Hybrid Ablation for Persistent Atrial Fibrillation: Initial Experience in a Community Hospital

Advances in catheter ablation for atrial fibrillation (AF) have dramatically changed the management of this condition over the last decade.¹ Improvements in both procedural outcomes and complication rates have made this an attractive treatment option for many patients with paroxysmal AF. However, acute and long-term results for patients with persistent and longstanding persistent AF are significantly less impressive.² While the character of symptoms in persistent AF may differ from those in patients with less advanced disease, the burden on quality of life can be equally or more severe.

Results of minimally invasive surgical (MIS) ablation for AF compare favorably with catheter ablation for treatment of persistent AF, but the former generally requires a longer hospital stay and more protracted recovery.² While MIS ablation provides direct visualization and improved tissue contact, the approach is largely anatomical and offers less information on the individual’s arrhythmic substrate. Additionally, access to these AF triggers may be limited with an epicardial approach.

A combined invasive approach to manage persistent AF has been used in numerous centers around the country. Both tertiary referral centers and community hospitals have utilized this strategy, commonly known as hybrid AF ablation, in order to maximize procedural outcomes. The following is our initial experience with four patients referred for hybrid ablation for persistent AF in a community hospital.

Initial Challenges

The first challenge was to organize the necessary team, with requisite experience and an enthusiasm for this collaborative venture. The procedure requires a cardiothoracic surgeon experienced in stand-alone MIS AF ablation and a cardiac electrophysiologist practiced in catheter ablation for persistent AF. Dr. Chris Wehr and I spent hours in the planning process, well before identifying the first patient. We used the DEEP AF trial protocol as the basis for the procedure.³

We recognized that the primary challenges at our institution would be logistic. We do not have a dedicated hybrid operative room suite, so the first procedure was performed entirely in the OR. This required use of a C-arm fluoroscopic unit and transportation of the EP recording system, 3D mapping system, and disposables to the OR. With this equipment and the additional EP lab personnel in the room, the limited OR space was a significant hurdle to overcome.

First Cases

We identified and approached the first patient, a 52-year-old male with symptomatic longstanding persistent atrial fibrillation, refractory to several antiarrhythmic drugs in the past and in continuous AF for nearly two years. He was otherwise healthy, with no pulmonary or other cardiac disease, but severely limited by fatigue and dyspnea on exertion. His left atrium was severely dilated, with a left atrial volume index of 51 ml/m² on transthoracic echocardiography. He had previously undergone an external cardioversion for AF, but no invasive cardiac procedures.

This procedure was performed entirely in the OR, under general anesthesia and with a preprocedural transesophageal echocardiogram. After placement of the EP recording catheters, we confirmed atrial fibrillation and the patient was cardioverted with a synchronized external shock. Dr. Wehr then performed stepwise right- and then left-sided thoracotomies to access the epicardial space, performing pulmonary vein isolation, then linear lesions to isolate the posterior wall and a mitral valve line. Ganglionic plexi were also targeted and the left atrial appendage was ligated. This was performed with AtriCure devices. I then placed additional endocardial linear lesion sets using 3D mapping and an externally-irrigated ablation catheter. Bidirectional block was confirmed across both the endocardial and epicardial lesion sets. No arrhythmias were induced with high-dose isoproterenol, and the procedure was completed. The patient was started on a three-month course of amiodarone, per protocol, and was discharged home three days later.

Our second patient was a 54-year-old male with persistent AF. He had undergone catheter ablation 18 months earlier, but AF recurred 14 months after that procedure. His left atrium was severely dilated, with a left atrial volume index measuring more than 60 ml/m². He elected to undergo hybrid ablation, and this was performed in a staged fashion during the same hospitalization, with surgical ablation on the day of admission and catheter ablation two days later in the EP lab. Surgical ablation was performed as described above. The EP procedure was then performed separately, using our standard protocol. We confirmed isolation of all four pulmonary veins, and additional left and right atrial linear lesion sets were required to restore sinus rhythm. No further arrhythmias were induced with aggressive programmed stimulation and high-dose isoproterenol challenge, and integrity of the lesion sets was confirmed. In this case, amiodarone was held after surgical ablation and initiated following catheter ablation.

Discussion

Management of appropriate periprocedural anticoagulation for AF ablation is complex and leaves the patient susceptible to both thrombotic and hemorrhagic complications. This is even more difficult for patients undergoing hybrid ablation. We perform stand-alone catheter ablation for AF with therapeutic levels of warfarin or on dabigatran, holding the dose the morning of the procedure. However, recent data suggests the inferiority of dabigatran to warfarin in this setting.⁴ Heparin is administered approximately 10–15 minutes before transseptal access in order to achieve and subsequently maintain activated clotting times (ACT) targeting 350 seconds during the procedure. Both baseline anticoagulation and ACT levels during the surgical portion of the hybrid ablation procedure increase the chance of significant bleeding, but anything less raises an unacceptable risk of thromboembolic events during catheter-based ablation in the left atrium. This is a primary factor that favors the staged hybrid approach. While therapeutic levels of anticoagulation are interrupted for the surgical procedure, heparin and warfarin can be resumed immediately afterward. Anticoagulation may then be controlled using the standard protocol during the catheter-based portion of the procedure. It is possible that in the early post-surgical ablation period, with heightened local and systemic proinflammatory mechanisms and poor transatrial flow in patients recently reverted from longstanding persistent AF, adequate anticoagulation is of even greater importance than in stand-alone catheter ablation for AF.

Two additional male patients, ages 55 and 68, underwent staged hybrid ablation in the next two months. Both had longstanding persistent AF, with duration of 14 and 45 months of persistent AF, respectively, and both with severe left atrial dilation. For these patients, we chose to provide an interval staged ablation procedure, with stand-alone MIS as described, and subsequent stand-alone catheter ablation if AF recurred at three months or beyond. This eliminated the logistic challenges we faced with the first procedure and the concerns for variable anticoagulation seen with both patients. In addition, there are patients for whom MIS ablation for AF is sufficient to restore and maintain sinus rhythm.⁵ With this in mind, a third patient underwent surgical ablation and has remained in sinus rhythm since, without the need for catheter ablation. A fourth patient did require catheter ablation, during which additional linear lesion sets and targeting of complex fractionated atrial electrograms resulted in restoration of sinus rhythm.

In selecting patients for hybrid AF ablation, we have approached those with longstanding persistent AF or persistent AF and failed prior catheter ablation. Patients must be symptomatic and have failed appropriate attempts at antiarrhythmic drug therapy. We exclude patients with prior cardiothoracic surgery, which may prevent adequate epicardial access. Following these criteria and with the approaches listed above, we are pleased to report that all four patients are doing well and remain in sinus rhythm.

Summary

Hybrid ablation for AF offers another therapeutic option to a sizable population that previously had few choices. However, it is more invasive and the recovery more difficult than our usual EP procedures. Additionally, the patient population has more advanced disease than most patients considered for AF ablation. These factors pose both logistic and therapeutic challenges, and do increase the risk for periprocedural complications. In our initial experience, we believe that an interval staged approach to hybrid ablation offers a safer and more effective long-term result for patients, while eliminating the logistic challenges of an all-in-one procedure. With this approach, careful planning, and a dedicated and enthusiastic team, hybrid ablation for AF can be performed successfully in a community hospital setting.

References

1. Calkins H, Kuck KH, Cappato R, et al. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: Recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design. Heart Rhythm 2012;9:632–696.
2. Han FT, Kasirajan V, Kowalski M, et al. 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 2009:2:370–377.
3. National Institutes of Health Clinical Trials. Dec 13, 2011. https://clinicaltrials.gov/ct2/show/NCT01246466.
4. Lakireddy D, Reddy YM, Di Biase L, et al. Feasibility and safety of dabigatran versus warfarin for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation: Results from a multicenter prospective registry. J Am Coll Cardiol 2012;59(13):1168–1174.
5. Lee R, McCarthy PM, Passman RS, et al. Surgical treatment for isolated atrial fibrillation: Minimally invasive vs. classic cut and sew maze. Innovations (Phila) 2011;6(6):373–377.