Case Study

Ablation of Longstanding Persistent Atrial Fibrillation Using a Convergent Ablation Approach

Joshua D. Lovelock, MD and Richard L. Harvey, MD

The CardioVascular Group and Gwinnett Medical Center

Lawrenceville, Georgia

Joshua D. Lovelock, MD and Richard L. Harvey, MD

The CardioVascular Group and Gwinnett Medical Center

Lawrenceville, Georgia

Introduction

Atrial fibrillation is the most common arrhythmia in the United States, affecting an estimated 2.7-6.1 million people.1 The treatment of atrial fibrillation includes both antiarrhythmic medications and invasive procedures. Numerous studies have provided clear evidence that pulmonary vein isolation (PVI) is effective in the treatment of paroxysmal atrial fibrillation.2,3 However, the treatment of persistent atrial fibrillation, whether early or longstanding, is not clear. A number of ablation strategies have been proposed and studied, but none have been proven superior to pulmonary vein isolation alone. Here we report the case of a patient with longstanding persistent atrial fibrillation treated with Convergent (hybrid) atrial fibrillation ablation.

Case Description

A 42-year-old male with a history of congestive heart failure (CHF) (New York Heart Association class III) presented with longstanding persistent atrial fibrillation. The patient was originally diagnosed with CHF during admission for shortness of breath, and diagnosed with an acute exacerbation in 2017. His heart failure was treated as an inpatient with diuretics, and he was noted to be in atrial fibrillation. As an outpatient, his heart failure regimen was optimized including titration of carvedilol, lisinopril, and spironolactone. His heart rates were controlled and anticoagulation initiated. He also underwent ICD placement after failing to see an improvement in his ejection fraction.

After aggressive treatment of his heart failure and adequate rate control of his atrial fibrillation, the patient remained highly symptomatic with dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea. He was referred to the EP clinic for consideration of an atrial fibrillation ablation.

The patient was seen in consultation. Given his symptoms despite optimal medical therapy, it was felt that a return to normal sinus rhythm may provide some symptomatic relief. Since we were unsure how long the patient had been in atrial fibrillation, we felt it would be prudent to try to restore normal sinus rhythm and reassess symptoms before considering more invasive options. The patient was loaded with oral amiodarone and underwent electrical cardioversion. He returned to clinic with a marked improvement in his symptoms at one week post procedure in normal sinus rhythm. Unfortunately, he had a recurrence of his atrial fibrillation by 2 weeks with a return of his heart failure symptoms.

On follow-up, we discussed treatment options with the patient. Since we had been able to convert him to normal sinus rhythm with a clear improvement in his symptoms, but failed to maintain sinus rhythm after amiodarone, we felt that ablation was an option. We discussed a conventional endocardial ablation approach, but felt that the recurrence rate would be high given his left atrial size of 5.2 cm with a left atrial volume index of 54 ml/m2. We thought the best chance of maintaining normal sinus rhythm would be a Convergent (hybrid) approach to ablate his atrial fibrillation. The patient agreed and was scheduled for the procedure.

The patient underwent epicardial ablation in the cardiovascular operating room. Epicardial access was obtained using a subxiphoid approach. Under direct visualization, a set of lesions were delivered to the epicardial surface of the posterior left atrium using a COBRA Fusion Ablation System (AtriCure), starting adjacent to the right upper pulmonary vein near the roof and moving across the back wall to the left upper pulmonary vein. This was continued until the back wall was completely ablated, from the roof to the inferior aspect of the lower veins. Impedance drop was used to determine effective lesion delivery. Upon completion of the lesion set, a pericardial drain was left in place.

After completion of the epicardial portion of the ablation, the intubated patient was transferred from the cardiovascular operating room to the EP lab and prepped in a standard fashion. Using the EnSite Precision Cardiac Mapping System (Abbott), a detailed voltage map was created with the patient in normal sinus rhythm (Figure 1A-D). We then proceeded to isolate the left upper and lower veins, and subsequently, the right upper and lower veins, with a cryoablation balloon catheter (Arctic Front Advance, Medtronic). After pulmonary vein isolation, we created another voltage map using a cutoff of 0.1 mV for scar and 0.5 mV for normal tissue (Figure 2A-D). We then did a radiofrequency ablation of the cavotricuspid isthmus. On completion of the procedure, protamine was given, and the patient was extubated and transferred to the cardiac telemetry floor with a pericardial drain in place. An intravenous heparin drip was initiated upon the completion of bedrest, and apixaban was started the morning of postoperative day 1. The patient received 2 mg/kg hydrocortisone post operatively for pericarditis and remained on prednisone 20 mg daily for 5 days. The patient remained on amiodarone 200 mg daily and was discharged postoperative day 3 after removal of the pericardial drain.

The patient maintained normal sinus rhythm, and at 6 months, amiodarone was discontinued. The patient has been able to maintain normal sinus rhythm off antiarrhythmic medications.

Discussion

The case presented describes the ablation of persistent atrial fibrillation using the Convergent procedure. Atrial fibrillation ablation has become a mainstay in the treatment of symptomatic atrial fibrillation. Numerous studies have demonstrated the effectiveness of pulmonary vein isolation for the treatment of paroxysmal atrial fibrillation. Recently, studies have also shown the benefit of atrial fibrillation ablation for patients with CHF and a depressed ejection fraction.4 Unfortunately, the optimal strategy for ablation of persistent atrial fibrillation has yet to be defined. After PVI, the ideal lesion set remains uncertain. The decision to create linear ablation lesions, ablate complex fractionated electrograms, chase rotors, or modify substrate is unclear.5 Our patient was symptomatic despite optimal CHF treatment and well-controlled atrial fibrillation. After determining the patient could still maintain normal sinus rhythm, albeit for a short duration, we felt that undergoing an atrial fibrillation ablation was the best option for symptom relief. We opted for a Convergent procedure over traditional PVI and additional endocardial ablation because the hybrid approach has provided us with the most robust outcomes with the least number of recurrences. In our practice, we favor the more invasive procedure as a first-line therapy in longstanding persistent atrial fibrillation with the hope of providing a more durable outcome and limiting the need for repeat ablations. Although the epicardial ablation is more invasive than the conventional endocardial approaches and requires a longer hospital stay, we believe the benefit in reducing the risk of esophageal injury and the need for repeat ablation outweighs the risks. Currently, there is limited evidence to support any approach in the longstanding persistent atrial fibrillation patient, but small nonrandomized studies have been promising as shown in a recent meta-analysis.6

Conclusion

Convergent atrial fibrillation ablation provided durable maintenance of normal sinus rhythm in a patient with congestive heart failure. It provided symptomatic relief with minimal risk. 

Disclosures: The authors have no conflicts of interest to report regarding the content herein.

References
  1. Atrial Fibrillation Fact Sheet. CDC. Published August 22, 2017. Available at https://www.cdc.gov/dhdsp/data_statistics/fact_sheets/fs_atrial_fibrillation.htm. Accessed August 7, 2019.
  2. Oral H, Knight BP, Tada H, et al. Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation. Circulation. 2002;105:1077-1081.
  3. Verma A, Jiang CY, Betts TR, et al. Approaches to catheter ablation for persistent atrial fibrillation. N Engl J Med. 2015;372:1812-1822.
  4. Marrouche NF, Brachmann J, Andresen D, et al. Catheter ablation for atrial fibrillation with heart failure. N Engl J Med. 2018;378:417-427.
  5. Mody BP, Raza A, Jacobson J, et al. Ablation of long-standing persistent atrial fibrillation. Ann Transl Med. 2017;5:305.
  6. Luo X, Li B, Zhang D, et al. Efficacy and safety of the Convergent atrial fibrillation procedure: a meta-analysis of observational studies. Interact Cardiovasc Thorac Surg. 2019;28(2):169-176.
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