occluder (Golden Valley, Minn). Seven patients had combined therapeutic procedures for associated anomalies before the implant: mitral balloon valvuloplasty (n = 1), stent coronary revascularization (n = 1), stent in pulmonary vein stenosis (n = 1), and internal catheter defibrillation (n = 4). After treatment, patients were followed up by clinical and echocardiographic Doppler studies every 6 months.

RESULTS

Immediately after the implantation, the peak systolic pulmonary pressure significantly decreased to 54 +/- 21 mm Hg (P <.001). A clear improvement in functional status was observed after the treatment in all symptomatic patients, especially in those with refractory heart failure. There were no major complications. Six patients who had atrial fibrillation at baseline study recovered to a stable sinus rhythm after treatment, and it was maintained at discharge. Complete ASD occlusion by echocardiographic Doppler at discharge was observed in 28 patients (97%). After a mean follow up of 21 +/- 14 months, clinical improvement persisted in all previously symptomatic patients, and the peak systolic pulmonary pressure, obtained by echocardiographic Doppler, further decreased to 31 +/- 11 mm Hg (P <.001) compared with baseline and immediately after hemodynamic measurements.

CONCLUSIONS

Our findings suggest that percutaneous device occlusion of ASD in adult patients with pulmonary hypertension is safe and effective and provides significant and prolonged relief.

Predisposing conditions for atrial fibrillation in atrial septal defect with and without operative closure

The aims of this study were to determine the prevalence and predisposing conditions for atrial fibrillation (AF) in adults with atrial septal defect (ASD) and to evaluate the influence of age at surgical repair. The study population consisted of 286 adults with ASD (mean age 39.5 +/- 19 years). All patients had >or = 1 follow-up visit and a Doppler echocardiographic study. One hundred ninety-two of the patients underwent surgical closure 1 to 34 years before the study. Analyzed variables were entered into univariate (Mann-Whitney U) and multivariate (stepwise logistic regression) models to assess independent predictors for AF. The prevalence of AF was similar in surgically treated patients (15.6%) and in the nonsurgical group (13.8%) (p = 0.69). Multivariate analysis showed that current age (RR 1.9 per each decade of age, 95% confidence interval [CI] 1.3 to 2.7, p = 0.001), mitral regurgitation (RR 3.0 per each degree of regurgitation, 95% CI 1.6 to 5.8, p = 0.001), left atrial enlargement (RR 2.8 per each 10 mm increase in size, 95% CI 1.5 to 5.2, p = 0.001), and tricuspid regurgitation (RR 1.9 per each degree of regurgitation, 95% CI 1.0 to 3.7, p = 0.04) were independent predictors of AF; however, gender, anatomic type, defect size, Qp:Qs, pulmonary artery pressure, right ventricular dimension, left ventricular shortening fraction, and prior surgical repair were not related to late AF development. In the surgical group, age >25 years at the time of surgery was the only predictor for AF independent of age at the time of the study (p = 0.02).

The surgical management of atrial fibrillation

Atrial fibrillation is the most common dysrhythmia encountered in clinical practice. For some patients, satisfactory rate control is not possible by pharmacologic means. This led us to develop a surgical approach to its cure, which in turn has led to a deeper understanding of the electrophysiologic basis of atrial fibrillation and to the development of a surgical procedure that is highly effective in restoring sinus rhythm with an acceptable mortality and morbidity. We review these findings as well as the clinical results obtained with the Maze procedure.

Survival and sinus rhythm maintenance after modified Cox/maze procedure and mitral valve operation in patients with chronic atrial fibrillation

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 follow-up.

Cox-Maze procedure for treatment of atrial flutter associated with an 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.

Medium-term results after the modified Cox/Maze procedure combined with other cardiac surgery

OBJECTIVE

Long-term results after the modified Cox/Maze III procedure combined with other cardiac procedure for the treatment of organic heart disease and chronic atrial fibrillation (AF) has not been clarified. This report describes our medium-term results after such operation.

METHODS

Between March 1993 and August 1995, 104 consecutive patients with chronic AF underwent the modified Cox/Maze III procedure combined with other cardiac procedure. There were 100 long-term survivors. There were 45 men and 55 women, with ages ranging from 21 to 77 years (mean 59.7). Patients were followed up and changes in rhythm, need for pacemaker implantation, and the incidence of CNS (central nervous system) complications were retrospectively studied.

RESULTS

The follow-up was complete in 103 patients and 99 long-term survivors (99%). The mean follow-up period was 44.6 +/- 1.1 months. In the immediate postoperative period, 73 patients regained sinus rhythm (SR group), 21 patients were in AF (AF group), and six patients underwent pacemaker implantation because of sick sinus syndrome (SSS). During the follow-up period, eight patients died. One- and 5-year survival rates (Kaplan-Meier) after surgery was 95.1 +/- 2.3 and 87.8 +/- 3.4% for the entire group. Preoperative NYHA class was 2.5 +/- 0.7 and medium-term NYHA class was 1.5 +/- 0.5. (P < 0.001) Changes in rhythm for the SR group were followed. Fifty-two patients of the SR group stayed in SR (72%), 16 patients converted back to AF (22%), and four patients had newly-developed SSS (6%) at follow-up period. Probability in SR maintenance for SR group at 1 year was 88.8 +/- 3.7% and at 5 years was 64.8 +/- 7.5%. Five patients experienced the CNS complication during the follow-up period. Two of the AF group and two of the SR group patients developed cerebral/cerebellar infarction. One of the SR group patients experienced small cerebral bleeding.

CONCLUSIONS

The medium-term results after the modified Cox/Maze III procedure concomitant with other cardiac procedure are good with improved functional status and good survival rate. However, there seems to be gradual but constant attrition in the rate of SR maintenance in SR group.

Left atrial tachycardia after right atrial separation for chronic atrial fibrillation with atrial septal defects

A right atrial separation procedure was performed for the ablation of chronic atrial fibrillation in four cases, concomitant with the repair of the atrial septal defect. After the operation, chronic atrial fibrillation disappeared in three of them and left atrial tachycardia occurred in the other one. Left atrial tachycardia is an arrhythmia encountered after a right atrial separation procedure.

Atrial arrhythmia after surgical closure of atrial septal defects in adults

BACKGROUND

Atrial flutter and atrial fibrillation are causes of morbidity in adults with an atrial septal defect. In this study, we attempted to identify risk factors for atrial flutter and fibrillation both before and after the surgical closure of an atrial septal defect.

METHODS

We searched for preoperative and postoperative atrial flutter or fibrillation in 213 adult patients (82 men and 131 women) who underwent surgical closure of atrial septal defects because of symptoms, a substantial left-to-right shunt (ratio of pulmonary to systemic blood flow, >1.5:1), or both at Toronto Hospital between 1986 and 1997.

RESULTS

Forty patients (19 percent) had sustained atrial flutter or fibrillation before surgery. As compared with the patients who did not have atrial flutter or fibrillation before surgery, those who did were older (59+/-11 vs. 37+/-13 years, P<0.001) and had higher mean pulmonary arterial pressures (25.0+/-9.7 vs. 19.7+/-8.2 mm Hg, P=0.001). There were no perioperative deaths. After a mean follow-up period of 3.8+/-2.5 years, 24 of the 40 patients (60 percent) continued to have atrial flutter or fibrillation. The mean age of these patients was greater than that of the 16 who converted to sinus rhythm (P=0.02). New-onset atrial flutter or atrial fibrillation was more likely to have developed at follow-up in patients who were older than 40 years at the time of surgery than in those who were 40 or younger (5 of 67 vs. 0 of 106, P=0.008). Late events (those occurring more than one month after surgery) included stroke in six patients (all but one with atrial flutter or fibrillation, one of whom died) and death from noncardiac causes in two patients. Multivariate analysis showed that older age (>40 years) at the time of surgery (P=0.001), the presence of preoperative atrial flutter or fibrillation (P<0.001), and the presence of postoperative atrial flutter or fibrillation or junctional rhythm (P=0.02) were predictive of late postoperative atrial flutter or fibrillation.

CONCLUSIONS

The risk of atrial flutter or atrial fibrillation in adults with atrial septal defects is related to the age at the time of surgical repair and the pulmonary arterial pressure. To reduce the morbidity associated with atrial flutter and fibrillation, the timely closure of atrial septal defects is warranted.

Operative results after the Cox/maze procedure combined with a mitral valve operation

BACKGROUND

There have been few reports on postoperative morbidity and mortality analyses after concomitant mitral valve operation and the Cox/maze procedure.

METHODS

Between April 1993 and August 1995, 87 consecutive patients with chronic atrial fibrillation underwent a mitral valve operation and concomitant Cox/maze procedure at Iwate Medical University. The patients were divided into the replacement group (n = 31) and repair group (n = 56) according to the method of mitral valve replacement. Our initial experience with the combined operative procedures is presented along with the operative mortality and morbidity rates. Univariate analysis on preoperative and intraoperative variables affecting early mortality and morbidity is carried out retrospectively.

RESULTS

Total cardiopulmonary bypass time in all patients was 177.2 +/- 70.1 minutes. Total aortic cross-clamp time was 121.7 +/- 30.8 minutes. Total intensive care unit stay was 5.3 +/- 7.9 days. The average intubation period was 55.5 +/- 187.6 hours. The intensive care unit stay and the intubation period of the replacement group were longer than those of the repair group. There were four operative deaths among the 87 patients (4.6%). All repair group patients survived operation, whereas 4 replacement group patients died after operation. In all patients, the New York Heart Association functional class was higher (p = 0.028) in those who died than in those who survived. The overall restoration rate from atrial fibrillation was 79.5% (66 of 83 survivors). Seventeen patients (20.5%) had persistent atrial fibrillation postoperatively. Sick sinus syndrome occurred in 7 patients (8.4%). In the repair group, the restoration rate was 76.8%, whereas in the replacement group it was 85.2% for the survivors.

CONCLUSIONS

The Cox/maze procedure can be combined with a mitral valve operation with acceptably low operative risk. Analysis of risk factors of early mortality revealed that the type of mitral valve operation (replacement versus repair) and higher preoperative New York Heart Association functional class were associated with mortality. Long-term results from this combined procedure should be clearly demonstrated before its universal acceptance.

Right atrial isolation for atrial fibrillation associated with atrial septal defect

Two patients with atrial fibrillation associated with an atrial septal defect underwent simultaneous surgical correction of the atrial septal defect and right atrial isolation. The right atrium was surgically isolated while the continuity with the sinoatrial node was preserved in the remainder of the heart. After the operation, the patients maintained normal sinus rhythm for 99 and 65 months. Thus, right atrial isolation offers an alternative to the current surgical treatment for atrial fibrillation associated with an atrial septal defect.

The role of electrolyte in lesion size using an irrigated radiofrequency electrode

Multiple attempts have been made to eliminate atrial fibrillation by performing the surgical maze procedure with radiofrequency energy. Currently, this is limited because of the risk of atrial perforation and the lack of transmural penetration. Saline irrigation has been investigated as a method of radiofrequency cautery tip cooling to prevent rapid temperature and impedance rises, which have been shown to lead to perforation or decreased radiofrequency penetration after eschar formation. There are few data on the influence that different types of electrolyte irrigation solutions have on lesion depth. Using a novel hollow cautery pen, we infused either an electrolyte solution (0.9%, 3%, 14.6%, or 23.4% sodium chloride), a nonelectrolyte solution (1.5% glycine), or no irrigation to produce 819 lesions on 14 left ventricles in swine using radiofrequency energy (450+/-10 kHz) applied at two output settings (20 and 75 watts). The nonelectrolyte solution increased lesion depth compared with no infusion at 20 watts but produced shallower lesion depths compared with electrolyte solutions at 75 watts. Compared with the other electrolyte solutions, the 0.9% sodium chloride solution produced the deepest lesions (3.34+/-0.06 mm) at 75 watts (p < 0.001). As the concentration of electrolyte increased, lesion depth decreased unless generator output increased. Formation of eschar and tissue destruction was seen in the noninfusion and nonelectrolyte groups but not in the electrolyte group. A conductive media coupled with radiofrequency energy allowed for greater lesion depth than irrigated cooling with a nonelectrolyte solution or no irrigation. There was an inverse relationship between electrolyte concentration and lesion depth. We conclude that the concentration of electrolyte irrigant is an important consideration when choosing a solution to improve transmural penetration and decrease the risk of tissue destruction from radiofrequency energy.

The maze procedure for cure of atrial fibrillation

Atrial fibrillation is the most common dysrhythmia encountered in clinical practice. A significant number of patients fail medical therapy because of inability to convert or control the rhythm pharmacologically, intolerance of the requisite medication, or persistent symptoms despite apparently satisfactory rate control. Based on experimental studies establishing the electrophysiologic basis of atrial fibrillation, a surgical procedure has been developed that is highly effective in restoring sinus rhythm without further requirement for medications. The evolution of this procedure, its current indications, and results are outlined.

Right atrial separation for chronic atrial fibrillation with atrial septal defects

A right atrial separation procedure was performed for the ablation of atrial fibrillation during the concomitant repair of an atrial septal defect. This procedure consisted of a Y-shaped incision in the right atrium, followed by cryoablation of the tricuspid annulus and the atrial septum without any procedures performed on the left atrium. This is a simple and effective method for the elimination of chronic atrial fibrillation associated with atrial septal defects in adults.

Predictors of sinus rhythm restoration after Cox maze procedure concomitant with other cardiac operations

BACKGROUND

There have been sporadic cases of persistent atrial fibrillation and sick sinus syndrome after the maze procedure. The purpose of this study was to identify the predictors of sinus rhythm restoration after operation.

METHODS

Between March 1993 and June 1995, we evaluated retrospectively 96 consecutive patients who underwent the maze procedure (maze III) in combination with another type of cardiac operation. Four patients who died and 6 patients who required permanent pacemaker implantation because of sick sinus syndrome were excluded. Ambulatory electrocardiographic monitoring was evaluated 1 year after operation. Multiple logistic regression analysis was applied to identify the predictors of sinus rhythm restoration.

RESULTS

The final population comprised 86 patients (mean age, 59.8 years; 67 patients with mitral valve disease). Overall, sinus rhythm was restored in 68 of 86 patients (79.1%). The magnitude of the atrial fibrillatory wave positively predicted postoperative sinus rhythm restoration. Conversely, left atrial diameter was inversely related to postoperative sinus rhythm restoration. The odds ratio of having both a fine atrial fibrillatory wave (< 1.0 mm) and enlarged left atrial diameter (> or = 65 mm) for patients with sinus rhythm restoration was 0.04 (95% confidence interval, 0.01 to 0.28).

CONCLUSIONS

Atrial fibrillatory wave and left atrial diameter were independent predictors of sinus rhythm restoration after the maze procedure in patients with chronic atrial fibrillation and organic heart disease.

Simultaneous surgical correction of a common atrium and impure flutter

We performed surgical correction and treatment of a common atrium and chronic impure flutter using a computerized mapping system in a 49-year-old man. A reentrant circuit was observed to exist around the left atrial appendage. In contrast to the regular activation in the left atrium, the activation sequence of the right atrium was extremely chaotic. Cryolesions were applied to the area of the reentrant pathway. After the operation, sinus rhythm was restored.

Right atrial separation procedure for eliminating chronic atrial fibrillation associated with atrial septal defect

Chronic atrial fibrillation (AF) had been documented in a patient with atrial septal defect for 7 years. A right atrial separation procedure was performed for ablation of chronic AF, concomitant with repair of the atrial septal defect, and followed by atrial electrophysiological mapping. A horizontal transectional incision extending to the borders of the atrial septum and the tricuspid annulus was made. Cryolesions of the atrial isthmus between the margin of the upper incision and the tricuspid valve annulus were created at -60 degrees C for 2 minutes at a time. After the operation, the patient had restored normal sinus rhythm during a subsequent follow-up period of 48 months.

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery

OBJECTIVE

To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated.

PATIENTS AND METHODS

Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram.

RESULTS

Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01).

CONCLUSIONS

The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Simple left atrial procedure for chronic atrial fibrillation associated with mitral valve disease

BACKGROUND

A computerized 48-channel mapping system was used to investigate the characteristics of an atrial epicardial electrogram during chronic atrial fibrillation (AF) in patients with solitary mitral valve disease. We have devised a simple left atrial procedure to eliminate the chronic AF during a mitral valve operation.

METHODS

Using this mapping system, we performed intraoperative atrial mapping in 11 patients with chronic AF associated with mitral valve disease. The AF duration ranged from 0.4 to 15 years (mean, 8.0 +/- 4.5 years). A simple surgical ablation of the AF on the left atrium only was performed during the mitral valve operations.

RESULTS

The mean AF cycle length of the atria ranged from 129 to 169 milliseconds in the right atrium and from 114 to 139 milliseconds in the left atrium. The mean AF cycle length of the left atrium was shorter than that of the right atrium. Regular and repetitive activation was found in the left atria of 7 of 11 patients. The AF disappeared in all patients immediately after the operation, and 10 of these patients continued to have a sinus rhythm postoperatively (AF-free rate, 91%).

CONCLUSIONS

Computerized intraoperative mapping revealed a shorter mean AF cycle length in the left atrium. A simple left atrial procedure was effective in eliminating chronic AF associated with solitary mitral valve disease.

Concomitant mitral valve or atrial septal defect surgery and the modified Cox-maze procedure

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 patient 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.

Atrial compartment surgery for chronic atrial fibrillation associated with congenital heart defects

In three adult patients, two with atrial septal defect and one with Ebstein's anomaly, chronic atrial fibrillation was documented for 13, 21, and 3 years, respectively. Atrial compartment surgery was performed for ablation of the atrial fibrillation concomitant with repair of the cardiac defects. The operation was performed with traditional cardiopulmonary bypass and crystalloid cardioplegia myocardial protection. A U-shaped incision was made in the right atrium: a longitudinal incision 1 cm lateral and parallel to the sulcus terminalis, extending along the borders of the atrial septum to 3 cm (upper margin) and 1 cm (lower margin) distant to the tricuspid anulus. Cryolesions of the atrial isthmus between the upper incision margin and the tricuspid valve anulus were created at -60 degrees C for 180 seconds at a time. After the operation, all three patients had restored and maintained normal sinus rhythm during follow-up periods of 32, 16, and 3 months. Doppler echocardiography detected the recovery of atrial contractility in all three patients. Atrial compartment surgery is a simple and effective method for elimination of chronic atrial fibrillation associated with congenital heart defects.

Atrial activation during chronic atrial fibrillation in patients with isolated mitral valve disease

BACKGROUND

A computerized 32-channel mapping system has been developed to investigate the characteristics of the atrial activation sequence. The system is capable of displaying sequential atrial maps and provides a rapid and dynamic means of verifying the activation sequence of atrial fibrillation.

METHODS

Using this system, we performed intraoperative atrial activation mapping in 10 patients with chronic atrial fibrillation who were undergoing isolated mitral valve operations.

RESULTS

Regular and repetitive activation (cycle length ranged from 131 to 228 milliseconds) originated in the left atrium in all 10 patients. Two patterns of repetitive activation in 2 patients and three patterns in 1 patient appeared alternately during the observation period in the left atrium. In contrast to the repetitive activation in the left atrium, the activation sequence of the right atrium was extremely complex and chaotic. In 7 of the 10 patients, the same pattern of right atrial activation was never repeated during the observation period. In 2 patients, revolution of repetitive activation in the right atrium sporadically appeared, but the pattern of activation immediately deteriorated to a complex and chaotic pattern. In 1 patient, repetitive activation emerged from the low lateral portion of the right atrium. Because our mapping technique was limited by the number of available atrial electrodes, discrete reentrant circuits or ectopic foci could not be demonstrated in the present study. However, the activation sequences during chronic atrial fibrillation suggested that (1) the left atrium would act as an electrical driving chamber for atrial fibrillation in the majority of the patients and (2) atrial activation patterns are different in each case.

CONCLUSIONS

Computerized intraoperative mapping should guide surgeons in determining the appropriate surgical procedure and facilitate operation for chronic atrial fibrillation associated with mitral valve disease.

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

BACKGROUND

Persistent atrial fibrillation (AF) leaves patients symptomatic and at increased risk of thromboembolism even after otherwise successful cardiac surgery.

METHODS AND RESULTS

To treat AF secondary to cardiac lesions requiring surgery, we combined a modified maze procedure in 101 patients simultaneously undergoing valvular procedures (87), repair of congenital anomalies (12), and other procedures (2), including 24 repeat operations. Duration of AF varied from 0.1 to 30 years (average +/- SD, 8.8 +/- 7.0 years); the f-wave voltage ranged from 0 to 0.45 mV (0.15 +/- 0.09 mV); and cardiothoracic ratio varied from 40% to 99% (63 +/- 9%). Aortic cross-clamp time varied from 75 to 229 minutes (138 +/- 31 minutes), with bypass time ranging from 119 to 326 minutes (217 +/- 42 minutes). There were two early deaths (2%), no late deaths, and one episode of transient neurological ischemic attack in follow-up ranging from 1.0 to 3.1 years, for a total of 190 patient-years. Postoperative rhythms were sinus in 83 patients (82%), junctional in 4 (4%), and persistent AF in 14 (14%), each of whom had mitral valve disease. Patients with other underlying pathology had complete recovery of atrial rhythm. A normal-sized A wave was detected in 88% for transtricuspid flow and in 73% for transmitral flow, suggesting concomitant recovery of atrial contraction. Among 36 patients without mechanical valves, 30 (83%) with atrial rhythm and contraction have been taken off anticoagulation therapy, including 10 who are free of all medication.

CONCLUSIONS

The results suggest that the combined approach is safe, effective, and indicated in patients who are judged capable of tolerating the procedure and likely to regain atrial rhythm.

Modification of the maze procedure for atrial flutter and atrial fibrillation. I. Rationale and surgical results

The original maze procedure that was described for the treatment of patients with atrial fibrillation was followed by an unacceptable incidence of two problems: (1) the frequent inability to generate an appropriate sinus tachycardia in response to maximal exercise and (2) occasional left atrial dysfunction. In an effort to overcome these problems, we modified the original technique (maze I) twice. The results of these modifications culminated in the maze III procedure, which is associated with a higher incidence of postoperative sinus rhythm, improved long-term sinus node function, fewer pacemaker requirements, less arrhythmia recurrence, and improved long-term atrial transport function. In addition, the maze III procedure is technically less demanding than either the maze I or maze II procedure. Therefore, the maze III procedure is now the technique of choice for the management of medically refractory atrial fibrillation.

From fisherman to fibrillation: an unbroken line of progress

The modern era of cardiac arrhythmia surgery was initiated by Dr Will C. Sealy in May 1968, when he performed the first successful surgical division of an accessory pathway for the treatment of the Wolff-Parkinson-White syndrome. During the subsequent 25 years, arrhythmia operations evolved through a series of innovative surgical procedures capable of curing essentially all refractory clinical arrhythmias. The lessons learned during the development of these surgical procedures ultimately led to the refinement and eventual success of less invasive catheter techniques that have now replaced most of these surgical techniques. The surgical experience gained during these years also made possible the current surgical procedure that is used to treat the most complex, and the most common, of all cardiac arrhythmias, atrial fibrillation. Few areas of any specialty are as clearly defined as the unbroken line of progress that extends from Dr Sealy's first procedure in 1968 to the successful surgical treatment of atrial fibrillation in 1994.