No abstract

Aims To evaluate the safety and effectiveness of pulmonary vein isolation in paroxysmal atrial fibrillation (PAF) using a standardized workflow aiming to enclose the veins with contiguous and optimized radiofrequency lesions. Methods and results This multicentre, prospective, non-randomized study was conducted at 17 European sites. Pulmonary vein isolation was guided by VISITAG SURPOINT (VS target ≥550 on the anterior wall; ≥400 on the posterior wall) and intertag distance (≤6 mm). Atrial arrhythmia recurrence was stringently monitored with weekly and symptom-driven transtelephonic monitoring on top of standard-of-care monitoring (24-h Holter and 12-lead electrocardiogram at 3, 6, and 12 months follow-up). Three hundred and forty participants with drug refractory PAF were enrolled. Acute effectiveness (first-pass isolation proof to a 30-min wait period and adenosine challenge) was 82.4% [95% confidence interval (CI) 77.4–86.7%]. At 12-month follow-up, the rate of freedom from any documented atrial arrhythmia was 78.3% (95% CI 73.8–82.8%), while freedom from atrial arrhythmia by standard-of-care monitoring was 89.4% (95% CI 78.8–87.0%). Freedom fromrepeat ablations by the Kaplan–Meier analysis was 90.4% during 12 months of follow-up. Of the 34 patients with repeat ablations, 14 (41.2%) demonstrated full isolation of all pulmonary vein circles. Primary adverse event (PAE) rate was 3.6% (95% CI 1.9–6.3%). Conclusions The VISTAX trial demonstrated that a standardized PAF ablation workflow aiming for contiguous lesions leads to low rates of PAEs, high acute first-pass isolation rates, and 12-month freedom from arrhythmias approaching 80%. Further research is needed to improve the reproducibility of the outcomes across a wider range of centres. Clinical trial registration: ClinicalTrials.gov, number NCT03062046, https://clinicaltrials.gov/ct2/show/NCT03062046.

OBJECTIVES This study sought to assess the relationship between fibrosis and re-entrant activity in persistent atrial fibrillation (AF). BACKGROUND The mechanisms involved in sustaining re-entrant activity during AF are poorly understood. METHODS Forty-one patients with persistent AF (age 56 ± 12 years; 6 women) were evaluated. High-resolution electrocardiographic imaging (ECGI) was performed during AF by using a 252-chest electrode array, and phase mapping was applied to locate re-entrant activity. Sites of high re-entrant activity were defined as re-entrant regions. Late gadolinium-enhanced (LGE) cardiac magnetic resonance (CMR) was performed at 1.25 × 1.25 × 2.5 mm resolution to characterize atrial fibrosis and measure atrial volumes. The relationship between LGE burden and the number of re-entrant regions was analyzed. Local LGE density was computed and characterized at re-entrant sites. All patients underwent catheter ablation targeting re-entrant regions, the procedural endpoint being AF termination. Clinical, CMR, and ECGI predictors of acute procedural success were then analyzed. RESULTS Left atrial (LA) LGE burden was 22.1 ± 5.9% of the wall, and LA volume was 74 ± 21 ml/m2. The number of re-entrant regions was 4.3 ± 1.7 per patient. LA LGE imaging was significantly associated with the number of re-entrant regions (R = 0.52, p = 0.001), LA volume (R = 0.62, p < 0.0001), and AF duration (R = 0.54, p = 0.0007). Regional analysis demonstrated a clustering of re-entrant activity at LGE borders. Areas with high re-entrant activity showed higher local LGE density as compared with the remaining atrial areas (p < 0.0001). Failure to achieve AF termination during ablation was associated with higher LA LGE burden (p < 0.001), higher number of re-entrant regions (p < 0.001), and longer AF duration (p = 0.008). CONCLUSIONS The number of re-entrant regions during AF relates to the extent of LGE on CMR, with the location of these regions clustering to LGE areas. These characteristics affect procedural outcomes of ablation.

Introduction The CLOSE protocol combines ablation index (AI) and ≤6 mm interlesion distance using standard power settings for the treatment of atrial fibrillation (AF). The purpose was to compare the safety and efficacy of a conventional CLOSE and a higher power shorter duration (HPSD)‐CLOSE pulmonary vein isolation (PVI) strategy. Methods and Results All consecutive patients referred for PVI were included after informed consent was obtained from them. Group 1 was treated with a standard CLOSE protocol and group 2 with a HPSD‐CLOSE protocol (45 W anterior and 35 W posterior). Procedural parameters and 6‐month follow‐up were analyzed. In total, 174 patients (group 1: n = 94 [paroxysmal: n = 74]; group 2: n = 80 [paroxysmal: n = 65], similar baseline characteristics) were included. PVI was reached in all, but procedure duration (82 ± 18 minutes vs 100 ± 22 minutes; P < .0001) and radiofrequency (RF) time (23 ± 5 minutes vs 36 ± 11 minutes; P < .0001) was shorter in group 2. First pass isolation was similar in groups 2 and 1 (left veins: 94% vs 90%; P = .42 and right veins: 83% vs 84%; P = .79, respectively). Six‐month off‐ antiarrhythmic drugs freedom of AF/AT was similar in groups 2 and 1 (82% [paroxysmal: 86%] vs 83% [paroxysmal: 88%]; P = .93, respectively). Major complications were similar (group 2: 1% vs group 1: 3%; P = .39). Conclusion A higher‐power short duration approach can shorten a CLOSE procedure and reduce ablation time without having a negative impact on safety or efficiency.

Image Integration-Guided VT Ablation. Background: Although multi-detector computed tomography (MDCT) and cardiac magnetic resonance (CMR) can assess the structural substrate of ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM), non-ICM (NICM), and arrhythmogenic right ventricular cardiomyopathy (ARVC), the usefulness of systematic image integration during VT ablation remains undetermined.Methods and Results: A total of 116 consecutive patients (67 ICM; 30 NICM; 19 ARVC) underwent VT ablation with image integration (MDCT 91%; CMR 30%; both 22%). Substrate was defined as wall thinning on MDCT and late gadolinium-enhancement on CMR in ICM/NICM, and as myocardial hypoattenuation on MDCT in ARVC. This substrate was compared to mapping and ablation results with the endpoint of complete elimination of local abnormal ventricular activity (LAVA), and the impact of image integration on procedural management was analyzed. Imaging-derived substrate identified 89% of critical VT isthmuses and 85% of LAVA, and was more efficient in identifying LAVA in ICM and ARVC than in NICM (90% and 90% vs. 72%, P < 0.0001), and when defined from CMR than MDCT (ICM: 92% vs. 88%, P = 0.026, NICM: 88% vs. 72%, P < 0.001). Image integration motivated additional mapping and epicardial access in 57% and 33% of patients. Coronary and phrenic nerve integration modified epicardial ablation strategy in 43% of patients. The impact of image integration on procedural management was higher in ARVC/NICM than in ICM (P < 0.01), and higher in case of epicardial approach (P < 0.0001).Conclusions: Image integration is feasible in large series of patients, provides information on VT substrate, and impacts procedural management, particularly in ARVC/NICM, and in case of epicardial

Multipolar mapping catheters with small electrodes provide more accurate and higher density maps, with a higher sensitivity to near-field signals. Agreement between PR and NAV is low.

Background— During the past years, many innovations have been introduced to facilitate catheter ablation of post–myocardial infarction ventricular tachycardia. However, the predictors of outcome after ablation were not thoroughly studied. Methods and Results— From 2009 to 2013, consecutive patients referred for post–myocardial infarction ventricular tachycardia ablation were included. The end point of the procedure was complete elimination of local abnormal ventricular activities (LAVA) and ventricular tachycardia (VT) noninducibility. The predictors of outcome with primary end point of VT recurrence were assessed. A total of 125 patients were included (age: 64±11 years; 7 women) for 142 procedures. The left ventricle was accessed via transseptal, retrograde aortic, and epicardial approaches in 87%, 33%, and 37% of patients, respectively. Three-dimensional electroanatomical mapping system was used in 70%, multipolar catheter in 51%, and real-time image integration in 38% (from magnetic resonance imaging in 39% and multidetector computed tomography in 93%) of patients. Before ablation, VT was inducible in 75%, and endocardial/epicardial LAVA were present in 88%/75%. After ablation, complete LAVA elimination was achieved in 60%, and VT noninducibility in 83%. During a median follow-up of 850 days (interquartile range, 439–1707), VT recurrence was observed in 36%. Multivariable analysis identified 3 independent outcome predictors: the ability to achieve complete LAVA elimination ( R 2 =0.29; P <0.0001; risk ratio=0.52 [0.38–0.70]), the use of real-time image integration ( R 2 =0.21; P =0.0006; risk ratio=0.49 [0.33–0.74]), and the use of multipolar catheters ( R 2 =0.08; P =0.05; risk ratio=0.75 [0.56–1.00]). Conclusions— Achievement of complete LAVA elimination and use of scar integration from imaging and multipolar catheters to focus high-density mapping are independent predictors of VT-free survival after catheter ablation for post–myocardial infarction ventricular tachycardia.

This is a simple approach, with a clear endpoint and the ability to ablate in sinus rhythm. This strategy significantly benefits from high-definition imaging, mapping, and epicardial access.