Map-guided surgery for atrial fibrillation

BACKGROUND: Although current surgical procedures result in a high success rate for atrial fibrillation, they are not guided by electrophysiologic findings in individual patients and thus might include unnecessary incisions in some patients or be inappropriate for other patients. We sought to determine whether intraoperative mapping is beneficial for the surgical treatment of atrial fibrillation. METHODS: A 256-channel 3-dimensional dynamic mapping system with custom-made epicardial patch electrodes was used to examine the atrial activation during atrial fibrillation and to determine the optimal procedure in 37 patients with continuous and 9 patients with intermittent atrial fibrillation intraoperatively. RESULTS: Surgical intervention for atrial fibrillation was not indicated in 3 patients in whom the atrial electrograms had a low voltage over a broad area. Concurrent, multiple, and repetitive activations arising from the pulmonary veins or left atrial appendage were observed in all patients. A simple left atrial procedure consisting of pulmonary vein isolation and left atrial incisions without any right atrial incisions was performed in 8 patients in whom the right atrial activation was passive, and all (100%) were cured of atrial fibrillation. The radial procedure was performed in the remaining 35 patients, and 31 (89%) of the patients were cured of atrial fibrillation. In this subset of patients, 10 exhibited reentrant or focal activation in the posterior left atrium between the right and left pulmonary veins and required an additional linear ablation on the posterior left atrium. The total amount of postoperative bleeding after the simple left atrial procedure was significantly less than after the radial procedure (378 +/- 135 vs 711 +/- 364 mL, P = .03). The right and left atrial transport functions were well preserved after both the radial and simple left atrial procedures. CONCLUSION: Intraoperative mapping facilitates determining the optimal procedure for atrial fibrillation in each patient.     

Possibility of focal activation around the left upper pulmonary vein during chronic atrial fibrillation with mitral valve disease.

Focal regular activations were sometimes observed during chronic atrial fibrillation (AF) associated with mitral valve disease. We present a 58 year-old male diagnosed with mitral valvular stenosis and regurgitation with chronic atrial fibrillation. Intraoperative mapping of both atria was performed during mitral valvular surgery. Regular and repetitive activations around the left superior pulmonary vein were observed, in contrast to irregular and chaotic activations of the right atrium. This regular activation was supposed to be the focus of chronic AF. Surgical ablation of the posterior left atrium was successfully performed and eliminated the chronic AF, concomitant with mitral valve replacement.     

The surgical treatment of atrial fibrillation. II. Intraoperative electrophysiologic mapping and description of the electrophysiologic basis of atrial flutter and atrial fibrillation

Computerized mapping of atrial fibrillation was performed in animals and man. To study atrial fibrillation in a systematic manner, we developed a clinically relevant experimental model of atrial fibrillation. Chronic mitral regurgitation was created surgically in 25 dogs without opening the pericardium. After several months of chronic mitral regurgitation, the atria became enlarged and sustained atrial fibrillation could be induced by standard programmed electrical stimulation techniques. Computerized isochronous activation maps of the atria were recorded during atrial fibrillation from 208 bipolar electrodes simultaneously. In a parallel study, human atrial fibrillation was mapped with a separate 160-channel intraoperative mapping system in patients with paroxysmal atrial fibrillation who were undergoing surgical correction of the Wolff-Parkinson-White syndrome. The canine activation sequence maps demonstrated a spectrum of rhythm abnormalities ranging from simple atrial flutter to complex atrial fibrillation. They also showed that macroreentrant circuits within the atrial myocardium were responsible for the entire spectrum of arrhythmias. Atrial reentry was also documented during human atrial fibrillation. All patients had nonuniform conduction around regions of bidirectional block in both atria resulting in multiple discrete wave fronts. In addition, six patients had a single reentrant circuit in the right atrium in which bidirectional block of the activation wave front occurred along the sulcus terminals between the venae cavae. The left atrium in all patients demonstrated multiple wave fronts and conduction block, but left atrial reentry could not be detected. Both the experimental study and the clinical study demonstrated that multiple wave fronts, nonuniform conduction, bidirectional block, and large (macroreentrant) reentrant circuits occur during atrial fibrillation. The presence of macroreentrant circuits and the absence of either microreentrant circuits or evidence of atrial automaticity suggests that atrial fibrillation should be amenable to surgical ablation.     

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 operation.

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.     

Validation of a left atrial lesion pattern for intraoperative ablation of atrial fibrillation

BACKGROUND: Evidence that atrial fibrillation may begin in early stages from triggers or reentry circuits primarily in the left atrium suggests that the entire Maze 3 lesion pattern may be unnecessary. In the present study we describe a new left atrial lesion pattern for intraoperative linear ablation of chronic atrial fibrillation. METHODS: Endocardial radiofrequency ablation was performed on 12 dogs with chronic atrial fibrillation. Lesions to isolate pulmonary veins in pairs, the left atrial appendage, and connecting lesions between these structures were administered in a randomized approach. RESULTS: Twelve dogs were in chronic atrial fibrillation for 31 +/- 21 days before ablation. Atrial fibrillation was successfully ablated and rendered noninducible in all 12 dogs. All treatment failures observed with less than the full lesion pattern became a success when the remaining lesions were given. CONCLUSIONS: Atrial fibrillation ablation using this left atrial lesion pattern is highly successful in this model. This approach may have significant utility as a concomitant procedure for patients with atrial fibrillation undergoing mitral valve procedures.     

Left atrial reduction and mitral valve surgery: the "functional-anatomic unit" concept

The desired outcome for patients undergoing mitral valve surgery includes both good function of the mitral valve, and preservation and restoration of sinus rhythm. To achieve such an outcome, we evolved the concept of the left atrium and mitral valve as a "functional anatomic unit." In this report, we describe a technique for reduction in left atrial size, isolation of the pulmonary veins, and amputation of the left atrial appendage in combination with mitral valve repair. We performed such a procedure in 4 patients, with rheumatic mitral valve disease and chronic atrial fibrillation, with restoration of good valve function and sinus rhythm at 16 to 20 months after surgery.     

Surgery for atrial fibrillation.

Surgical treatment is highly effective in converting atrial fibrillation back to sinus rhythm and significantly prevents thromboembolism postoperatively. Indications for surgery include patients with atrial fibrillation associated with structural heart disease who undergo cardiac surgical procedures, high-risk patients for systemic thromboembolic complications related to left atrial thrombi, patients with failure or recurrence following one or more sessions of catheter ablation, and patients with intolerable symptoms or an impaired quality of life due to atrial fibrillation. The maze and radial procedures cure atrial fibrillation in the majority of patients, however, the procedures are not guided by electrophysiologic findings in individual patients, and thus may include unnecessary incisions in some patients or be inappropriate for other patients. Intraoperative mapping may facilitate determining the optimal procedure for atrial fibrillation in each patient. Surgical procedure for atrial fibrillation consists of isolation of all four pulmonary veins to prevent propagation of the repetitive activation and multiple incisions on the right and left atria to block the reentrant activation. A number of ablation devices have been developed to make a complete conduction block during the past decade. The challenge in atrial fibrillation surgery is in the development and establishment of an off-pump thoracoscopic procedure. Furthermore, intraoperative electrophysiological assessment of the mechanism of atrial fibrillation and verification of conduction block over the ablation line should be established to accomplish a high success rate for atrial fibrillation.     

慢性心房颤动合并二尖瓣病的迷宫手术

作者自１９９５年至１９９６年１０月共作２０例慢性心房颤动的迷宫手术和二尖瓣替换或修复术。术吣外膜标测结果左房多为扑（１４／２０）,右房则往往是颤动（１８／２０）。无早期死亡。２０例随访３个月以上,其中１４例随访在１年以上,经电生理检查均为窦性心率,房室同步活动,不能诱发房颤;经多普勒超声心动图检查,左和右心房输出功能正常。晚期死亡１例,手术后４年半月死于急性坏死性肝炎,对迷宫手术作了一些改进,术后     

A simple way to treat chronic atrial fibrillation during mitral valve surgery: the epicardial radiofrequency approach.

OBJECTIVE: We describe an original radiofrequency ablation technique to treat chronic atrial fibrillation in patients undergoing mitral valve surgery. Most of the procedure is carried out epicardially, in order to avoid an undue increase of surgical time and trauma. METHODS: The ablations are performed using a temperature-controlled multipolar radiofrequency catheter. Two encircling lesions around the ostia of the right and of the left pulmonary veins are carried out epicardially, usually before cardiopulmonary bypass. Through a conventional left atriotomy the ablation procedure is completed with two endocardial lesions connecting the two encirclings between them and to the mitral valve annulus. After the mitral valve procedure is performed, the left appendage is sutured. RESULTS: From February 1998 to May 1999, 40 patients with chronic atrial fibrillation (43. 1+/-51.9 months) underwent combined radiofrequency ablation and mitral valve surgery. Mean left atrial diameter was 56.8+/-10.7 mm. Mean cardiopulmonary bypass and aortic cross-clamp time were, respectively, 119.1+/-26.3 and 76.7+/-21.0 min. Mean postoperative blood loss was 287.2+/-186.6 ml. No reexploration for bleeding occurred. One patient died of pneumonia 12 days after operation. No patient needed permanent pacemaker implantation. Mean postoperative hospital stay was 7.3+/-5.6 days. At follow-up (mean 11.6+/-4.7 months), 30/39 (76.9%) of the patients were in stable sinus rhythm. All patients in sinus rhythm 3 months after operation recovered both left and right atrial contractility at echocardiographic control (mean 7.3+/-3.4 months). The left atrial diameter decreased significantly in patients recovering sinus rhythm. CONCLUSIONS: Epicardial radiofrequency ablation is a safe means to achieve surgical ablation of atrial fibrillation with a high success rate. The simplicity of the technique and the low procedure-related risk should dictate combined treatment virtually in all patients with atrial fibrillation undergoing open heart operations.     

A new device for beating heart bipolar radiofrequency atrial ablation

OBJECTIVE: A technique for mimicking left atrial atriotomies using an ablation device that can be deployed without cardiopulmonary bypass has been developed. METHODS: In 12 healthy large (35-50 kg) adult pigs, maze-like ablation lesions were directly applied to the left atrial epicardium on the beating heart. The ablation device is irrigated, with a bipolar "hemostat" morphology, utilizing radiofrequency energy. Prior to and after ablation, left atrial electromechanical properties were measured during sinus rhythm in the latest 5 pigs using percutaneous endocardial catheter electromechanical mapping and intracardiac echocardiography. Pathologic analysis was performed acutely. RESULTS: All ablation lesions demonstrated conduction block along their entire course. Global left atrial conduction time (49.4 +/- 8.8 milliseconds before vs 58.8 +/- 9 milliseconds after) and pattern were not significantly altered. Although a significant amount (17.12% +/- 9%) of myocardium was either ablated or electrically isolated, ablation was not associated with significant alterations in global left atrial mechanics (left atrium ejection fraction 19% before vs 17% after; pulmonary vein peak flow velocity 1.22 m/s before vs 1.38 m/s after; peak mitral inflow velocity 2.34 m/s before vs 2.64 m/s after), mitral valve function, nor left ventricular function. There was no evidence of atrial thrombus formation. Transmurality was achieved in most lesions with no evidence of charring or barotrauma. CONCLUSIONS: Utilizing this ablation device, atrial lesions similar to the left component of the Maze procedure were deployed with uniform success in a beating heart without cardiopulmonary bypass or atriotomy and without adverse effects on left atrial electromechanics.     

Electrocautery maze in chronic atrial fibrillation: An early experience

Introduction The maze procedure is the only surgical treatment that can alleviate the three physiologic sequelae of atrial fibrillation i.e. tachycardia, thromboembolic events and hemodynamic compromise. In the present study, we attempted ablation of atrial fibrillation (AF) using monopolar conventional cautery. Objective is to demonstrate efficacy of electroxcautery maze in chronic AF in patients undergoing mitral valve surgery and long term efficacy of it in maintaining sinus rhythm. Methods In this series 25 patients who underwent electrocautery maze since 2002 were studied, the age ranged from 20–60 years, 60% of patients were females. 20 patients were in NYHA class IV and 5 patients were in class III, who had left atrium (LA) ranging from 5–6.5 cms with LA appendage clot in 8 patients. All patients underwent mitral valve replacement, 3 patients under went tricuspid valve repair and 2 underwent aortic valve replacement as concomitant procedures. The electrocautery maze was done encircling left & right pulmonary veins along with interconnecting portion. Left atrial appendage was ligated only in cases with LA clot. Results The hospital mortality rate was nil in this group of patients. Freedom from atrial fibrillation or atrial flutter was 92% at 6mths followup. Patients were followed up with regular electrocardiography. Conclusion Electrocautery maze procedure, an adjunctive procedure is safe, time sparing & effective in eliminating atrial fibrillation & restoring atrial transport function. Presented at the 50^th Annual Meeting of IACTS, New Delhi, Feb., 2004.     

A modified maze procedure performed only on the left atrium for chronic atrial fibrillation associated with mitral valve disease: Report of a case

We describe herein the successful treatment of a patient with chronic atrial fibrillation (AF) associated with mitral valve stenosis and regurgitation, achieved by performing a modified maze procedure on the left atrium alone. The patient was a 51-year-old man who had suffered from intractable AF for 17 years, causing multiple cerebral emboli and palpitations. He had undergone open mitral commissurotomy and balloon commissurotomy 15 and 7 years ago, respectively. On admission, an echocardiogram revealed mitral valve restenosis and thrombosis in the left atrial appendage. Prosthetic valvular replacement was performed following isolation of all pulmonary veins with cryoablation to the posterior wall of the left atrium and excision of the left atrial appendage. Postoperatively, the AF disappeared and echocardiogram demonstrated a left atrial kick in the mitral valvular inflow without any evidence of thrombosis in the left atrium. Thus, we believe that our modified left side only maze procedure is a simple and efficient method for the treatment of chronic AF with mitral valve disease.     

Curative treatment of atrial fibrillation with intraoperative radiofrequency ablation: short-term and midterm results

OBJECTIVE: This report describes the early and midterm results after intraoperative radiofrequency ablation of atrial fibrillation for patients with isolated chronic atrial fibrillation or atrial fibrillation in combination with additional valvular and nonvalvular cardiac diseases. METHODS: From August 1998 to March 2001, a total of 234 patients with chronic atrial fibrillation underwent isolated intraoperative radiofrequency ablation alone (n = 74, 31.6%) or in combination with other cardiac procedures, such as mitral valve reconstruction (n = 57, 24.4%), mitral valve replacement (n = 38, 16.2%), aortic valve replacement (n = 11, 5.1%), coronary artery bypass grafting (n = 8, 5.0%), or a combination of the last with other cardiac procedures (n = 46, 19.7%). In all cases anatomic reentrant circuits confined within the left atrium were eliminated by placing contiguous lesion lines involving the mitral anulus and the orifices of the pulmonary veins through the use of radiofrequency energy application (exposure time, 20 seconds). A median sternotomy was used in 101 cases (43.2%), and video assistance through a right lateral minithoracotomy was used in 133 cases (56.8%). RESULTS: A total of 188 patients (83.9%) were discharged in sinus rhythm, 17 patients (7.6%) had atrial fibrillation, and 19 patients (8.5%) had atypical flutter. Pacemakers were implanted in 23 patients (9.8%). There were 10 in-hospital deaths (4.2%), and 30-day mortality was 5 patients (2.1%). In 3 cases (1.3%) an atrioesophageal fistula developed, necessitating surgical repair. Six months' follow-up was complete for 122 (61.0%) of 200 patients, with 99 patients still in stable sinus rhythm (81.1%, 95% confidence interval 73.1%-89.9%). Twelve months' follow-up was complete for 80 (90.9%) of 88 patients, with 58 patients still in sinus rhythm (72.5%, 95% confidence interval 61.3%-83.2%). CONCLUSIONS: Intraoperative radiofrequency ablation is a curative procedure for chronic atrial fibrillation. It is technically less challenging than the maze procedure and can be applied through a minimally invasive approach. Protection of the esophagus seems mandatory to avoid the deleterious complication of a left atrioesophageal fistula, such as was observed in 3 cases.     

Bilateral endoscopic technique for left atrial appendectomy and robot-assisted mitral valve repair

We report a bilateral thoracoscopic technique in which robot-assisted mitral valve repair was achieved concomitantly with stapler division of the large left atrial appendage. The patient was a 65-year-old male with severe mitral regurgitation, paroxysmal atrial fibrillation and a large-sized atrial appendage. Closure of the appendage was completed off-pump using a left thoracoscopic stapler-division technique previous to right thoracoscopic robot-assisted mitral valve repair and cryoablation. Complete closure of the appendage was confirmed in thoracoscopic views. The bilateral thoracoscopic technique could be preferable for the minimally invasive treatment of mitral valvular disease and concomitant large-sized atrial appendage management.     

Efficacy of pulmonary vein isolation for the elimination of chronic atrial fibrillation in cardiac valvular surgery

BACKGROUND: Haissaguerre and colleagues emphasize the importance of the pulmonary veins as a source of ectopic foci for initiating paroxysmal atrial fibrillation (AF). We hypothesized that ectopic foci from the pulmonary veins could also act as drivers for maintaining chronic AF, and that surgical ablation of the pulmonary vein orifices could terminate chronic AF. METHODS: Using a computerized 48-channel mapping system, we performed intraoperative atrial mapping in 12 patients with chronic AF associated with mitral valve disease. Patient age ranged from 24 to 82 years (mean, 60.4 years). AF duration ranged from 3 to 240 months (mean, 92+/-84 months). Simple surgical isolation of the pulmonary vein orifices was performed during the mitral valve operation. RESULTS: Regular and repetitive activation was found in the left atria of 9 out of 12 patients, and irregular and chaotic activation was found in both atria of 3 out of 12 patients. Chronic AF in the 9 patients (75%) with regular and repetitive activation of their left atria was successfully treated by a simple surgical isolation of the pulmonary vein orifices. The other 3 patients did not recover sinus rhythm after this procedure. In 1 case of recurrent AF, the patient recovered sinus rhythm during the follow-up period (AF-free rate, 83%). CONCLUSIONS: Surgical ablation of the pulmonary vein orifices was effective in the treatment of chronic AF associated with mitral valve disease. Intraoperative mapping may be useful in predicting the efficacy of a single pulmonary vein orifice isolation procedure.     

Surgical cure of automatic atrial tachycardia by partial left atrial isolation

Partial left atrial isolation was performed in a 16-year-old girl with persistent atrial tachycardia refractory to antiarrhythmic agents for 3 years. Intraoperative atrial epicardial and endocardial mapping showed that the earliest atrial activation occurred in an area lateral to the junction of the right superior pulmonary vein and the left atrium. An incision isolating the right half of the left atrial body containing the area of the earliest atrial activation and both right pulmonary veins from the remainder of the left atrium was made. The incision was then reapproximated. An excision encircling the interatrial septum containing the upper anterior portion of the septum with early activation was also made, and the atrial septal defect was repaired with a pericardial patch. The patient has been in sinus rhythm and free of arrhythmia for a follow-up period of 12 months.     

Electroanatomic mapping of transseptal conduction during coronary sinus pacing in patients with paroxysmal atrial fibrillation

OBJECTIVE: To delineate the electrophysiological properties of transseptal conduction from the left to the right atrium in patients with paroxysmal atrial fibrillation (AF). DESIGN AND RESULTS: Right atrial mapping using the electroanatomic mapping technique was performed at 111 +/- 16 sites in 16 patients with paroxysmal AF during pacing from distal coronary sinus (CS). A single transseptal breakthrough near the CS ostium was observed in all patients. The activation time from the pacing site to the earliest septal activation site was 47 +/- 13 ms. The total septal activation time (68 +/- 16 ms) was markedly longer but the total right atrial activation time (118 +/- 17 ms) was similar to that in patients without AF in a previous observation. CONCLUSION: During distal CS pacing, a preferential site of transseptal conduction near the CS ostium was demonstrated in patients with paroxysmal AF. This has clinical implications when surgical dissection or catheter ablation is considered to eliminate interatrial connection in patients with AF.     

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.     

Cor triatriatum in adulthood with mitral valve regurgitation and atrial fibrillation

Cor triatriatum is a rare congenital heart disease. A 57‐year‐old woman had cor triatriatum with severe mitral valve regurgitation (MR) and atrial fibrillation (AF). We performed mitral valve repair, left atrial appendage resection, and maze procedure by resection of the anomalous septum in the left atrium. As a result, MR was controllable and AF disappeared after the operation. Although there is no established maze procedure with cor triatriatum, removing the septum was effective to complete it.     

Combined atrial fibrillation and mitral valve surgery using microwave technology

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