Safety and effectiveness of very high-power short duration ablation in patients with atrial fibrillation: early results

Background

Pulmonary vein isolation (PVI) is at the forefront of treatment methods of rhythm control in patients with atrial fibrillation (AF) (1). The novel contact-force sensing catheter, QDot MicroTM (Biosense Webster) was designed to improve effectiveness of AF ablation and allow better time management due to shorter procedure time. It is a very high power-short duration (vHP-SD) catheter optimized for high density mapping and temperature control, which enables the application of high energy (up to 90W, 4s) (2).

Purpose

The aim of the study was to compare the QDot MicroTM catheter with the ThermoCool SmarttouchTM SF catheter with regard to the effectiveness and safety of PVI ablation.

Methods

It is a single center, cross-sectional, observational study enrolling 101 consecutive patients suffering from symptomatic paroxysmal or persistent AF, referred for first catheter ablation between 16 December 2019 and 03 December 2021. In 47 procedures (mean age 54 years; 70% male; 77% paroxysmal) the QDot Micro catheter was used (vHP-SD group; Qmode+ 90W, 4s), whereas the remaining 54 patients (mean age 57 years; 70% male; 67% paroxysmal) were treated with the ThermoCool SmarttouchTM SF catheter (control group, Ablation Index guided ablation). The primary endpoint was freedom from AF at 3-months after ablation. The secondary endpoints included the amount of opioids administered as well as the incidence of early-onset treatment-emergent adverse events (TEAEs).

Results

AF recurrence was documented in 14.9% patients in vHP-SD group and in 31.5% patients in control group (p=0.06). The mean dose of remifentanil was reported to be lower during Qmode+ catheter-based PVI (0.50 (0.40–0.60) vs. 0.70 (0.55–0.90) mg; p<0.001). There was no statistically significant difference in TEAEs between both groups (6.3 vs. 0%; p=0.10). One severe adverse event (cerebral vascular incident 2 days after PVI – due to thrombus in the left ventricle) was observed in vHP-SD group.

Conclusions

This study suggests that the vHP-SD ablation is safe and enables sedative-analgesic medications demand reduction during procedure. vHP-SD mode may enhance the success rate of catheter-based PVI, however further research is needed to provide additional evidence of its superiority.

Funding Acknowledgement

Type of funding sources: None.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Pharmacological cardioversion of recent-onset atrial fibrillation in patients with chronic kidney disease: sub-analysis of the CANT study

Purpose

Pharmacological cardioversion (PCV) is commonly a primary option for termination of recent-onset atrial fibrillation (AF) at the emergency departments (ED), and there are reports proving that antazoline is a noteworthy agent to restore sinus rhythm. This is a sub-analysis of the CANT study evaluating the effectiveness and safety of antazoline in patients with AF at different stages of chronic kidney disease (CKD).

Methods

Total n=777 patients admitted to ED for the urgent termination of AF were included into this analysis. We analysed the results concerning effectiveness and safety of PCV with special consideration of antazoline, in patients at 3 stages of CKD defined on the basis of eGFR (CKD-EPI): Group I ≥60 mL/min (n=531), Group II 45–59 mL/min (n=149), and Group III <45 mL/min (n=97). Primary end-point was the termination of AF, a restoration of a sinus rhythm and its persistence until discharge.

Results

Patients of group III were older and with higher prevalence of comorbidities, however, we have not found statistically significant differences in overall effectiveness of PCV in comparison with the other groups. In patients receiving amiodarone, the PCV success rate was similar in all the studied groups, but along with a renal function decline, it decreased in patients receiving antazoline (79.1 vs 35%; p<0.001), and it increased close to a significant manner in patients receiving propafenone (69.9 vs 100%; p=0.067; Figure). In patients of Group I, antazoline restored a sinus rhythm as effectively as propafenone and amiodarone, however in patients of Group III, both antazoline and amiodarone became less effective in restoring a sinus rhythm than propafenone (p=0.002 and p=0.034, respectively). The rate of safety endpoint was highest in patients of Group III (eGFR<45 mL/min), and it was significantly higher than in patients of Group I and II (p=0.008 and p=0.036, respectively). We have not observed antazoline-related adverse events in any of studied groups of patients.

Conclusion

This real-world registry analysis revealed a different influence of CKD on individual drug effectiveness, and while propafenone and amiodarone maintained their AF termination efficacy, antazoline became significantly less effective in restoring sinus rhythm. Its favourable safety profile has not changed.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The study received no external funding

Clinical characteristics and risk profile of patients with atrial fibrillation with mid-range ejection fraction, insights from the Polish part of EORP-AF Long-Term General Registry

Background

Atrial fibrillation (AF) comprises a wide range of patients (pts), from those with preserved to those with reduced left ventricular ejection fraction (LVEF). According to 2016 ESC guidelines, pts with LVEF in the range of 40–49% represent a “grey area”, which is defined as heart failure with mid-range ejection fraction (HFmrEF). Not much is known about the clinical characteristics of AF pts with mid-range ejection fraction.

Purpose

To determine the potential differences in the clinical characteristics, risk profile, and the outcomes of AF with moderate systolic dysfunction, measured by LVEF.

Methods

The EURObservational Research Programme on AF (EORP-AF) Long-Term General Registry analyzed consecutive AF patients who have presented to cardiologists in 250 centers from 27 European countries, including 25 centers from Poland. We analyzed data collected at baseline and at a 1-year follow-up visit from 568 Polish patients included in 25 Polish centers in the years 2013–2016. Pts were divided into three groups based on LVEF: the preserved LVEF (pEF) group (LVEF ≥50%), the mid-range LVEF (mrEF) group (40–49%), and the reduced LVEF (rEF) group (<40%).

Results

117/568 pts with rEF represented 20,6%, 105/568 mrEF 18,5% and 346/568 pEF 60,9% of the whole analyzed group. With regard to the most typical risk factors, the mrEF population appeared between rEF and pEF, presenting a moderate risk profile with the exception of hypertension, which was the most common in the mrEF group. While permanent AF was the most common in the rEF group and paroxysmal in the pEF pts, pts with mrEF had a higher rate of long-lasting persistent AF. Taking into account the risk factors profile, surprisingly, pts with AF and mrEF more often presented with dyspnea/shortnes of breath (mrEF 38,1% vs. rEF 18,8% vs. pEF 22,5%; p=0,001) and fatigue (mrEF 38,1% vs. rEF 23,9% vs. pEF 25,4%; p=0,025). AF pts with mrEF also had the highest thrombo-embolic risk estimated with the CHA2DS2-VASc score (mrEF 4 [2–5], n=105; rEF 3 [2–5], n=117, pEF 3 [2–4], n=346, p=0.005). However, this did not translate into the highest number of thromboembolic events after one year which did not significantly differ (mrEF 10.5%, rEF 15.4%, pEF 11.3%, p=0.30) between the three groups.

Conclusions

The risk factor profile of AF pts with mrEF was milder than for those with rEF and more severe than for pEF pts. AF pts with mrEF more often presented HF symptoms. Their estimated thrombo-embolic risk was higher but the number of events in the one year follow-up did not significantly differ between groups.

Funding Acknowledgement

Type of funding source: None

P968Impact of contact force sensing catheters on fluoroscopy time in left-sided atrial procedures

Funding Acknowledgements

None.

OnBehalf

Go for Zero Fluoroscopy Project investigators

Background Contact force sensing catheters provide electrophysiologists with direct feedback and therefore improve safety and help to generate more effective lesions. The use of contact force may also reduce fluoroscopy and procedure times.

Purpose The aim of this study was to systematically evaluate the impact of using contact force sensing catheters (CFSCs) on fluoroscopy times and procedure times in left-sided atrial procedures.

Methods In this multinational, multicenter study, data from 622 left-sided procedures (142 without and 480 with CFSCs) of 25 participating European centers were prospectively collected with a structured questionnaire. Examinations comprised 393 pulmonary vein isolations (PVIs, group 1[G1]), 122 PVIs with linear lesions (group 2[G2]), 65 left-sided accessory pathway ablations (group 3 [G3]) and 42 ablations for left atrial tachycardia (group 4 [G4]). Fluoroscopy and procedure times were compared with respect to the use of CFSCs, procedure type, and level of operator experience as possible confounders. A Mann-Whitney U-test was applied for comparison, and a p-value <0.05 was considered statistically significant.

Results With the use of CFSCs, fluoroscopy time was significantly reduced when performing pulmonary vein isolations (G1 median [IQR]: 19 [11.0-33.7] vs. 7.2 [4.0-13.0] min., p < 0.001, G2: 45.3 [34.9-61.8] vs. 7.3 [5.0-14.0], p < 0.001, respectively). For groups G3 and G4, no difference could be detected. Procedure times were shortened for pulmonary vein isolations with additional lesions only (G4: 210 [180-240] vs. 153 [127-200] min., p < 0.001). When assessing the effect of operator experience, all left-sided atrial procedures were combined. Significantly shorter fluoroscopy times with contact force were found at all career levels (early career < 5 years: median -6 min., p = 0.024, mid-career 5-15 years: -15 min., p < 0.001, mentor status with experience > 15 years: -6.5 min., p < 0.001). The use of contact force proved to be especially beneficial in reducing fluoroscopy time in operators performing one to 19 procedures per month (1-9: median -15.8 min., p < 0.001, 10-19: -15.9 min., p < 0.001), whereas it lost its statistical significance when more than 20 procedures per month were performed (20-39: - 3.2 min., p = 0.100, >40: -1.5 min., p = 0.346).

Conclusion Contact force sensing catheters can help to reduce fluoroscopy times, especially when performing pulmonary vein isolations. This effect could be demonstrated for all career levels. However, it diminished with the operator"s caseload. A shortening of procedure time was found for PVIs with additional linear lesions.

P1384Radiation safety and electrophysiologists: radiation protection status

INTRODUCTION

 Ionizing radiation is typically used during variety electrophysiological (EP) procedures, although it may contribute to deterministic effects especially for staff. 

PURPOSE

 The purpose of this study was to perform an analysis of EP operators’ radiation protective devices for occupational exposure. 

METHODS

 Data reported herein were gathered from international, multi-site, prospective, Go 4 Zero Fluoroscopy registry. The registry encompassed 25 European EP centers, and up to 5 operators from each center. The presence of operators’ X-ray protection tools was examined to determine the level of operators’ protection. Additionally, the tests included availability of measures to decrease radiation output and exposure control measures. Finally, the analysis of correlation between the X-ray protection and degree of operators’ experience (<5, 5-15,>15 years) as well as number of procedures performed per month (1-9, 10-19, 20-39, >40 procedures/month) was performed. 

RESULTS

 Our analysis included 95 operators (median age: 39 years, 85% of male, median training time: 5 years). The whole study group performed annually medical examinations due to radiation exposure and 56% of them received dosimetry reports once a month, 5% - once every 3 months, and 39% - once a year. Irrespectively of experience or number of performed procedures the most frequently used X-ray protection tools (used by >80% of group) were lead apron, thyroid shields, screen below the table, glass in the lab, and least often (used by < 6% of group) – protective gloves and cabin. The most often exposure control measures used were chest (95%) followed by collar (31%), ring (24%) and eye (7%) dosimeters. The inverse correlation between level of experience and measures to decrease radiation output was observed (collimation: 84%, 80% and 78%; minimizing the tube-to intensifier distance: 100%, 93% and 91% of operators with <5, 5-15 and >15 years of experience, respectively). There were not observed differences between type of radiation protection equipment and operators’ level of experience or number of procedures. Additionally, there were no differences between male and female operators regarding protective equipment, expect eyeglasses or cabin that were more often used by men. Operators who were protected by >4 X-ray protection tools were exposed for higher radiation levels as compared to those protected by <4 X-ray protection tools (median [IQR] radiation exposure: 0.6 [0.2-1.1] vs 0.2 [0.1-0.2] mSv per month, p < 0.0001; 1.1 [0.1-12.0] vs 0.5 [0.1-1.1] mSv per year, p < 0.0001). There were no differences between the type of (universitary vs non-universitary) or institution’s localization (Eastern vs Central vs Western Europe) and used protective equipment.  

CONCLUSIONS

 Both proper radiation protective equipment, and regular medical examination due to professional exposure are mandatory to reduce radiation exposure in practice.

P738 Association of galectin-3 and soluble ST2, and their changes, with echocardiographic parameters and development of heart failure after ST-segment elevation myocardial infarction

Background

The occurrence of HF (heart failure) with preserved ejection fraction (HFpEF) has risen significantly over the past decade. Galectin-3 (Gal-3) and soluble ST2 (sST2) are involved in inflammatory processes and fibrosis and might be useful in estimation of the risk of HFpEF development after myocardial infarction (MI).Purpose: To investigate the association of Gal-3 and sST2, and their follow-up changeswith echocardiographic parameters of systolic and diastolic dysfunctionin patients (pts) with ST-segment elevation MI (STEMI) treated with primary percutaneous coronary intervention (pPCI). Methods:A prospective, observational study, BIOSTRAT (NCT03735719), enrolled 117 pts. Gal-3 and sST2 serum collection and echocardiography were performed twice (during index hospitalization and on a control visit at one-year follow-up). Assessedat baseline and at one-year echocardiographic indices included left ventricular ejection fraction (LVEF), atrial and ventricular size, LV posterior wall and septal thickness, LV hypertrophy based on LV mass index, mitral inflow velocities, and early diastolic tissue velocities at the lateral and medial mitral annulus. Results:Mean baseline concentrations of Gal-3 and sST2 (7.5 and 26.4 ng/mL, respectively) were increased at one-year follow-up (8.5 ng/mL, p < 0.001 and 31.4 ng/mL, p = 0.001, respectively). Fifty of 105 pts (48%) developed HF and 30% of the study population had LVEF <50% at one-year. There were no significant differences between pts with LVEF <50% and ≥50% in terms of baseline, follow-up, nor changes in Gal-3 and sST2 concentrations from baseline to the one-year visit. Gal-3 and sST2 concentrations at baseline, after one-year, and their changes were correlated with echocardiographic parameters. Correlation analysis revealed that higher baseline Gal-3 concentrations correlated inversely only with LV end-diastolic volume at one-year. There were no other significant correlations of baseline, follow-up, nor changes in Gal-3 concentration with echocardiographic parameters. Baseline sST2 values correlated positively with LV end-diastolic diameter, LV end-systolic volume, LV mass index, and inversely with LVEF at one-year, but not with baseline echocardiographic parameters. Changes in sST2 concentration correlated positively only with LVEF at one-year. There were no significant correlations of sST2 concentrations at follow-up with echocardiographic parameters. Only pts with a higher sST2 baseline level had lower LVEF at baseline and after one-year, and pts with higher concentrations of both Gal-3 and sST2 at baseline were more likely to have LV hypertrophy initially and after one-year. There was no clear association of rising biomarkers’ quartiles with other echocardiographic parameters. Conclusions:There was no clear association between both biomarkers and echocardiographic parametersof diastolic dysfunction. Increasing levels of Gal-3 and sST2 do not reflect the HFpEF development in pts after STEMI.

Classical conditioned learning using transcranial magnetic stimulation

This study examined whether brain responses to transcranial magnetic stimulation (TMS) would be amenable to classical conditioning. Motor cortex in human participants was stimulated with TMS pulses, which elicited a peripheral motor response in the form of a motor evoked potential (MEP). The TMS pulses were paired with audio-visual cues that served as conditioned stimuli. Over the course of training, MEPs following the conditioned stimuli decreased in amplitude. Two experiments demonstrated that the attenuated response only occurred when the TMS was preceded by the conditioned stimulus. Unsignaled TMS and TMS preceded by a cue that was not previously paired did not attenuate the response. The experiments demonstrate that the modulation of the motor response depended on the prior pairings of the conditioned stimuli and TMS and that the effects were stimulus specific. Thus we demonstrate here, for the first time, that TMS can serve as the unconditioned stimulus in Pavlovian conditioning.

An optimal period for setting sustained variability levels

In two experiments, we investigated how explicit reinforcement of highly variable behavior at different points in training affected performance after the requirement was eliminated. Two versions of a computer game, differing in the number of possible solution paths, were used. In each, an optimal period of training for producing sustained high variability was found. Exposure to a high lag requirement shortly after acquisition sustained variability. Rewarding variability at other times did not have a sustained effect. The implications for learning and problem solving are discussed.

Organization of quinto-frontal structures in hatchling ring doves (Streptopelia risoria)

Transganglionic and retrograde tracing procedures were applied to peripheral and central trigeminal structures in hatchling ring doves. The organization of the trigeminal ganglion, its somatotopic projections upon the principal sensory nucleus (PrV), and the projections of PrV upon the telencephalon are similar in adult and hatchling Columbiformes. The results suggest that development of feeding patterns in these species involves experiential differentiation of trigeminal sensorimotor circuits present at hatching.

Reversible inhibition by lanthanum of the hydrosmotic response to serosal hypertonicity in toad urinary bladder

In the urinary bladder of amphibia, hypertonicity of the serosal bath (SH) evokes an increase in transepithelial water permeability, the characteristics of which resemble the response to antidiuretic hormone (ADH). The ionic dependency, in particular for Ca2+, appears very similar for SH- and ADH-induced water fluxes. In the present experiments La3+ was used as a probe to study the Ca2+-dependency of the hydrosmotic response to SH in isolated urinary bladder of the toad Bufo marinus. Addition of La3+ (5 mM) on the serosal side of the membrane produced a significant and reversible increase in basal transepithelial water flux. The hydrosmotic response elicited by adding 250 mM mannitol to the serosal Ringer's solution was inhibited by 30% in the absence of serosal Ca2+. Similarly, the hydrosmotic response to SH was inhibited by 37%, 30% and 40% when 5 mM La3+ was added to the serosal medium 30 min before, concommitantly with, or 60 min after induction of SH. The inhibition of transepithelial water flux observed in the absence of serosal Ca2+ or in the presence of serosal La3+ was reversible. The results support a critical role for Ca2+ in the modulation of transepithelial water permeability in the urinary bladder of amphibia. Ca2+ presumably exerts its effects at a post-cyclic AMP step.