Background-Reduced electrogram amplitude has been shown to correlate with diseased myocardium. We describe a novel individualized approach for catheter ablation of atrial fibrillation (AF) based on low-voltage areas (LVAs) in the left atrium (LA). We sought to assess (1) the incidence of LVAs in patients undergoing AF catheter ablation, (2) the distribution of LVAs within the LA, and (3) the effect of an individualized ablation strategy on long-term rhythm outcomes. Methods and Results-In 178 patients with paroxysmal or persistent AF, LA voltage maps were created during sinus rhythm after circumferential pulmonary vein isolation. Subsequent substrate modification was confined to the presence of LVA (<0.5 mV) and inducible regular atrial tachycardias. LVAs were identified in 35% and 10% of patients with persistent and paroxysmal AF, respectively. The LA roof and the anterior, septal, and posterior wall LA were most often affected. The 12-month atrial tachycardias/AF-free survival was 62% for patients without LVAs and 70% for patients with LVAs and tailored substrate modification (P=0.3). Success rate in a comparison group of 26 LVA patients without further substrate modification was 27%. Conclusions-LVAs can be found at preferred sites in 10% of patients with paroxysmal AF and in 35% of patients with persistent AF. This is the first clinical report describing a consistent voltage-based approach for substrate modification in addition to circumferential pulmonary vein isolation irrespective of AF type. Application of this limited individualized approach may have the potential to compensate for the impaired 12-month outcome of patients with endocardial structural defects. (Circ Arrhythm Electrophysiol. 2014;7:825-833.)

In this single-centre study, individually tailored substrate modification guided by voltage mapping was associated with a significantly higher arrhythmia-free survival rate compared with a conventional approach applying linear ablation according to AF type.

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Background-Steerable sheath technology is designed to facilitate catheter access, stability, and tissue contact in target sites of atrial fibrillation (AF) catheter ablation. We hypothesized that rhythm control after interventional AF treatment is more successful using a steerable as compared with a nonsteerable sheath access. Methods and Results-One hundred thirty patients with paroxysmal or persistent drug-refractory AF undergoing their first ablation procedure were prospectively included in a randomized fashion in 2 centers. Ablation was performed by 10 operators with different levels of clinical experience.

Patients with persistent AF including those with unsuccessful prior ablation can be treated successfully by rotor targeted ablation, using the elimination of all rotors rather than acute AF termination as the procedural endpoint.

Background-We sought to determine the relationship between the size of the left atrial isolated surface area (ISA) after pulmonary vein antrum isolation for paroxysmal atrial fibrillation (AF) and rhythm outcome during a 12-month follow-up. Methods and Results-One hundred one consecutive patients with paroxysmal AF (mean age, 59±11 years; median [range] AF history, 36 months; mean left atrial size, 42±6 mm) were enrolled. The ISA was defined as the ratio of the total isolated antral surface area excluding the pulmonary veins to the sum of the total isolated antral surface area and the left atrial posterior wall surface area, while considering the individual characteristics of antral anatomy. All surface areas were assessed using the NavX system. Patients were divided into 4 groups according to ISA (group I: <50%; group II: 50 to <60%; group III: 60 to <70%; group IV: ≥70%). The average ISA for all patients was 59.2±11.6%. Subgroup analysis showed that ISA was 42.8±4.2% in group I (n=23), 54.2±3.0% in group II (n=23), 64.3±3.0% in group III (n=33), and 73.9±3.6% in group IV (n=22). After a 12-month follow-up period, 70% of patients in group I, 78% in group II, 97% in group III, and 100% in group IV were free from AF and atrial macroreentrant tachycardia. There was a significant difference between groups I and III, I and IV, II and III, and II and IV but not groups I and II and groups III and IV (logrank test P=0.024, 0.016, 0.037, 0.044, 0.584, and 0.500, respectively). Receiver operating characteristic curve analysis yielded an optimal cutoff value of 55% for ISA. Conclusions-After Methods Patient SelectionThe study was conducted on 101 consecutive patients with highly symptomatic, medically refractory paroxysmal AF, who had been treated with PVAI between January and December 2009. Paroxysmal AF was defined as a self-terminating AF of <1 week duration. Mapping and Ablation ProcedureBefore the procedure, transesophageal echocardiography was performed to exclude thrombus formation. Patients were studied under deep propofol sedation, breathing spontaneously. Standard electrode catheters were placed in the right ventricular apex and the coronary sinus, after which a single transseptal puncture was made. Unfractionated heparin was administered in bolus form immediately after the transseptal puncture to maintain an activated clotting time of >250 s. If AF occurred an external electrical cardioversion was performed to restore sinus rhythm. Mapping and ablation were performed using the NavX system (St. Jude Medical, Inc, St. Paul, MI) as a guide after integration of a 3-dimensional model of the left atrium (LA) and PV anatomy obtained from preinterventional computed tomography (CT), as described previously. 10 Before the ablation, the circular mapping catheter-reconstructed PV anatomies were aligned with the CT-PVs. Furthermore, the multipolar mapping catheter was replaced by a 4-mm M-curve irrigated tip ablation catheter (IBI Therapy Cooled Path; St Jude Medical, Inc). Fine adjustment of image integration was ach...

The use of NFCV technology enables safe, consistent, and 'near lead-free' performance of AF ablation in routine clinical practice.