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Objectives: Left atrial (LA) low-voltage substrate (LVS) potentially slows intra-atrial conduction, which might identify patients at risk for arrhythmia recurrence following pulmonary vein isolation (PVI)., Background: Up to 50% of patients with persistent atrial fibrillation (AF) have arrhythmia recurrence following PVI, mostly due to arrhythmogenic LA LVS., Methods: Seventy-two patients with persistent AF underwent electrocardioversion to sinus rhythm and high-density voltage mapping of the left atrium. Invasively measured LA activation time and P-wave duration (PWD; total PWD and LA PWD [measured from -dV/dt in leads V 1 and V 2 until the end of the P-wave]) on amplified (40 to 50 mm/mV, 100 to 200 mm/s) digitized 12-lead electrocardiography (ECG) were compared with the extent of LA LVS (<0.5 and <1. 0mV). Freedom from arrhythmia following PVI was evaluated in 143 patients with persistent AF stratified according to amplified PWD before ablation., Results: LA LVS resulted in regional conduction delay, which increased LA activation time (r = 0.79). LA PWD strongly correlated with LA activation time (r = 0.96) and LA LVS (r = 0.80). As the first (right atrial) portion of the P-wave (from P-wave beginning until -dV/dt in leads V 1 and V 2 ) was not affected by LA LVS, total PWD correlated with LA LVS (r = 0.84). PWD ≥150 ms identified advanced LA LVS with 94.3% sensitivity and 91.7% specificity. One-year arrhythmia freedom following PVI-only was significantly higher in patients with PWD <150 ms (n = 73) compared with those with prolonged PWD ≥150 ms (n = 70) (72.0% vs. 40.8%; p = 0.003)., Conclusions: Advanced arrhythmogenic LVS is associated with significant intra-atrial conduction delay, which is accurately measurable by prolongation of PWD on amplified 12-lead ECG. PWD ≥150 ms during sinus rhythm measured prior to ablation identifies patients with persistent AF who are at increased risk for arrhythmia recurrence following PVI., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Aims: The number of pulmonary vein isolation (PVI) ablation procedures is steadily increasing worldwide resulting in a substantial radiation exposure to patients and operators. The aim of our study was to reduce radiation exposure during these procedures to a critical amount without compromising patient safety., Methods and Results: First, we assessed radiation exposure for primary PVI procedures over time (2005-2015) at the University Heart Center Freiburg-Bad Krozingen. Second, we prospectively evaluated in 52 patients, the efficacy and safety of a novel radiation reduction program (particularly applying an enhanced fluoroscopy pulse dose-reduction and optimized 3D-mapping system use). In 2035 primary PVI procedures, radiation exposure, assessed as estimated effective dose (eED in mSv, dose area product * 0.002 * conversion factor for females), fluoroscopy-time, and procedure-time decreased significantly from 2005 to 2015 (e.g. eED decreased from 9.3 (interquartile range (IQR) 6.4-13.4) mSv to 0.9 (IQR 0.5-1.6) mSv, p for trend <0.001). Importantly, application of the enhanced radiation reduction program further reduced eED to 0.4 mSv (IQR 0.3-0.6, P < 0.001 vs. control), a value not significantly different from slow-pathway ablation procedures (P = 0.41). Multiple linear regression analysis identified the radiation reduction program as the only independent variable associated with a decrease in radiation exposure., Conclusion: Radiation exposure during PVI decreased over the last decade and can further be reduced significantly by the implementation of an enhanced radiation reduction program., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.)

Background: Complex-fractionated atrial electrograms and atrial fibrosis are associated with maintenance of persistent atrial fibrillation (AF). We hypothesized that pulmonary vein isolation (PVI) plus ablation of selective atrial low-voltage sites may be more successful than PVI only., Methods and Results: A total of 85 consecutive patients with persistent AF underwent high-density atrial voltage mapping, PVI, and ablation at low-voltage areas (LVA < 0.5 mV in AF) associated with electric activity lasting > 70% of AF cycle length on a single electrode (fractionated activity) or multiple electrodes around the circumferential mapping catheter (rotational activity) or discrete rapid local activity (group I). The procedural end point was AF termination. Arrhythmia freedom was compared with a control group (66 patients) undergoing PVI only (group II). PVI alone was performed in 23 of 85 (27%) patients of group I with low amount (< 10% of left atrial surface area) of atrial low voltage. Selective atrial ablation in addition to PVI was performed in 62 patients with termination of AF in 45 (73%) after 11 ± 9 minutes radiofrequency delivery. AF-termination sites colocalized within LVA in 80% and at border zones in 20%. Single-procedural arrhythmia freedom at 13 months median follow-up was achieved in 59 of 85 (69%) patients in group I, which was significantly higher than the matched control group (31/66 [47%], P < 0.001). There was no significant difference in the success rate of patients in group I with a low amount of low voltage undergoing PVI only and patients requiring PVI+selective low-voltage ablation (P = 0.42)., Conclusions: Ablation of sites with distinct activation characteristics within/at borderzones of LVA in addition to PVI is more effective than conventional PVI-only strategy for persistent AF. PVI only seems to be sufficient to treat patients with left atrial low voltage < 10%., (© 2016 American Heart Association, Inc.)

Introduction: Pulmonary vein reconnection (PVR) is an important cause of AF recurrence after ablation. With the advent of force sensing catheters, catheter-tissue contact can be determined quantitatively. Since contact force (CF) plays a major role in determining the characteristics of RF lesion, we prospectively assessed the mechanisms of PVR with regard to catheter-contact and lesion distances in patients undergoing AF ablation., Methods and Results: Forty symptomatic AF patients underwent wide circumferential PV isolation (PVI) with SmartTouch™ CF catheter. The exact locations of acute PVI and spontaneous or adenosine-provoked PVR were annotated on CARTO. One thousand nine hundred and twenty-six RF lesions isolated 153 PVs. PVR occurred in 35 (23%) PVs: 22 (63%) adenosine-provoked and 13 (37%) spontaneous. CF was significantly lower at PVR versus PVI sites for RF lesions within 6 mm from these sites: mean CF 5 versus 11 g (P < 0.0001) and force-time integral (FTI) 225 versus 415 gs (P < 0.0001); 86% of PVR occurred with a mean CF < 10 g (FTI < 400 gs); and the remaining 14% occurred at ablation sites with a long interlesion distance (≥5 mm) despite mean CF ≥ 10 g. Eighty percent of PVR sites were located anteriorly. There were no significant differences in regard to arrhythmia freedom between the patients without (69%) versus with PVR (67%; P = 1.0)., Conclusions: Acutely durable PVI can be achieved when RF lesions are delivered with a mean CF ≥ 10 g and an interlesion distance <5 mm. The majority of PVR occur anteriorly due to inadequate CF or long interlesion distances., (© 2014 Wiley Periodicals, Inc.)

Introduction: Irrigated tip radiofrequency (RF) catheter ablation is the most frequently used technology for pulmonary vein isolation (PVI). The purpose of this study was to compare the efficiency and the safety of 2 different open irrigated tip RF ablation catheters., Methods and Results: A total of 160 patients with symptomatic AF (29% persistent, 68% male, 61 ± 10 years) were randomized to circumferential PVI using 2 different irrigated tip catheters: (1) the novel Thermocool SF(®) with a porous tip (56 holes) or (2) the Thermocool(®) catheter with 6 irrigation holes at the distal tip in both power- and temperature-controlled modes. PVI procedural time and RF duration were significantly shorter with SF(®) versus Thermocool(®) catheter: 104.5 versus 114 minutes (P = 0.023) and 35.4 minutes versus 39.9 minutes (P < 0.001), respectively. Similarly, the total fluoroscopy time and dose were shorter with SF(®) versus. Thermocool(®) catheter: 21 minutes versus 24 minutes (P = 0.02) and 1014.5 μGy*m(2) versus 1377 μGy*m(2) (P < 0.0001), respectively. Irrigation volume was lower with SF(®): 600 mL versus 1100 mL, (P < 0.0001) and the rates of complications were not significantly different (0.6% vs 0.49%, P = 0.66). At 20.5 ± 7.5 months follow-up, there were no significant differences with regard to arrhythmia freedom between SF(®) (59.2%) and TC® groups (59.3%), (P = 0.61)., Conclusions: Using the novel irrigated tip SF catheter, PVI is achieved within a shorter ablation and procedural durations. The underlying mechanisms and potential differences in RF lesion size remain to be elucidated., (© 2013 Wiley Periodicals, Inc.)

Background: More extensive ablation strategies for the treatment of atrial fibrillation (AF) have increased success rates but are associated with new and sometimes serious complications. We describe a new complication after extensive radiofrequency (RF) ablation in the left atrium (LA) for persistent AF., Methods and Results: Electroanatomic guided circumferential ablation around both ipsilateral pulmonary veins (PV) was performed with the endpoint of complete conduction block. When necessary, supplementary RF applications were added, including ablation of complex fractionated potentials and/or isolation of other thoracic veins and/or linear left atrial lesions. RF energy was delivered via an irrigated tip catheter with a maximum power of 30-35 W. Four out of 120 patients undergoing extensive RF ablation for persistent AF (including two patients with additional LA substrate modification) developed dyspnea, bilateral pulmonary edema, and signs of a systemic inflammatory response syndrome (SIRS) (rise in body temperature, leukocyte count, and C-reactive protein (CRP levels) 18-48 hours after the procedure. There were no signs of PV stenosis, focal lung injury, left ventricular dysfunction, circulatory failure, or infection. All patients had complete recovery with supportive therapy within 3-4 days after the onset of symptoms., Conclusions: Extensive LA radiofrequency ablation bears the risk of a severe pulmonary edema. Although the precise mechanism is elusive, clinical features point toward a systemic inflammatory response.