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Atrial fibrillation is the most common sustained arrhythmia affecting over 33 million people worldwide. Approximately 70% of AF patients have non-paroxysmal AF. As AF progresses from paroxysmal to non-paroxysmal forms, the prevalence of comorbidities increases. The efficacy of catheter ablation for persistent and long standing persistent (LSP) AF is <40%, often requiring multiple ablation procedures with greater cost and potentially more complications. There is an unmet need to effectively treat such patients. CONVERGE is an investigational device exempt, prospective, multi-center, open label 2:1 randomized controlled pivotal study to evaluate the overall success of the Convergent hybrid procedure compared to endocardial catheter ablation for the treatment of symptomatic persistent AF refractory or intolerant to at least one Class I and /or III anti-arrhythmic drug (AAD). A total of 153 subjects at 27 centers are treated in the study. The CONVERGE study is differentiated from other studies currently being conducted on the persistent AF population, because a) there is no time restriction on the duration of diagnosed AF in the patients being studied and b) the trial allows patients with left atrial sizes up to 6 centimeters. The ongoing trials are limited to either 6 months, 12 months or 3-years of continuous AF making CONVERGE the only ablation trial thus far to include a substantial portion of patients with longstanding persistent AF. The convergent procedure involves combination of minimally invasive pericardioscopic epicardial ablation with endocardial left atrial ablation. The primary endpoint is freedom from AF/AFL/AF absent class I/III AAD, except for a previously failed class I/ III AAD with no increase in dosage following 3-months through 12-months. The primary safety endpoint is the incidence of major adverse events from the procedure through 30-days post procedure. CONVERGE AF compares the overall success of the Convergent hybrid procedure to endocardial catheter ablation for the treatment of persistent and longstanding persistent AF. By providing objective comparative data, the study aims to provide guidance on the treatment of such patients.

Background Multiple studies have demonstrated the importance of adequate catheter–tissue contact in the creation of effective lesions during radiofrequency catheter ablation. The development of contact force (CF)-sensing catheters has contributed significantly to improve clinical outcomes in atrial fibrillation. However, CF-sensing technology is not used in the ablation of paroxysmal supraventricular tachycardia (PSVT). The possible reason for this is that PSVT ablation with the conventional approach (i.e. nonirrigated, non-CF-sensing catheters) is considered a relatively low-risk procedure with fairly high success rates (short and long term). The aim of this study is to determine whether CF sensing can further improve the outcomes of PSVT ablation. Methods/design The COBRA-PATH study is a single-center, two-armed, randomized controlled trial. Patients without structural heart disease being referred for electrophysiology study, because of PSVT and potential treatment with radiofrequency (RF) catheter ablation, will be randomly assigned to either manual ablation with standard nonirrigated ablation catheters or manual ablation with an open-irrigated ablation catheter equipped with CF sensing (used in a virtual nonirrigated modus). The primary study endpoint is the difference in the number of RF applications during the ablation of atrioventricular nodal re-entry tachycardia, and that of Wolff–Parkinson–White syndrome and atrioventricular re-entrant tachycardia. Secondary outcome parameters include acute and long-term procedural success rates, overall duration of RF applications, procedure/fluoroscopy durations and safety parameters. Discussion We expect to see a reduced number/duration of RF applications required to achieve effective lesion creation, and consequently a decrease in total procedure/fluoroscopy times. Although a significant improvement in procedural success rates (acute/long term) might not be feasible to demonstrate (given the relatively high success rate of the standard ablation method), the possible decrease in procedure duration and the consequential reduction of radiation exposure has important clinical implications for both operators and patients undergoing the procedure. Trial registration ClinicalTrials, NCT04078685 . Retrospectively registered on 2 September 2019.

Purpose We evaluated the correlation between pulmonary venous (PV) anatomy and acute and long-term success of PV isolation (PVI) with two balloon-based ablation catheter techniques. Methods One hundred consecutive patients were analyzed in two equal groups treated with either the second-generation cryoballoon (CRYO) catheter or the visually guided laser ablation (VGLA) catheter. All patients underwent multi-detector computed tomography (CT) imaging. The primary and secondary efficacy endpoints were the procedural achievement of proven electrical isolation of all veins and freedom from atrial fibrillation (AF) within a 1-year follow-up period, respectively. Results Variant PV anatomy was observed in 32 % of patients in the CRYO group and in 40 % of patients in the VGLA group. All PVs were targeted with either the CRYO catheter ( n  = 199) or the VGLA catheter ( n  = 206). One hundred ninety-three of 199 PVs (97 %) were successfully isolated in the CRYO group and 194 of 206 PVs (94 %) in the VGLA group ( p  = 0.83). Over a 12-month follow-up, AF recurrence was documented in 11/45 (24 %) and 7/43 (16 %) patients in the CRYO and the VGLA groups, respectively ( p  = 0.21). In the CRYO group, a larger left inferior PV size was associated with worse long-term outcome ( p  = 0.001). In the VGLA group, a larger left superior PV size ( p  = 0.003) and more oval right inferior PV were associated with worse acute success ( p  = 0.038). There was no absolute cutoff between PV anatomy and clinical success. Conclusions The variability of PV anatomy did not significantly compromise acute success of PVI or patient outcomes.

Use of the antiarrhythmic ibutilide after isolated pulmonary vein isolation (PVI) might distinguish atrial remodeling severity and cases requiring further substrate modification, thereby improving efficacy of persistent atrial fibrillation (AF) treatment. Ninety-six consecutive patients with persistent AF were randomized after PVI to either direct current synchronized cardioversion (DCC group, n = 48) or 1 mg of intravenous ibutilide (ibutilide group, n = 48) followed by no further intervention if AF converted to sinus rhythm (SR) within 30 minutes (ibutilide conversion subgroup) or by complex fractionated atrial electrogram (CFAE) ablation until SR recovery or complete CFAE elimination (ibutilide nonconversion subgroup). With similarly distributed baseline characteristics and no serious postablation complications, the primary end point of 12-month SR maintenance rate after PVI was significantly higher for ibutilide versus the DCC group before (75% vs 56%; p = 0.042) or after (83% vs 60%; p = 0.011) reablation at physician's discretion for recurrence beyond 3 months after PVI. After ibutilide administration, 21 of 48 patients (44%) converted to SR at 17 ± 8 minutes (mean ± SD); those in the ibutilide nonconversion subgroup had larger atrial size (47 ± 4 vs 45 ± 4; p = 0.025) and CFAE area (29 ± 8 vs 12 ± 5; p = 0.001) and longer AF duration (27 ± 6 vs 21 ± 10; p = 0.026). Among ibutilide conversion and nonconversion subgroups and DCC group, procedure, ablation, and x-ray exposure times differed significantly, as did 12-month SR maintenance rate before (81% vs 70% vs 56%; p = 0.043) or after reablation (86% vs 81% vs 60%; p = 0.042). In conclusion, in persistent AF treatment, ibutilide-guided ablation after PVI yields higher 1-year SR maintenance rate than PVI only.

The aim of this study is to evaluate the safety and feasibility of using the Amigo Remote Catheter System (RCS) in arrhythmia ablation procedures. Because Amigo allows the physician to operate all catheter function outside of the radiation field, operator exposure time was also evaluated. This is a nonrandomized, prospective clinical trial conducted at 1 site (identifier: NCT01834872). The study prospectively enrolled 50 consecutive patients (mean age 59 ± 15 years, 72% men) with any type of arrhythmia (23 atrial fibrillation ablation, 12 common atrial flutters, 10 patients with other supraventricular tachycardia, 4 ventricular tachycardia, and 1 patient with palpitations with no arrhythmia induced) referred for catheter ablation, in which we used RCS. Fifty matched ablation procedures (mean age 57 ± 14 years, 70% men) performed during the same time period, without RCS, were enrolled into the control group. Acute ablation success was 96% with RCS and 98% in the manual group. In only 2 cases, the physician switched to manual ablation (1 ventricular tachycardia and 1 accessory pathway) to complete the procedure. There were no complications related to the use of RCS. No differences were observed in total procedure time, total fluoroscopy time, or total radiofrequency delivery compared with the manual group. In procedures performed with RCS, the operator's fluoroscopy exposure time was reduced by 68 ± 16%. In conclusion, arrhythmia ablation with RCS is safe and feasible. Furthermore, it significantly reduces operator's exposure to radiation.

Purpose Recently, diffusion-weighted magnetic resonance imaging (DW-MRI) revealed silent cerebral events (SCEs) as an acute complication of pulmonary vein isolation (PVI). We investigated whether SCEs following PVI are associated with neuropsychological deficits observed during patients’ follow-up examinations. Methods After PVI, 52 patients were eligible for follow-up. PVI was performed using a variety of ablation technologies (duty-cycled phased radiofrequency (RF) multipolar ablation with the Pulmonary Vein Ablation Catheter® (PVAC) in 24 patients, cooled-tip RF ablation in 23 patients, and cryoballoon ablation in five patients). Fluid-attenuated inversion recovery (FLAIR)- and DW-MRI studies were performed 1 day before PVI and 1 day and 1 month afterward to detect pre-existing cerebral lesions or post-ablation SCEs. At the same times, eight neuropsychological tests were administered. We evaluated changes in patients’ neuropsychological capabilities and compared changes in patients with SCEs to those without SCEs. Results FLAIR-MRI revealed pre-existing cerebral lesions in 42 patients (81 %), and DW-MRI demonstrated new SCEs in 25 patients (48 %) (17 treated with phased RF (PVAC) (71 %), six treated with irrigated RF (26 %), and two treated with cryoablation (40 %)). Neuropsychological test results showed no significant impairment (in median z scores) 1 day and 1 month after the ablation procedure. There was no difference in neuropsychological capabilities between patients with SCEs and those without SCEs except in one subtest (part of the verbal working memory test). Conclusions The incidence of pre-existing cerebral lesions and post-ablation SCEs was high. The frequency of SCEs depends on the ablation technology used. Neither PVI nor post-ablation SCEs have any effect on neuropsychological capabilities.

Purpose We prospectively investigated the differences in pulmonary vein reconnections (PVRs) and clinical outcomes between contact force (CF)-guided and conventional circumferential PV isolation (CPVI) of atrial fibrillation (AF). Methods One hundred twenty consecutive AF patients (63 ± 10 years; 88 males) undergoing an initial CPVI were randomized to ablation with a target CF of 20 g (CF group; n  = 60) or that with operators blinded to the CF information (blind group; n  = 60). Results The CF group had fewer PVRs (0.67 ± 0.91/patient vs. 1.16 ± 1.16/patient; P  = 0.007), a lower incidence of persistent PVRs (13.2 vs. 41.2 %; P  < 0.001), and a shorter procedural time for the CPVI (50 vs. 56 min; P  = 0.019) than the blind group. The mean CF was higher in the CF group than the blind group (18.0 vs. 16.1 g; P  < 0.001), with the most significant difference observed along the posterior right-sided PVs (P-RPVs) and anterior left-sided PVs (A-LPVs). In logistic regression models, the mean CF was a negative predictor of PVRs along the P-RPVs and A-LPVs in the blind group (odds ratios, 0.728 and 0.786; P  < 0.001 and 0.007), while no significant predictor was identified in the CF group or elsewhere in the blind group. In the Kaplan-Meier analysis, the arrhythmia-free survival rate at 12 months was 89.9 % in the CF group and 88.2 % in the blind group, respectively ( P  = 0.624). Conclusions CF-guided CPVI can reduce PVRs and the procedural time and be particularly beneficial along regions where a relatively low CF tends to be applied: the P-RPVs and A-LPVs. The comparable clinical outcomes may be due to the learning curve effect obtained by the CF-guided technique and repeated provocation of dormant PV conduction.

Some children with asymptomatic Wolff–Parkinson–White syndrome are at high risk for tachyarrhythmias and sudden death. These children can be identified because they have inducible tachyarrhythmias on electrophysiological testing. This randomized clinical trial found that such children benefit from radiofrequency catheter ablation of accessory conduction pathways. The results of this study will change the management of high-risk asymptomatic Wolff–Parkinson–White in children. Natural-history studies in children with the Wolff–Parkinson–White syndrome have been limited by short follow-up, small sample size, and selection bias. 1 – 4 Although the incidence of sudden death in children with the Wolff–Parkinson–White is unclear, 5 the lifetime incidence is estimated to be about 3 to 4 percent. 6 – 8 Ventricular fibrillation can be the presenting arrhythmia, and the consequences of a “missed” sudden death in children are devastating. 4 , 9 – 11 Recently, it was reported that high-risk, asymptomatic ventricular preexcitation is associated with a poor prognosis. 12 Prophylactic ablation improves outcome in high-risk adult patients, 13 emphasizing the need to readdress guidelines in this setting. . . .

Background The clinical utility of an automated lesion tagging module based on catheter stability information (VisiTag) with the CARTO system during atrial fibrillation (AF) ablation remains to be established. We investigated whether VisiTag-guided extensive encircling pulmonary vein isolation (EEPVI) produces durable lesions. Methods The study involved 54 patients undergoing EEPVI for paroxysmal AF. We performed EEPVI guided by the module-generated ablation tags, i.e., “VisiTags,” which are point-by-point ablation tags placed on 3D maps. The patients were divided into two groups: those treated under a moderate catheter stability VisiTag setting, i.e., a 3-mm distance limit for at least 5 s and a minimum contact force (CF) of 8 g over 25 % of the set time period with a target force-time integral (FTI) ≥300 g*s ( n  = 27), and those treated under a strict catheter stability setting, i.e., a 3-mm distance limit for at least 10 s and a minimum CF of 10 g over 50 % of the set time period with a target FTI ≥400 g*s ( n  = 27). Results After EEPVI, adenosine triphosphate-provoked dormant PV conduction was observed in six (22 %) patients in the moderate catheter stability group and in one (4 %) patient in the strict catheter stability group ( p  = 0.1003); the 12.9-month success rate was 81 % in both groups. Conclusions The strict catheter stability setting for automated lesion tagging together with a target FTI of >400 g*s, vs. the moderate catheter stability setting with a target FTI of >300 g*s, produces less frequent ATP-provoked PV conduction and yields a comparably high mid-term success rate.

Background The aim of this study was to evaluate the impact of contact force (CF) visualization on the incidence of low and high CF during left atrial (LA) mapping and pulmonary vein isolation (PVI). Methods CF was assessed in 70 patients who underwent PVI. Three highly experienced operators performed all procedures. The operators were blinded to CF in group A (35 patients), and CF was displayed in group B (35 patients). In group B, optimal CF was defined as mean CF between 10 and 39 g , and operators attempted to acquire points and ablate within this range. Results A total of 8401 mapping points were analyzed during LA mapping (group A: 4104, group B: 4297). Low CF <10 g and high CF ≥40 g were noted in a significantly larger number of points in group A (37.7 vs. 12.0 %, P  < 0.001; 11.5 vs. 1.5 %, P  < 0.001). At the mitral isthmus and ridge areas, CF was significantly lower (7.7 vs. 12.2 g , P  < 0.001; 5.3 vs. 11.7 g , P  < 0.001) in group A than in group B. PVI was successfully achieved in all patients. There were significant site-dependent CF differences between the two groups. Optimal CF was achieved in significantly more applications in group B ( P  < 0.001). There was no significant difference in atrial fibrillation (AF) recurrence rates after a minimum follow-up of 1 year between the two groups in this cohort ( P  = 0.24). No significant peri-procedural complications occurred in either group. Conclusions CF visualization can assist in avoiding both low and high CF, which may have the potential to improve lesion formation and patient safety profile. In this study, CF-guided ablation did not affect AF recurrence.