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A new automated vector-based mapping algorithm (AMA) for 3-dimensional (3D) mapping has been introduced. The aim of this study was to present our experience using AMA to recognize additional catheter ablation targets in patients with ventricular arrhythmias (VA). A total of 16 patients (ICM; ischemic cardiomyopathy, n  = 6; NICM; non-ischemic cardiomyopathy n  = 10) suffering from VA underwent catheter ablation. Following bipolar voltage mapping, AMA was utilized to reveal zones of decelerated conduction velocity vectors (CVV) and this information was superimposed onto the 3D reconstructions and compared with the presence of scar. Mapping time was 28.1 ± 10 min for the endocardial reconstruction of the left ventricle (LV) and 17 ± 5.4 min for the epicardium ( n  = 6 patients). The mean area of LV low voltage was 13.9 ± 15% (endocardial) and 11.9 ± 5.7% (epicardial). Decelerating CVV zones were revealed in all patients (mean conduction velocity threshold of 39.3 ± 13%). Sustained VA have been terminated through ablation and substrate modification was performed in all patients. Correlation between the presence of CVV deceleration zones and areas of abnormal low voltage from bipolar mapping was revealed in only 37.5% of patients, but there was good correlation between scar from unipolar voltage mapping and the presence of CCV deceleration zones (94%; p  = 0.008). The novel AMA may improve the understanding of individual VA substrates due to the visualization of decelerated CVV zones and their correlation with abnormal low voltage predominantly from unipolar mapping.

Catheter ablation has emerged as an effective treatment for atrial arrhythmias, and pulmonary vein isolation (PVI) is the cornerstone of ablation strategies. Significant technological evolution and widespread increase in operator experience have facilitated the effectiveness of catheter ablation to achieve durable PVIs in single or multiple ablation procedures. Nevertheless, arrhythmia recurrence is a common problem even after establishing PVI. Data on catheter ablation in these patients are sparse and repeat ablation in this population is highly challenging. In this review we have summarized the available data as well as potential strategies of catheter ablation following the initial PVI.

The non-fluoroscopy approach with the use of a three-dimensional (3D) navigation system is increasingly recognized as a future technology in the treatment of arrhythmias. However, there are a limited number of articles published concerning transseptal puncture without the use of fluoroscopy. Presented in this paper is the first series of patients (n = 10) that have undergone transseptal puncture without the use of fluoroscopy under transesophageal echocardiography control using a radiofrequency transseptal needle and a 3D navigation system. All patients were treated without complications. In six patients, re-pulmonary vein isolation was performed. In 5 cases, linear ablation of the left atrium for treatment of left atrial macro re-entry tachycardia was provided. In 2 patients, focal atrial tachycardia was treated, 1 patient underwent cavo tricuspidal isthmus (CTI) ablation and one patient, re-CTI ablation. The ablation of complex fragmented atrial electrograms was done in 2 patients. In 1 case, right atrial macro re-entry tachycardia was treated. Transseptal puncture without using fluoroscopy is safe and effective when using a radiofrequency needle, a 3D navigation system and transesophageal echocardiography.

Background Cardiovascular magnetic resonance (CMR) imaging may be used to visualize post-ablation atrial scar (PAAS), and three-dimensional late gadolinium enhancement (3D LGE) is the most widely employed technique for imaging of chronic scar. Detection of PAAS provides a unique non-invasive insight into the effects of the ablation and may help guide further ablation procedures. However, there is evidence that PAAS is often not detected by CMR, implying a significant sensitivity problem, and imaging parameters vary between leading centres. Therefore, there is a need to establish the optimal imaging parameters to detect PAAS. Methods Forty subjects undergoing their first pulmonary vein isolation procedure for AF had detailed CMR assessment of atrial scar: one scan pre-ablation, and two scans post-ablation at 3 months (separated by 48 h). Each scan session included ECG- and respiratory-navigated 3D LGE acquisition at 10, 20 and 30 min post injection of a gadolinium-based contrast agent (GBCA). The first post-procedural scan was performed on a 1.5 T scanner with standard acquisition parameters, including double dose (0.2 mmol/kg) Gadovist and 4 mm slice thickness. Ten patients subsequently underwent identical scan as controls, and the other 30 underwent imaging with a reduced, single, dose GBCA ( n  = 10), half slice thickness ( n  = 10) or on a 3 T scanner ( n  = 10). Apparent signal-to-noise (aSNR), contrast-to-noise (aCNR) and imaging quality (Likert Scale, 3 independent observers) were assessed. PAAS location and area (%PAAS scar) were assessed following manual segmentation. Atrial shells with standardised %PAAS at each timepoint were then compared to ablation lesion locations to assess quality of scar delineation. Results A total of 271 3D acquisitions (out of maximum 280, 96.7%) were acquired. Likert scale of imaging quality had high interobserver and intraobserver intraclass correlation coefficients (0.89 and 0.96 respectively), and showed lower overall imaging quality on 3 T and at half-slice thickness. aCNR, and quality of scar delineation increased significantly with time. aCNR was higher with reduced, single, dose of GBCA ( p  = 0.005). Conclusion 3D LGE CMR atrial scar imaging, as assessed qualitatively and quantitatively, improves with time from GBCA administration, with some indices continuing to improve from 20 to 30 min. Imaging should be performed at least 20 min post-GBCA injection, and a single dose of contrast should be considered. Trial registration Trial registry- United Kingdom National Research Ethics Service 08/H0802/68 – 30th September 2008.

Background The second-generation cryoballoon (CB2) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging clinical outcome data. The novel third-generation cryoballoon (CB3) incorporates a 40 % shorter distal tip. This design change may translate into an increased rate of PVI real-time signal recording, facilitating an individualized ablation strategy using the time to effect (TTE). Methods and results Thirty consecutive patients with paroxysmal or short-standing persistent atrial fibrillation underwent CB3-based PVI and were compared to 30 patients treated with the CB2. Individual freeze-cycle duration was set to TTE + 120 s for both groups. A total of 118 (CB3) and 119 (CB2) pulmonary veins (PV) were identified and all PVs successfully isolated utilizing the CB3 and CB2, respectively. The real-time PVI visualization rate was 74 % (CB3) and 40 % (CB2; p  = 0.001) and the mean freeze-cycle duration 204 ± 88 s (CB3) and 215 ± 90 s (CB2; p  = 0.15). Per individual PV, a shorter mean freeze-duration was found for the CB3 and the right superior PVs (188 ± 92 vs. 211 ± 124 s, p  = 0.04) and right inferior PVs (192 ± 75 vs. 200 ± 37 s, p  = 0.02). No differences were found for the left-sided PVs. Conclusions A higher rate of real-time electrical PV recordings is seen using the novel CB3 as compared to CB2, which may facilitate an individualized ablation strategy using the TTE.

Background Pulmonary vein stenosis (PVS) is a severe complication of atrial fibrillation (AF) ablation resulting in narrowing of affected pulmonary veins (PVs). Interventional treatment consists of angioplasty with or without PV stenting. The optimal postprocedural antithrombotic therapy is not known. Study aims To investigate the impact of antithrombotic medical therapy on recurrence of PVS after PV angioplasty. Methods A retrospective study of patients undergoing PV angioplasty with or without stent implantation in two German centers was performed. Postinterventional antithrombotic therapy consisted of either dual antiplatelet therapy (DAPT) or a combination of oral anticoagulation with single or dual antiplatelet therapy for 3–12 months after intervention. Angiographic follow‐up was recommended 3, 6, and 12 months after intervention and in case of symptom recurrence. Results Thirty patients underwent treatment of 42 PVS. After intervention, twenty‐eight patients received triple therapy and 14 patients received dual therapy/DAPT; restenosis occurred in 5/22 (22.7%) patients with triple therapy and 8/14 (57.1%) patients with dual therapy/DAPT PV (p = .001). Estimated freedom from PV restenosis after 500 days was 18.8 ± 15.8% (dual therapy/DAPT) and 76.2 ± 10.5% (triple therapy) (p = .003). Univariate regression analysis revealed postprocedural medication as a significant risk factor for restenosis (p = .019). No bleeding events occurred regardless of applied antithrombotic therapy. Conclusion Triple antithrombotic therapy after PV angioplasty is associated with less frequent restenosis as compared to dual antiplatelet therapy or a combination of anticoagulation and single antiplatelet therapy. No severe bleeding events occurred in patients on triple therapy. These findings need to be confirmed in larger patient cohorts. The current study analyzed medical antithrombotic therapy in patients undergoing angioplasty of pulmonary vein stenosis related to atrial fibrllation ablation. The study found significant longer re‐stenosis‐free survival in patients on triple anti‐thrombotic therapy with anticoagulation and dual anti‐platelet therapy as compared to patients on dual anti‐thrombotic therapy with anticoagulation and single anti‐platelet therapy withoout occurrence of serious bleeding events in any patient. The study results point to a potential use of triple anti‐thrombotic therapy in patients undergoing pulmonary vein stenosis angioplasty.

Radiofrequency (RF) linear ablation at the left atrial (LA) roof and bottom to isolate the LA posterior wall using contiguous and optimized RF lesions was evaluated. Achieving isolation of the LA posterior wall is challenging as two continuous linear lesion sets are necessary. Forty consecutive patients with symptomatic atrial fibrillation (AF) and arrhythmia substrates affecting the LA posterior wall underwent posterior wall isolation by linear lesions across the roof and bottom. The cohort was divided into two groups: group 1 (20 patients) linear ablation guided by contact force (CF) only; group 2 (20 patients) guided by ablation index (AI) and interlesion distance. Bidirectional block across the LA roof and bottom was achieved in 40/40 patients. Additional endocardial RF applications in 5 patients from group 1 vs. 3 patients from group 2 resulted in posterior wall isolation in all patients. Procedure duration was almost equal in both groups. CF and AI were significantly higher in group 2 for the roof line, whereas no statistical difference was found for the bottom line. AI-guided LA posterior wall isolation led to a significantly lower maximum temperature increase. The mean AI value as well as the mean value for catheter-to-tissue CF for the roof line were significantly higher when AI-guided ablation was performed. Standard deviation in group 2 showed a remarkably lower dispersion. Ablation index guided posterior wall isolation for substrate modification is safe and effective. AI guided application of the posterior box lesion allows improved lesion formation.

AimsThis study aimed to evaluate feasibility and safety as well as 1-year clinical outcome of pulmonary vein isolation (PVI) using a unique radiofrequency ablation catheter (“Thermocool SmartTouch SurroundFlow”; STSF) incorporating both, contact force (CF) sensing technology and enhanced tip irrigation with 56 holes, in one device.MethodsA total of 110 patients suffering from drug-refractory atrial fibrillation underwent wide area circumferential PVI using either the STSF ablation catheter (75 consecutive patients, study group) or a CF catheter with conventional tip irrigation (“Thermocool SmartTouch”, 35 consecutive patients, control group). For each ablation lesion, a target CF of ≥ 10–39 g and a force time integral (FTI) of > 400 g s was targeted.ResultsAcute PVI was achieved in all patients with target CF obtained in > 85% of ablation points when using either device. Mean procedure time (131.3 ± 33.7 min in the study group vs. 133.0 ± 42.0 min in the control group; p = 0.99), mean fluoroscopy time (14.0 ± 6 vs. 13.5 ± 6.6 min; p = 0.56) and total ablation time were not significantly different (1751.0 ± 394.0 vs. 1604.6 ± 287.8 s; p = 0.2). However, there was a marked reduction in total irrigation fluid delivery by 51.7% (265.52 ± 64.4 vs. 539.6 ± 118.2 ml; p < 0.01). The Kaplan–Meier estimate 12-month arrhythmia–free survival after the index procedure following a 3-month blanking period was 79.9% (95% CI 70.4%, 90.4%) for the study group and 66.7% for the control group (95% CI 50.2%, 88.5%). This finding did not reach statistical significance (p = 0.18). Major complications occurred in 2/75 patients (2.7%; one pericardial tamponade and one transient ischemic attack) in the study group and no patient in the control group (p = 18).ConclusionPVI using the STSF catheter is safe and effective and results in beneficial 1-year clinical outcome. The improved tip irrigation leads to a significant reduction in procedural fluid burden.

Background The Rhythmia mapping system was recently launched and allows for rapid ultra-high-resolution electroanatomical mapping. We evaluated the feasibility, acute efficacy and safety of this novel system for ablation of atrial fibrillation (AF) and left atrial (LA) tachycardia (AT). Methods and results A total of 35 consecutive patients (age 64.3 ± 8.6 years, LA diameter 44.4 ± 5.8 mm) underwent catheter ablation for AF and/or AT. All procedures were performed using Rhythmia in conjunction with the Orion mini-basket catheter. Pulmonary vein isolation (PVI) and linear lesions were performed applying radiofrequency (RF) energy. PVI was confirmed by presence of entrance and exit block using the mini-basket catheter. In addition, pacing maneuvers assessed bidirectional conduction block across linear lesions. Procedure duration was 110.3 ± 33 min, fast acquisition mapping (FAM) time was 19 ± 9 min. A mean number of 10165 ± 5904 mapping points were acquired during the initial map and 6379 ± 3191 for a remap. A total number of 31 ± 15 RF applications were delivered within 45 ± 22 min. Total fluoroscopy time was 21 ± 5, 5 ± 2 min were used for FAM. We observed a significant learning curve for mapping duration ( p  = 0.01). Complications included pericardial tamponade ( n  = 1), transient air embolism in the right coronary artery ( n  = 1), and mild groin hematoma ( n  = 2). Conclusions The present study is the largest to describe experience of LA ablation procedures using Rhythmia. PVI was achieved in all patients. Applying this ultra high-resolution electroanatomical mapping system under routine conditions leads to a high level of confidence. More data will be mandatory before final conclusions can be drawn.