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.     

Atrial fibrillation surgery simplified with cryoablation to improve left atrial function.

BACKGROUND: The Maze procedure restores atrial fibrillation to normal sinus rhythm. However, concurrent left atrial functional recovery is not always achieved. To address this limitation, a modification using linear cryoablation is described. METHODS: Between July 1997 and December 1999, 83 patients received atrial fibrillation surgery in association with mitral valve surgery with or without additional concurrent procedures by either the conventional technique, group I (n = 30) or the modified technique, group II (n = 53). Onset of sinus conversion and echocardiographic assessment of postoperative left ventricular function, left atrial size, and mitral A-wave velocity were compared in the early postoperative period and 6 months after surgery. RESULTS: Sinus conversion occurred significantly earlier in group II, 2.4 +/- 5 days versus group I, 7.0 +/- 10 days. The mean transmitral A-wave velocity and the incidence of A-wave appearance in the early postoperative period and 6 months postoperatively were greater in group II than group I. CONCLUSIONS: With the current modification, restoration of sinus rhythm and superior left atrial contractile function occurred earlier than with the standard Maze III technique.     

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.     

Outcome of the modified maze procedure for atrial fibrillation combined with rheumatic mitral valve disease using cryoablation

This study evaluated the mid-term results of the modified maze procedure using cryoablation for treating atrial fibrillation associated with rheumatic mitral valve disease. Between March 2000 and February 2004, 177 consecutive patients underwent the modified maze procedure using cryoablation concomitant with mitral valve surgery, were divided into the modified Cox-Maze III (group CM, n=88), modified Kosakai-Maze (group KM, n=63) and left atrial maze (group LA, n=26) procedures. Postoperative and follow-up results were analyzed and compared between the groups, with a mean follow-up time of 22.4+/-15.1 months. There were three hospital deaths (1.7%). The operative time was significantly longer in the group CM than the KM or LA groups, respectively. One late death developed in the CM group. At last follow-up, 139 patients had sinus rhythm (79.9%), which was regained in 67 CM (77.9%), 50 KM (80.7%) and 22 (84.6%) LA group (P=0.743) patients. Freedom from stroke at 4 years was 84.6% in the CM, 95.0% in the KM, and 92.9% in the LA (P=0.916) groups. There were no significant differences in the sinus conversion or stroke rate between patients with the left atrial appendage preserved and those with it excised or obliterated. The modified maze procedure using cryoablation is safe and effective, with an acceptable sinus conversion rate and clinical improvement.     

Surgical treatment of chronic atrial fibrillation combined with rheumatic mitral valve disease: Effects of the cryo-maze procedure and predictors for late recurrence.

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

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.     

Factors predicting the time until atrial fibrillation recurrence after concomitant left atrial ablation.

OBJECTIVE: Treatment of atrial fibrillation, a risk factor for morbidity and mortality, by left atrial ablation is a less complex procedure which is increasingly performed in conjunction with surgery for various heart diseases. Although restoration of sinus rhythm is effective initially, atrial fibrillation may recur. We investigated factors predicting the time until its recurrence. METHODS: Between January 2003 and December 2005, 162 consecutive patients (52.5% male, age 69+/-8.7 years) with permanent atrial fibrillation underwent concomitant left atrial ablation and isolated or combined mitral valve surgery (42.6%), isolated or combined aortic valve surgery (32.1%), and isolated or combined coronary artery bypass grafting (24.1%). Ablation was performed by microwave (n=93, 57.4%) or radiofrequency (n=69, 42.6%) technology. Follow-up was after 3, 6, 12 months and yearly thereafter. Predictive values of variables for postoperative atrial fibrillation were examined using techniques of univariate and multivariate survival analysis (proportional hazards regression). RESULTS: Eight patients died perioperatively and 13 during follow-up (not ablation related). Two patients were lost to follow-up. At last follow-up (19+/-11.3 months), 86 patients (62%) were in stable sinus rhythm, 73 (52%) without antiarrhythmic drugs, and 43 (31%) were in atrial fibrillation. Predictors for the time until recurrence of atrial fibrillation in a multivariate model were preoperative atrial fibrillation duration (hazard ratio 1.005, 95% confidence interval 1.003-1.007, p<0.001) and left atrial diameter (hazard ratio 1.056, 95% confidence interval 1.020-1.093, p=0.002). Overall, sinus rhythm conversion rate was 75% when preoperative atrial fibrillation duration was less than 2 years, but 42% in longer lasting atrial fibrillation with left atrial dilatation (>50mm). Age, gender, primary heart disease, history of thromboembolism or cardioversion, presence of concomitant diseases, EuroScore, left ventricular size and function, aortic cross-clamp time, ablation technology, and treatment with antiarrhythmic drugs did not predict rhythm outcome. CONCLUSIONS: Preoperative atrial fibrillation duration and left atrial diameter predict the time until atrial fibrillation recurrence after concomitant left atrial ablation, whereas age, type of primary cardiac surgery, ablation technology and antiarrhythmic therapy do not.     

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.     

A case of constrictive pericarditis with atrial fibrillation after mitral valve repair and Maze III procedure]

We report a case of constrictive pericarditis with atrial fibrillation after mitral valve repair and the Maze III procedure. A 66-year-old male underwent mitral valve repair and the Maze procedure for mitral valve regurgitation and chronic atrial fibrillation. About 4 months after discharge, he suffered from shortness of breath. Physical examination revealed a heart rate of 80 beats/min with irregular rhythm, external jugular venous dilatation and abdominal ascites. Electrocardiography revealed atrial fibrillation, and chest X-ray revealed moderate left pleural effusion. Computed tomographic images of the chest showed a that thickened pericardium. A distinct diastolic dip and plateau pattern were recognized on cardiac catheterization. The right atrial, right ventricular end-diastolic, and pulmonary wedge pressures were elevated. Idiopathic pericarditis and recurrent atrial fibrillation were diagnosed and pericardiectomy was performed through a median sternotomy incision. Intraoperatively, the atrial fibrillation converted spontaneously to sinus rhythm. The postoperative hemodynamics improved after pericardiectomy. Total pericardiectomy alone may not convert the rhythm to sinus rhythm in patients with constrictive pericarditis and chronic atrial fibrillation. In this case, atrial fibrillation converted to sinus rhythm during the procedure. This case report suggests that adequate unloading of atrial pressures is necessary for the maintenance of sinus rhythm in patients who have undergone the Maze procedure.     

A case of constrictive pericarditis with atrial fibrillation after mitral valve repair and Maze III procedure

We report a case of constrictive pericarditis with atrial fibrillation after mitral valve repair and the Maze III procedure. A 66-year-old male underwent mitral valve repair and the Maze procedure for mitral valve regurgitation and chronic atrial fibrillation. About 4 months after discharge, he suffered from shortness of breath. Physical examination revealed a heart rate of 80 beats/min with irregular rhythm, external jugular venous dilatation and abdominal ascites. Electrocardiography revealed atrial fibrillation, and chest X-ray revealed moderate left pleural effusion. Computed tomographic images of the chest showed a that thickened pericardium. A distinct diastolic dip and plateau pattern were recognized on cardiac catheterization. The right atrial, right ventricular end-diastolic, and pulmonary wedge pressures were elevated. Idiopathic pericarditis and recurrent atrial fibrillation were diagnosed and pericardiectomy was performed through a median sternotomy incision. Intraoperatively, the atrial fibrillation converted spontaneously to sinus rhythm. The postoperative hemodynamics improved after pericardiectomy. Total pericardiectomy alone may not convert the rhythm to sinus rhythm in patients with constrictive pericarditis and chronic atrial fibrillation. In this case, atrial fibrillation converted to sinus rhythm during the procedure. This case report suggests that adequate unloading of atrial pressures is necessary for the maintenance of sinus rhythm in patients who have undergone the Maze procedure.     

A new cryoprobe for intraoperative ablation of atrial fibrillation

We describe the use of a new argon cryoprobe (SurgiFrost) for isolated endocardial surgical ablation. A right lateral minithoracotomy and femoro-femoral cardiopulmonary bypass were applied. The basic mechanism of cryoablation is to remove heat from the targeted arrhythmogenic tissue followed by electrical isolation. In this first case of isolated treatment of atrial fibrillation using the new flexible SurgiFrost cryocatheter, we were able to perform pulmonary vein isolation reaching temperatures as low as -144 degrees C. The patient was discharged in sinus rhythm. This new argon cryoprobe represents an encouraging technology for the isolated endocardial as well as concomitant treatment of atrial fibrillation.     

Minimally invasive cardiac surgery with surgical ablation of atrial fibrillation

Surgical ablation for atrial fibrillation with mitral valve operations has been often performed in patients who have chronic atrial fibrillation associated with mitral valve disease. We describe a case of the combined operation through a small incision. A 49-year-old woman presented with a 1-month history of left hemiplegia. Echocardiography confirmed mitral stenosis and electrocardiogram revealed atrial fibrillation. The duration of the atrial fibrillation before admission was 12 years. Mitral commissurotomy, removal of clots, and surgical ablation for atrial fibrillation was performed through an 8-cm right parasternal incision. The right femoral artery and vein were used for cannulation. Another cannula was inserted into the superior vena cava. The extended use of cryoablation was carried out instead of atriotomy or reanastomosis. The patient was extubated for 5 hours after the operation. Atrial fibrillation was converted to a sinus rhythm. On the basis of our experience, this procedure seemed promising.     

Atrial remodeling after mitral valve surgery in patients with permanent atrial fibrillation

BACKGROUND: Mitral valve pathology is frequently associated with auricular dilatation and atrial fibrillation. Mitral surgery allows an immediate surgical auricular remodeling and besides in those cases in which sinus rhythm is reached, it is followed by a late remodeling. The aim of this study is to investigate the process of postoperative auricular remodeling in patients with permanent atrial fibrillation undergoing mitral surgery. METHODS: In a prospective randomized trial, 50 patients with permanent atrial fibrillation and dilated left atrium, submitted to surgical mitral repair, were divided into two groups: Group I contained 25 patients with left auricular reduction and mitral surgery, and Group II contained 25 patients with isolated valve surgery. Both groups were considered homogeneous in the preoperative assessment. RESULTS: After a mean follow-up of 31 months, 46% of patients included in Group I versus 18% of patients included in Group II restarted sinus rhythm (p = 0.06). An auricular remodeling with size regression occurred in those patients who recovered from sinus rhythm, worthy of remark in Group II (-10.8% of left auricular volume reduction in Group I compared to -21.5% in Group II; p < 0.05). A new atrial enlargement took place in those patients who remained with atrial fibrillation (+16.8% left auricular volume in Group I vs. +8.4% in Group II; p < 0.05). CONCLUSIONS: Mitral surgery produces an atrial postoperative volume that decrease especially when reduction techniques are employed. Late left atrial remodeling depended on the type of atrial rhythm and postoperative surgical volume.     

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).     

Excellent results for atrial fibrillation surgery in the presence of giant left atrium and mitral valve disease.

OBJECTIVE: The incidence of sinus conversion in the enlarged left atrium after atrial fibrillation surgery is reported to be low. The purpose of the current study was to investigate the effects of atrial fibrillation surgery on mitral valve disease associated with a giant left atrium (GLA). METHOD: From July of 1997 to February of 2002, 188 patients received mitral valve and atrial fibrillation surgery. The patients were placed in either GLA group (n = 94), or NGLA group (n = 94), based on LA size. The presence and onset of sinus rhythm and the incidence and velocity of transmitral A waves were monitored during the early postoperative period and throughout the follow up period of 42 months. RESULTS: The onset of postoperative sinus rhythm was slightly earlier in the NGLA group than in the GLA group at 1.3+/-0.4 days versus 3.1+/-1.2 days, respectively, (P = 0.008). The sinus conversion rates in the GLA and the NGLA groups were 91.5 and 97.9% in the early postoperative period, and 94.7 and 95.7% at 6 months after surgery, respectively. A wave appearance rates in the early postoperative period in the GLA and the NGLA groups were 62.2 and 71.7%, and continued to improve over time to 94 and 95% by 36 months, respectively. Peak A wave velocities in the early postoperative period in GLA and NGLA groups were 67.4+/-34.0 and 61.1+/-29.5 cm/s without significant change during the follow up. CONCLUSION: The results suggest that atrial fibrillation surgery is effective at inducing sinus rhythm and restoring left atrial contractile function after concomitant mitral valve surgery regardless of LA size.     

Evaluation of superior transseptal approach for the removal of left atrial myxoma

We compared the operative outcomes among 14 patients who underwent the removal of left atrial myxoma with four different approaches; right lateral (n = 2), transseptal bi-atrial (Dubost, n = 4), conventional transseptal (n = 4) and superior transseptal approach (STA, n = 4). Concomitant operations were performed in 4 cases (CABG, two; aortic valvuloplasty, one; mitral valve replacement, one), and two out of 4 cases were in the STA group. The mean operation, cardiopulmonary bypass and aortic cross-clamp times were shorter in the STA group compared to the other three group. The total amount of postoperative drain discharge and the peak value of creatine kinase were also lower in the STA group compared to the other three groups. Among the patients in sinus rhythm before operation, the use of STA was associated with a greater incidence (100%) of postoperative atrial fibrillation or junctional rhythm. These rhythm disturbances were temporary, and all returned to sinus rhythms during hospital stay. We conclude that STA is an excellent approach with a nice surgical view to expose and remove the left atrial myxoma.     

Left atrial isolation associated with mitral valve operations.

Surgical isolation of the left atrium was performed for the treatment of chronic atrial fibrillation secondary to valvular disease in 100 patients who underwent mitral valve operations. From May 1989 to September 1991, 62 patients underwent mitral valve operations (group I); 19, mitral valve operations and DeVega tricuspid annuloplasty (group II); 15, mitral and aortic operations (group III); and 4, mitral and aortic operations and DeVega tricuspid annuloplasty (group IV). Left atrial isolation was performed, prolonging the usual left paraseptal atriotomy toward the left fibrous trigone anteriorly and the posteromedial commissure posteriorly. The incision was conducted a few millimeters apart from the mitral valve annulus, and cryolesions were placed at the edges to ensure complete electrophysiological isolation of the left atrium. Operative mortality accounted for 3 patients (3%). In 79 patients (81.4%) sinus rhythm recovered and persisted until discharge from the hospital. No differences were found between the groups (group I, 80.7%; group II, 68.5%; group III, 86.7%; group IV, 75%; p = not significant). Three late deaths (3.1%) were registered. Long-term results show persistence of sinus rhythm in 71% of group I, 61.2% of group II, 85.8% of group III, and 100% of group IV. The unique risk factor for late recurrence of atrial fibrillation was found to be preoperative atrial fibrillation longer than 6 months. Due to the satisfactory success rate in recovering sinus rhythm, we suggest performing left atrial isolation in patients with chronic atrial fibrillation undergoing valvular operations.     

Combined atrial fibrillation and mitral valve surgery using radiofrequency technology

Recently, intraoperative radiofrequency ablation of the left atrium combined with mitral valve surgery has become widely used. In our center, 30 patients underwent this combined procedure; median sternotomy was used in 16 patients, and port access was used in 14 patients. At hospital discharge, 18 patients (60%) were no longer in atrial fibrillation, and at 6 months, 19 patients (65%) remained in sinus rhythm. All sinus rhythm patients had a well-defined transmitral A wave detectable by echocardiography. One patient sustained a major stroke. Two patients required pacemaker implantation. Such encouraging preliminary results have triggered worldwide interest in the percutaneous and surgical treatment of atrial fibrillation. However, the excellent long-term results with the classic Cox-Maze III operation have not yet been achieved with these newer approaches. Further basic and clinical research is required before a predictable simple and safe technique can be introduced as a new standard for the surgical treatment of atrial fibrillation in patients with or without structural heart disease.     

Cryoablation for surgical treatment of chronic atrial fibrillation combined with mitral valve surgery: a clinical observation

OBJECTIVE: Although the classical Cox-Maze III is the gold standard surgical therapy with a proven efficacy in the treatment of atrial fibrillation (AF), complexity of this procedure has resulted in a search for a simpler, less invasive and more cost-effective method. In this study we evaluated the results of cryosurgical ablation in the treatment of chronic AF in patients undergoing concomitant mitral valve surgery. METHODS: Ninety patients (mean age: 50.9+/-12 years) with chronic AF who were having mitral valve surgery as the main procedure underwent cryoablation with a newly designed N(2)O-based cryotherapy device. Pulmonary vein isolation with or without left atrial appendage closure (group A) was carried out in 65 cases and cryoablative bi-atrial Cox-Maze III (group B) in 25 patients. This additional procedure took only an extra 10 min for group A and about 20 min for group B. Half of the patients received a beta-blocker following the procedure. RESULTS: The overall success rate of cryoablation was 65.5%. Normal sinus rhythm was achieved in 26.7% in the operating room, 10% in ICU and the remaining cases reverted to sinus rhythm during the follow-up period. There were no major ablation-related complications such as bleeding, thromboembolic events or A-V block. The only predictor for failure of ablative procedure was left atrial size of greater than 6 cm. CONCLUSION: Although in this study the efficacy rate of cryoablative surgery was not the same as classical Cox-Maze III, it seems that this procedure is safe, simple, cost-effective and at the same time does not increase the operative time significantly. Using cryoablation may enhance the cure rate of chronic AF during mitral valve surgery.     

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.