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

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.

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.

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 Ablation of Atrial Fibrillation

The Cox-maze procedure for the restoration of normal sinus rhythm, initially developed by Dr. James Cox, underwent several iterations over the years. The main concept consists of creating a series of transmural lesions in the right and left atria that disrupt re-entrant circuits responsible for propagating the abnormal atrial fibrillation rhythm. The left atrial appendage is excluded as a component of the Maze procedure. For the first three iterations of the Cox- maze procedure, these lesions were performed using a surgical cut-and-sew approach that ensured transmurality. The Cox-Maze IV is the most currently accepted iteration. It achieves the same lesion set of the Cox- maze III but uses alternative energy sources to create the transmural lesions, potentially in a minimally invasive approach on the beating heart. High-frequency ultrasound, microwave, and laser energy have all been used with varying success in the past. Today, bipolar radiofrequency heat or cryotherapy cooling are the most accepted sources for creating linear lesions with consistent safety and transmurality. The robust and reliable nature of these energy delivery methods has yielded a success rate reaching 90% freedom from atrial fibrillation at 12 months. Such approaches offer a significant long-term advantage over catheter-based ablation, especially in patients having longstanding, persistent atrial fibrillation with characteristics such as dilated left atrial dimensions, poor ejection fraction, and failed catheter ablation. Based on these improved results, there currently is significant interest in developing a hybrid ablation strategy that incorporates the superior transmural robust lesions of surgical ablation, the reliable stroke prevention potential of epicardial left atrial appendage exclusion, and sophisticated mapping and confirmatory catheter-based ablation technology. Such a minimally invasive hybrid strategy for ablation may lead to the development of multidisciplinary "Afib teams" to obtain optimal long-term sinus rhythm control. This article provides an overview of current surgical strategies for patients with atrial fibrillation and addresses the two main goals in its management.

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.

Surgical Treatment of Concomitant Atrial Fibrillation: Focus onto Atrial Contractility

BACKGROUND

Maze procedure aims at restoring sinus rhythm (SR) and atrial contractility (AC). This study evaluated multiple aspects of AC recovery and their relationship with SR regain after ablation.

METHODS

122 mitral and fibrillating patients underwent radiofrequency Maze. Rhythm check and echocardiographic control of biatrial contractility were performed at 3, 6, 12, and 24 months postoperatively. A multivariate Cox analysis of risk factors for absence of AC recuperation was applied.

RESULTS

At 2-years follow-up, SR was achieved in 79% of patients. SR-AC coexistence increased from 76% until 98%, while biatrial contraction detection augmented from 84 to 98% at late stage. Shorter preoperative arrhythmia duration was the only common predictor of SR-AC restoring, while pulmonary artery pressure (PAP) negatively influenced AC recuperation. Early AC restoration favored future freedom from arrhythmia recurrence. Minor LA dimensions correlated with improved future A/E value and vice versa. Right atrial (RA) contractility restoring favored better left ventricular (LV) performance and volumes.

CONCLUSIONS

SR and left AC are two interrelated Maze objectives. Factors associated with arrhythmia "chronic state" (PAP and arrhythmia duration) are negative predictors of procedural success. Our results suggest an association between postoperative LA dimensions and "kick" restoring and an influence of RA contraction onto LV function.

Surgical options in atrial fibrillation

Atrial fibrillation (AF) is not benign and its prevalence is increasing. The two main goals in management of atrial fibrillation are to optimize hemodynamics through rate or rhythm control and to prevent systemic thrombo-embolism. To date, these two goals are still sub-optimally achieved, raising the need for alternative methods and strategies both pharmacologically and through interventions. In this review, we discuss surgical strategies of achieving both goals with insights on the evolution and potential future of these strategies.

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.

Transseptal access and atrial fibrillation ablation guided by intracardiac echocardiography in patients with atrial septal closure devices

BACKGROUND

Percutaneous positioning of closure devices is a well-established treatment of atrial septal defects (ASDs). However, patients who have undergone the procedure are at increased risk for developing atrial fibrillation (AF), and treatment by catheter ablation is underutilized due to the perceived difficulty of obtaining transseptal access in the presence of the closure device.

OBJECTIVE

The purpose of this study was to report the acute and long-term results of radiofrequency catheter ablation of AF in patients with ASD closure devices.

METHODS

Thirty-nine patients (age 54 ± 6 years, 72% males) with drug-refractory AF (33% paroxysmal, 51% persistent, 16% long-standing persistent) and ASD closure devices (82% Amplatzer, 18% CardioSEAL) underwent radiofrequency catheter ablation. A double transseptal access guided by intracardiac echocardiography was obtained in all patients.

RESULTS

In 35 of 39 patients (90%), the transseptal access was obtained in a portion of the native septum, whereas in 4 of 39 patients (10%), a direct access through the device was required. The latter group had a significantly longer time for achieving the double transseptal access (73.6 ± 1.1 minutes vs. 4.3 ± 0.4 minutes, P < .001), longer fluoroscopy time (122 ± 5 minutes vs. 80 ± 8 minutes, P < .001), and total procedural time (4.1 ± 0.2 hours vs. 3.1 ± 0.3 hours, P < .001). At follow-up of 14 ± 4, months the overall success rate was 77% (85% in paroxysmal AF, 73% in nonparoxysmal AF). Transthoracic contrast-enhanced echocardiography with the Valsalva maneuver, performed between 3 and 6 months after the procedure, failed to detect shunt in all patients.

CONCLUSION

Radiofrequency catheter ablation of AF is feasible, safe, and effective in patients with ASD closure devices. Transseptal access can be obtained in portions of the native septum in the majority of cases. Direct transseptal puncture of the device is feasible and safe but requires longer time for each transseptal access.

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.

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.

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.

Radiofrequency pulmonary veins isolation of atrial fibrillation in patients undergoing mitral valve replacement

Introduction: Pulmonary veins isolation (PVI) is useful method in patients (pts) with mitral valve disease (MVD) and chronic atrial fibrillation (AF) during prosthetic valve implantation.

The aim of the study: To evaluate e.ectiveness of PVI in the treatment of AF in pt with MVD during valve implantation.

Material and methods: 45 pts (mean age 55 yrs) with AF were operated on for MVD.RF ablation around the pulmonary veins, a lesion between them and to the mitral annulus were performed. There were 44 prostheses implanted, 1 case of mitral valve annuloplasty, associated with tricuspid valve repair (5 pts), aorto-coronary bypass procedure (2 pts), ASD II closure (1 pt).

Results: SR was achieved in 2 (44,5%) pts, 21 (46,5%)pts were in AF, 4 (9%) pts needed pacing. No correlation between SR restoration and preoperative echocardiographic parameters, age, gender, NYHA functional class were found. In long-term follow-up 1 pt have reversed AF to SR spontaneously. There were 6 cases of paroxysmal AF,1 pt needed pacemaker implantation. 20 (44,5%) pts are in SR, 20 (44,5%) in AF, 5 (11%) in permanent pacing.

Conclusion: PVI with RF use is effective in restoring sinus rhythm in patients with chronic AF secondary to mitral valve disease.

Open mitral commissurotomy in the current era: indications, technique, and results

BACKGROUND

The present retrospective study is focused on indications, techniques, and results of open mitral commisurotomy in the current era.

METHODS

Of the 1,280 patients undergoing open-heart surgical procedures for rheumatic mitral stenosis between January 1990 and July 2000, 276 (21.6%) patients underwent open mitral commissurotomy. Major indications included presence of left atrial thrombus/clot (n = 82, 29.7%), severe subvalvular disease (n = 110, 39.8%), mitral valve calcification (n = 42, 15.2%), mild mitral regurgitation (n = 28, 10.0%), associated aortic valve disease (n = 55, 19.9%), organic tricuspid valve disease (n = 20, 7.2%), and failure or restenosis after closed or balloon mitral valvuloplasty (n = 55, 19.9%). Age of patients ranged from 7 to 67 years (mean, 30.2 +/- 12 years). The majority (76%) were in New York Heart Association class III or IV, and 6.9% were in congestive heart failure. Atrial fibrillation was present in 134 (48.6%) patients. Mitral valve area ranged from 0.3 to 0.7 cm2 (mean, 0.52 +/- 0.12 cm2). Mid-diastolic gradients across the mitral valve ranged from 8 to 34 mm Hg (mean, 14.5 +/- 6.2 mm Hg), and end-diastolic gradients ranged from 8 to 42 mm Hg (mean, 15.2 +/- 5.7 mm Hg). Open mitral commissurotomy was performed using standard cardiopulmonary bypass. Associated aortic valve procedure was performed in 55 patients, and either tricuspid valvotomy or repair was performed in 28 patients.

RESULTS

There were four early deaths. All these patients had associated aortic valve procedure (Ross procedure in 2 and homograft aortic valve replacement in 2). Three patients developed severe mitral regurgitation in early postoperative period (< or = 30 days) and required reoperation. Predischarge echocardiography showed mitral valve area from 1.4 to 3.5 cm2 (mean, 2.6 +/- 0.6cm2) and moderate mitral regurgitation in 4 patients. Follow-up ranged from 1 to 130 months (mean, 64.5 +/- 28.6 months). There was no late death. There were three reoperations for mitral valve failure, and an additional 2 patients developed severe mitral stenosis (mitral valve area < 1.0 cm2). In operative survivors, freedom from mitral valve failure at 10 years was 87.0% +/- 3.5%. In patients with isolated open mitral commissurotomy, the incidence of thromboembolism was 0.5%/patient-year.

CONCLUSIONS

Open mitral commissurotomy provides excellent early and long-term results in a selected group of patients.

Simple surgical isolation of pulmonary veins for treating secondary atrial fibrillation in mitral valve disease

BACKGROUND

Chronic atrial fibrillation (AF) due to mitral valve disease has been successfully treated by surgery. We performed a study to evaluate the effectiveness of a surgical method of simple pulmonary vein isolation (PVI) without radiofrequency or cryoablation in the restoration of sinus rhythm in a group of patients.

METHODS

Fifteen patients were operated on for mitral valve disease and chronic AF. The technique consists basically of a circumferential incision excluding the pulmonary vein ostia from the left atrium.

RESULTS

Sinus rhythm was achieved in 92.3% of the patients at 6-month follow-up. Echocardiograms 2 months after surgery showed a mean decrease of 1.1 cm in left atrial size. Effective atrial ejection was reestablished in all patients in whom sinus rhythm was achieved (mean LA ejection fraction 41% +/- 14%). Twenty-four hour Holter recordings did not show episodes of paroxysmal atrial fibrillation in any patients. Four patients had isolated episodes of ventricular ectopic beats. Stress electrocardiograms showed mean maximal ventricular response was 64% +/- 11% and 73% +/- 9% of predicted value at 2 and 6 months, respectively. All patients had improved NYHA functional class after surgery; 74% of patients were in NYHA functional class I at 6 months compared with 13.3% preoperatively.

CONCLUSIONS

Pulmonary vein isolation without the use of radiofrequency or cryoablation is effective in restoring sinus rhythm in patients with chronic AF secondary to mitral valve disease. Based on simple surgical incisions, this technique is more advantageous than others requiring additional instrumentation.

Preserved atrial response to dobutamine stress after the modified maze procedure for chronic atrial fibrillation: echocardiographic assessment of atrial function

BACKGROUND

The maze operation is effective in varying degrees for the restoration of atrial function at rest. However, the atrial mechanical function under stressed conditions has not been investigated.

METHODS

Thirteen patients who regained normal sinus rhythm after the modified maze procedure for atrial fibrillation (Af) associated with valvular disease were enrolled in this study. A two-staged, low-dose protocol (at doses of 5 and 10 microg/kg/min) of dobutamine stress echocardiography (DSE) was performed to assess the probability of the appearance of atrial wave in 20 consecutive beats (Paw), the velocity of atrial filling wave (Av), and the early filling wave (Ev) with their ratio (A/E), as well as the left atrial area fraction (LAAF) which represents an ejection fraction of the left atrium.

RESULTS

Under resting conditions, Paw was 72% and 50% at tricuspid (T) and mitral (M) position, respectively. During dobutamine stress (5 microg/kg/min), Paw tended to increase both at T and M position (86% and 60%, respectively). Av was significantly accelerated by dobutamine stress (10 microg/kg/min) in both T (from 0.36 to 0.54 m/s) and M (from 0.46 to 0.69 m/s) valvular flow, which was accompanied by a significant increase in A/E (from 0.69 and 0.31 to 0.87 and 0.40, respectively). Although heart rate was significantly increased during dobutamine stress, LAAF remained at the same level (0.18, 0.22 and 0.19 at rest, 5 and 10 microg/kg/min) and atrial output was expected to be enhanced by dobutamine stress.

CONCLUSION

Restoration of atrial mechanical function after the maze operation is accompanied by preserved response to dobutamine stress.

Long-term follow-up of atrial contraction after the maze procedure in patients with mitral valve disease

OBJECTIVES

We sought to determine the effectiveness of the maze procedure for maintaining sinus rhythm and atrial contraction for a long period in patients with mitral valve disease.

BACKGROUND

Although the maze procedure for atrial fibrillation (AF) has been effective in restoring sinus rhythm in patients with mitral valve disease, the long-term results of this procedure have not been determined.

METHODS

We echocardiographically studied 94 consecutive patients with mitral valve disease before, as well as early (3.1 +/- 3.3 months) and late (2.2 +/- 0.9 years) after, the maze procedure. Peak velocity and the time-velocity integral of the left ventricular (LV) diastolic filling wave during atrial contraction (A wave), as well as the atrial filling fraction (calculated as the ratio of the time-velocity integral of the A wave to total diastolic filling), were obtained from transmitral flow recordings. Peak A wave velocity > or =10 cm/s was considered to indicate echocardiographic evidence of effective atrial contraction.

RESULTS

Regular rhythm with P waves was restored in 70 patients (74%) in the early stage and in 59 patients (63%, p = 0.09) in the late stage after the maze procedure. Forty-seven patients (50%) in the early stage and 36 patients (38%, p = 0.14) in the late stage showed effective atrial contraction by Doppler echocardiography. Left atrial (LA) and LV end-diastolic diameters significantly decreased after the procedure (from 59 +/- 13 to 48 +/- 7 mm, p < 0.01; and from 54 +/- 9 to 47 +/- 5 mm, p < 0.01, respectively) and did not show significant changes during the follow-up period. Once atrial contraction was resumed, its degree did not change between the early and late stages after the maze procedure (17 +/- 6% vs. 17 +/- 6% for atrial filling fraction).

CONCLUSIONS

Sinus rhythm and atrial contraction recovered early after the maze procedure in most patients and were maintained for more than two years. Once active atrial contraction was resumed, the degree of contraction did not change thereafter. These results demonstrate that the maze procedure is effective for a long period in patients with mitral valve disease.

The radiofrequency modified maze procedure. A less invasive surgical approach to atrial fibrillation during open-heart surgery

OBJECTIVE

Patients with mitral valve disease and suffering of atrial fibrillation of more than 1 year's duration have a low probability of remaining in sinus rhythm after valve surgery alone. Intraoperative radiofrequency ablation was used as an alternative to simplify the surgical maze procedure.

METHODS

Seventy-two patients with mitral valve disease, aged 63+/-11 years ranging from 31 to 80 years, underwent valve surgery and radiofrequency energy applied endocardially, based on the maze III procedure to eliminate the arrhythmia. The right-sided maze was performed on the beating heart and the left-sided maze during aorta cross-clamping.

RESULTS

Surgical procedures included mitral valve repair (n=38) or replacement (n=34) and in addition tricuspid valve repair (n=42), closure of an atrial septal defect (n=2) and correction of cor triatriatum (n=1). The left-sided maze needed 14+/-3 min extra ischemic time. There were two in-hospital deaths (2.7%) and three patients (4.2%) died during follow-up of 20+/-15 months. Among 67 surviving patients, 51 patients (76%) were in sinus rhythm, two patients (3%) had an atrial rhythm and eight patients (12%) had persistent atrial fibrillation or atrial flutter. Four patients had a pacemaker implanted, in one patient because of sinus node dysfunction. Doppler echocardiography in 64 patients demonstrated right atrial contractility in 89% and left atrial transport in 91% of patients.

CONCLUSIONS

Intraoperative radiofrequency ablation of atrial fibrillation is an effective and less invasive alternative for the original maze procedure to eliminate atrial fibrillation.

The maze III procedure for atrial fibrillation: should the indications be expanded?

BACKGROUND

We favor the maze III procedure over nonsurgical treatments for atrial fibrillation and have advocated addition of the maze in symptomatic patients with other compelling indications for cardiac surgery.

METHODS

Characteristics and perioperative outcomes of our 76 cumulative maze recipients between 1993 to 1998 were reviewed. The original maze III technique was employed without modification.

RESULTS

Isolated maze III was performed in 19 patients (25%) and combined with other procedures in 57 patients (75%), 49 of these involving one or more valves. Patients having combined procedures were taking fewer antiarrhythmics (p < 0.0001), but were older (p < 0.01), more often female (p < 0.05), and more often had chronic atrial fibrillation (p < 0.01) compared with isolated maze III recipients. The mean duration of aortic clamping and cardiopulmonary bypass for isolated maze was 69 +/- 11 and 145 +/- 22 minutes, and for combined valve procedures it was 122 +/- 38 and 205 +/- 47 minutes. There was no operative mortality. Complications occurred in 15 patients (19.7%). At 3 months atrial fibrillation was cured in 73 of 75 patients (97.3%). Sick sinus syndrome required pacemaker implantation in 3 patients (4.0%).

CONCLUSIONS

The maze III can be performed alone or as a combined procedure with equivalent success, and technical modifications may be unnecessary. A lower threshold for its expanded use in symptomatic patients with atrial fibrillation who require isolated or combined operations is appropriate.

In vivo and in vitro study of radio-frequency application with a new long linear probe: implication for the maze operation

BACKGROUND

The maze operation for atrial fibrillation is effective but highly invasive. We tested, both in vitro and in vivo, a new technique for creating long linear atrial lesions with a custom-made, 25-mm long, stainless-steel, linear probe and a corresponding 500-kHz generator for assistance in the maze operation.

METHODS

In the in vitro study with the isolated canine atria, the power of the delivered radio-frequency energy and the saline irrigating flow rate were changed independently, and the sizes of the lesions were measured. In the in vivo study radio-frequency energy was delivered to 4 portions (ie, the smooth and trabeculated portions of the right and left atria). The sizes of the lesions were measured, and the histologic features of the lesions were examined. Electrical isolation of the right atrial appendage from the remaining right atrium was attempted by using this linear probe.

RESULTS

In the in vitro study the size of the lesion became larger as the delivered power was increased, although the lesion was limited when the flow rate was high. In the in vivo study the size of the lesion was equal at the 4 different sites. Histologic examinations demonstrated linear and transmural lesions, and electrophysiologic examinations revealed conduction block between the right atrial appendage and the remaining right atrium.

CONCLUSIONS

The new original long linear probe was effective for creating transmural linear atrial lesions with the irrigation method, presenting the possibility of an intraoperative technique that mimics the maze procedure.

Mechanism, localization and cure of atrial arrhythmias occurring after a new intraoperative endocardial radiofrequency ablation procedure for atrial fibrillation

OBJECTIVES

The purpose of this study was to test a new pattern of radiofrequency ablation for atrial fibrillation (AFib) intended to optimize atrial activation, and to demonstrate the usefulness of catheter techniques for mapping and ablation of postoperative atrial arrhythmias.

BACKGROUND

Linear radiofrequency lesions have been used to cure AFib, but the optimal pattern of lesions is unknown and postoperative tachyarrhythmias are common.

METHODS

A radial pattern of linear radiofrequency lesions (Star) was made using an endocardial open surgical approach in 25 patients. Postoperative arrhythmias were induced and characterized during electrophysiological studies in 15 patients.

RESULTS

The AFib was abolished in most patients (91%), but atrial flutter (AFlut) occurred in 96% of patients postoperatively. At postoperative electrophysiological studies, 37 flutter morphologies were studied in 15 patients (46% spontaneous, cycle length [CL] 223 +/- 25 ms). Seven mechanisms (lesions discontinuity, n = 6; focal mechanism, n = 1) of AFlut were characterized in six patients. In these cases, flutter was abolished using further catheter radiofrequency ablation. In the remaining cases, flutter was usually localized to an area involving the interatrial septum, but no critical isthmus was identified for ablation. After 16 +/-10 months, 15 patients (65%) were asymptomatic with (n = 3) or without (n = 12) antiarrhythmic medications. Eight (35%) patients had persistent arrhythmias. Postoperative atrial electrical activation was near physiological.

CONCLUSIONS

The AFib maybe abolished using a radial pattern of linear endocardial radiofrequency lesions, but postoperative AFlut is common even when lesions are made under optimal conditions. Endocardial mapping techniques can be used to characterize the flutter mechanisms, thus enabling subsequent successful catheter ablation.

Influence of the maze procedure on the treatment of rheumatic atrial fibrillation - evaluation of rhythm control and clinical outcome in a comparative study

OBJECTIVE

The aim of this study was to evaluate the influence of the maze procedure on the treatment of rheumatic atrial fibrillation in patients with mitral valve disease.

METHODS

Fifty-five patients (mean age 51 years; 47 females) with rheumatic mitral valve disease and associated atrial fibrillation in New York Heart Association functional class III or IV, preoperatively, were operated upon. Thirty-five had double dysfunction, 19 had stenosis, and one had mitral regurgitation. None had other associated heart diseases or previous operations. The patients were divided into two groups: GI, 20 patients were treated for mitral valve disease with associated maze procedure; GII, 35 patients were treated for mitral valve disease without the maze procedure. The preoperative echocardiogram showed a left atrial diameter in GI of 5.35 mm and in GII of 5.57 mm (P=0.779). The groups were considered clinically similar (P=0.759). Cardiopulmonary bypass was used in all patients. The mitral valve was replaced with a biological prosthesis in 24 patients and repaired in 31 patients.

RESULTS

Three hospital deaths occurred, one in GI, two in GII. After cardiopulmonary bypass, 37.1% of patients in GII remained in atrial fibrillation. All patients in GI recovered regular rhythm (P<0.0001). In the ICU, atrial fibrillation was detected in 80% of patients in GII and maintained in 76.4% in a mean follow-up period of 38.5 months. In GI, atrial fibrillation occurred in 20% of patients in the ICU and maintained in 5.3% in 41 months of mean follow-up (P=0.0001). None of the patients in GI and 20.6% of patients in GII had a thromboembolic episode 1-63 months after the operation (P=0.041). Four late deaths occurred (two in each group), two being due to progression of valvular disease, one after an episode of pulmonary infection and one with no cardiac cause.

CONCLUSION

The maze procedure is effective in treating atrial fibrillation in patients with rheumatic mitral valve disease. The results are sustained in the mid-term follow-up period, preventing postoperative thromboembolic episodes, and with acceptable morbidity and mortality.

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.

Effect of atrial radiofrequency ablation designed to cure atrial fibrillation on atrial mechanical function

INTRODUCTION

The effects of linear radiofrequency lesions in the atria for cure of atrial fibrillation on atrial contraction have not previously been quantified.

METHODS AND RESULTS

Atrial function was measured before and 30 +/- 24 days after a biatrial ablation procedure designed to cure atrial fibrillation in eight dogs and after a sham procedure in three dogs. Atrial mechanical function was assessed using Doppler diastolic blood flow velocities, atrial systolic pressure wave amplitude, and assessment of atrial contribution to cardiac output estimated by comparison of AV sequential pacing to ventricular pacing at the same heart rate. The mitral Doppler A/E velocity ratio was 1.03 +/- 0.45 before and 0.72 +/- 0.43 after ablation (P = 0.048). The tricuspid A/E ratio was 0.88 +/- 0.17 before and 0.71 +/- 0.12 after ablation (P = 0.04). The estimated atrial contribution to cardiac output was 18% +/- 9% before and 5% +/- 4% after ablation (P < 0.01). The left atrial systolic pressure wave amplitude was 2.8 +/- 1.5 mmHg before and 1.7 +/- 1.0 mmHg after ablation (P = 0.1). These changes were not observed in control dogs. Lesions covered 25% +/- 6% of the atrial endocardial surface.

CONCLUSION

Multiple linear radiofrequency lesions in the atria designed to cure atrial fibrillation may impair atrial contractility. Reduced atrial function is partly due to loss of atrial myocardial mass, but regional delays in atrial activation and splinting of the atria by scarring also may contribute.

Outcome of valve repair and the Cox maze procedure for mitral regurgitation and associated atrial fibrillation

OBJECTIVE

The objective was to determine whether the Cox maze procedure provides adjunctive benefit in patients with atrial fibrillation undergoing mitral valve repair.

METHODS

We compared the outcome of 39 patients who had the Cox maze procedure plus mitral valve repair between January 1993 and December 1996 (maze group) with that of 58 patients with preoperative atrial fibrillation who had mitral valve repair during the same interval by the same surgeons (control group). Patients in the 2 cohorts were similar for age, gender, preoperative New York Heart Association class III or IV, and duration of preoperative atrial fibrillation. The control group had a higher incidence of previous heart surgery and coronary artery disease.

RESULTS

No operative deaths occurred, and 1 patient in each group required pacemaker implantation after the operation. Duration of cardiopulmonary bypass (122 +/- 40 minutes vs 58 +/- 27 minutes, P <.0001) and hospitalization (12.6 +/- 6.4 vs 9.3 +/- 3.4 days, P <.0025) were prolonged in patients having the Cox maze procedure. Overall, 2-year survival was similar (92% +/- 5% for maze patients and 96% +/- 3% for controls). Freedom from atrial fibrillation in the maze group was 74% +/- 8% 2 years after the operation compared with 27% +/- 7% for the control group (P <.0001). Freedom from stroke or anticoagulant-associated bleeding in the maze group was 100% 2 years after the operation compared with 90% +/- 8% in the control group (P =.04). At most recent follow-up, 82% of maze patients were in normal sinus rhythm (53% in control group).

CONCLUSION

The addition of the Cox maze procedure to mitral valve repair is safe and effective for selected patients, and elimination of atrial fibrillation decreased late complications.

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.

Experimental ablation study using a new long linear probe in isolated porcine hearts

We studied a new technique for creating long linear lesions in hearts using a custom-made linear probe. Radiofrequency (RF) energy applications using a 25-mm long stainless steel linear probe and a corresponding 500-kHz energy generator were tested, creating 90 lesions in isolated porcine hearts. The RF current was applied between the linear probe and a large patch electrode attached to the back of the specimen. Three parameters, comprising the power of the delivered energy, the pressure of contact between the probe and the specimen, and the duration of energy delivery were changed independently and the size of the resulting lesions was measured. All 90 lesions were transmural, well demarcated and created by a single stationary RF application. Lesion length and width increased with: 1) increasing power, when the other two parameters were maintained at constant levels, 2) increasing contact pressure, when the other two parameters were maintained at constant levels, and 3) increasing duration of energy delivery when the other two parameters were maintained at constant levels. The maximum width of the lesions was 3.7 mm. No overheating of any of the specimens was observed. In conclusion, the new original long linear probe used in this study was effective for creating transmural linear lesions, presenting the possibility of a worthwhile contribution to the maze surgical procedure applied to atrial fibrillation.

Predictive factors for persistence of atrial fibrillation after mitral valve operation

BACKGROUND

The majority of patients operated on for mitral valve disease with chronic atrial fibrillation (AF) do not recover sinus rhythm with conventional postoperative treatment. The maze procedure may be used in these circumstances. To define the precise indications for the maze procedure, it would be necessary to identify those patients based on preoperative factors.

METHODS

A retrospective study was undertaken on 100 consecutive patients operated on for mitral valve disease in chronic AF. The return to sinus rhythm was analyzed with relation to age, gender, AF duration, left atrial size, left ventricular ejection fraction, lesion type, valve procedure, associated procedures, and reoperation.

RESULTS

At late follow-up (more than 1 year) 26 (26%) patients presented sinus rhythm and 74 (74%) remained in AF. Statistical single parametric analysis demonstrated that mitral stenosis was a risk factor for maintaining AF, whereas regurgitation was more associated to sinus rhythm recovery. There was no relation with the other parameters with return to sinus rhythm. It should be noted, however, that 96% of this series had AF for more than 6 months preoperatively.

CONCLUSIONS

The majority of patients with mitral valve disease remain in AF and this may justify the association of maze procedure. Pure regurgitation may be a single predictor for return to sinus rhythm after mitral valve operation in chronic AF.

Radiofrequency and cryoablation of atrial fibrillation in patients undergoing valvular operations

BACKGROUND

Previous studies have shown that the maze operation can restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation. The purpose of this study was to test the feasibility of the application of radiofrequency and cryoablation as an alternative to the classic maze operation.

METHODS

Twelve patients undergoing mitral valve procedures were included in this study. Radiofrequency and cryoablation were applied to create lesions in both atria to simulate the classic maze operation.

RESULTS

There were two surgical deaths. At the mean follow-up of 10.25 months for the remaining 10 patients; 6 were in sinus rhythm, 2 in atrial rhythm, 1 in paroxysmal atrial tachycardia, and 1 in atrial fibrillation. Doppler echocardiography at 6-month follow-up showed emergence of biatrial transport function in 3 patients and right atrial contractility in 8. At 12-month follow-up of 5 patients, Doppler echocardiography showed biatrial transport function in 3 and right atrial contractility in 4.

CONCLUSIONS

Our modified maze procedure during valvular operation is effective for achieving an acceptable success rate to restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation.

Rhythm management in atrial fibrillation--with a primary emphasis on pharmacologic therapy: Part 3

Atrial fibrillation (AF) is the most common, sustained, symptomatic tachyarrhythmia that clinicians are called upon to manage. Management strategies include ventricular rate control coupled with anticoagulation, versus restoration and maintenance of sinus rhythm. Rate control may be achieved pharmacologically, with agents that impair AV nodal conduction directly and/or by increasing parasympathetic/sympathetic balance, or by modifying or ablating the AV nodal region anatomically. Rhythm control may be achieved by electrical or pharmacologic conversion followed by maintenance of sinus rhythm by pharmacologic (or occasionally ablative) therapies. This article will present current approaches to rate and rhythm control issues in atrial fibrillation. Parts 1 and 2, published previously, dealt with rate control and with the restoration of sinus rhythm. Part 3, the current article, details the selection process of choosing a therapy to maintain sinus rhythm, including the likelihood of success, the risks of therapy, and individualization of therapy as dependent upon the nature of the structural heart disease present. It also discusses nonpharmacologic approaches that have been recently developed or are undergoing development. One suggested drug selection algorithm is provided.

Right-sided maze procedure for right atrial arrhythmias in congenital heart disease

BACKGROUND

Atrial fibrillation and flutter, commonly associated with congenital heart anomalies that cause right atrial dilatation, may cause significant morbidity and reduction of quality of life, even after surgical repair of the anomalies.

METHODS

In an effort to reduce the incidence of atrial tachyarrhythmias after repair of right-sided congenital heart disease, we performed a concomitant right-sided maze procedure.

RESULTS

Eighteen patients with paroxysmal atrial fibrillation or flutter (n = 12) or chronic atrial fibrillation or flutter (n = 6) aged 10.9 to 68.4 years (mean 34.9 years) underwent a right-sided maze in association with repair of Ebstein's anomaly (n = 15), congenital tricuspid insufficiency (n = 2), and isolated atrial septal defect (n = 1). There were no early deaths, reoperations, or complete heart block. Discharge rhythm was sinus (n = 16) or junctional (n = 2). Follow-up was complete in all 18 patients and ranged from 3.1 to 17.2 months (mean 8.1 months); all are in New York Heart Association class I. Early postoperative arrhythmias developed in 3 patients (all were converted to sinus rhythm by antiarrhythmic drugs). There were no late deaths or reoperations.

CONCLUSIONS

The inclusion of a right-sided maze procedure with cardiac repair in patients having congenital heart anomalies that cause right atrial dilatation and associated atrial tachyarrhythmias is effective in eliminating or reducing the incidence of those arrhythmias.

When and how to report results of surgery on atrial fibrillation

OBJECTIVE

Several medical, interventional and surgical techniques are used to treat atrial fibrillation, aimed at different goals and having variable success rates. To be able to assess and compare all these techniques a methodology of study and a classification is proposed.

METHODS

We developed a five grade score, named the Santa Crus Score, based upon the post-operative atrial rhythm and the effective atrial contraction. Score 0 corresponds to a persistence of atrial fibrillation, the presence of a regular rhythm is grade 1, 2 or 3 if there is no atrial contraction; right atrial contraction; or bilateral atrial contraction, respectively. Score 4 corresponds to sinus rhythm and bilateral atrial contraction. Surgery for atrial fibrillation was performed on 51 patients since 1992. All patients but two had associated mitrial surgery. Three different maze techniques were performed on 17 patients and the pulmonary veins isolation procedure on 34 patients. Patients were reassessed at 1, 6, 12, 24 and 36 months.

RESULTS

After the maze I procedure atrial fibrillation eradication was achieved in 88% of patients but none scored 4. Three patients changed score during the first year. All maze III patients scored 0 initially and one changed to score 3 in the first year. Sixty percent of the maze IIIA patients scored 4, but one evolved to score 0 at 6 months. The pulmonary veins isolation technique eliminated atrial fibrillation in 71% of the patients initially, and in 60% after 1 year, and achieved a score of 4 in a third of the patients.

CONCLUSION

This classification considers the intermediate grades of success that can occur with absence of atrial fibrillation and is applicable to all forms of therapy.

Nonpharmacologic treatment of atrial fibrillation: current and evolving strategies

Atrial fibrillation is the most common cardiac arrhythmia requiring treatment. Limitations of medical treatment have prompted development of nonpharmacologic therapies for this arrhythmia. These are aimed at ventricular rate control during atrial fibrillation, termination of the arrhythmia, and/or prevention of recurrences. Ventricular rate control can be achieved with transcatheter ablation or modification of the atrioventricular node. The MAZE operation is effective in preventing arrhythmia recurrence, but because it requires cardiac surgery, its appeal is limited. Development of the technique for direct transcatheter ablation of atrial fibrillation is eagerly anticipated and may represent the standard curative treatment of the future. In appropriately selected patients, implantable device therapy may play an important role in the treatment of paroxysmal atrial fibrillation.

Long-term follow-up of corridor operation for lone atrial fibrillation: evidence for progression of disease?

INTRODUCTION

Currently, surgery- and catheter-mediated ablation is applied when drug refractoriness of atrial fibrillation is evident, although little is known about the long-term incidence of new atrial arrhythmia and the preservation of sinus node function.

METHODS AND RESULTS

To address this issue, 30 patients with successful corridor surgery for lone paroxysmal atrial fibrillation and normal preoperative sinus node function were followed in a single outpatient department. Five years after surgery, the actuarial proportion of patients with recurrence of atrial fibrillation arising in the corridor was 8% +/- 5%, with new atrial arrhythmias consisting of atrial flutter and atrial tachycardia in the corridor 27% +/- 8%, and with incompetent sinus node requiring pacing therapy 13% +/- 6%. Right atrial transport was preserved in 69% of the patients without recurrence of atrial fibrillation and normal sinus node function. Stroke was documented in two patients.

CONCLUSIONS

Corridor surgery for atrial fibrillation is a transient or palliative treatment instead of a definitive therapy for drug refractory atrial fibrillation. This observation strongly affects patient selection for this intervention and constitutes a word of caution for other, nonpharmacologic interventions for drug refractory atrial fibrillation.

Effect of the maze procedure for atrial fibrillation on atrial and brain natriuretic peptide

We studied plasma levels of atrial and brain natriuretic peptides at rest and after exercise before and after intracardiac surgery with and without the maze procedure in patients with chronic heart failure secondary to valvular heart disease. The present study found that an increased response of both cardiac natriuretic peptides is attenuated with resulting water retention after the maze procedure.