Convergent Approach to Persistent Atrial Fibrillation

Parkridge Medical Center was the first hospital in Chattanooga to offer the Convergent procedure as a treatment for persistent atrial fibrillation (AF). The minimally invasive modality (sometimes referred to as the hybrid procedure) combines proven electrophysiological and surgical approaches to restore normal sinus rhythm (NSR) to those patients who have failed other traditional therapies. Stephen L. Martin, MD, a cardiothoracic surgeon with Parkridge Medical Center, and Timothy M. Talbert, MD, an electrophysiologist with Diagnostic Cardiology Group, along with our surgical open-heart and electrophysiology teams, championed this unique leading-edge approach at Parkridge. Christian Allan, MD, an electrophysiologist with Diagnostic Cardiology Group, also recently performed this procedure with Dr. Martin. We describe our initial experience with the Convergent procedure here. 

About the Convergent Procedure

The Convergent procedure combines traditional endocardial ablation via femoral vein/transseptal access with epicardial ablation via a subxiyphoid direct approach, allowing for radiofrequency (RF) lesion placement on the posterior left atrium, which typically cannot be effectively reached during the traditional endocardial ablation procedure. The Convergent procedure requires patients to be under general anesthesia and the surgeon uses a direct epicardial approach via a subxiphoid incision (2-3 cm) to access the pericardium. The diaphragm is opened and a pericardial window is established allowing for direct visualization. Using AtriCure’s EPi-Sense Guided Coagulation System, the EPi-Sense device (catheter) is positioned on the posterior aspect of the left atrium.* RF lesions are then applied at 30 watts for 90 seconds in a uniform manner to the posterior wall of the left atrium.* Esophageal temperatures are monitored, and a rise in temperature greater than 1 ºC indicates the parameter for stopping RF application. Irrigation and suction (part of the coagulation system) are used during RF applications. Once all epicardial ablations are delivered, a drain is placed in the pericardial space and the incisions are closed. Next, the patient is ready for transfer to the EP lab for the second part of the procedure, traditional endocardial ablation. General anesthesia is continued and the patient is transported down the hall to the EP suite. An EP/OR hybrid suite is ideal to eliminate the need for patient transfer.

Case Description

The patient is a 71-year-old female with a history of chronic AF with rapid ventricular response despite prior RF ablation with pulmonary vein isolation (PVI) and prior MAZE procedure for left atrial flutter. The patient’s chronic AF improved to paroxysmal atrial fibrillation, but she remained symptomatic and sought out ablation treatment. Her medication regimen included apixaban 5 mg po bid and sotalol 160 mg bid. Her symptoms included fatigue and palpitations. This patient’s most recent visit to the EP lab included a permanent pacemaker implant for sinus bradycardia exacerbated by sotalol despite lower dosage.

After a lengthy discussion with the patient, the cardiothoracic surgeon (Dr. Martin) was consulted to assess the patient’s candidacy for the Convergent procedure. The surgeon and electrophysiologist discussed the risks and benefits with the patient. Pre-admission testing was scheduled for 1-2 weeks prior to the procedure date. Pre-procedural orders included: Admit to inpatient status, type and cross 2 units packed red blood cells (PRBCs), obtain consent for “Electrophysiology Study with Possible Intracardiac Ablation” per Dr. Talbert and “Endoscopic Surgical Maze and Transesophageal Echocardiogram (TEE)” per Dr. Martin, hold apixaban 48 hours prior to procedure, and acquire CT angiogram of chest with 3D reconstruction of all four chambers of the heart.

The patient was prepped from 2 inches above the femoral pulse location to 2 inches above the knee and from the entire chest. A radial arterial line was placed by anesthesia, along with an esophageal temperature probe. Elective intubation was done and a TEE was performed to visualize the left atrium and, more importantly, rule out atrial appendage thrombus. The epicardial ablation procedure begins after atrial appendage thrombus is ruled out. 

An allied health professional from AtriCure was present throughout the procedure. Once subxiphoid access was obtained and the pericardium was identified and opened, the AtriCure catheter was placed into the pericardial space. Landmarks such as the right and left inferior pulmonary veins were identified. The coronary sinus was identified. The cardiothoracic surgeon attained direct visualization of the targeted anatomy and applied RF ablation to create 2 row of lesions, moving right to left in the first row and left to right in the second. Twenty-two applications of RF were applied, resulting in excellent scar formation along the posterior wall of the left atrium. The catheter was removed and the incision was closed. A 36 French right angle chest tube was then placed in the pericardial space via a separate stab wound. The patient was ready for transport to the EP lab for her traditional PVI/MAZE procedure.

On arrival to the EP lab, the patient was gently rolled to her side and CARTO 3D mapping (Biosense Webster, Inc., a Johnson & Johnson company) patches were placed on her back, along with the usual R2 indifferent electrode grounding pads. The patient was then transferred onto the fluoroscopy procedure table using the traditional slide board. The CRNA remained at the patient’s head, maintaining the airway and monitoring V/S. The remaining anterior CARTO patches were placed, and bilateral groins were prepped for traditional catheter placement. Diagnostic catheters were placed (coronary sinus and RV quad), followed by an ICE catheter and steerable ablation sheath. The electrophysiologist performed a transseptal puncture and the left atrium was reached. Bivalirudin (.75 mg/kg) was given as a bolus, followed by 1.75 mg/kg infusion as intraprocedure anticoagulation. A Biosense Webster irrigated tip ablation catheter was placed through the steerable sheath into the left atrium and anatomical mapping was started, creating a geometric shell of the left atrium and pulmonary veins. If AF is identified, synchronized cardioversion is then performed.

The left atrium and pulmonary veins were mapped using voltage to guide and identify areas that were electrically active in preparation for RF ablation via the traditional endovascular catheter. The posterior left atrium was mapped to confirm the absence of electrical activity and validate the success of the patient’s visit to the OR. Next, RF lesions were created around both pulmonary vein pairs, across the roof of the left atrium from the RSPV to the LSPV, from the MVA to the roof line and from the LIPV to the RIPV. The empiric MAZE procedure, combined with the direct visualization posterior wall ablation procedure, positioned this patient for the best possible outcome to eliminate her atrial fibrillation.

Post procedure, diagnostic catheters were removed and the steerable sheath was exchanged for a smaller short sheath. The patient was transferred to the SICU for overnight recovery. Sheaths were removed 2 hours post discontinuance of the bivalirudin drip. The mediastinal chest tube was monitored for excessive bleeding. POD #1, the patient was extubated and sitting up in a chair following transfer from the SICU to the cardiac stepdown unit. POD #2, the chest tube was removed and the patient was discharged home with medication instructions for sotalol 160 mg bid, methylprednisolone dose pack 4 mg, aspirin 162 mg daily, and apixaban 5 mg bid to resume in 5 days. Follow-up visits with both the surgeon and electrophysiologist were scheduled for 4-week post-op.

The patient’s 4-week follow-up revealed NSR with an occasional skipped beat reported. The same medications were continued (sotolol and apixaban) as at hospital discharge. Her 12-week follow-up revealed maintenance of NSR and improvement of symptoms. Medication regimen remained the same except for discontinuance of apixaban. We look forward to this patient’s ongoing follow-up, along with our other Convergent patients, to reveal the true success of this new approach in managing persistent atrial fibrillation.

Discussion

The Convergent procedure raises logistical and practical concerns for those facilities without hybrid OR rooms. These include questions about patient flow from the OR to the EP lab, how to get CARTO patches on a fully anesthetized patient, and if anesthesia will be hesitant to allow this type of patient transfer. Our strategy began with a meeting between the key players: the EP manager, CVOR manager, nurse liaisons for both the surgeon and electrophysiologist, a representative from anesthesia, and our service line directors from both disciplines. One of the more difficult tasks we encountered was merging pre-operative and post-operative orders from the two different proceduralists. We also had to decide whether we would bring the patient in for preadmission testing as done for OR patients, or if on the day of surgery, we would bring the patient into our cardiac recovery area as we do for our EP lab patients. Would we continue anticoagulation until the day of surgery — and what would the surgeon think about that? We discussed the logistics of moving a patient from the OR to the EP lab and the timing of each procedure, which was tremendously important to the physicians. 

We developed a timeline and plan. The OR procedure typically begins at 0800, and at approximately 1000, the EP lab staff are expecting the arrival of the patient. The CRNA that begins the case in the OR transfers with the patient and continues care of the patient once in the EP lab. A hand-off report is given from the OR circulator to the EP lab circulator. Then, a post-procedure hand-off report is given to the SICU nurse receiving the patient. Lastly, education was provided for all staff involved. 

Parkridge’s EP and OR staff, along with Drs. Talbert and Martin, are all very proud of the success we have thus far achieved with this procedure. We are excited to be the first hospital in the Chattanooga area to offer this groundbreaking therapy to patients who might otherwise suffer from a reduced quality of life.

* The EPi-Sense Guided Coagulation System with VisiTrax is intended for the coagulation of cardiac tissue using radiofrequency energy using thoracoscopic, endoscopic, and laparoscopic surgical techniques.

Disclosure: The author has no conflicts of interest to report regarding the content herein.