Case: Ablation of Persistent Atrial Fibrillation Utilizing the Best of Both Worlds
A 66-year-old male with history of atrial fibrillation was referred for ablation for treatment of symptomatic persistent atrial fibrillation. The patient was diagnosed with atrial fibrillation 6 years ago and had previously failed treatment with Amiodarone and Sotalol. He was started on dofetilide and became paroxysmal but continued to have symptomatic episodes of atrial fibrillation. Other notable history includes coronary artery disease with balloon angioplasty performed in 2001.
Two- dimensional echocardiogram revealed normal left ventricular function with an estimated ejection fraction of 55%. His left atrial diameter was 4.4 cm. He had no significant valvular heart disease.
The patient was scheduled for a convergent procedure which is a codisciplinary epicardial and endocardial radiofrequency ablation procedure performed sequentially at the same sitting. It addresses patients with paroxysmal, persistent and longstanding persistent atrial fibrillation, those with large left atrial size, and those who have failed catheter ablation. It is a totally endoscopic trans-diaphragmatic approach to the epicardium without the need for chest incisions or lung deflations. It is followed by a conventional percutaneous endocardial ablation.
The procedure was performed under general anesthesia. Perioperative anticoagulation consisted of cessation of warfarin 5 days before the procedure and initiation of aspirin 325 mg daily. Transesophageal echocardiography was used to exclude LA thrombus.
For the epicardial ablation, the patient's chest and abdomen were prepped and draped in a standard sterile fashion. A 5 mm OptiVu trocar was then inserted in the left upper quadrant of the abdomen for laparoscopic exploration. CO2 pneumoperitoneum was created. An additional trocar (10/12 mm) was inserted in the subxiphoid region as well as an additional 5mm trocar in the right upper quadrant. After general exploration of the abdomen, no abnormalities were identified. The central tendon of the right hemi-diaphragm was identified. Just above the left lobe of the liver a 1.5 cm incision was made in the central tendon of the diaphragm. Once the pericardium was identified a 1.5 cm incision in the pericardium was created. The nContact cannula was then inserted under direct guidance through the diaphragm and pericardial incisions. A 7mm scope was advanced through the cannula, and exploration of the pericardial sac was performed. The left inferior, left superior, right superior, right inferior pulmonary veins, and coronary sinus were identified. Using the Visitrax epicardial ablation catheter, radiofrequency ablation was performed starting from the coronary sinus to the left inferior pulmonary vein up towards the left superior pulmonary vein. The roof of the left atrium was crossed connecting the ablation from the left superior vein to the right superior pulmonary vein. The ablation was continued along the floor of the atrium adjacent to the right superior and inferior veins. This ablation line was brought as close to the oblique sinus as possible. Next, ablation was performed anterior to the left superior and inferior pulmonary veins ablation using the Visitrax catheter off the wire. An additional ablation line connecting the left inferior pulmonary vein to the right inferior pulmonary vein was performed. (Figure ) Next, we crossed the IVC and identified the superior vena cava (SVC), right superior and right inferior pulmonary veins. An ablation line was created under the SVC and followed along the pulmonary veins anteriorly on the right towards the oblique sinus. Once the ablation was completed, a Blake drain was placed posteriorly in the pericardial sac. The Blake drain was brought out of the skin through the left upper abdominal port. The fascia was closed in the midline incision using interrupted 0 Vicryl sutures. Subcutaneous tissues and skin were closed with serial Vicryl sutures. Total epicardial procedure time was 91 minutes.
Following the epicardial ablation the patient is prepped for a conventional pulmonary vein atrum isolation. Two 8-French sheaths were placed in the right femoral vein. An 11-French sheath and an 8-French sheath were placed in the left femoral vein. A 10.5-French intracardiac echo (Acuson, Siemens Inc) was advanced into the right atrium. This catheter was used to assist in the trans-septal catheterization, to monitor for pericardial effusions and to identify the os of all 4 pulmonary veins. A deflectable decapolar catheter (Webster Bidirectional CS, Biosense Webster) was advanced into the coronary sinus.
A circular mapping catheter (Lasso, Biosense Webster) and a 3.5 mm tip irrigated radiofrequency (RF) ablation catheter (Thermocool, Biosense Webster) were passed through a Mullins Sheath and SLO Sheath, respectively using a double transeptal catheterization. Intravenous heparin was administered to achieve activated clotting times of 300 – 350 seconds during the procedure.
Ablation was assisted with nonflouroscopic electroanatomical mapping (Carto, Biosense Webster). Since the patient had an epicardial ablation, pulmonary vein potentials were targeted first at the areas of pericardial reflections (Figure 1 ). The pulmonary vein potentials were assessed with the circular mapping catheter pre- and post ablation. Maximal power was limited to 25 W on the posterior wall and 35 W elsewhere, and temperature was limited to 45 degrees.
Prior to the percutaneous endocardial ablation there were pulmonary vein potentials seen around the left superior pulmonary vein (Figure 2), partially around the left inferior pulmonary vein (Figure 3), and around the right inferior pulmonary vein (Figure 4). The right superior pulmonary vein was completely isolated (Figure 5). All pulmonary veins were isolated individually. Endpoints were pulmonary vein potential and posterior wall potential abolition (Figure 6). Following complete isolation of all veins, burst pacing was performed down to 220 milliseconds inducing atrial flutter. The atrial flutter appeared to be a typical right-sided atrial flutter with earliest activation in the proximal CS and a sawtooth pattern on the inferior leads. A cavotricuspid isthmus ablation was performed resulting in termination of the atrial flutter. Trans-isthmus conduction times were 150 ms in both the clockwise and counter clockwise direction. Following this burst pacing was performed a second time. This time inducing an atypical flutter which terminated after approximately 2 minutes and was non sustained on repeat induction. A biphasic external 30 J shock synchronized to the R wave was delivered as a further test for inducible AF[i], which did not induce atrial fibrillation. Total endocardial procedure time was 126 minutes. Fluoroscopy time was 23 minutes. Total procedure time of the combined endocardial and epicardial ablation was 250 minutes.
After ablation, anticoagulation was reinitiated and dofetilide was continued for 8 weeks.
Following the procedure the patient was transferred to the CICU overnight. Follow up echo revealed a trivial pericardial effusion. The Blake drain was pulled on post operative day 2. The patient was discharged home on post operative day 4.
The patient did not have any symptomatic episodes of atrial fibrillation in the first 8 weeks post ablation. His dofetilide was discontinued and he has remained free of any episodes of atrial fibrillation or atrial flutter. Holter monitor performed at 8 weeks did not reveal any episodes of atrial fibrillation. A 7 day event monitor performed at 6 months did not reveal any episodes of atrial fibrillation
Although surgical procedures, such as the “Cut and Sew” Cox - Maze have been successful in the treatment of atrial fibrillation it requires cardiopulmonary bypass and has a higher rate of bleeding and need for permanent pacing[ii]. The invasive nature of this procedure and number of surgeons who perform the procedure has also limited its use. Minimally invasive surgical ablation procedures, such as the “Mini-Maze” which uses epicardial bipolar radiofrequency energy to isolate the pulmonary veins has not resulted in the success rates of open chest procedures.[iii] The procedure can also be proarrhythmic by promoting macro reentrant circuits[iv], is not truly minimally invasive requiring chest incisions and lung deflations, and fails to deliver a right sided lesion set. These factors have resulted in limited widespread acceptance.
Percutaneous pulmonary vein atrum isolation has also been challenging for electrophysiologists and has not been demonstrated to result in the efficacy that has been seen in the Cox Maze for patients with persistent and permanent atrial fibrillation.[v] [vi] Procedures that create comprehensive biatrial lesion patterns,and ensure isolation of the PVs and the posterior left atrium, may improve efficacy when treating persistent and longstanding persistent AF.
Much debate has been made between cardiothoracic surgeons and electrophysiologists regarding the best way to treat our patient who have drug resistant atrial fibrillation. The Convergent Procedure ends the debate by combining the best of both disciplines using a truly minimally invasive treatment solution in a single procedure. The cardiothoracic surgeon can isolate the pulmonary veins except the areas protected by the pericardial reflections. Since they are directly visualizing the lesions it allows them to insure their lesions are connected. This technique also directs radiofrequency energy away from the esophagus during posterior wall ablation and results in significant debulking of the posterior wall. The EP can then complete the pulmonary vein isolation and provide diagnostic confirmation that all veins are isolated, verify reentrant circuits have been blocked, and confirm posterior left atrial wall silence. If needed they can also perform a mitral valve annulus ablation, tricuspid valve annulus ablation or Coronary sinus ablation.
This new hybrid surgical/epicardial and electrophysiologic/endocardial approach to patients with longstanding persistent and persistent AF offers high early success rates.[vii] [viii] It reduces electrophysiologist procedural times (~1.5 hours) with reduced patient and physician fluoroscopy exposure (~10-30 min) as compared with historical and same institution catheter ablation data.[ix]
The convergent experience combining surgical and electrophysiological expertise provides encouraging results in achieving freedom from AF in patients with atrial fibrillation. Further studies are enrolling to quantify the efficacy and safety of this procedure.[x] [xi]
[i] Wylie JV Jr, Essebag V, Reynolds MR, Josephson ME. Inducibility of atrial fibrillation with a synchronized external low energy shock post-pulmonary vein isolation predicts recurrent atrial fibrillation. J Cardiovasc Electrophysiology. 2009 Jan;20(1):29-36.
[ii] Prasad, Sunil M., Maniar, Hersh S., Camillo, Cindy J., Schuessler, Richard B., Boineau, John P., Sundt, Thoralf M., III, Cox, James L., Damiano, Ralph J., Jr. The Cox maze III procedure for atrial fibrillation: long-term efficacy in patients undergoing lone versus concomitant procedures. J Thorac Cardiovasc Surg 2003 126: 1822-1827.
[iii] Han FT, Kasirajan V, Kowalski M, Kiser R, Wolfe L, Kalahasty G, Shepard RK, Wood MA, Ellenbogen KA. Results of a minimally invasive surgical pulmonary vein isolation and ganglionic plexi ablation for atrial fibrillation: single-center experience with 12-month follow-up. Circ Arrhythm Electrophysiol. 2009 Aug;2(4):370-7.
[iv] Jordana Kron, Vigneshwar Kasirajan, Mark A. Wood, Marcin Kowalski, Frederick T. Han, Kenneth A. Ellenbogen. Management of Recurrent Atrial Arrhythmias After Minimally Invasive Surgical Pulmonary Vein Isolation and Ganglionic Plexi Ablation for Atrial Fibrillation. Heart Rhythm. 2010 Apr;7(4):445-51.
[v] Bhargava M, Di Biase L, Mohanty P, Prasad S, Martin DO, Williams-Andrews M, Wazni OM, Burkhardt JD, Cummings JE, Khaykin Y, Verma A, Hao S, Beheiry S, Hongo R, Rossillo A, Raviele A, Bonso A, Themistoclakis S, Stewart K, Saliba WI,Schweikert RA, Natale A. Impact of type of atrial fibrillation and repeat catheter ablation on long-term freedom from atrial fibrillation: results from a multicenter study. Heart Rhythm. 2009 Oct;6(10):1403-12.
[vi] Claude S. Elayi, Atul Verma, Luigi Di Biase, Chi Keong Ching, Dimpi Patel, Conor Barrett, David Martin, Bai Rong, Tamer S. Fahmy, Yaariv Khaykin, Richard Hongo, Steven Hao, Gemma Pelargonio, Antonio Dello Russo, Michela Casella, Pietro Santarelli, Domenico Potenza, Raffaele Fanelli, Raimondo Massaro, Mauricio Arruda, Robert A. Schweikert, Andrea Natale. Ablation for longstanding permanent atrial fibrillation: Results from a randomized study comparing three different strategies. Heart Rhythm. 2008 Dec;5(12):1658-64.