Insight into contact force local impedance technology for predicting effective pulmonary vein isolation.

Background: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have the potential to act as a reliable predictor of the durability of the lesions created. Objective: We aimed to collect data on the procedural parameters affecting LI-guided ablation in a large multicenter registry. Methods: A total of 212 consecutive patients enrolled in the CHARISMA registry and undergoing their first pulmonary vein (PV) isolation for paroxysmal and persistent AF were included. Results: In all, 13,891 radiofrequency (RF) applications of ≥3 s duration were assessed. The first-pass PV isolation rate was 93.3%. A total of 80 PV gaps were detected. At successful ablation spots, baseline LI and absolute LI drop were larger than at PV gap spots (161.4 ± 19â€…Ω vs. 153.0 ± 13 Ω, p < 0.0001 for baseline LI; 22.1 ± 9â€…Ω vs. 14.4 ± 5 Ω, p < 0.0001 for LI drop). On the basis of Receiver operating characteristic curve analysis, the ideal LI drop, which predicted successful ablation, was >21â€…Ω at anterior sites and >18â€…Ω at posterior sites. There was a non-linear association between the magnitude of LI drop and contact-force (CF) (r = 0.14, 95% CI: 0.13-0.16, p < 0.0001) whereas both CF and LI drop were inversely related with delivery time (DT) (-0.22, -0.23 to -0.20, p < 0.0001 for CF; -0.27, -0.29 to -0.26, p < 0.0001 for LI drop). Conclusion: An LI drop >21â€…Ω at anterior sites and >18â€…Ω at posterior sites predicts successful ablation. A higher CF was associated with an increased likelihood of ideal LI drop. The combination of good CF and adequate LI drop allows a significant reduction in RF DT. Clinical trial registration: http://clinicaltrials.gov/, identifier: NCT03793998.

Improved procedural workflow for catheter ablation of paroxysmal AF with high-density mapping system and advanced technology: Rationale and study design of a multicenter international study.

BACKGROUND: The antral region of pulmonary veins (PV)s seems to play a key role in a strategy aimed at preventing atrial fibrillation (AF) recurrence. Particularly, low-voltage activity in tissue such as the PV antra and residual potential within the antral scar likely represent vulnerabilities in antral lesion sets, and ablation of these targets seems to improve freedom from AF. The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. METHODS: The improveD procEdural workfLow for cathETEr ablation of paroxysmal AF with high density mapping system and advanced technology (DELETE AF) study is a prospective, single-arm, international post-market cohort study designed to demonstrate a low rate of clinical atrial arrhythmias recurrence with an improved procedural workflow for catheter ablation of paroxysmal AF, using the most advanced point-by-point RF ablation technology in a multicenter setting. About 300 consecutive patients with standard indications for AF ablation will be enrolled in this study. Post-ablation, all patients will be monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Healthcare resource utilization, clinical data, complications, patients' medical complaints related to the ablation procedure and patient's reported outcome measures will be prospectively traced and evaluated. DISCUSSION: The DELETE AF trial will provide additional knowledge on long-term outcome following a structured ablation workflow, with high density mapping, advanced algorithms and local impedance technology, in an international multicentric fashion. DELETE AF is registered at ClinicalTrials.gov (NCT05005143).

When local impedance meets contact force: preliminary experience from the CHARISMA registry.

PURPOSE: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have emerged as a viable real-time indicator of tissue characteristics and the consequent durability of the lesions created. We investigated the impact of catheter-tissue contact force (CF) on LI behavior during pulmonary vein isolation (PVI). METHODS: Forty-five consecutive patients of the CHARISMA registry undergoing de novo AF radiofrequency (RF) catheter ablation with a novel open-irrigated-tip catheter endowed with CF and LI measurement capabilities (Stablepoint™ catheter, Boston Scientific) were included. RESULTS: A total of 2895 point-by-point RF applications were analyzed (RF delivery time (DT) = 8.7±4s, CF = 13 ±±8 g, LI drop = 23 ±±7 Ω). All PVs were successfully isolated in an overall procedure time of 118 ±±34 min (fluoroscopy time = 13 ±±8 min). The magnitude of LI drop weakly correlated with CF (r = 0.13, 95% confidence interval (CI): 0.09 to 0.16, p < 0.0001), whereas both CF and LI drop inversely correlated with DT (r = -0.26, 95%CI: -0.29 to -0.22, p < 0.0001 for CF; r = -0.36, 95%CI: -0.39 to -0.33, p < 0.0001 for LI). For each 10 g of CF, LI drop markedly increased from 22.4 ± 7 Ω to 24.0 ± 8 Ω at 5 to 25 g CF intervals (5-14 g of CF vs 15-24 g of CF, p < 0.0001), whereas it showed smooth transition over 25 g (24.8 ± 7Ω at ≥ 25 g CF intervals, p = 0.0606 vs 15-24 g of CF). No major complications occurred during the procedures or within 30 days. CONCLUSIONS: CF significantly affects LI drop and probable consequent lesion formation during RF PVI. The benefit of higher contact (> 25 g) between the catheter and the tissue appears to have less impact on LI drop. TRIAL REGISTRATION: Catheter Ablation of Arrhythmias With High Density Mapping System in the Real World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

Contact-Force Guided Posterior Wall Isolation as an Adjunctive Ablation Strategy for Persistent Atrial Fibrillation.

BACKGROUND: The efficacy of posterior wall isolation (PWI) on top of pulmonary vein isolation (PVI) in patients affected by persistent atrial fibrillation (AF) is still controversial and little is known about the impact of contact-force (CF) technology. OBJECTIVE: In this retrospective study, we present our experience with PWI using CF sensing catheters and its efficacy and safety as an adjunctive ablation strategy on top of PVI for management of patients with persistent and longstanding persistent AF. METHODS: A total of 73 consecutive patients (20.5% female) affected by persistent atrial fibrillation (10.9% long-standing) underwent PWI as an adjunctive therapy to PVI using CF sensing catheters. Outcomes were reported as incidence of atrial arrhythmic recurrences (ARs) lasting >30 seconds at follow up and in addition, in patients provided with insertable cardiac monitors (ICM), as burden of AF or atrial tachycardias (AT) at relevant time points. RESULTS: PWI was successfully achieved in 65 (89.0%) patients. Two (2.7%) minor vascular procedural complications were observed. At 1 and 2-year follow-up, ARs free survival was observed in 80.5% and 64.1% of patients, respectively with 75.3% of patients off antiarrhythmic drugs at the last follow-up. Ten patients underwent repeat ablations during the follow-up. At multivariate analysis, early ARs within 3 months after procedure, were associated with a two-fold increased risk of late ARs at follow-up. Among patients provided with ICM, PWI on top of PVI was able to reduce the mean AT/AF burden of more than 50% compared with pre-ablation time, reporting very low levels (≤ 5%) over 2 years. CONCLUSIONS: In persistent atrial fibrillation, PWI on top of PVI using CF sensing catheters is safe and effective, providing great reduction of burden of ARs. Early ARs are associated with a greater risk of late recurrences.

Combined therapy with subcutaneous implantable cardiac defibrillator and leadless pacemaker in a patient with persistent left superior vena cava and mega coronary sinus: A challenging case for the best treatment.

In a patient requiring pacing and defibrillation therapy, but without superior venous access, combined therapy with S-ICD and leadless pacemaker could be the best solution. An appropriate programming of both devices represents the technical challenge in order to avoid inappropriate shocks due to leadless pacing oversensing.

Updated national multicenter registry on procedural safety of catheter ablation for atrial fibrillation.

INTRODUCTION: Despite catheter ablation (CA) becoming an accepted treatment option for symptomatic, drug-resistant atrial fibrillation (AF), safety of this procedure continues to be cause for concern. Aim of the present multicenter registry was to assess the incidence of early CA complications and detect their predictors in a contemporary, unselected AF population METHODS AND RESULTS: From January 1, 2011 to December 31, 2011, data from 2,323 consecutive patients who underwent CA (median age 60 [52-67]; 72.3% male) for AF in 29 Italian centers were collected. All major complications occurring to the patient from admission to 30th postprocedural day were recorded. No procedure-related death was observed. Major complications occurred in 94 patients (4.0%): 50 patients (2.2%) suffered vascular access complications; 12 patients (0.5%) developed cardiac tamponade; 14 patients (0.6%) presented with pericarditis; 5 patients (0.2%) had transient ischemic attack; 4 patients had stroke; 3 patients (0.1%) had phrenic nerve paralysis; 3 patients (0.1%) had hemothorax. Other isolated but serious adverse events were documented in 3 patients (0.1%). Female gender (OR 2.643; 95% CI 1.686-4.143; P < 0.0001) and longer procedural duration (OR 2.195; 95% CI 1.388-3.473; P < 0.001) independently predicted a higher risk of complications. CONCLUSION: Major complications occurred in 4.0% of the CA procedures for AF, with vascular access complications being the most frequent events.

Selection of Medications to Prevent Stroke Among Individuals With Atrial Fibrillation : Update on Prevention of Stroke in Patients with AF.

OPINION STATEMENT: Vitamin K antagonists have been the only available orally active anticoagulants for decades. Although effective, their numerous limitations have driven the introduction of new oral anticoagulants (NOAs) that showed effectiveness at fixed doses without the need for routine coagulation monitoring. However, the safety and efficacy observed in controlled clinical trials may be hard to translate in clinical practice. Clinical conditions as well as drug interactions may considerably impact on patient outcomes. Moreover, the inability to monitor the pharmacological activity of NOAs and the absence of any antidote in the setting of bleeding or emergent invasive procedures may limit their use. Vitamin K antagonists will be still used in many circumstances, including patients with an optimal control of the INR, with mechanical heart valves, and other indications for which these new agents have not been investigated. Nevertheless, these new agents will reduce the burden of anticoagulation management at the patient as well as Health Care level.

Nonfluoroscopic mapping reduces radiation exposure in ablation of atrial fibrillation.

BACKGROUND: Radiofrequency catheter ablation (RFCA) of atrial fibrillation is an effective and definitive treatment. The methods used to guide RFCA have evolved over the years from a purely electrophysiological approach, in which anatomical lesions were guided solely by fluoroscopy and angiographic imaging of the pulmonary veins, to an approach guided by modern nonfluoroscopic electroanatomical mapping, integrated or not with computed tomography (CT). The aim of this study was, therefore, to compare radiation exposure of RFCA based on a fast three-dimensional nonfluoroscopic mapping system with 'traditional' mapping integrated with CT imaging. METHODS: Thirty consecutive patients with atrial fibrillation who underwent RFCA were treated with two different approaches: 3D-Fast-Anatomical-Mapping and One-Map tool (FAM-One Map group, 21 patients) vs. 3D-Fast-Anatomical-Mapping integrated with CT images (MERGE-CT group, nine patients). Fluoroscopy time and radiation doses (expressed in milliGray) were compared. RESULTS: No statistically significant difference was detectable between FAM-One Map group and MERGE-CT group considering RFCA success rates and fluoroscopy times. Radiation exposure was higher in the MERGE-CT group (965 ±â€Š138  mGy MERGE-CT group vs. 532 ±â€Š216  mGy FAM-One Map group, P < 0.001) because of supplemental radiation exposures due to CT imaging (470 ±â€Š126  mGy). CONCLUSION: A fast nonfluoroscopic electroanatomical mapping system may reduce radiation exposure in RFCA of atrial fibrillation, with preserved success rates.

Catheter ablation of atrial fibrillation in patients with diabetes mellitus type 2: results from a randomized study comparing pulmonary vein isolation versus antiarrhythmic drug therapy.

INTRODUCTION: Atrial fibrillation (AF) and diabetes mellitus type 2 (DM2) often coexist; however, a small number of patients with DM2 undergoing catheter ablation (CA) of AF have been included in previous studies. The aim of this study was to evaluate safety and efficacy of ablation therapy in DM2 patients with drug refractory AF. METHODS AND RESULTS: From January 2005 to September 2006, 70 patients with a diagnosis of DM2 and paroxysmal (n = 29) or persistent (n = 41) AF were randomized to receive either pulmonary vein isolation or a new antiarrhythmic drug treatment (ADT) with a 1-year follow-up. The primary endpoint was the time to first AF recurrence. By Kaplan-Meier analysis, at the end of follow-up, 42.9% of patients in the ADT group and 80% of patients who received a single ablation procedure and were without medications were free of AF (P = 0.001). In the ablation group, a significant improvement in quality-of-life (QoL) scores as compared with ADT group was observed. Six patients in the ADT group (17.1%) developed significant adverse drug effects. Hospitalization rate during follow-up was higher in the ADT group (P = 0.01). The only complication attributable to ablation was one significant access-site hematoma. CONCLUSION: In patients with DM2, CA of AF provides significant clinical benefits over the ADT and appears to be a reasonable approach regarding feasibility, effectiveness, and low procedural risk.

Gender-related differences in catheter ablation of atrial fibrillation.

AIMS: Women have an increased risk for atrial fibrillation (AF)-related complications and there is evidence towards a reduced efficacy of the rhythm control strategy than men. A catheter-based strategy is therefore widely attractive, but the impact of gender on catheter ablation (CA) of AF remains undefined. METHODS AND RESULTS: We included 221 consecutive patients (150 men) who underwent CA of drug-refractory AF. Gender differences in clinical presentation and outcomes were compared. Women were older (P = 0.002), had a longer history of AF (P = 0.04), and were more likely to have hypertension (P = 0.04). Moreover, a concomitant valvular heart disease tended to be more common in women (32.4 vs. 23.3%; P = 0.28) and left atrium dimensions were significantly larger (P = 0.003). However, acute success rate and complications rate were similar between genders. After 22.5 +/- 11.8 months of follow-up, the overall freedom from arrhythmia recurrences was similar (83.1 vs. 82.7% in men), and a similar improvement in SF-36 quality of life scores was achieved in both groups. CONCLUSION: Women are referred for AF ablation later with a more complex clinical pre-operative presentation. Despite this higher risk profile in women, no differences were detected in clinical outcomes. Our findings indicate that CA of AF appears to be safe and effective in women as in men.

Estimation of coronary flow reserve by Tc-99m sestamibi imaging in patients with coronary artery disease: comparison with the results of intracoronary Doppler technique.

BACKGROUND: This study compared coronary flow reserve (CFR) estimated by technetium 99m sestamibi imaging with the results obtained with intracoronary Doppler in patients with coronary artery disease. Intraobserver and interobserver reproducibility of the radionuclide-estimated CFR was also assessed. METHODS AND RESULTS: Fourteen consecutive patients (mean age, 54 +/- 7 years) with documented coronary artery disease in whom percutaneous coronary intervention was planned underwent dipyridamole (0.74 mg/kg) sestamibi imaging and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the pulmonary artery and myocardial counts from single photon emission computed tomography images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. In the study vessels, CFR was 1.36 +/- 0.43 as estimated by sestamibi and 1.39 +/- 0.42 by intracoronary Doppler ( P = .69). A significant relationship between CFR estimated by sestamibi and CFR obtained by intracoronary Doppler was observed ( r = 0.85, P < .001). On Bland-Altman analysis, the mean difference between CFR by sestamibi and by Doppler was 0.03 and the intraclass correlation coefficients for intraobserver and interobserver reproducibility were high (all P < .001) for both global and regional CFR. CONCLUSIONS: This study demonstrates a good agreement between CFR estimated by sestamibi imaging and by intracoronary Doppler results and a lack of intraobserver and interobserver variability of this noninvasive approach.