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Minimally Invasive Approach to Left Atrial Wall Ablation (Convergent Procedure) and Left Atrial Appendage Clip Ligation

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posted on 2021-02-10, 15:45 authored by Kathryn Mulryan, Stephen Frohlich, Jonathan Lyne, Karen Redmond

Atrial fibrillation (AF) is a major cause of structural heart disease, stroke, and increased hospitalizations. It has been estimated that 6-12 million people in the US will suffer from this condition by 2050 and 17.9 million people in Europe by 2060 (1). Management options by electrophysiologists include pharmacological therapy, cardioversions, and catheter ablations (2). Patients with AF refractory to these interventions can be offered the Convergent procedure TM (3). Radiofrequency ablation to the posterior wall of the left atrium (LA) is performed through a subxiphoid approach by a cardiothoracic surgeon as an adjunct to catheter ablations. This staged hybrid technique increases the success rate of returning patients to normal sinus rhythm (NSR) from 50% to 81% (4, 5).

This video illustrates the Convergent procedure with application of a left atrial appendage (LAA) clip. The patient and operative set-up is outlined in the video. A product specialist is on-site to support the procedure.

The patient was a 44-year-old woman with a history of persistent atrial fibrillation refractory to two previous endocardial ablations. Her medical history was significant for a transient ischemic attack and obesity (BMI 43). Medications at the time of the procedure included dabigatran 150 mg BD, metoprolol 50mg QDS, and flecainide 100 mg BD. She remained symptomatic on this regimen, limiting her exercise tolerance and quality of life. Anticoagulation was discontinued 24 hours before surgery and restarted day one post-operation.

Transthoracic echocardiogram (ECHO) and computed tomography (CT) 3D reconstruction of the LAA were performed to review the anatomy and exclude clot prior to induction of the patient. A transesophageal ECHO confirmed these findings and defined the LAA anatomy prior to and after clipping. A defect of up to 5 mm was permitted but defects greater than 5 mm preclude clip application (6).

A 2-3 cm subxiphoid incision was made to access the pericardial space. The xiphoid was excised and a pericardotomy was carried out to insert a 20 mm cannula to allow direct access and visualization of the back wall of the left atrium and pulmonary veins. The Episense (Atricure®) device was placed into the cannula. Fluoroscopic imaging was then used to verify the position of the esophageal temperature probe adjacent to the Episense device to alarm for temperature increases of more than 1© that would predispose to esophageal injury.

Unipolar suction assisted radiofrequency ablation was achieved with the Episense device. A vacuum seal was created to ensure constant contact between the Episense device and wall of the LA. Saline was perfused continuously to cool the device during the ablation, overlapping proximal and distal rows between the left and right-sided pulmonary veins. No drain was required at closure.

A left VATS was performed with a 5 mm port, a 12 mm incision, and if required, an extra stab incision. With the support of CO2 insufflation, a pericardotomy was perfomed below the left phrenic nerve extending to beyond the left main pulmonary artery. The neck of the LAA was sized and in this case a 45 mm clip was applied (AtriClip LAA exclusion system, AtriCure, Mason, OH, USA). A 24 fr chest drain was placed. A cardioversion was subsequently performed.

Postoperatively, patients are prescribed six weeks of a proton pump inhibitor to protect against esophagitis. They remain anti-coagulated until follow-up review with an electrophysiologist. Fluid monitoring, fluid restriction, and diuretic use for two weeks counteracts fluid retention, thought to be caused by a reduction in atrial natriuretic peptide (ANP) secreted from the LAA (7). Patients should be made aware that NSR may not be achieved immediately and a further cardioversion, catheter mapping, or ablation may be required at follow-up with their electrophysiologist.

References

Lippi G, Sanchis-Gomar F, Cervellin G. Global epidemiology of atrial fibrillation: An increasing epidemic and public health challenge. Int J Stroke. 2021 Feb;16(2):217-221.
Hindricks G, Potpara T, Dagres N, Arbelo E, Bax JJ, Blomström-Lundqvist C, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association of Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2020 Aug 29;ehaa612.
Makati KJ, Sood N, Lee LS, Yang F, Shults CC, DeLurgio DB, et al. Combined epicardial and endocardial ablation for atrial fibrillation: Best practices and guide to hybrid convergent procedures. Heart Rhythm. 2021 Feb;18(2):303-312.
Yubing W, Yanping X, Zhiyu L, Weijie C, Li S, Huaan D, et al. Long-term outcome of radiofrequency catheter ablation for persistent atrial fibrillation. Medicine (Baltimore). 2018;97(29):e11520.
Geršak B, Jan M. Long-term success for the convergent atrial fibrillation procedure: 4-year outcomes. Ann Thorac Surg. 2016;102(5):1550-1557.
Toale C, Fitzmaurice GJ, Eaton D, Lyne J, Redmond KC. Outcomes of left atrial appendage occlusion using the AtriClip device: a systematic review. Interact Cardiovasc Thorac Surg. 2019;29(5):655-662.
Lakkireddy D, Turagam M, Afzal MR, Rajasingh J, Atkins D, Dawn B, et al. Left atrial appendage closure and systemic homeostasis: The LAA HOMEOSTASIS Study. J Am Coll Cardiol. 2018;71(2):135-144.