Biatrial radiofrequency ablation for atrial fibrillation: epicardial and endocardial surgical approach

Radiofrequency energy applied by means of surgical probes permits the ablation of atrial fibrillation (AF). This study presents our initial experience on 55 consecutive cardiac patients with permanent AF with radiofrequency ablation through biatrial epicardial and endocardial surgical approach. At discharge, 8.1% of the patients had persistent AF-atrial flutter. Hospital incidence of arrhythmias were, 9% of paroxysmal atrial fibrillation, 10.9% of atrial flutter, and 34.5% of persistent atrial fibrillation. After a mean follow-up of 7 months, 83.6% patients have recovered sinus rhythm, and echocardiographic biatrial contraction was re-established in 73%. Biatrial radiofrequency ablation applied from the endocardium and the epicardium has achieved satisfactory results, without increasing the surgical risk.     

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.     

Surgical ablation of atrial fibrillation using the epicardial radiofrequency approach: mid-term results and risk analysis

BACKGROUND: The minor technical and time requirements with respect to the maze operation combined with a comparable efficacy has led to an increasing popularity of left atrial approaches to treat atrial fibrillation. We report our experience with a left atrial procedure based on extensive use of epicardial radiofrequency ablation in an effort to minimize cardiac arrest time. METHODS: A total of 132 consecutive patients with atrial fibrillation (121 chronic, 11 paroxysmal) undergoing open heart surgery had combined intraoperative ablation. An original set of left atrial lesions was performed using a radiofrequency linear catheter. Most of the ablations were performed epicardially before aortic cross-damping. Patients with contraindications to the epicardial approach had the whole lesion set performed endocardially. RESULTS: The mean cardiac arrest time spent for open heart ablations was significantly shorter (5.2 +/- 0.9 minutes with modem catheters) when the epicardial approach was used (107 of 132 patients, 81%). Hospital mortality was 0.8%. Freedom from atrial fibrillation was 77% 3 years after the operation. Of all the variables analyzed, only age at surgery and early postoperative arrhythmias increased the risk of recurrent atrial fibrillation. Overall 3-year survival was 94%. The 3-year actuarial freedom from stroke was 98%. No patient required implantation of a permanent pacemaker. Atrial contractility was recovered in all patients with stable sinus rhythm. CONCLUSIONS: Left atrial radiofrequency ablation allows recovery of sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who undergo open heart surgery. The epicardial radiofrequency approach is a safe and effective means to cure atrial fibrillation with negligible technical and time requirements.     

Chronic transmural atrial ablation by using bipolar radiofrequency energy on the beating heart

BACKGROUND: Recently, there has been renewed interest in the development of minimally invasive procedures to treat atrial fibrillation. Unipolar radiofrequency catheters are plagued by poor results, in part because of their inability to produce transmural lesions. This study tested the ability of bipolar radiofrequency energy to create chronic transmural lesions on the beating heart that isolated atrial myocardium. METHODS: Five sheep underwent a right thoracotomy. Baseline pacing was performed from the following targeted areas: right atrial appendage, superior vena cava, inferior vena cava, and right pulmonary veins. A cuff of atrial myocardium around the targeted tissue was clamped between the 2 arms of the device. Radiofrequency energy was delivered at 750 mA and continued until the tissue conductance between the electrodes reached a stable minimum level. After ablation, pacing was used to document tissue isolation. The animals survived for 30 days. RESULTS: Twenty circumferential lesions were produced at the initial operation. The mean ablation time was 9.3 +/- 4.0 seconds, and the mean peak temperature was 48.4 degrees C +/- 6.4 degrees C. All lesions acutely and chronically isolated the targeted tissue. Trichrome staining showed that all lesions were transmural. There were no instances of pulmonary vein stenosis or thrombosis. CONCLUSIONS: Bipolar radiofrequency energy can produce permanent transmural linear lesions on the beating heart. Online measurement of tissue conductance reliably predicted lesion transmurality. This new technology may enable surgeons to perform a curative minimally invasive operation for atrial fibrillation on the beating heart.     

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).     

Epicardial ablation of atrial fibrillation on the beating heart without cardiopulmonary bypass

The Cox-Maze procedure is the gold standard in surgical treatment of atrial fibrillation. Alternative techniques using cryoablation, radiofrequency, or microwaves have been proven to be equally effective. However, up to now, all techniques require the opening of the atria and, hence, the use of extracorporeal circulation. We describe a technique to perform epicardial ablation of atrial fibrillation on the beating heart without the use of cardiopulmonary bypass.     

Off-pump epicardial compartmentalization for ablation of atrial fibrillation

The Cox-Maze-III procedure still remains the gold standard in surgical treatment of atrial fibrillation. The major hazard of atrial fibrillation is thromboembolic event to the brain. Left atrial appendage (LAA) represents the source of thrombus and subsequent embolism although LAA obliteration is a key point to prevent thrombogenesis. We describe a simplified off-pump compartmentalization procedure using epicardial radiofrequency ablation of the left atrium and LAA stapling on the beating heart without cardiopulmonary bypass.     

Epicardial radiofrequency ablation for chronic atrial fibrillation undergoing simultaneous on-pump beating coronary artery bypass grafting

Off-pump coronary artery bypass grafting has become an attractive surgical alternative for myocar-dial revascularization because of the advantage of myocardial protection and other benefits of patients. However, it is still regarded as a controversial treatment for the coronary artery disease accompanied by atrial fibrillation (AF). A significant number of patients in need of coronary revascularization have chronic AF. Although the Cox-Maze III procedure is the gold standard for the surgical treatment of AF, few of these patients undergo AF operations at the time of their coronary bypass grafting. We report herein a case of the pulmonary vein isolation to eliminate the AF by means of epicardial radiofrequency ablation combined with 2 vessels coronary artery bypass grafting on the beating heart with the aid of cardiopulmonary bypass.     

射频消融迷宫术治疗心房纤颤

作者采用射频消融迷宫术治疗心房纤颤２０例，其中１９例合并风湿性二尖瓣病的患者，同时行瓣膜替换术，１例合并房间隔缺损患者进行修复。射频消融的路线采用小板井嘉夫的手术径路。术后１６例恢复窦性心律，占８０％，未恢复窦性心律的４例，２例为房颤，１例为房扑，另１例为结性心律。射频消融迷宫术耗时短，仅增加钳闭主动脉时间平均２０．５分钟，无术后出血的潜在危险。但术后７～１０天之内，有１８例出现过房颤、房扑、房速等室上性心律失常，可能由于射频消融不均匀，干扰心房的心电活动所致。     

射频消融迷宫治疗心房纤颤

作者采用射频消融迷宫术治疗心房纤颤２０例,其中１９例合并风湿性二尖瓣病的患者,同时行瓣膜替换术,１例合并房间隔缺损患者进行修得。射频消融的路线采用小板井嘉夫的手术径路。术后１６例恢复窦性心律,占８０％,未恢复窦性心律的４例,２例为房颤,１例为房扑,另１例为结性心律。     

Experience with unipolar radiofrequency ablation for atrial fibrillation

BACKGROUND: The cut and sew Cox maze procedure for atrial fibrillation (AF), although effective, is not widely used because of technical complexity, prolonged duration and significant risk of postoperative bleeding. This study reviews our experience with the unipolar radiofrequency ablation (RFA) procedure, which was used to create a modified maze to treat AF. METHODS: A retrospective review of 31 patients undergoing consecutive cardiac surgery who had concomitant RFA for AF over a 16-month period was carried out. A Cobra unipolar RFA probe (EPT; Boston Scientific, San Jose, CA, USA) was used to create a standard set of lesions. RESULTS: There were 20 men and 11 women (mean age, 66 +/- 9 years; range, 48-87 years). AF was continuous in 21 patients and intermittent in 10. The median duration of AF leading up to surgery was 48 months (range, 6 months-20 years). Left atrium was enlarged in 81% of the patients. Operations included mitral valve repair (7 patients), replacement (5), coronary artery bypass (10), aortic valve replacement (1) and combined procedures (8). There were no complications directly attributable to RFA. There were three early deaths. One patient required a permanent pacemaker. Median follow up was 22 months (range, 12-30 months). One patient died 2 years after the operation from a stroke. Cardioversion was attempted in five patients within 3 months of operation and was successful in four. At 2 years following the procedure, the probability of the patient remaining in sinus rhythm was 0.71 +/- 0.15. CONCLUSION: Surgical RFA can be carried out as a useful adjunct to conventional cardiac surgery. Although the results were satisfactory in this series, further studies are needed to refine the indication of the procedure and to assess its longer-term efficacy.     

Hemodynamic changes during displacement of the beating heart using epicardial stabilization for off-pump coronary artery bypass graft surgery

OBJECTIVE: To evaluate the hemodynamic alterations during off-pump coronary artery bypass graft surgery to determine the degree of impairment caused and the techniques to rectify them. DESIGN: Prospective, observational cohort study performed from January 2000 through September 2000. PARTICIPANTS: Patients (n = 500) with coronary artery disease undergoing multivessel off-pump coronary artery bypass graft surgery using the Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, MN). Unstable patients with ongoing ischemia were excluded from the study. INTERVENTIONS: All patients were monitored with radial artery and pulmonary artery catheters and continuous transesophageal echocardiography monitoring with a multiplane transducer. The perioperative requirement of an intracoronary shunt, inotropes, or an intra-aortic balloon pump was noted. The effect of the Trendelenburg position and fluids on hemodynamics was observed. The need for defibrillation and institution of emergency cardiopulmonary bypass were major endpoints to determine the inability of the patient to tolerate displacement of the heart. MEASUREMENTS AND MAIN RESULTS: Mean patient age was 59.3 +/- 11.6 years. There were 204 (40%) patients in the high-risk category; 54 (10.8%) patients had left ventricular ejection fraction <25%. The mean number of grafts was 2.7 +/- 0.8. Vertical displacement of the heart to access the lateral and inferior walls decreased the mean arterial pressure by 18 +/- 4% (p < 0.01), with a concomitant increase in central venous pressure of 66 +/- 18% (p < 0.001). The stroke volume and the cardiac index were reduced by 35.7 +/- 11% (p < 0.001) and 45 +/- 13% (p < 0.001). On transesophageal echocardiography, there was development of new regional wall motion abnormalities in 59.2% and a decrease in global left ventricular functions in 61.2%. The use of inotropes was highest during anastomosis on the posterior wall-78.4% compared with 21.9% for the anterior wall. An intra-aortic balloon pump was used in 55 (11.2%) patients, and 7 (0.71 %) patients had to be put on emergency CPB. The in-hospital mortality was 1.2%. CONCLUSION: Most patients had hemodynamic changes easily correctable by fluids and inotropes. Monitoring of left ventricular and right ventricular function by transesophageal echocardiography enhances safety of the procedure and is recommended. The use of the Octopus II tissue stabilizer proved to be a safe and versatile means to stabilize the heart during off-pump coronary artery bypass procedures, especially in high-risk patients.     

心外科手术同期行双极射频消融术治疗房颤

目的 总结应用双极射频消融术在心外科手术同期治疗房颤的疗效,探讨房颤近期疗效的影响因素.方法 2007年6月至2010年2月,81例房颤患者被纳入研究.其中男45例,女36例;年龄(48.2±11.0)岁.合并先天性心脏病8例,冠心病16例,风湿性心脏病57例.房颤持续(7.56±7.47)年,其中永久性房颤26例,持续性房颤44例,阵发性房颤11例.左房直径36～ 72mm,其中小于60 mm者65例.术前心功能Ⅱ-Ⅳ级.应用Atricure双极消融系统49例,Metronic单双极消融系统32例.2009年6月至2010年2月期间22例患者进行房颤标测.所有患者均按照迷宫IV径路行双极房颤射频消融手术,同期行非体外循环冠状动脉旁路移植术(OPCAB) 16例,二尖瓣置换术(MVR)[或+三尖瓣成形术(TVP) ]33例,MVR+冠状动脉旁路移植术(CABG)1例,二尖瓣成形术(MVP)1例,主动脉瓣置换术(AVR)4例,二尖瓣主动脉瓣置换术(DVR)(或+TVP)18例,先心纠治8例.术后随访12 ～44个月.结果 住院期间死亡1例,无远期死亡.体外循环(105.0±26.9) min,主动脉阻断(64.1±21.4) min(OPCAB病例除外).术后即刻、出院时及平均随访(26.1±13.6)个月时房颤消融成功率分别为100％、82.5％及84.8％.左房内径小于60mm、房颤标测患者消融成功率显著提高(P＜0.05).结论 心外科手术同期行双极房颤射频消融术是安全有效的.左房内径小于60 mm、房颤标测为影响房颤近期疗效的独立影响因素,可能带来更佳的消融结果.