Remote magnetic navigation for persistent atrial fibrillation ablation via a retrograde aortic access: an approach for patients after atrial septal defect device closure.

Abstract

Sirs: Patients after device closure of an atrial septal defect (ASD) presenting with left atrial (LA) arrhythmias are a challenge for the electrophysiologist as conventional transseptal puncture might be demanding. In patients with complex congenital heart disease, remote magnetic navigation (RMN) has been used to access anatomical structures that are difficult to reach [1–3]. The present case demonstrates the feasibility and efficacy of a complex LA ablation procedure for persistent atrial fibrillation (AF) via a retrograde aortic approach using RMN [4]. A 46-year-old woman with a history of a large secundum ASD had undergone successful transcatheter ASD occlusion with a 30-mm Amplatzer Occluder (AGA Medical Corp., Plymouth, MN, USA) 5 years ago. In 2012, successful ablation of typical atrial flutter had been performed. Subsequently, the patient developed persistent AF and complained of palpitations and shortness of breath. After electrical cardioversion, AF recurred and neither flecainide nor amiodarone was efficient. The patient was referred to our center for a second opinion. The echocardiogram showed no residual interatrial shunt, a normal ventricular ejection fraction and moderate dilation of both atria (LA anteroposterior diameter of 46 mm) (Fig. 1a). We decided to offer the patient an AF ablation via a retrograde approach using the Niobe II magnetic navigation system (Stereotaxis, St. Louis, MO, USA). The procedure was performed under conscious sedation. A 6F octapolar Bard EP-XT Steerable Catheter was advanced into the coronary sinus (CS). A 3.5-mm-tip irrigated magnetic catheter (Thermocool RMT, Biosense Webster, Diamond Bar, CA, USA) was inserted through a short 8F sheath in the femoral artery and manually advanced just below the subclavian artery. The ablation catheter was maneuvered across the aortic and mitral valve to the LA (Fig. 1b). Heparin was used to maintain the activated clotting time at the level of 300 s. An electroanatomic map of the LA using a three-dimensional (3D) mapping system (Carto3 RMT; Biosense Webster, Diamond Bar, CA, USA) was performed integrating a complex fractionated atrial electrogram (CFAE) software allowing automatical detection of CFAE sites (Fig. 2). After mapping, circumferential pulmonary vein isolation (PVI) was performed. CFAE ablation guided by the CFAE map and the operators’ judgment of local electrograms followed. Details of the CFAE ablation have been described previously [5, 6]. The endpoint of electrogram-guided ablation was elimination of all CFAE areas or AF conversion to atrial tachycardia or sinus rhythm. The effect of ablation was assessed by AF cycle length (AFCL). CFAE ablation was mainly performed at the anterior wall [including left atrial appendage (LAA)], inferior LA and LA roof with 30–35 W and a maximal temperature of 43 with an irrigation rate of 30 mL/min. After CFAE ablation, the AFCL measured in the LAA had prolonged significantly from 140 ms at baseline to 170 ms. Sinus rhythm was restored with direct current cardioversion. PV isolation was confirmed by mapping the ablation line around the PV and assessing the absence of PV potentials with the map catheter. The total procedure duration was 396 min. The total radiofrequency (RF) delivery time was 131 min (min) and the total fluoroscopy time was 6 min. No adverse events were observed. The patient was followed every 3 months in outpatient clinic with repeated 7-day holter ECGs. The endpoint was A. Buiatti (&) G. Hessling V. Semmler S. Ammar Department of Electrophysiology, German Heart Center Munich, Munich, Germany e-mail: elam4@libero.it