Atricure bipolar radiofrequency clamp for intraoperative ablation of atrial fibrillation

PURPOSE: This work reports our initial evaluation and clinical experience with the Atricure bipolar radiofrequency (RF) system for intraoperative ablation of atrial fibrillation (AF). DESCRIPTION: The Atricure system includes a bipolar RF clamp and an RF generator. Lines of conduction block are created by delivery of RF energy (75 volts, 750 milliamps) to tissue compressed between the jaws of the clamp. Energy delivery is continued until the lesion is transmural, indicated by steady and reduced conductance between electrodes in the clamp. EVALUATION: The Atricure device was used for intraoperative treatment of AF in 120 patients. Lesion sets varied, as the device was used for pulmonary vein isolation, creation of right atrial lesions, or both. There were no device-related complications. Initial incomplete pulmonary vein isolation, identified by pacing, was uncommon, occurring with very thick atrial tissue and when tightening the clamp caused tissue to become folded upon itself in the jaws or to extrude beyond the jaws of the clamp. In such cases, reapplication of the RF clamp produced complete pulmonary vein isolation. CONCLUSIONS: The Atricure bipolar RF system facilitates surgical treatment of AF. Proper application of the clamp is essential to ensure continuous transmural lesions.     

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.     

Epicardial radiofrequency ablation of both atria in the treatment of atrial fibrillation: experience in patients

BACKGROUND: Despite success with the Maze procedure and its modifications in treating atrial fibrillation, longer procedure times and increased morbidity have precluded widespread use. The operative treatment for atrial fibrillation associated with aortic valve disease and ischemic heart diseases have not been established. We report the early results of epicardial radiofrequency coagulation on both atria and discuss the availability of this procedure. METHODS: The Australasian database of radiofrequency ablation lists 130 patients with established or frequent intermittent atrial fibrillation that underwent various cardiac surgical procedures between March 2000 and March 2002. Forty patients without mitral valve disease underwent epicardial radiofrequency coagulation on both atria. Twenty-eight patients were in established chronic atrial fibrillation, 9 in paroxysmal atrial fibrillation, and 3 patients had atrial flutter. The primary surgical procedures were coronary artery bypass grafting in 19 patients, aortic valve replacement in 9, coronary artery bypass grafting plus aortic valve replacement in 8, and other procedures in 4 patients. RESULTS: The procedure increased the cross-clamp time by a mean of 10 minutes. Three patients required defibrillation postoperatively, within the first 3 months and have since stayed in sinus rhythm. One patient had late atrial flutter that was cardioverted to sinus rhythm. Sinus recovery rate was 93.7% (15 of 16 patients) at 6 months and 100% in 8 patients reviewed at 12 months. Atrial contractility was maintained. CONCLUSIONS: Epicardial radiofrequency coagulation may be a very effective way of converting patients with atrial fibrillation into sinus rhythm.     

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.     

Repair of left atrial-esophageal fistula following percutaneous radiofrequency ablation for atrial fibrillation

Atrial-esophageal fistula is a rare but often fatal complication of percutaneous radiofrequency ablation for atrial fibrillation. We present a patient who was diagnosed with this complication in a delayed fashion and successfully treated with primary repair via left thoracotomy. The details of the surgical approach are discussed.     

Cox/Maze III operation versus radiofrequency ablation for the surgical treatment of atrial fibrillation: a comparative study

BACKGROUND: The purpose of this study was to evaluate the efficacy of radiofrequency (RF) ablation in the treatment of atrial fibrillation, by comparatively analyzing the outcomes of the patients who underwent RF ablation with those of patients who underwent Cox/Maze III surgery. METHODS: Between April 1995 and June 2002, 70 patients underwent surgery for atrial fibrillation and open-heart surgery at the Department of Cardiovascular Surgery of the University of Bologna: 30 patients underwent the surgical Cox/Maze III procedure (group 1), and 40 patients underwent the RF ablation according to the Maze III configuration at least on the left atrium (group 2). There were 14 males and 56 females, with a mean age of 61.5 +/- 12.5 years (range 22 to 80 years old). RESULTS: Groups 1 and 2 did not differ in terms of baseline characteristics. The perioperative mortality rate was not significantly different between the two groups (6.6% in group 1 vs 7.5% in group 2). The overall cumulative rates of sinus rhythm were 68.9% in group 1 and 88.5% in group 2 (not statistically significant). Biatrial contraction was assessed by transthoracic echocardiography in 70.4% of the patients in group 1 and 76.5% of the patients in group 2 (p = 0.65). CONCLUSIONS: The RF ablation procedure offers as good results as the Cox/Maze III operation, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent open heart surgery; it is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements.     

Intraoperative saline-irrigated radiofrequency modified Maze procedure for atrial fibrillation

BACKGROUND: This study was conducted to evaluate the effectiveness of the saline-irrigated radiofrequency modified Maze operation for treatment of chronic atrial fibrillation, and to compare the results of the left and biatrial procedures. METHODS: During a period of 11 months, 62 patients with chronic atrial fibrillation who were having concomitant cardiac surgery underwent the procedure. The mean age of the patients was 52 +/- 14 years. Patients underwent either a biatrial (group A; n = 39) or left atrial (group B; n = 23) procedure. RESULTS: Two patients (3.2%) died early in the postoperative period. Three patients (4.8%) required reoperation for bleeding. One patient in group A (1.6%) received a permanent pacemaker. Patients in both groups were free of atrial fibrillation at the end of the procedure (group A: sinus 86.9%, pacemaker 13%; group B: sinus 90.5%, pacemaker 9.5%) (p > 0.05). At 1-month and longer-term follow-up, sinus rhythm was maintained in 92% and 95% of cases in group A, respectively, whereas this rate was 71% and 81% in group B (p > 0.05). Holter monitor surveillance revealed a higher rate of atrial fibrillation, atrial arrhythmias, and atrial flutter in group B (p < 0.05). Transthoracic echocardiography revealed improvement over time in left atrial transport function in both groups (p < 0.05). CONCLUSIONS: The saline-irrigated radiofrequency modified Maze procedure was performed safely and efficiently. Both the left and biatrial procedures were successful in terms of restoring sinus rhythm during short-term follow-up. Long-term follow-up with more cases is needed to show the superiority of one method over the other.     

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.     

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).