Successful Performance of Cox-Maze Procedure on Beating Heart Using Bipolar Radiofrequency Ablation: A Feasibility Study in Animals

Objective Bipolar radiofrequency ablation recently has been used to replace many of the incisions of the Cox-Maze procedure in the surgical treatment of atrial fibrillation. The unique aspect of this technology is that it uses an algorithm based on changes in tissue conductance to determine the energy required to achieve a transmural lesion instead of relying on predetermined time and/or temperature criteria to determine ablation duration, as with most other ablation technologies. The purpose of this study was to determine variations in the different parameters of ablation needed to create transmural lesions in human atria. Methods Initial impedance, total energy, temperature, and ablation time were measured in 38 patients undergoing surgery, using an impedance-controlled bipolar radiofrequency device (AtriCure Isolator, Cincinnati, OH). Lesions were categorized into the following groups: right atrial free wall, left atrial free wall, atrium up to mitral valve annulus, atrium up to tricuspid valve annulus, and right or left pulmonary veins. Results There was a wide range of initial impedance (32.3 to 760.7 Ohms), and this correlated with total energy delivered (r = −0.31, P = 0.002). Ablation times varied widely (2.0 to 29.9 seconds) and were longer on left atrial structures than right (P < 0.005) and shortest near the tricuspid annulus (P < 0.001). Mean tissue temperature 1 mm from the electrode was only 45.7 ± 7.8°C (range, 23.7°C to 69.3°C). Conclusions Bipolar ablation of different atrial structures required widely different amounts of energy and ablation times, probably as the result of the inhomogeneity of atrial geometry and tissue impedance. These data cast doubt on the efficacy of any fixed-time or temperature ablations in the clinical setting.

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Modified mini-maze via left thoracic cavity under VATS for paroxysmal atrial fibrillation in a patient with complete interruption of the inferior vena cava

10.22541/au.161080830.05435158/v1 ◽

2021 ◽

Author(s):

Fan He ◽

Bijun Xu ◽

Shiqiang Wang ◽

Huai-Dong Chen ◽

Weimin Zhang

Keyword(s):

Atrial Fibrillation ◽

Radiofrequency Ablation ◽

Inferior Vena Cava ◽

Left Atrium ◽

Inferior Vena ◽

Vena Cava ◽

Maze Procedure ◽

Thoracic Cavity ◽

Left Chest ◽

Bipolar Radiofrequency

Objectives: We sought to determine the technical feasibility of surgical bipolar radiofrequency ablation (endoscopic maze procedure) through the left chest cavity in patients with an interrupted inferior vena cava (IVC). Methods and Results: A 57-year-old female with paroxysmal atrial fibrillation (AF) and an interrupted IVC was referred to our hospital for radiofrequency ablation. Transseptal puncture and left atrium (LA) ablation failed through a standard IVC approach via the femoral vein due to intrahepatic interruption of IVC. We performed a modified surgical bipolar radiofrequency ablation (RF) on the beating heart through 3 ports in the left chest wall. Pulmonary vein isolation and ablation of the left atrium were achieved by bipolar radiofrequency ablation. Ganglionic plexus ablation was completed using the ablation pen. The left atrial appendage was excluded. No complications occurred during or after the procedure. The patient was discharged with sinus rhythm 3 days later after the procedure. She was taking amiodarone (100mg bid) within 6 months after the procedure, and had no recurrence of AF. Conclusions: We successfully performed a modified mini-maze procedure in a patient with paroxysmal AF and IVC interruption through the left thoracic cavity under video-assisted thoracoscopic surgery (VATS). We can successfully complete pulmonary vein (PV) isolation, left atrium box isolation, cardiac ganglia ablation, Marshall ligament ablation, and coronary sinus epicardium ablation using this technique.

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Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: A long-term porcine study

Journal of Thoracic and Cardiovascular Surgery ◽

10.1016/j.jtcvs.2009.06.034 ◽

2010 ◽

Vol 140 (1) ◽

pp. 203-208 ◽

Cited By ~ 17

Author(s):

Rochus K. Voeller ◽

Andreas Zierer ◽

Shelly C. Lall ◽

Shun-ichiro Sakamoto ◽

Richard B. Schuessler ◽

...

Keyword(s):

Atrial Fibrillation ◽

Radiofrequency Ablation ◽

Beating Heart ◽

Atrial Fibrillation Ablation ◽

Bipolar Radiofrequency

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Epicardial Ablation on the Beating Heart

Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery ◽

10.1097/imi.0b013e3181a348a2 ◽

2009 ◽

Vol 4 (2) ◽

pp. 86-92 ◽

Cited By ~ 12

Author(s):

Anson M. Lee ◽

Abdulhameed Aziz ◽

Shun-Ichiro Sakamoto ◽

Richard B. Schuessler ◽

Ralph J. Damiano

Keyword(s):

Pulmonary Veins ◽

Median Sternotomy ◽

Invasive Procedure ◽

Beating Heart ◽

Microwave Device ◽

Maze Procedure ◽

Dose Response Relationship ◽

Bipolar Radiofrequency ◽

Internally Cooled ◽

Better Than

Objective To perform a minimally invasive procedure for atrial fibrillation without cardiopulmonary bypass, it is necessary to create transmural lesions on the beating heart. Although bipolar radiofrequency clamps can isolate the pulmonary veins, they have difficulty in performing any other left atrial lesions, particularly those of the traditional Cox-Maze procedure. This study examined the performance of an internally cooled, bipolar radiofrequency device designed for such an application. Methods Eleven domestic pigs underwent median sternotomy. Five animals had eight atrial lesions created with the radiofrequency device at times of 20, 30, 40, and 50 seconds. In six other pigs, the device was compared with another technology that has been used clinically for epicardial, beating heart ablation, the Guidant Flex 4 microwave device. The tissue was stained with 2,3,5-triphenyltetrazoluim chloride, and the lesions were sectioned at 5-mm intervals. Lesion width, depth, and transmurality were evaluated. Results The radiofrequency device had a linear dose-response relationship. Lesions were wider and deeper with increasing ablation times. A total of 40%, 45%, 60%, and 67% of lesions were transmural at times of 20, 30, 40, and 50 seconds, respectively. Ninety-one percent of lesions in tissue up to 4-mm thick were transmural after 50 seconds. However, performance in thicker tissue was poor. Lesions created by the device were deeper and more likely to be transmural than the Flex 4. Conclusions This internally cooled, bipolar radiofrequency device can reliably create transmural lesions on tissue up to 4-mm thick and performs better than a microwave device.

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Performance of a Novel Dual-Electrode Bipolar Radiofrequency Ablation Device a Chronic Porcine Study

Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery ◽

10.1097/imi.0b013e31820bc57f ◽

2011 ◽

Vol 6 (1) ◽

pp. 17-22 ◽

Cited By ~ 11

Author(s):

Rochus K. Voeller ◽

Andreas Zierer ◽

Richard B. Schuessler ◽

Ralph J. Damiano

Keyword(s):

Cardiopulmonary Bypass ◽

Radiofrequency Ablation ◽

Left Atrial Appendage ◽

Thrombus Formation ◽

Pulmonary Veins ◽

Maze Procedure ◽

En Bloc ◽

Energy Delivery ◽

Bipolar Radiofrequency ◽

The Mean

Objective Over recent years, a variety of energy sources, including bipolar radiofrequency, have been used to replace the traditional incisions of the Cox-Maze procedure for the surgical treatment of atrial fibrillation (AF). The purpose of this study was to evaluate the safety and efficacy of a novel dual-electrode bipolar radiofrequency ablation device Synergy (Atricure, Inc., Cincinnati, OH USA) for AF in a chronic porcine model. Methods Six domestic pigs underwent a modified Cox-Maze IV procedure without cardiopulmonary bypass using the Synergy device. Animals survived for 30 days. Each pig then underwent induction of AF and was killed to remove the heart en bloc for histologic assessment. Each ablation line was dissected perpendicularly at 5-mm intervals to assess the lesion width, depth, and transmurality. Results All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins were documented by pacing acutely and at 30 days after the operation in all six animals. All animals failed to be induced in AF at 30 days. There was no gross evidence of intra-atrial thrombus formation or stricture of the pulmonary veins. All ablations (n = 209) examined were discrete, linear, and transmural, with a mean lesion width of 3.0 ± 0.7 mm and a mean lesion depth of 5.4 ± 3.3 mm. The mean ablation time was 16.3 ± 4.4 seconds, with a mean total energy delivery of 238 ± 170 J. Conclusions The Atricure Synergy was able to create reliable chronic transmural lesions of the modified Cox-Maze IV procedure on a porcine beating heart without cardiopulmonary bypass. The ablation lines were significantly wider when compared with its predecessor, the Isolator II.

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