A randomized double-blind study of epicardial left atrial cryoablation for permanent atrial fibrillation in patients undergoing mitral valve surgery: The SWEDish Multicentre Atrial Fibrillation study (SWEDMAF)

Department of Cardiology, Uppsala University Hospital, SE-75185 Uppsala, Sweden.
European Heart Journal (Impact Factor: 15.2). 01/2008; 28(23):2902-8. DOI: 10.1093/eurheartj/ehm378
Source: PubMed


The efficacy of epicardial left atrial (LA) cryoablation in eliminating atrial fibrillation (AF) in patients undergoing mitral valve surgery (MVS) is unknown. We hypothesized that MVS combined with LA cryoablation is superior to MVS alone.
Sixty-nine patients with permanent AF, included at four centres, underwent MVS with or without epicardial LA cryoablation. The primary endpoint was regained sinus rhythm. Risk factors for failed AF cryoablation were elucidated. Sixty-five out of 69 patients reached the primary endpoint. At 6 and 12 months follow-up, 73.3% of patients who underwent cryoablation had regained sinus rhythm at both follow-ups, compared with 45.7 and 42.9% of patients, respectively, who underwent MVS alone (group differences, at 6 months P = 0.024, after 12 months P = 0.013). The in-hospital complication rate was 11.4% in the MVS group and 26.5% in the cryoablation group (P = 0.110). Risk factors for failed elimination of AF by cryoablation were duration of permanent AF (P = 0.012) and presence of coronary artery disease (P = 0.047), according to multiple logistic regression analysis.
This first prospective randomized study showed that combining MVS with epicardial LA cryoablation is significantly better in eliminating pre-operative permanent AF than MVS alone.

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    • "Since the maze operation for the treatment of AF was introduced in 1987 [4], it has been simplified by replacing most incisions for making the mazes with cryoablation or radiofrequency (RF) ablation [5]. Some randomized trials have demonstrated an excellent conversion rate of the sinus rhythm (SR) with RF ablation [6], but, 20% to 30% of those undergoing the maze operation showed recurrent AF during the follow-up period [7]. An enlarged left atrium (LA) was a major factor in the initiation and maintenance of AF [8] and LA volume reduction was helpful for the elimination of AF in patients undergoing mitral valve surgery [9]. "
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    ABSTRACT: We examined perioperative predictors of sustained sinus rhythm (SR) in patients undergoing the Cox maze operation and concomitant cardiac surgery for structural heart disease. From October 1999 to December 2008, 90 patients with atrial fibrillation (AF) underwent the Cox maze operation and other concomitant cardiac surgery. Eighty-nine patients, all except for one postoperative death, were followed-up with serial electrocardiographic studies, 24-hour Holter monitoring tests, and regular echocardiographic studies. Eighty-nine patients undergoing the maze operation were divided into two groups according to the presence of SR. At the time of last follow-up (mean follow-up period, 51.0±30.8 months), 79 patients (88.8%) showed SR (SR group) and 10 patients (11.2%) had recurrent AF (AF group). Factors predictive of sustained SR were the immediate postoperative conversion to SR (odds ratio, 97.2; p=0.001) and the presence of SR at the 6th month postoperatively (odds ratio, 155.7; p=0.002). Duration of AF, mitral valve surgery, number of valves undergoing surgery, left atrial dimension, and perioperative left ventricular dimensions and ejection fractions were not predictors of postoperative maintenance of SR. Immediate postoperative SR conversion and the presence of SR at the 6th postoperative month were independent predictors of sustained SR after the maze operation.
    Full-text · Article · Apr 2013 · Korean Journal of Thoracic and Cardiovascular Surgery
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    • "These studies enrolled only patients scheduled for mitral valve surgery—thus, the efficacy of surgical ablation in patients undergoing other types of surgery, e.g. coronary artery bypass graft (CABG) or aortic valve replacement (AVR), is even less well established, with one study showing an increased rate of peri-operative complications in the ablation group.12 Most studies were able to demonstrate sinus rhythm (SR) restoration rates, but whether this has any (positive or negative) impact on major clinical events is not known. "
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    ABSTRACT: AimsSurgical ablation procedure can restore sinus rhythm (SR) in patients with atrial fibrillation (AF) undergoing cardiac surgery. However, it is not known whether it has any impact on long-term clinical outcomes.Methods and resultsThis multicentre study randomized 224 patients with AF scheduled for valve and/or coronary surgery: group A (left atrial surgical ablation, n = 117) vs. group B (no ablation, n = 107). The primary efficacy outcome was the SR presence (without any AF episode) during a 24 h electrocardiogram (ECG) after 1 year. The primary safety outcome was the combined endpoint of death/myocardial infarction/stroke/renal failure at 30 days. A Holter-ECG after 1 year revealed SR in 60.2% of group A patients vs. 35.5% in group B (P = 0.002). The combined safety endpoint at 30 days occurred in 10.3% (group A) vs. 14.7% (group B, P = 0.411). All-cause 1-year mortality was 16.2% (A) vs. 17.4% (B, P = 0.800). Stroke occurred in 2.7% (A) vs. 4.3% (B) patients (P = 0.319). No difference (A vs. B) in SR was found among patients with paroxysmal (61.9 vs. 58.3%) or persistent (72 vs. 50%) AF, but ablation significantly increased SR prevalence in patients with longstanding persistent AF (53.2 vs. 13.9%, P < 0.001).Conclusion Surgical ablation improves the likelihood of SR presence post-operatively without increasing peri-operative complications. However, the higher prevalence of SR did not translate to improved clinical outcomes at 1 year. Further follow-ups (e.g. 5-year) are warranted to show any potential clinical benefit which might occur later.
    Full-text · Article · Aug 2012 · European Heart Journal
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    • "For mitral and atrial septal defect (ASD) patients, the endocardial approach was used with a box lesion around all four pulmonary veins (PV) and a connecting lesion to the mitral annulus, either as a left atrial procedure alone (endoLA group), or more recently, as a cryo-maze procedure (cryo-maze group) with surgical endocardial ablations in both atria mimicking the full CM III lesion set [6]. In aortic valve replacement (AVR) and coronary artery bypass graft (CABG) cases, in which the atria are not naturally opened, an epicardial left atrial approach (epiLA group) was used, with ipsilateral pair-wise PV isolation and connecting epicardial lesions between the right and left PVs, and to the mitral annulus on the posterior surface of the LA [9]. Basically, all left atrial cryolesions in this series were performed on the cardioplegia arrested heart, for 90 seconds reaching local temperatures of –130 °C. "
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    ABSTRACT: Atrial fibrillation (AF) in cardiac surgical patients is detrimental in the long perspective. Concomitant surgical ablation of AF is recommended in guidelines and performed in most centers. The article describes the experiences in a single institution with concomitant surgical argon-based cryoablation in 115 patients using three different application techniques (epicardial left atrium, endocardial left atrium, biatrial cryo-maze) and a structured local follow-up to one year postoperatively. Results showed cryoablation to be safe with few complications related to the ablation procedure and few thromboembolic events. In this study, a complete biatrial lesion set according to the classic Cox-maze III (CM III) lesion pattern yielded a higher success rate than left atrial procedures. At 12 months, patients in sinus or pacing rhythm, free of AF without antiarrhythmic drugs, were 27/39 (69%), 24/32 (74%) and 36/44 (82%) in the EpiLA, EndoLA and cryo-maze groups, respectively. A consistent prospective follow-up is essential not only for research purposes but also for assessing the local results of AF surgery in everyday practice. It may direct and develop the surgical ablation program, guide individual postoperative arrhythmia management and is needed to increase overall quality of surgical AF ablation.
    Preview · Article · Aug 2011 · Interactive Cardiovascular and Thoracic Surgery
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