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.     

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.     

Beating-heart surgical treatment of atrial fibrillation with microwave ablation

BACKGROUND: In this feasibility study, early results are presented of our first series of patients with microwave ablation for atrial fibrillation (AF) on the beating heart. METHODS: From June 2001 until December 2001, a total of 24 patients underwent beating-heart epicardial ablation for AF. With a microwave antenna, the left and right pulmonary veins were isolated and connected to each other followed by amputation of the left atrial appendage. Subsequently, patients underwent either off-pump coronary artery bypass graft or valve surgery on pump. The mean age of the patients was 67.4 +/- 6 years. Three patients experienced paroxysmal atrial fibrillation and all others chronic AF. Mean left atrial diameter was 5.4 +/- 0.6 cm, and mean ablation time was 13 min. RESULTS: All procedures but one were completed successfully on the beating heart. All patients were in sinus rhythm after the procedure. A total of 15 patients experienced periods with postoperative AF during hospital stay; 9 of these patients were discharged with AF. All patients received either sotalol or amiodarone. At latest follow-up (3 to 9 months), 20 of 23 patients were in sinus rhythm. CONCLUSIONS: With microwave ablation, electrical isolation of the pulmonary veins can be achieved epicardially without cardiopulmonary bypass support.     

Microwave ablation of atrial fibrillation during mitral valve operations

Although the Cox-Maze III procedure cures atrial fibrillation in the majority of patients, it has not had widespread application. Development of new operations that use alternate energy sources and different lesion sets have caused resurgence in the surgical treatment of atrial fibrillation. Microwave creates lines of conduction block by thermal damage and subsequent scar formation. We describe a rapid and simple technique for microwave ablation of atrial fibrillation in patients having mitral valve operations.     

A fatal complication due to radiofrequency ablation for atrial fibrillation: atrio-esophageal fistula

Treatment of chronic atrial fibrillation with intraoperative radiofrequency ablation is gaining more acceptance in patients with rheumatic valve disease. This article reports a case of fatal atrio-esophageal fistula after radiofrequency ablation in a patient with rheumatic mitral and aortic valve disease with chronic atrial fibrillation.     

Intraoperative left atrial ablation (for atrial fibrillation) using a new argon cryocatheter: early clinical experience

PURPOSE: Recently surgical treatment of atrial fibrillation has gained more popularity and presently is being performed in large numbers of patients. This report describes our early experience in treatment of patients with chronic or paroxysmal atrial fibrillation with a new tool for left atrial cryoablation. DESCRIPTION: From July 2002 through January 2003, 28 patients underwent left atrial cryoablation with the Surgifrost CryoCath. Patients underwent cryotherapy as an isolated procedure (n = 1), in combination with mitral valve surgery (n = 13), or with other surgical procedures (n = 14). In all patients contiguous lesion lines to the orifices of the pulmonary veins connected to the mitral annulus and the atriotomy were created. Surgery was performed through a conventional sternotomy in 8 patients (29%) and a right lateral minithoracotomy using video-assistance in 20 patients (71%). EVALUATION: Postoperatively sinus rhythm was restored in 27 patients (96%). At discharge 82% (23/28) of patients were in sinus rhythm and 18% (5/28) were in atrial fibrillation. Four patients (14%) required pacemaker implantation. There was no in-hospital mortality. At 6-months follow-up (19/28 patients) all were alive and 74% were in stable sinus rhythm, New York Heart Association functional class was 1.2 +/- 0.4. CONCLUSIONS: As indicated by our small and early patient cohort left atrial cryoablation with the Surgifrost argon cryocatheter is effective for the treatment of atrial fibrillation. This new device is technically easy to handle, it can be applied through a median sternotomy or lateral minithoracotomy. Long-term follow-up is necessary to evaluate further rhythm outcome.     

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.