A Novel Alternately Energy Source Strategy for Re-Ablation of Patients with Recurrent Atrial Fibrillation—Cryoballoon or Radiofrequency Current Energy Ablation. A Case-Control Study

Background: Atrial fibrillation recurrence after circumferential pulmonary vein (PV) isolation was common. Which ablation technique is better for repeat ablation in patients with recurrent atrial fibrillation (AF) remains unclear. We aimed to investigate long-term efficacy of repeat ablation using a novel alternately energy source sequence for re-ablation of patients with recurrent atrial fibrillation: cryoballoon (CB) re-ablation for patients with a failed radiofrequency (RFC) ablation (RFC-CB redo group); radiofrequency energy re- ablation for patients with a failed cryoballoon ablation (CB-RFC redo group).Method: Recurrent AF patients received a repeat ablation procedure in our hospital were enrolled into the study. Demographic and re-ablation procedural characteristics and outcomes were compared among groups.Results: A total of 156 patients were enrolled into the study, 60 patients (38.5%) were in the CB-RFC-redo group and 96 patients (61.5%) were in the RFC-CB-redo group. Longer duration of AF (69.31±64.69 vs 50.78 ±51.48 months; P=0.039) and longer time from first ablation to re-ablation (54.02 ±38.10 vs 14.2 ±10.5 months; P=0.001) were observed in the RFC-CB-redo group as compared with the CB-RFC redo group. Early recurrence rates of atrial fibrillation following initial ablation were equal among groups (RFC-CB-redo group: 42.7% vs CB-RFC-redo group:48.3% , p=0.515).The number of reconnected PVs was significantly higher in the RFC-CB redo group than the CB-RFC redo group (3.36 ± 0.96 vs 1.50 ± 0.81, p=0.01). During the average follow-up of 10.7 ±2.41 months, significantly less AF recurrence was observed in the CB-RFC redo group (16.7% vs 31.3%, p=0.045). In the multivariate analysis, different energy ablation sequence, AF type and early recurrence after the initial ablation were independent predictors of AF recurrence after re-ablation.Conclusions: Alternate energy source sequence strategy for re-ablation of patients with recurrent atrial fibrillation was safe and moderately effective. However, Large multi-center studies must be warranted to provide conclusive evidence.

Spatial Correction Improves Accuracy of Catheter Positioning During Ablation of Premature Ventricular Contractions: Differences Between Ventricular Outflow Tracts And Other Localizations.

1.1. PurposeHybrid activation mapping is a novel tool to correct for spatial displacement of the mapping catheter due to asymmetrical contraction of myocardium during premature ventricular contractions (PVC). The aim of this study is to describe the extent and cause of spatial displacement during PVC mapping and options for correction using hybrid activation mapping. 1.2. Methods and ResultsWe analyzed 5798 hybrid mapping points in 40 acquired hybrid maps of 22 consecutive patients (age 63±16 years, 45% female) treated for premature ventricular contractions (PVCs). Median PVC-coupling interval was 552 ms (IQR 83 ms). Spatial displacement was determined by measuring the dislocation of the catheter tip during PVC compared to the preceding sinus beat. Mean spatial displacement was 3.8±1.5 mm for all maps. The displacement was 1.3±0.4 mm larger for PVCs with non-outflow-tract origin compared to PVCs originating from the ventricular outflow tracts (RVOT/LVOT; p=0.028). Demographic parameters, PVC-coupling-interval and chamber of origin had no significant influence on the extent of spatial displacement. 1.3. ConclusionEctopic activation of the ventricular myocardium during PVCs results in spatial displacement of mapping points that is significantly larger for PVCs with non-outflow-tract origin. The correction for spatial displacement may improve accuracy of radiofrequency current (RFC)-application in catheter ablation of PVCs.

High-Field Pulsed ENDOR with Intra-cavity Radiofrequency Coil

This study compares the performance of two coil configurations for W-band pulsed ENDOR using a setup with both a radiofrequency ‘hairpin’ coil internal to a microwave non-radiative resonator and Helmholtz-like coils external to the resonator. Evaluation of the different coil performances is achieved via the ENDOR study of two model systems. The efficiencies of the coil configurations are first investigated numerically, showing that a higher radiofrequency current-to-magnetic field conversion factor can be achieved with the intra-cavity coil, with a similar radiofrequency magnetic field uniformity. This result is then confirmed by the broadband ENDOR spectra acquired with the two coil arrangements. A gain in the signal-to-noise ratio enabled by the internal coil of about a factor 10 was observed. In some cases, the high conversion factor of the intra-cavity coil led to a saturation of the ENDOR transitions. The possibility to implement a similar intra-cavity radiofrequency coil configuration in higher field spectrometers is finally discussed.

QRS complex axis deviation changing in catheter ablation of left fascicular ventricular tachycardia

Aims The mechanisms of the QRS complex axis deviation changing of idiopathic left fascicular ventricular tachycardia (FVT) during or after radiofrequency catheter ablation were investigated in this study, which were still not well defined. Methods and results In the index procedure, FVTs characterized by right bundle branch block configuration and left-axis deviation (LAD-FVT) were ablated at the VT exit site guided by the earliest ventricular activation with fused presystolic Purkinje potential (PP) in 234 consecutive patients. A new type of FVT characterized by right-axis deviation (RAD-FVT) was identified after successful elimination of the LAD-FVT in 12 patients, including 9 patients during the index procedure and 3 patients during follow-up. The QRS duration of RAD-FVT was shorter than that of LAD-FVT (115.3 ± 15.2 vs. 125.3 ± 16.4 ms, P = 0.006). The RAD-FVTs showed an earliest ventricle activation site localized at anterior fascicle area in 11 patients and anterior-median fascicle area in 1. However, the earliest PP during the RAD-FVT was still identified within the posterior fascicular network. Elimination of the RAD-FVTs was successfully achieved by applying radiofrequency current at a more proximal site within the left posterior fascicular network guided by the earliest PP. After a mean of 1.6 ± 0.8 ablation procedures and median follow-up of 132 (range 19–216) months since the last procedure, no recurrence was observed in any patients. Conclusion The axis deviation changing of QRS complex in FVT may be attributed to the different exit sites of the reentry.