Correlation between atrial fibrillation driver locations and complex fractionated atrial electrograms in patients with persistent atrial fibrillation.

INTRODUCTION: The aim of this study was to evaluate a spatial correlation between active atrial fibrillation (AF) drivers measured by electrocardiographic imaging and complex fractionated atrial electrograms (CFAEs) in patients with persistent AF. METHODS: Sixteen patients with persistent AF were included. A biatrial geometry relative to an array of 252-body-surface-electrodes was obtained from a noncontrast computed tomography scan. The reconstructed unipolar AF electrograms were signal-processed (ECVUE™, CardioInsight Technologies Inc., Cleveland, OH, USA) to identify AF drivers. Before driver ablation, a biatrial mapping using the NavX system (St. Jude Medical, St. Paul, MN, USA) was performed to identify CFAEs. CFAE and driver regions were then quantified and compared. RESULTS: AF was terminated by driver ablation in 11/16 (70%) patients. The mean number of ablated driver regions was 4 ± 1 per patient. The most frequent driver locations were the inferior left atrium and coronary sinus, the right pulmonary veins, and the right atrium. In 49/63 (78%) of the driver locations, more than 75% of the driver site showed CFAEs. The mean ablated driver area was 58 ± 24 cm2 (19 ± 11% of total surface area). The mean CFAE area was 178 ± 59 cm2 (49 ± 16%). The percentage of non-ablated CFAE area was 76 ± 13% of total CFAEs. In 9/11 patients with AF termination, the termination site showed CFAEs. CONCLUSIONS: There is a significant overlap between AF driver regions identified by the ECVUE™ system and CFAE areas identified by the NavX system. AF driver regions are smaller and mostly embedded in larger CFAE areas. Selective ablation of drivers in CFAE areas seems sufficient to terminate persistent AF in the majority of patients.

Ablation of Complex Fractionated Electrograms With or Without ADditional LINEar Lesions for Persistent Atrial Fibrillation (The ADLINE Trial).

BACKGROUND: For persistent atrial fibrillation (AF) ablation, different strategies including complex fractionated atrial electrograms (CFAE) ablation and linear lesions (LL) have been used in addition to pulmonary vein isolation (PVI). However, it is still a matter of debate if extended substrate modification improves long-term outcome. The aim of this study was to determine the benefit of LL in addition to PVI and CFAE ablation regarding freedom from arrhythmia recurrence in patients with persistent AF. METHODS: The study was a prospective randomized trial including 90 patients with persistent and longstanding persistent AF. All patients underwent PVI and CFAE ablation. If AF did not terminate to atrial tachycardia (AT) or sinus rhythm, patients were randomized to direct current cardioversion (Group 1; n = 45) or LL (Group 2; n = 45). Primary endpoint was freedom from any atrial arrhythmia off antiarrhythmic drugs at 12 months. (NCT02059369) RESULTS: Baseline characteristics were similar between the two groups with more than half of the patients having structural heart disease. The primary endpoint was reached in 37% in Group 1 (G1) and 16% in Group 2 (G2; P = 0.03). After a total number of 1.4 ± 0.5 (G1) versus 1.7 ± 0.4 (G2; P = 0.01) procedures, freedom from any arrhythmia was reached in 54% in G1 and 65% in G2 (P = 0.35). CONCLUSION: In persistent AF ablation, LL in addition to PVI and CFAE show a significantly lower success rate after a single procedure compared to PVI and CFAE. Following LL, significantly more patients needed a reablation to reach a similar success rate during a 12-month follow-up.

Transseptal Puncture Guided by CT-Derived 3D-Augmented Fluoroscopy.

BACKGROUND: Transseptal puncture for left atrial (LA) access is still mainly performed using fluoroscopy and transesophageal or intracardiac echocardiography. We present an easily applicable approach for the guidance of transseptal puncture that uses the combination of a 3D-mapping system and CT-derived 3D-overlayed anatomy. METHODS AND RESULTS: A computer tomographic (CT) LA-angiography was performed in n = 65 patients prior to a scheduled atrial fibrillation ablation procedure. The CARTO3 (Biosense Webster, Diamond Bar, CA, USA) segmentation tool was used to create a 3D-reconstruction of cardiac anatomy and the spine. The CARTO UNIVU module was then used to overlay and register the segmented 3D-anatomy onto fluoroscopy. The 3D-reconstructed spine and cardiac anatomy were congruently aligned to their fluoroscopic counterparts in fluoroscopic views. The feasibility of the technique, its safety, and accuracy (assessed as contour offsets between 3D-overlay and angiographic LA anatomy) were evaluated. Overlay registration accuracy was analyzed by CARTO3 registration matrices. Transseptal puncture was feasible without complications in all 65 patients using the new 3D-overlay technique. Three-dimensional-overlay contour offsets were 1.6 ± 1.2 mm in left PV, 1.7 ± 1.2 mm in right PV, and 1.3 ± 1.0 mm in the LA roof region. Overlay registration accuracy was 4.9 ± 2.7 mm. The average time needed for anatomy segmentation was 204 ± 61 seconds, time needed for overlay registration was 18 ± 8 seconds. CONCLUSIONS: Three-dimensional-augmented fluoroscopy is feasible, safe, and easy to apply as guidance for transseptal puncture and demonstrates a high level of accuracy.

Electromagnetic Contact-Force Sensing Electrophysiological Catheters: How Accurate is the Technology?

BACKGROUND: Contact-force (CF) sensing catheters are increasingly used in clinical electrophysiological practice due to their efficacy and safety profile. As data about the accuracy of this technology are scarce, we sought to quantify accuracy based on in vitro experiments. METHODS AND RESULTS: A custom-made force sensor was constructed that allowed exact force reference measurements registered via a flexible membrane. A Smarttouch Surround Flow (ST SF) ablation catheter (Biosense Webster, Diamond Bar, CA, USA) was brought in contact with the membrane of the force sensor in order to compare the ST SF force measurements to force sensor reference measurements. ST SF force sensing technology is based on deflection registration between the distal and proximal catheter tip. The experiment was repeated for n = 10 ST SF catheters, which showed no significant difference in accuracy levels. A series of measurements (n = 1200) was carried out for different angles of force acting to the catheter tip (0°/perpendicular contact, 30°, 60°, 90°/parallel contact). The mean absolute differences between reference and ST SF measurements were 1.7 ± 1.8 g (0°), 1.6 ± 1.2 g (30°), 1.4 ± 1.3 g (60°), and 6.6 ± 5.9 g (90°). Measurement accuracy was significantly higher in non-parallel contact when compared with parallel contact (P < 0.01). CONCLUSIONS: Catheter force measurements using the ST SF catheters show a high level of accuracy regarding differences to reference measurements and reproducibility. The reduced accuracy in measurements of 90° acting forces (parallel contact) might be clinically important when creating, for example, linear lesions.

Evaluation of a new very low dose imaging protocol: feasibility and impact on X-ray dose levels in electrophysiology procedures.

AIMS: This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. METHODS AND RESULTS: From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose-area products were 877.9 ± 624.7 µGym² (n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² (n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² (n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² (n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min (P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min (P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min (P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min (P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups (P = 1.0). CONCLUSION: The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures.

First-line catheter ablation of paroxysmal atrial fibrillation: outcome of radiofrequency vs. cryoballoon pulmonary vein isolation.

AIMS: First-line ablation prior to antiarrhythmic drug (AAD) therapy is an option for symptomatic paroxysmal atrial fibrillation (PAF); however, the optimal ablation technique, radiofrequency (RF), or cryoballoon (CB) has to be determined. METHODS AND RESULTS: The FREEZE Cohort Study compares RF and CB ablation. Treatment-naïve patients were documented in the FREEZEplus Registry. Periprocedural data and outcome were analysed. From 2011 to 2014, a total of 373/4184 (8.9%) patients with PAF naïve to AAD were identified. Pulmonary vein isolation (PVI) was performed with RF (n = 180) or CB (n = 193). In the RF group, patients were older (65 vs. 61 years, P < 0.01) compared with the CB group. The procedure time was significantly shorter and radiation exposure higher in the CB group. Major adverse events occurred in 1.6% (CB) and 3.7% (RF) of patients (P = 0.22). AF/atrial tachycardia (AT) recurrence until discharge was 4.5% (RF) and 8.5% (CB, P = 0.2). Follow-up (FU) ≥12 months was available in 99 (RF) and 107 (CB) patients. After 1.4 years of FU, freedom from AF/atrial tachycardia (AT) was 61% (RF) and 71% (CB, P = 0.11). In the RF group, more patients underwent cardioversion, and a trend for more repeat ablations was observed. Persistent phrenic nerve palsy was observed in one patient treated by CB. CONCLUSION: First-line ablation for PAF is safe and effective with either RF or CB. The procedure was faster with the CB, but the radiation exposure was higher. Although there was a trend for more recurrences and complications in the RF group, a more favourable risk profile in patients undergoing CB ablation might have biased the results. CLINICALTRIALSGOV IDENTIFIER: NCT01360008.

Atrial Tachycardias Following Persistent Atrial Fibrillation Ablation: Predictors of Recurrence After the Repeat Ablation.

BACKGROUND: Repeat procedures after persistent atrial fibrillation (AF) ablation are frequently performed for secondary atrial tachycardias (AT). Predictors of AT recurrence after the first repeat ablation have not yet been studied. METHODS: We investigated predictors of AT recurrence in 117 patients who underwent ablation for secondary AT arising after a previous ablation for persistent AF using the Cox proportional hazards model. RESULTS: Acute ablation success rate was 94%. Over a follow-up period of 12 months, 61 patients (53%) were free from AT recurrence. Of the assessed predictors of AT recurrence, the number of ablated AT forms (>1 vs. 1) was significantly associated with AT recurrence (hazard ratio 2.01, 95% CI 1.18-3.43, P = 0.01). Other variables including left atrial diameter, AT mechanism, or the characteristics of previous AF ablation did not have significant influence on AT recurrence (P>0.05). Men had a tendency toward fewer AT recurrences than women (OR 0.60, 95% CI 0.34-1.05, P = 0.07). During a second AT ablation procedure, 19 (49%) patients were identified to have a recurrence of the previously ablated AT, whereas in 20 patients (51%) a new AT form was diagnosed. CONCLUSION: Ablation of atrial tachycardias following persistent AF ablation has a high acute success rate. However, a substantial number of patients develop new onset AT during follow-up. The occurrence of multiple AT forms during the repeat ablation procedure was the only predictive factor for AT recurrence.

Sensor-Based Electromagnetic Navigation (Mediguide®): How Accurate Is It? A Phantom Model Study.

BACKGROUND: Data about localization reproducibility as well as spatial and visual accuracy of the new MediGuide® sensor-based electroanatomic navigation technology are scarce. We therefore sought to quantify these parameters based on phantom experiments. METHODS AND RESULTS: A realistic heart phantom was generated in a 3D-Printer. A CT scan was performed on the phantom. The phantom itself served as ground-truth reference to ensure exact and reproducible catheter placement. A MediGuide® catheter was repeatedly tagged at selected positions to assess accuracy of point localization. The catheter was also used to acquire a MediGuide®-scaled geometry in the EnSite Velocity® electroanatomic mapping system. The acquired geometries (MediGuide®-scaled and EnSite Velocity®-scaled) were compared to a CT segmentation of the phantom to quantify concordance. Distances between landmarks were measured in the EnSite Velocity®- and MediGuide®-scaled geometry and the CT dataset for Bland-Altman comparison. The visualization of virtual MediGuide® catheter tips was compared to their corresponding representation on fluoroscopic cine-loops. Point localization accuracy was 0.5 ± 0.3 mm for MediGuide® and 1.4 ± 0.7 mm for EnSite Velocity®. The 3D accuracy of the geometries was 1.1 ± 1.4 mm (MediGuide®-scaled) and 3.2 ± 1.6 mm (not MediGuide®-scaled). The offset between virtual MediGuide® catheter visualization and catheter representation on corresponding fluoroscopic cine-loops was 0.4 ± 0.1 mm. CONCLUSIONS: The MediGuide® system shows a very high level of accuracy regarding localization reproducibility as well as spatial and visual accuracy, which can be ascribed to the magnetic field localization technology. The observed offsets between the geometry visualization and the real phantom are below a clinically relevant threshold.

Correction to: Electromagnetic interference in implantable cardioverter defibrillators: present but rare.

The original version of this article unfortunately contained a mistake.

Safety of Uninterrupted Periprocedural Edoxaban Versus Phenprocoumon for Patients Who Underwent Left Atrial Catheter Ablation Procedures.

Data about the safety of edoxaban in patients who underwent left atrial (LA) radiofrequency (RF) ablation procedures are lacking. This study sought to compare the safety of uninterrupted edoxaban with uninterrupted phenprocoumon administration during LA RF ablation for atrial fibrillation and atrial tachycardia. In total, 231 patients (mean age 64 ± 11years, male 71%) who underwent LA RF ablation under continuous oral anticoagulation (OAC) with edoxaban or phenprocoumon were included in the study. Patients on uninterrupted edoxaban (60 mg or 30 mg/day for at least 4 weeks) were matched for gender, age and type of arrhythmia with 2 patients on uninterrupted phenprocoumon (international normalized ratio 2 to 3). We identified 77 consecutive patients on edoxaban and n = 154 patients on phenprocoumon. Heparin was administered periprocedurally to achieve an activated clotting time of 280 to 300 seconds. No protamine was administered periprocedurally. The primary end point was a composite of bleeding, thromboembolic events, and death. The primary end point was met in 9 patients in the edoxaban group and in 22 patients in the phenprocoumon group (p = 0.69). No patient in either group died or had a thromboembolic complication. No major bleeding complication was observed in the edoxaban group, whereas one was found in 1 patient in the phenprocoumon group (p ≥0.99). Minor bleeding complications occurred in 9 patients (12%) in the edoxaban group and in 21 patients (14%) in the phenprocoumon group (p = 0.84). Uninterrupted OAC with edoxaban appeared to be as safe as uninterrupted OAC with phenprocoumon in patients who underwent LA RF ablation procedures.

Multicenter, randomized comparison between magnetically navigated and manually guided radiofrequency ablation of atrioventricular nodal reentrant tachycardia (the MagMa-AVNRT-trial).

BACKGROUND: Remote magnetic navigation (RMN) is attributed to diminish radiation exposure for both patient and operator performing catheter ablation for different arrhythmia substrates. The purpose of this prospective, randomized study was to compare RMN with manually guided catheter ablation for AV nodal reentrant tachycardia (AVNRT) regarding fluoroscopy time/dosage, acute and long-term efficacy as well as safety. METHODS AND RESULTS: A total of 218 patients with AVNRT undergoing catheter ablation at three centers (male 34%, mean age 50 ± 17 years) were randomized to a manual approach (n = 113) or RMN (n = 105) using the Niobe® magnetic navigation system. The primary study endpoint was total fluoroscopy time/dosage for patient and operator at the end of the procedure. Secondary endpoints included acute success, procedure duration, complications and success rate after 6 months. Fluoroscopy time and dosage for the patient were significantly reduced in the RMN group compared to the manual group (6 ± 6 vs. 11 ± 10 min; p < 0.001 and 425 ± 558 vs. 751 ± 900 cGycm2, p = 0.002). A reduction in fluoroscopy time/dose also applied to the operator (3 ± 5 vs. 7 ± 9 min 209 ± 444 vs. 482 ± 689 cGycm2, p < 0.001). Procedure duration was significantly longer in the RMN group (88 ± 29 vs. 79 ± 29 min; p = 0.03) and crossover from the RMN group to manual ablation occurred in 7.6% of patients (7.6 vs. 0.1%; p = 0.02). Acute success was achieved in 100% of patients in both groups. Midterm success after 6 months was 97 vs. 98% (p = 0.67). No complications occurred in both groups. CONCLUSION: The use of RMN for catheter ablation of AVNRT compared to a manual approach results in a reduction of fluoroscopy time and dosage of about 50% for both patients and physicians. Acute and midterm success and safety are comparable. RMN is a good alternative to a manual approach for AVNRT ablation.

Electromagnetic interference in implantable cardioverter defibrillators: present but rare.

PURPOSE: Electromagnetic interference (EMI) with implantable cardioverter defibrillators (ICDs) can cause oversensing and subsequently inappropriate ICD therapies. We retrospectively investigated the current incidence and clinical relevance of oversensing related EMI in a large cohort of ICD patients. METHODS: From January 2005 to April 2013, all ICD interrogations performed at our institution were analyzed for the occurrence of oversensing related EMI. EMI episodes were classified as clinically significant, potentially significant or of minor significance. To identify risk factors for EMI, we also analyzed different lead models in our cohort (integrated vs true bipolar leads). RESULTS: Data of 2940 ICD patients (mean age 63 ± 16 years, 2322 male patients, 7772 patient-years) were retrospectively analyzed for the occurrence of EMI. During the observation period, a total of 145 (hospital environment n = 97, non-hospital environment n = 48) episodes occurred and resulted in an overall EMI incidence, i.e. event rate, of 1.87 % per patient per year. Focusing on clinically significant or potentially significant episodes, the EMI incidence was 0.27 % per patient per year. Cox proportional hazards regression analysis did not reveal a statistically significant higher hazard of oversensing for patients with integrated bipolar leads compared to patients with true bipolar leads (HR = 2.21; 95 % CI 0.90-5.39; p = 0.083). CONCLUSIONS: Our data demonstrate that EMI continues to occur in everyday life. Patients should be well informed about the potential sources and risks of EMI but they need not be overly concerned since the risk of EMI-especially in a non-hospital environment-is low.