Impact of left atrial size reduction and endocardial radiofrequency ablation on continuous atrial fibrillation in patients undergoing concomitant cardiac surgery: three-year results

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the efficacy of left atrial (LA) size reduction combined with radiofrequency (RF) ablation in the treatment of continuous atrial fibrillation (AF), by comparative analysis of the outcomes of patients undergoing RF ablation with and without LA size reduction. METHODS: A total of 46 patients with continuous AF and cardiac disease underwent cardiac surgery and RF ablation alone (group I, n = 20) or combined with LA size reduction (group II, n = 26). Patients were followed for three years postoperatively, with evaluation of cardiac rhythm, neurological complications, LA size (by echocardiography) and atrial contractility. RESULTS: At three years after surgery, sinus rhythm (SR) was restored in 61.1% and 70% of patients in groups I and II, respectively. Mean LA diameter was reduced from 60 +/- 15 mm to 57 +/- 5 mm in group I, and from 69 +/- 19 mm to 55 +/- 6 mm in group II. The overall three-year survival was 90% in group I, and 88.5% in group II. Three-year freedom from stroke was 88.9% and 86.2% in groups I and II, respectively. Two patients in each group received transvenous permanent pacemaker implantation. Atrial contractility was recovered in all patients with stable SR. CONCLUSION: LA size reduction improves SR conversion rate after RF ablation for continuous AF in patients undergoing concomitant cardiac surgery.     

Atrial size reduction as a predictor of the success of radiofrequency maze procedure for chronic atrial fibrillation in patients undergoing concomitant valvular surgery

INTRODUCTION: Previous studies showed that the surgical maze procedure can restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation (AF). However, no previous studies discussed the association of atrial size reduction and the success of sinus conversion by the radiofrequency (RF) maze procedure for chronic AF. METHODS AND RESULTS: A total of 119 chronic AF patients undergoing valvular operations were included in this study. Sixty-one patients received RF and cryoablation to create lesions in both atria to simulate the surgical maze II or III procedure (RF maze II or RF maze III; 13 patients, group 1) or a modified maze pattern (RF maze "IV"; 48 patients, group 2). The other 58 patients who underwent valvular operations alone without the maze procedure served as control (group 3). At 3-month follow-up after operation, sinus rhythm was restored in 73%, 81%, and 11% of patients in groups 1, 2 and 3, respectively. Preoperative left and right atrial sizes were not statistically significant predictors of sinus conversion by the RF maze procedure. However, as a result of postoperative reduction of atrial sizes, postoperative left atrial diameter was significantly smaller in patients who had sinus conversion by the RF maze procedure than in patients who did not regain sinus rhythm (45.0+/-7.0 mm vs 51.0+/-8.0 mm; P = 0.03). Postoperative right atrial area of patients who had sinus conversion by the RF maze procedure also was significantly smaller than that of patients who did not regain sinus rhythm (18.1+/-4.4 cm2 vs 28.5+/-8.2 cm2; P = 0.008). CONCLUSION: Atrial size reduction appears to predict the success of sinus conversion with the RF maze procedure used in conjunction with valvular surgery.     

Intraoperative Radiofrequency Ablation of Chronic Atrial Fibrillation: A Left Atrial Curative Approach by Elimination of Anatomic "Anchor" Reentrant Circuits

INTRODUCTION: The percutaneous approach to radiofrequency (RF) catheter ablation for curative treatment of atrial fibrillation (AF) is an investigational technique, and the optimal composition of lesion lines is unknown. We tested an intraoperative RF ablation concept with elimination of left atrial anatomic "anchor" reentrant circuits. METHODS AND RESULTS: In 12 patients with an indication for valve surgery and chronic AF, a right atrial-transseptal approach was chosen for access to the left atrium. AF had been present for 4.3 +/- 3.9 years; the left atria measured 56 +/- 7 mm. Under direct vision, contiguous lesion lines were placed endocardially with temperature-guided RF energy applications for treatment of AF with a specially designed probe. The lesion lines were placed between the mitral annulus and the left lower pulmonary vein, further to the left upper pulmonary vein, from there to the right upper pulmonary vein, and finally to the right lower pulmonary vein. The antiarrhythmic ablation procedure lasted 19 +/- 4 minutes. One patient died postoperatively of low cardiac output. During follow-up of 11 +/- 6 months, chronic AF was ablated successfully in 9 of 11 patients (82%). Six patients were in stable sinus rhythm or intermittent pacemaker rhythm, and three patients were in sinus rhythm with intermittent atypical atrial flutter. CONCLUSIONS: Intraoperative RF energy application for induction of contiguous lesion lines is feasible. Elimination of anatomically defined "anchor" reentrant circuits within the left atrium prevented chronic AF in > 80% of the patients treated. Intraoperative validation of lesion line concepts for curative treatment of AF may be transferred to percutaneous ablation techniques.     

Impact of left atrial size reduction on chronic atrial fibrillation in mitral valve surgery

BACKGROUND AND AIM OF THE STUDY: Left atrial enlargement is a risk factor for the development of atrial fibrillation (AF). Large atrial size increases thromboembolic risk and reduces the success rate of cardioversion. The study aim was to evaluate if left atrial size reduction affects cardiac rhythm in patients with chronic AF undergoing mitral valve surgery. METHODS: Twenty-seven patients were analyzed prospectively. The left atrial incision was extended to the left inferior pulmonary vein. Left atrial size reduction was achieved by closure of the left atrial appendage from inside with a double running suture. The same suture plicated the left lateral atrial wall to the roof of the left pulmonary vein inflow and the inferior atrial wall. The atrial septum was plicated by placing stitches of the closing suture line across the fossa ovalis. Rhythm, neurological complications, cardioversion, anticoagulation and anti-arrhythmic medication were evaluated at one year postoperatively and at recent follow up (mean 40 +/- 15 months). RESULTS: At discharge, five patients (19%) were in sinus rhythm (SR). At one year postoperatively, SR was restored in 17 patients (63%), but five (19%) reported episodes of arrhythmia and AF persisted in 10 (37%). At recent follow up, four patients had died and three were lost to follow up. Among 20 patients examined, 13 (65%) had SR but six reported episodes of arrhythmia and AF persisted in seven (35%). LA diameter was significantly reduced, from 60.2 +/- 9.8 mm preoperatively to 44.5 +/- 7.0 mm at one year after surgery. CONCLUSION: The addition of left atrial size reduction to mitral valve surgery is technically simple, and was effective in 63% of patients with chronic AF, restoring predominant SR. In order to influence pathogenetic factors other than size, additional ablative steps may further increase the SR conversion rate. Size reduction may also improve the outcome of other ablative approaches.     

Left atrial radiofrequency ablation during cardiac surgery in patients with atrial fibrillation

Introduction: Intraoperative left atrial radiofrequency (RF) ablation recently has been suggested as an effective surgical treatment for atrial fibrillation (AF). The aim of this study was to verify the outcome of this technique in a controlled multicenter trial. Methods and Results: One hundred three consecutive patients (39 men and 65 women; age 62 ± 11 years) affected by AF underwent cardiac surgery and RF ablation in the left atrium (RF group). The control group consisted of 27 patients (6 men and 21 women; age 64 ± 7 years) with AF who underwent cardiac surgery during the same period and refused RF ablation. Mitral valve disease was present in 89 (86%) and 25 (92%) patients, respectively (P = NS). RF endocardial ablation was performed in order to obtain isolation of both right and left pulmonary veins, a lesion connecting the previous lines, and a lesion connecting the line encircling the left veins to the mitral annulus. Upon discharge from the hospital, sinus rhythm was present in 65 patients (63%) versus 5 patients (18%) in the control group (P < 0.0001). Mean time of cardiopulmonary bypass was longer in the RF group (148 ± 50 min vs 117 ± 30 min, P = 0.013). The complication rate was similar in both groups, but RF ablation‐related complications occurred in 4 RF group patients (3.9%). After a mean follow‐up of 12.5 ± 5 months (range 4–24), 83 (81%) of 102 RF group patients were in stable sinus rhythm versus 3 (11%) of 27 in the control group (P < 0.0001). The success rate was similar among the four surgical centers. Atrial contraction was present in 66 (79.5%) of 83 patients in the RF group in sinus rhythm. Conclusion: Endocardial RF left atrial compartmentalization during cardiac surgery is effective in restoring sinus rhythm in many patients. This technique is easy to perform and reproducible. Rare RF ablation‐related complications can occur. During follow‐up, sinus rhythm persistence is good, and biatrial contraction is preserved in most patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1289‐1295, December 2003)     

Combined atrial fibrillation ablation with mitral valve surgery

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the efficacy and outcome of radiofrequency (RF) atrial fibrillation (AF) ablation in patients undergoing mitral valve (MV) surgery. METHODS: Between March 2002 and December 2004, 61 patients (mean age 65.4 +/- 10 years) underwent isolated endo-left atrial AF ablation using a unipolar RF device (Cardioblate; Medtronic, USA) in conjunction with 34 MV repairs and 27 MV replacements. AF was paroxysmal in 13 patients (21%), and permanent in 48 (79%), with a mean duration of 3.6 +/- 3.5 years. The etiology was degenerative in 35 patients (57%), rheumatic in 17 (28%), and ischemic in nine (17%). All patients received amiodarone postoperatively. RESULTS: No patients died during the study, and there were no thromboembolic complications. All patients had intraoperative conversion. Forty-one patients (67%) presented with postoperative relapse; definitive conversion was achieved in 34 (83%) cases within three months. The overall success rate was 75.4% at 14 +/- 8.8 months; success was greater in the MV repair group (85%) than in the MV replacement group (66.7%), though not significantly so (p = 0.09). Factors associated with definitive conversion included smaller left atrial size (p = 0.007), decreased left ventricular end-diastolic diameter (p = 0.04), and NYHA class I (p = 0.05). Age, AF duration and etiology were not associated with conversion, but associated coronary artery bypass grafting showed a strong trend towards significance (p = 0.07). In these patients, AF duration did not predict conversion to sinus rhythm. CONCLUSION: Combined AF ablation with MV surgery is safe and effective. Although AF ablation seems more beneficial with MV repair, the success rate may vary significantly according to patient characteristics.     

Factors related to sinus rhythm at discharge after radiofrequency ablation of permanent atrial fibrillation in patients undergoing mitral valve surgery

Late recovery of sinus rhythm is unusual in patients with permanent AF treated by (radiofrequency) RF maze procedure during mitral valve surgery. Identification of clinical and instrumental preoperative factors predictive of early success of RF ablation in patients with permanent AF undergoing mitral valve surgery may improve selection of subjects to obtain long-term results. Hundred and thirty consecutive patients with permanent AF and mitral valve disease underwent modified RF maze procedure during concomitant mitral valve surgery. Rheumatic valve disease (61 pts) and mitral valve prolapse (41 pts) were the more common aetiology of valve abnormalities. Mitral valve replacement was performed in 54 % of patients and mitral valve repair in the remaining 46 %. Four patients died after surgery. At discharge, 87 patients (69 %) were in sinus rhythm (group 1) and 43 patients in AF persisted (group 2). At an average 24-month follow-up, sinus rhythm was present in 67 % of patients, and 33 % were in atrial fibrillation. In this period, late recovery of sinus rhythm was observed only in five patients, while eight discharged in sinus rhythm developed again atrial fibrillation. Among preoperative parameters at univariate analysis female sex, atrial fibrillation >24 months, left atrial diameter >54 mm, left atrial area >24 cm², rheumatic valve disease and NYHA class were associated with persistence of AF. At Cox regression multivariate analysis, increased left atrial area (OR 1.07 per unit increase—95 % CI 1.01–1.131) and rheumatic aetiology of valve disease (OR 4.52, 95 % CI 1.65–12.4) were associated with persistence of AF at hospital discharge. Persistence of AF after RF ablation in patients undergoing mitral valve surgery is related to aetiology, e.g. rheumatic valve disease, and to increasing left atrial diameter. Due to low rate of late recovery of sinus rhythm, indication to RF ablation associated with MV surgery should be carefully considered in patients with large atria and rheumatic mitral valve disease.     

Permanent atrial fibrillation ablation surgery in CABG and aortic valve patients is at least as effective as in mitral valve disease

BACKGROUND: Data on combined permanent atrial fibrillation (pAF) surgery and coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR) are scarce, and the mid- and long-term effects on survival and cardiac rhythm are unknown. MATERIAL AND METHODS: In a prospective analysis 125 patients (Group I: CABG and/or AVR, n = 50; Group II: mitral valve [MV] surgery, n = 75) with pAF (> or = 6 months) underwent either concomitant monopolar (Group I: n = 20; Group II: n = 75) or bipolar (Group I: n = 30) radiofrequency (RF) ablation procedures. Group I patients had a significantly smaller left atrial (LA) size than Group II patients (LA-diameter: 47.7 +/- 4.6 vs. 58.2 +/- 6.1 mm; p < 0.01). Regular follow-up was performed from 3 to 36 months after surgery to assess survival, NYHA-class, and conversion rate to stable sinus rhythm (SR). RESULTS: Early mortality (< 30 days) of Group I patients was 0% (Group II: 2.7%), cumulative survival at long-term follow-up was 0.95 vs. 0.82 (p = 0.31) and NYHA-class improved significantly in both groups, particularly in cases with stable SR. At follow-up 80% of Group I patients had SR (Group II: 70%). In Group I patients the bipolar approach was associated with significantly shorter ablation procedure times compared to the monopolar procedure (12.1 +/- 3.4 vs. 18.9 +/- 1.6 min; p < 0.05). CONCLUSIONS: Concomitant pAF ablation surgery in CABG and/or AVR is safe and at least as effective as in MV surgery, presumably because severe LA enlargement is exceptionally rare in this group.     

心脏瓣膜手术同期行射频消融术后血栓和出血事件发生率的研究

目的:研究心脏瓣膜手术同期行射频消融术治疗永久性心房纤颤(房颤)术后脑血管事件的发生。方法:回顾2003年1月至2006年12月758例瓣膜病合并房颤病例,其中行瓣膜手术+房颤射频消融374例(射频消融组),仅行瓣膜手术384例(对照组)。术后随访6～54个月,平均(32±6.23)个月,对比分析2组病例术后脑血管事件随访数据。结果:术后随访证实消融组在术后脑血管事件发生率、生存率、窦性心律转复率等均优于对照组。结论:心脏瓣膜置换术同期行射频消融术治疗永久性房颤的远期疗效确切,可降低脑血管事件的发生,并提高远期生存率、窦性心律转复率。     

Anatomic atrial remodeling after mitral valve surgery in permanent atrial fibrillation

BACKGROUND: Mitral valve pathology is frequently associated with atrial dilation and fibrillation. Mitral surgery allows immediate surgical atrial remodeling, and in those cases in which sinus rhythm is achieved, it is followed by late remodeling. The aim of this study was to investigate the process of postoperative atrial remodeling in patients with permanent atrial fibrillation who undergo mitral surgery. PATIENTS AND METHOD: In a prospective randomized trial, 50 patients with permanent atrial fibrillation and dilated left atrium, repaired surgically, were divided into two groups: group I, 25 patients with left atrial reduction and mitral surgery, and group II, 25 patients with isolated valve surgery. The characteristics of both groups were considered homogeneous in the preoperative assessment. RESULTS: After a mean follow-up of 31 months, 46% of the patients in group I versus 18% in group II regained sinus rhythm (p = 0.06). Atrial remodeling with shrinkage occurred in patients who recovered sinus rhythm, with larger changes in group II (-10.8% left atrial volume reduction in group I compared to -21.5% in group II; p < 0.05). The atrium became enlarged again in patients whose atrial fibrillation did not remit (+16.8% left atrial volume increase in group I versus +8.4% in group II; p < 0.05). CONCLUSIONS: Mitral surgery produces a postoperative decrease in atrial volume, especially when reduction techniques are used. Late left atrial remodeling was influenced by the type of atrial rhythm and postoperative surgical volume.     

Effect of mitral valve repair/replacement surgery on atrial arrhythmia behavior

BACKGROUND AND AIMS OF THE STUDY: Few data have been published on the effects of mitral valve surgery on atrial rhythm. The study aims were to determine the effects of surgery on: (i) persistence of atrial fibrillation (AF); (ii) measures of left atrial and ventricular dimensions; and (iii) ECG P-wave duration. METHODS: A retrospective case-note review of 92 patients with chronic mitral regurgitation was undertaken. Variables determined included prevalence and duration of AF; incidence of new-onset or persistence of AF after surgery; rhythm changes in relation to age, gender, left atrial and ventricular dimensions and function, anti-arrhythmic drug usage and ECG P-wave duration in sinus rhythm prior to surgery. RESULTS: Only 4/47 (8.5%) patients with any history of AF before surgery were in sinus rhythm at six months after surgery. All 28 patients with persistent AF for >12 months and 41/45 (91%) in sinus rhythm before surgery retained these rhythms after surgery. The left atrial dimension was decreased after surgery, in the whole group (51.3 +/- 9.0 versus 48.4 +/- 9.5 mm; p = 0.011) and in the subgroup in sinus rhythm, but not in the subgroup in AF. The left ventricular end-diastolic dimension decreased in the group as a whole (60.6 +/- 6.2 versus 53.0 +/- 8.7 mm; p = 0.0001) and in both subgroups after surgery. In 24 patients with 12- lead ECGs in sinus rhythm before and three months after surgery, P-wave duration remained unchanged. However, this measure decreased in the 18 patients in sinus rhythm consistently, but increased in the six patients continuing to have paroxysmal AF after surgery. CONCLUSION: Mitral valve surgery alone restored sinus rhythm in only 8.5% of patients with any previous history of AF. Concomitant anti-arrhythmic procedures should be considered for all patients with AF who undergo mitral valve surgery.     

Atrial structural remodelling and restoration of atrial contraction after linear ablation for atrial fibrillation.

AIMS: We determined late atrial function following a surgical linear endocardial radiofrequency (RF) ablation procedure that aimed to restore and maintain sinus rhythm (SR) in atrial fibrillation (AF). We tested the hypothesis that successful restoration of SR is accompanied by measurable mechanical atrial function that is at normal or near normal levels. METHODS: Forty-seven patients who underwent the surgical RF procedure at least 6 months previously (median 2.86 years; range: 0.6-4.2 years) were studied using an array of echocardiographic variables. Two patient groups (SR restored [RF-SR], persistent AF [RF-AF]) and an age matched control group were studied. Among the echocardiographic variables measured were left atrial (LA) size and volume, LA active fractional emptying and mitral annular displacement corresponding to atrial contraction (A' velocity) by Doppler tissue imaging. RESULTS: At long term follow up 29/47of patients who underwent the RF procedure were in SR with atrial contraction present echocardiographically. Of the patients initially restored to SR, the proportion remaining in SR at 3 years was 79% (SE 9%). The atrial-emptying fraction was reduced in comparison to that seen in normal controls (27+/-14% vs 46+/-10%). The A' velocity was decreased in the surgical RF cohort vs controls (4.4+/-1.3 vs 9.7+/-1.7cm/s; P=0.0001). Despite LA size preoperatively being similar in both surgical groups, atrial size decreased in those in whom SR was restored (48.6+/-7.6 vs 44.8+/-4.7mm; P=0.0001) but increased in those in whom AF persisted (48.2+/-8.1mm vs 52.3+/-7.8mm; P=0.0001). CONCLUSION: The radial pattern of linear radiofrequency ablation used in the present study resulted in restoration of SR and atrial function. Procedural success was independent of preoperative atrial size. Restoration of SR results in 'reverse' atrial remodelling and improved atrial function. However atrial function remains modestly impaired, either due to the ablation lesions or pre-existing atrial disease.     

Efficacy of intra-operative radiofrequency ablation in patients with permanent atrial fibrillation undergoing concomitant mitral valve replacement

BACKGROUND: Permanent atrial fibrillation (AF) is present before operation and persists after surgery in 30-40% of patients undergoing mitral valve surgery. Using the maze procedure, 75-82% of patients can be cured of AF, but the procedure is difficult and long lasting. Percutaneous radiofrequency (RF) ablation has emerged as an effective therapy for AF in recent years. AIM: To assess the efficacy of intra-operative RF ablation of AF in patients undergoing mitral valve surgery. METHODS: 100 adults with permanent AF underwent mitral valve replacement. Patients were divided into two groups: the RF group--50 patients qualified for mitral valve replacement and RF ablation; and the control group--50 patients selected for mitral valve replacement without ablation. Odds ratio and 95% confidence interval were examined to assess the influence of several factors on the outcome (free from AF during one-year follow-up based on symptoms and serial Holter ECG recordings). RESULTS: Baseline clinical, demographic and echocardiographic characteristics were similar in both groups. Electrical cardioversion following surgery was required in 76% of patients from the RF group compared with 94% from the control group (p<0.002). In those who underwent cardioversion, sinus rhythm was restored more frequently in RF than control patients (32 vs. 16%, p<0.002). Sinus rhythm at hospital discharge was present in 56% of RF patients compared with 22% of controls (p=0.0001), and after one-year follow-up in 54 vs. 16% (p<0.001), respectively. The use of amiodarone was significantly lower in RF patients compared with controls (32 vs. 70%, p<0.05). NYHA class III (OR 8.5, CI 1.0-394) or IV (OR 36, CI 1.2-1958) and left atrial diameter >6 cm (OR 9.3, CI 0.5-5230) were identified as predictors of AF. CONCLUSIONS: Intra-operative RF ablation performed in the left atrium in patients with chronic AF undergoing mitral valve replacement significantly improves sinus rhythm restoration rate. Advanced heart failure (NYHA class IV) and left atrial diameter >6 cm are negative prognostic factors for sinus rhythm maintenance.     

Echocardiographic changes and predictors of arrhythmia recurrence after long-term use of the atrial defibrillator

BACKGROUND: The patient-activated atrial defibrillator allows patients to cardiovert themselves from atrial fibrillation soon after the onset of symptoms. The long-term effects of early cardioversion from persistent atrial fibrillation on left ventricular performance and left atrial size are unknown. METHODS: Eighteen patients, mean age 63.4, 83% male, had the Jewel((R)) AF atrial defibrillator implanted for persistent atrial fibrillation only. Transthoracic echocardiography was performed 3-monthly following implant. Parasternal long axis measurements were taken using conventional M-mode techniques. RESULTS: Over follow-up of 28.0+/-9 months, 377 episodes of persistent atrial fibrillation were terminated by patient-activated cardioversion (median 15 per patient). Echocardiographic measurements at implant were; left atrium 44+/-6 mm, left ventricular end-diastolic diameter 49+/-7 mm, left ventricular end-systolic diameter 34+/-7 mm, fractional shortening 33+/-10% and ejection fraction 65+/-17%. After 1 year there had been a significant decrease in mean left atrial size to 41+/-6 mm (P=0.02) and an increase in mean ejection fraction to 73+/-8% (P=0.04). At long-term follow-up however, all parameters reverted to pre-implant levels. Baseline echocardiographic variables did not predict which patients would demonstrate serial increases in sinus rhythm duration between shocks during long-term follow-up. Patients on antiarrhythmic drug therapy however were more likely to demonstrate "sinus rhythm begetting sinus rhythm". CONCLUSIONS: Use of the atrial defibrillator for spontaneous persistent atrial fibrillation is associated with a medium-term (1 year) reduction in left atrial size and an increase in ejection fraction. These changes were not maintained in the long-term. Synergistic therapy with antiarrhythmic drugs may prolong periods of sinus rhythm between arrhythmia recurrences.     

Partial left atriectomy in the treatment of atrial fibrillation associated with mitral valve disease]

BACKGROUND: Atrial fibrillation is frequently observed under conditions associated with atrial dilatation. Atrial size is a factor related to the genesis and maintenance of atrial fibrillation. Predictive parameters of persistence of atrial fibrillation after maze procedure are atrial size and long duration of atrial fibrillation. The aim of this study was to investigate the effects of surgical left atrial reduction in chronic atrial fibrillation by mitral valvulopathy. PATIENTS AND METHOD: nineteen patients with chronic atrial fibrillation and dilated left atrium undergoing mitral valve procedures were included in this prospective study: group I with left atrial reduction (10 patients) and group II including control (9 patients). Both groups were with similar preoperative characteristics. RESULTS: At the mean follow-up of 12 months, all the patients in group II had chronic atrial fibrillation, and 7 patients in group I showed in atrial rhythm (p < 0.003). The patients in whom atrial fibrillation continued after surgery showed left atrial area of 33.8 +/- 12.3 cm2 and a volume of 98.5 +/- 53.9 ml; and the patients with normal rhythm had a left atrial area of 24.5 +/- 5.3 cm2 and a volume 60.3 +/- 21.2 ml. CONCLUSIONS: Preliminary results indicate that surgical left atrial reduction in patients with chronic atrial fibrillation may be a mechanism implicated in the elimination of arrhythmia after surgery.     

Left atrial radiofrequency compartmentalization for chronic atrial fibrillation during heart surgery

BACKGROUND: The excellent results of the Maze III operation have demonstrated that a surgical cure of atrial fibrillation (AF) is possible. A simplified Maze procedure with radiofrequency (RF)ablation of the atrial tissue added to open heart surgery may help to cure chronic AF with low risk. METHODS: From May 1998 to March 2001, an RF left atrial compartmentalization concomitant to a cardiac surgical intervention was performed on 40 of 1,258 patients (3.2 %). Thirty-seven patients had mitral valve disease, two had aortic valve disease and one had coronary artery disease. All patients presented with chronic refractory AF for a mean time of 40.4 months ranging from 4 months to 18 years. RESULTS: Mitral valve replacement (MVR) was performed in 19 patients, mitral valve repair in 12, combined aortic and mitral valve procedures were performed in 6, aortic valve replacement(AVR) in 2 and CABG in 1 patient. Cardiopulmonary bypass time for the complete procedure was 138 +/- 32 minutes with an ablation time of 19 +/- 5 minutes. No complication related to RF application was noted. Sinus rhythm was present in 68% after 12.5 +/- 8.5 months. CONCLUSIONS: RF left atrial compartmentalization combined with cardiac surgical interventions proved to be easy and safe to perform. The long-term results still have to be confirmed with further regular patient follow-up examinations.     

Early and late results of permanent atrial fibrillation ablation surgery in aortic valve and CABG patients

OBJECTIVE: The study investigates the early and late results of permanent atrial fibrillation (AF) ablation surgery concomitant to coronary artery bypass grafting (CABG) and/or aortic valve (AV) surgery. METHODS: Between February 2001 and April 2006, a selective group of 80 patients with permanent AF (median: 48 months [Perc25/75 24/110; range: 6 - 360 months]) underwent either bipolar (n = 60) or monopolar (n = 20) radiofrequency (RF) ablation procedures concomitant to CABG and/or AV surgery (CABG: n = 39; AV: n = 30; AV + CABG: n = 11). All patients were restudied to assess survival, conversion rate to stable sinus rhythm (SR) and New York Heart Association (NYHA) class early (3 +/- 1 months) and late after surgery (30 +/- 15 months). Data were analyzed exploratively. RESULTS: Survival at 3 and 30 months was 98 % and 96 %, respectively. Stable SR could be documented in 73 % and 77 % of patients. Long-term AF before surgery and larger LA size were predictive for AF return after surgery ( P = 0.004 and P = 0.032, respectively). Neither age, gender, the application modus of the RF energy nor the underlying cardiac disease influenced the postoperative cardiac rhythm significantly. NYHA class improved significantly after surgery ( P < 0.0005), particularly when stable SR was achieved ( P = 0.049). CONCLUSION: Preoperative permanent AF duration time and larger LA size are useful variables to predict the success rate of concomitant ablation surgery in CABG and/or AV patients. Further it could be demonstrated that established SR remained stable over time.     

Serial evaluation of left atrial dimension after cardioversion for atrial fibrillation and relation to atrial function

The size of the left atrium is usually increased during atrial fibrillation (AF). The aim of the present study was to evaluate changes in left atrial (LA) dimension after cardioversion for AF, and the relation between LA dimension and atrial function. The initial study population included 171 consecutive patients. Patients who had spontaneous cardioversion to sinus rhythm (56 patients) were compared with patients who had random cardio-version with drugs (50 patients) or direct-current (DC) shock (50 patients). Echocardiographic evaluations included LA size and volume. LA passive and active emptying volumes were calculated, and LA function was assessed. Atrial stunning was observed in 18 patients reverted with DC shock and in 7 patients reverted with drugs. The left atrium was dilated in all patients during AF (48 +/- 5 mm). The size of the left atrium decreased after restoration of sinus rhythm in all patients with spontaneous reversion to sinus rhythm, in 73% of patients reverted with drugs, and in 50% of patients reverted with DC shock. The comparison between patients with a normal mechanical atrial function and patients with reduced atrial function showed that a higher atrial ejection force was associated with a more marked reduction in LA size after restoration of sinus rhythm. A relation between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanical function (r = -0.78; p <0.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. Thus, a depressed atrial mechanical function after cardioversion for AF was associated with a persistence of LA dilation.     

Short-term sinus rhythm predicts long-term sinus rhythm and clinical improvement after intraoperative ablation of atrial fibrillation

Aims: Our aim was to compare the long-term effects on rhythm and qualityof life (QoL) after left atrial epicardial radiofrequency (RF)ablation vs. no ablation in patients undergoing cardiac surgery. Methods and results: Thirty-nine patients with ECG documented atrial fibrillation(AF) scheduled for coronary artery bypass grafting (CABG) withor without concomitant valve surgery were consecutively electedfor epicardial RF ablation. Thirty-nine age- and gender-matchedpatients scheduled for CABG with or without concomitant valvesurgery only and with documented AF served as controls. Thefollow-up after ablation was 32 ± 11 months. The percentageof patients in sinus rhythm (SR) at long-term follow-up was62 vs. 33% (P = 0.03) after ablation and no ablation, respectively.SR at 3 months was highly predictive of that at 32 months (sensitivity95%, positive predictive value 86%). Long-term SR was associatedwith better QoL, fewer symptoms, higher ejection fraction, andsmaller left and right atria than AF. Conclusion: SR at 3 months was highly predictive of long-term SR that wasassociated with clinical improvement when compared with patientsstill in AF. AF at 3 months did not preclude a later stabilizationto SR.     

Acute effects of left atrial radiofrequency ablation on atrial fibrillation

INTRODUCTION: Acutely, when left atrial ablation is performed during atrial fibrillation (AF), the AF may persist and require cardioversion, or it may convert to sinus rhythm or to atrial tachycardia/flutter. The prevalence of these acute outcomes has not been described. METHODS AND RESULTS: Left atrial ablation, usually including encirclement of the pulmonary veins, was performed during AF in 144 patients with drug-refractory AF. Conversion to sinus rhythm occurred in 19 patients (13%), to left atrial tachycardia in 6 (4%), and to atrial flutter in 6 (4%). In the 6 patients with a focal atrial tachycardia, the mean cycle length was 294 +/- 45 ms. The tachycardia arose in the left atrial roof in 3 patients, the left atrial appendage in 2, and the anterior left atrium in 1. In 3 of 6 patients, the focal atrial tachycardia originated in an area that displayed a relatively short cycle length during AF. In 6 patients, AF converted to macroreentrant atrial flutter with a mean cycle length of 253 +/- 47 ms, involving the mitral isthmus in 5 patients and the septum in 1 patient. All atrial tachycardias and flutters were successfully ablated with 1 to 15 applications of radiofrequency energy. CONCLUSION: When left atrial ablation is performed during AF, the AF may convert to atrial tachycardia or flutter in approximately 10% of patients. Focal atrial tachycardias that occur during ablation of AF may be attributable to driving mechanisms that persist after AF has been eliminated, whereas atrial flutter results from incomplete ablation lines.