Detecting deceased patients on cardiac device remote monitoring: A case series and management guide for cardiac device services

BACKGROUND

Remote monitoring (RM) of implantable cardiac devices provides substantial and complex information, presenting new challenges such as detection of a patient's death.

OBJECTIVE

This study aims to describe RM transmissions indicating death and propose a management strategy for services.

METHODS

The study included consecutive ambulatory outpatients whose deaths were detected via RM. Clinical and device data were collected from electronic records, and ethical approval was obtained from the service's institutional review board.

RESULTS

Over a 9-year period (2014-2023), 28 patients were detected. The deceased patients had implantable cardioverter-defibrillators, pacemakers, and implantable loop recorders. In 54% of the cases, the patient's death had already been recognized. Alert transmissions indicating death were commonly related to ventricular arrhythmia events, but also due to lead measurements, and implantable loop recorder battery status. Several diagnostic features may indicate a patient's death. The most reliable was the presenting electrogram, demonstrating base rate pacing with no capture. Device diagnostics, lead parameters, and arrhythmia recordings may indicate death; however, not all cases present with recordings and diagnosis may not be conclusive. A majority (82%) had ventricular arrhythmia at the time of death. In cases where defibrillator shocks were delivered, the arrhythmia reinitiated shortly after successful cardioversion. Delayed therapy was observed, and some patients did not receive defibrillator shocks because of discriminators or because the arrhythmia rate fell below the shock zone.

CONCLUSION

Detecting a patient death via RM presents unique challenges and considerations for services. Standard operational policies and legal consultation should be established to address the implications.

The BLISTER Score: A Novel, Externally Validated Tool for Predicting Cardiac Implantable Electronic Device Infections, and Its Cost-Utility Implications for Antimicrobial Envelope Use

BACKGROUND

Antimicrobial envelopes reduce the incidence of cardiac implantable electronic device infections, but their cost restricts routine use in the United Kingdom. Risk scoring could help to identify which patients would most benefit from this technology.

METHODS

A novel risk score (BLISTER [Blood results, Long procedure time, Immunosuppressed, Sixty years old (or younger), Type of procedure, Early re-intervention, Repeat procedure]) was derived from multivariate analysis of factors associated with cardiac implantable electronic device infection. Diagnostic utility was assessed against the existing PADIT score (Prior procedure, Age, Depressed renal function, Immunocompromised, Type of procedure) in both standard and high-risk external validation cohorts, and cost-utility models examined different BLISTER and PADIT score thresholds for TYRX (Medtronic; Minneapolis, MN) antimicrobial envelope allocation.

RESULTS

In a derivation cohort (n=7383), cardiac implantable electronic device infection occurred in 59 individuals within 12 months of a procedure (event rate, 0.8%). In addition to the PADIT score constituents, lead extraction (hazard ratio, 3.3 [95% CI, 1.9-6.1]; P<0.0001), C-reactive protein >50 mg/L (hazard ratio, 3.0 [95% CI, 1.4-6.4]; P=0.005), reintervention within 2 years (hazard ratio, 10.1 [95% CI, 5.6-17.9]; P<0.0001), and top-quartile procedure duration (hazard ratio, 2.6 [95% CI, 1.6-4.1]; P=0.001) were independent predictors of infection. The BLISTER score demonstrated superior discriminative performance versus PADIT in the standard risk (n=2854, event rate: 0.8%, area under the curve, 0.82 versus 0.71; P=0.001) and high-risk validation cohorts (n=1961, event rate: 2.0%, area under the curve, 0.77 versus 0.69; P=0.001), and in all patients (n=12 198, event rate: 1%, area under the curve, 0.8 versus 0.75, P=0.002). In decision-analytic modeling, the optimum scenario assigned antimicrobial envelopes to patients with BLISTER scores ≥6 (10.8%), delivering a significant reduction in infections (relative risk reduction, 30%; P=0.036) within the National Institute for Health and Care Excellence cost-utility thresholds (incremental cost-effectiveness ratio, £18 446).

CONCLUSIONS

The BLISTER score (https://qxmd.com/calculate/calculator_876/the-blister-score-for-cied-infection) was a valid predictor of cardiac implantable electronic device infection, and could facilitate cost-effective antimicrobial envelope allocation to high-risk patients.

Feasibility of double-blinded, placebo-controlled interventional study for assessing catheter ablation efficacy in persistent atrial fibrillation: Insights from the ORBITA AF feasibility study

BACKGROUND

To date, there are no randomized, double-blinded clinical trials comparing catheter ablation to DC cardioversion (DCCV) with medical therapy in patients with persistent atrial fibrillation (PersAF). Conducting a large-scale trial to address this question presents considerable challenges, including recruitment, blinding, and implementation. We conducted a pilot study to evaluate the feasibility of conducting a definitive placebo-controlled trial.

METHODS

This prospective trial was carried out at Barts Heart Centre, United Kingdom, employing a randomized, double-blinded, placebo-controlled design. Twenty patients with PersAF (duration <2 years) were recruited, representing 10% of the proposed larger trial as determined by a power calculation. The patients were randomized in a 1:1 ratio to receive either PVI ± DCCV (PVI group) or DCCV + Placebo (DCCV group). The primary endpoint of this feasibility study was to evaluate patient blinding. Patients remained unaware of their treatment allocation until end of study.

RESULTS

During the study, 35% of patients experienced recurrence of PersAF prior to completion of 12 months follow-up. Blinding was successfully maintained amongst both patients and medical staff. The DCCV group had a trend to higher recurrence and repeat procedure rate compared to the PVI group (recurrence of PersAF 60% vs 30%; p = .07 and repeat procedure 70% vs 40%; p = .4). The quality of life experienced by individuals in the PVI group showed improvement, as evidenced by enhanced scores on the AF specific questionnaire (AF PROMS) (3 [±4] vs 21 [±8]) and SF-12 mental-component raw score (51.4 [±7] vs 43.24 [±15]) in patients who maintained sinus rhythm at 12 months.

CONCLUSION

This feasibility study establishes the potential for conducting a blinded, placebo-controlled trial to evaluate the efficacy of PVI versus DCCV in patients with PersAF.

Spatial and temporal relationship between focal and rotational activations and their relationship to structural remodeling in patients with persistent atrial fibrillation

BACKGROUND

Focal and rotational activations have been demonstrated in atrial fibrillation (AF), but their relationship to each other and to structural remodeling remains unclear.

OBJECTIVE

The purpose of this study was to assess the relationship of focal and rotational activations to underlying low-voltage zones (LVZs) (<0.5 mV) and to determine whether there was a temporal (≤500 ms) and spatial (≤12 mm) relationship between these activations.

METHODS

Patients undergoing catheter ablation for persistent AF were included. All patients underwent pulmonary vein isolation. Unipolar signals were collected to identify focal and rotational activations using a wavefront propagation algorithm.

RESULTS

In 40 patients, 105 activations were identified (57 [54.3%] focal; 48 [45.7%] rotational). Rotational activations were co-localized to LVZs (35/48 [72.9%]) whereas focal activations were not (11/57 in LVZ [19.3%]; P <.001). The proportion of the left atrium occupied by LVZs predicted rotational activations occurrence (area under the curve 0.96; 95% confidence interval 0.90-1.00; P <.001). In patients with a relatively healthy atrium, in which the atrium consisted of ≤15% LVZs, only focal activations were identified. Thirty-two of the 35 rotational activations (91.4%) located in LVZs also showed a temporal and spatial relationship to a focal activation. The presence of a LVZ within 12 mm of the focal activation was a strong predictor for whether a paired rotational activation would also occur in that vicinity.

CONCLUSION

Rotational activations are largely confined to areas of structural remodeling and have a clear spatial and temporal relationship with focal activations suggesting they are dependent on them. These novel mechanistic observations outline a plausible model for patient-specific mechanisms maintaining AF.

Constructing bilayer and volumetric atrial models at scale

To enable large in silico trials and personalized model predictions on clinical timescales, it is imperative that models can be constructed quickly and reproducibly. First, we aimed to overcome the challenges of constructing cardiac models at scale through developing a robust, open-source pipeline for bilayer and volumetric atrial models. Second, we aimed to investigate the effects of fibres, fibrosis and model representation on fibrillatory dynamics. To construct bilayer and volumetric models, we extended our previously developed coordinate system to incorporate transmurality, atrial regions and fibres (rule-based or data driven diffusion tensor magnetic resonance imaging (MRI)). We created a cohort of 1000 biatrial bilayer and volumetric models derived from computed tomography (CT) data, as well as models from MRI, and electroanatomical mapping. Fibrillatory dynamics diverged between bilayer and volumetric simulations across the CT cohort (correlation coefficient for phase singularity maps: left atrial (LA) 0.27 ± 0.19, right atrial (RA) 0.41 ± 0.14). Adding fibrotic remodelling stabilized re-entries and reduced the impact of model type (LA: 0.52 ± 0.20, RA: 0.36 ± 0.18). The choice of fibre field has a small effect on paced activation data (less than 12 ms), but a larger effect on fibrillatory dynamics. Overall, we developed an open-source user-friendly pipeline for generating atrial models from imaging or electroanatomical mapping data enabling in silico clinical trials at scale (https://github.com/pcmlab/atrialmtk).

Atrioventricular nodal ablation is an effective management strategy for atrial fibrillation in patients with hypertrophic cardiomyopathy

BACKGROUND

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and can be challenging to manage. Atrioventricular nodal (AVN) ablation may be an effective management strategy for AF in these patients.

OBJECTIVE

The purpose of this study was to assess the efficacy of AVN ablation in HCM patients who have failed medical therapy and/or catheter ablation for AF.

METHODS

A multicenter study with retrospective analysis of a prospectively collated HCM registry was performed. AVN ablation patients were identified. Baseline characteristics and device and procedural indications were collected. Symptoms defined by New York Heart Association and European Heart Rhythm Association classification and echocardiographic findings during follow-up were assessed.

RESULTS

Fifty-nine patients were included in the study. Indications for AVN ablation were 6 (10.2%) inappropriate implantable cardioverter-defibrillator shock, 35 (59.3%) ineffective rate control, and 18 (30.5%) to regularize rhythm for symptom improvement. During post-AVN ablation follow-up of 79.4 ± 61.1 months, left ventricular ejection fraction (LVEF) remained stable (pre-LVEF 48.9% ± 12.6% vs post-LVEF 50.1% ± 10.1%; P = .29), even in those without a cardiac resynchronization therapy (CRT) device (pre-LVEF 54.3% ± 8.0% vs post-LVEF 53.8% ± 8.0%; P = .65). Forty-nine patients (83.1%) reported an improvement in symptoms regardless of AF type (17/21 [81.0%] paroxysmal vs 32/38 [84.2%] persistent; P = 1.00), presence of baseline left ventricular impairment (22/26 [84.6%] LVEF ≤50% vs 27/33 [81.8%] LVEF ≥50%; P = 1.00) or CRT device (27/32 [84.4%] CRT vs 22/27 [81.5%] no CRT; P = 1.00). Symptoms improved in 16 patients (89.0%) who underwent AVN ablation to regularize rhythm.

CONCLUSION

AVN ablation improved symptoms without impacting left ventricular function in the majority of patients. The data suggest that AVN ablation is an effective and safe management approach for AF in HCM and should be further evaluated in larger prospective studies.

Atrial fibrillation cryoablation is an effective day case treatment: the UK PolarX vs. Arctic Front Advance experience

AIMS

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF). There are limited data on the PolarX Cryoballoon. The study aimed to establish the safety, efficacy, and feasibility of same day discharge for Cryoballoon PVI.

METHODS AND RESULTS

Multi-centre study across 12 centres. Procedural metrics, safety profile, and procedural efficacy of the PolarX Cryoballoon with the Arctic Front Advance (AFA) Cryoballoon were compared in a cohort large enough to provide definitive comparative data. A total of 1688 patients underwent PVI with cryoablation (50% PolarX and 50% AFA). Successful PVI was achieved with 1677 (99.3%) patients with 97.2% (n = 1641) performed as day case procedures with a complication rate of <1%. Safety, procedural metrics, and efficacy of the PolarX Cryoballoon were comparable with the AFA cohort. The PolarX Cryoballoon demonstrated a nadir temperature of -54.6 ± 7.6°C, temperature at 30 s of -38.6 ± 7.2°C, time to -40°C of 34.1 ± 13.7 s, and time to isolation of 49.8 ± 33.2 s. Independent predictors for achieving PVI included time to reach -40°C [odds ratio (OR) 1.34; P < 0.001] and nadir temperature (OR 1.24; P < 0.001) with an optimal cut-off of ≤34 s [area under the curve (AUC) 0.73; P < 0.001] and nadir temperature of ≤-54.0°C (AUC 0.71; P < 0.001), respectively.

CONCLUSIONS

This large-scale UK multi-centre study has shown that Cryoballoon PVI is a safe, effective day case procedure. PVI using the PolarX Cryoballoon was similarly safe and effective as the AFA Cryoballoon. The cryoablation metrics achieved with the PolarX Cryoballoon were different to that reported with the AFA Cryoballoon. Modified cryoablation targets are required when utilizing the PolarX Cryoballoon.

ECGI targeted ablation for persistent AF not responding to pulmonary vein isolation: Results of a two-staged strategy (TARGET AF2)

Background

Mechanisms sustaining persistent atrial fibrillation (AF) remain unclear.

Objectives

The study sought to evaluate both the clinical outcomes and response to ablation of potential drivers in patients with recurrent persistent AF recurrence following pulmonary vein isolation (PVI).

Methods

A total of 100 patients with persistent AF of <2 years' duration underwent cryoballoon PVI (ECGI phenotyping of persistent AF based on driver burden and distribution to predict response to pulmonary vein isolation). Patients with documented recurrence of atrial arrhythmia within 12 months were recruited and underwent repeat PVI (if needed) followed by ablation of potential drivers (PDs) identified by electrocardiographic imaging (ECGI). PDs were defined as rotational activity >1.5 revolutions or focal activations. Cycle lengths were measured pre- and postablation. The primary outcome was freedom from atrial arrhythmia off antiarrhythmic drugs at 1 year as per guidelines.

Results

Of 37 patients recruited, 26 had recurrent AF and underwent ECGI-guided ablation of PDs. An average of 6.4 ± 2.7 PDs were targeted per patient. The mean ablation time targeting PDs was 15.5 ± 6.9 minutes. An ablation response occurred in 20 patients (AF termination in 6, cycle length prolongation ≥10% in 14). At 1 year, 14 (54%) of 26 patients were free from arrhythmia, and 12 (46%) of 26 were off antiarrhythmic drugs. Considering the 96 patients who completed follow-up out of the original cohort of 100 patients undergoing cryoablation in this staged strategy, freedom from arrhythmia at 1 year following the last procedure was 72 (75%) of 96, or 70 (73%) of 96 off antiarrhythmic drugs.

Conclusions

In patients with recurrent AF despite PVI, ECGI-guided ablation caused an acute response in a majority with reasonable long-term outcomes.

In Atrial Fibrillation, Omnipolar Voltage Maps More Accurately Delineate Scar Than Bipolar Voltage Maps

BACKGROUND

Optimal method for voltage assessment in AF remains unclear.

OBJECTIVES

This study evaluated different methods for assessing atrial voltage and their accuracy in identifying pulmonary vein reconnection sites (PVRSs) in atrial fibrillation (AF).

METHODS

Patients with persistent AF undergoing ablation were included. De novo procedures: voltage assessment in AF with omnipolar voltage (OV) and bipolar voltage (BV) methodology and BV assessment in sinus rhythm (SR). Activation vector and fractionation maps were reviewed at voltage discrepancy sites on OV and BV maps in AF. AF voltage maps were compared with SR BV maps. Repeat ablation procedures: OV and BV maps in AF were compared to detect gaps in wide area circumferential ablation (WACA) lines that correlated with PVRS.

RESULTS

Forty patients were included: 20 de novo and 20 repeat procedures. De novo procedure: OV vs BV maps in AF; average voltage 0.55 ± 0.18 mV vs 0.38 ± 0.12 mV; P = 0.002, voltage difference of 0.20 ± 0.07 mV; P = 0.003 at coregistered points and proportion of left atrium (LA) area occupied by low-voltage zones (LVZs) was smaller on OV maps (42.4% ± 12.8% OV vs 66.7% ± 12.7% BV; P < 0.001). LVZs identified on BV maps and not on OV maps correlated frequently to wavefront collision and fractionation sites (94.7%). OV AF maps agreed better with BV SR maps (voltage difference at coregistered points 0.09 ± 0.03 mV; P = 0.24) unlike BV AF maps (0.17 ± 0.07 mV, P = 0.002). Repeat ablation procedure: OV was superior in identifying WACA line gaps that correlated with PVRS than BV maps (area under the curve = 0.89, P < 0.001).

CONCLUSIONS

OV AF maps improve voltage assessment by overcoming the impact of wavefront collision and fractionation. OV AF maps correlate better with BV maps in SR and more accurately delineate gaps on WACA lines at PVRS.

Catheter ablation of atrial fibrillation with a multi-electrode radiofrequency balloon; first and early two centre experience in Europe

INTRODUCTION

The Heliostar™ ablation system is a novel RF balloon ablation technology with an integrated three-dimensional mapping system. Here, we describe our early experience and procedural outcomes using this technology for atrial fibrillation catheter ablation.

METHODS

We sought to comprehensively assess the first 60 consecutive patients undergoing pulmonary vein isolation using the novel HELISOTAR™ RF balloon technology including procedural outcomes. A comparison of the workflow between two different anaesthetic modalities (conscious sedation [CS] vs. general anaesthesia [GA]) was made. Procedural data were collected prospectively from two high-volume centers (Barts Heart Centre, UK and University Hospital of Zurich, Zurich). A standardized approach for catheter ablation was employed.

RESULTS

A total of 35 patients had the procedure under CS and the remaining under GA. Mean procedural and fluoroscopy times were 84 ± 33 min and 1.1 min. The median duration of RF energy application was 7 (5-9.8) mins per patient. All veins were successfully isolated, and the median isolation time was 10 (7-15) seconds. Our cohort's rate of procedural complications was low, with no mortality within 30 days postprocedure.

CONCLUSION

Our early experience shows that catheter ablation using the Heliostar™ technology can be performed efficiently and safely; however, long-term data is yet to be established. Low fluoroscopy requirements, short learning curves and use of this technology with CS is possible, including the use of an oesophageal temperature probe.

Exploiting SMART pass filter deactivation detection to minimize inappropriate subcutaneous implantable cardioverter defibrillator therapies: a real-world single-centre experience and management guide

AIMS

The SMART Pass™ (SP) algorithm is a high-pass filter that aims to reduce inappropriate therapy (IT) in subcutaneous internal cardiac defibrillator (S-ICD), but SP can deactivate due to low amplitude sensed R waves or asystole. The association between IT and SP deactivation and management strategies were evaluated, hypothesizing SP deactivation increases the risk of IT and device re-programming, or lead/generator re-positioning could reduce this risk.

METHODS AND RESULTS

Retrospective single-centre audit of Emblem™ S-ICD devices implanted 2016 to 2020 utilizing health records and remote monitoring data. Cox regression models evaluated associations between SP deactivation and IT. A total of 348 patients (27 ± 16.6 months follow-up) were studied: 73% primary prevention. Thirty-eight patients (11.8%) received 83 shocks with 27 patients (7.8%) receiving a total of 44 IT. Causes of IT were oversensing (98%) and aberrantly conducted atrial fibrillation (2%). SP deactivation occurred in 32 of 348 patients (9%) and was significantly associated with increased risk of IT (hazard ratio 5.36, 95% CI 2.37-12.13). SP deactivation was due to low amplitude R waves (94%), associated with a higher defibrillation threshold at implant and presence of arrhythmogenic right ventricular cardiomyopathy. No further IT occurred 16 ± 15.5 months after corrective interventions, with changing the sensing vector being successful in 59% of cases.

CONCLUSION

To reduce the risk of IT, the cause of the SP deactivation should be investigated, and appropriate reprogramming, device, or lead modifications made. Utilizing the alert for SP deactivation and electrograms could pro-actively prevent IT.

Right ventricular function is a predictor for sustained ventricular tachycardia requiring anti-tachycardic pacing in arrhythmogenic ventricular cardiomyopathy: insight into transvenous vs. subcutaneous implantable cardioverter defibrillator insertion

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) patients develop ventricular arrhythmias (VAs) responsive to anti-tachycardia pacing (ATP). However, VA episodes have not been characterized in accordance with the device therapy, and with the emergence of the subcutaneous implantable cardioverter defibrillator (S-ICD), the appropriate device prescription in ARVC remains unclear. Study aim was to characterize VA events in ARVC patients during follow-up in accordance with device therapy and elicit if certain parameters are predictive of specific VA events.

METHODS AND RESULTS

This was a retrospective single-centre study utilizing prospectively collated registry data of ARVC patients with ICDs. Forty-six patients were included [54.0 ± 12.1 years old and 20 (43.5%) secondary prevention devices]. During a follow-up of 12.1 ± 6.9 years, 31 (67.4%) patients had VA events [n = 2, 6.5% ventricular fibrillation (VF), n = 14], 45.2% VT falling in VF zone resulting in ICD shock(s), n = 10, 32.3% VT resulting in ATP, and n = 5, 16.1% patients had both VT resulting in ATP and ICD shock(s). Lead failure rates were high (11/46, 23.9%). ATP was successful in 34.5% of patients. Severely impaired right ventricular (RV) function was an independent predictor of VT resulting in ATP (hazard ratio 16.80, 95% confidence interval 3.74-75.2; P < 0.001) with a high predictive accuracy (area under the curve 0.88, 95%CI 0.76-1.00; P < 0.001).

CONCLUSION

VA event rates are high in ARVC patients with a majority having VT falling in the VF zone resulting in ICD shock(s). S-ICDs could be of benefit in most patients with ARVC with the absence of severely impaired RV function which has the potential to avoid consequences of the high burden of lead failure.

Contact force and catheter stability are predictive metrics of successful pulmonary vein isolation with high-power short duration ablation in atrial fibrillation

INTRODUCTION

Preliminary data suggest that high power short duration (HPSD) ablation for pulmonary vein isolation (PVI) are safe. Limited data are available on its effectiveness. Aim was to evaluate HPSD ablation in AF ablation using a novel Qdot Micro catheter.

METHODS AND RESULTS

Prospective multi-centre study evaluating safety and efficacy of PVI with HPSD ablation. First pass isolation (FPI) and sustained PVI was assessed. If FPI was not achieved additional ablation index (AI)-guided ablation with 45W was performed and metrics predictive of this were determined. Sixty-five patients and 260 veins were treated. Procedural and LA dwell time was 93.9±30.4 and 60.5±23.1 minutes respectively. FPI was achieved in 47 (72.3%) patients and 231 veins (88.8%) with an ablation duration of 4.6±1.0 minutes. Twenty-nine veins required additional AI-guided ablation to achieve initial PVI with 24 anatomical sites ablated with the right posterior carina being the most common site (37.5%). A contact force of ≥8g (AUC 0.81; p<0.001) and catheter position variation of ≤1.2mm (AUC 0.79; p<0.001) with HPSD were strongly predictive of not requiring additional AI-guided ablation. Out of the 260 veins, only 5 (1.9%) veins showed acute reconnection. HPSD ablation was associated with shorter procedure times (93.9min vs.159.4min; p<0.001), ablation times (6.1min vs. 27.7min; p<0.001) and lower rates of PV reconnection (9.2% vs. 30.8%; p=0.004) compared to moderate power cohort.

CONCLUSIONS

HPSD ablation is an effective ablation modality which results in effective PVI whilst maintaining a safety profile. Its superiority needs to be evaluated in randomised controlled trials. This article is protected by copyright. All rights reserved.

Long-term outcomes following catheter ablation versus medical therapy in patients with persistent atrial fibrillation and heart failure with reduced ejection fraction

AIMS

The ARC-HF and CAMTAF trials randomized patients with persistent atrial fibrillation (AF) and heart failure (HF) to early routine catheter ablation (ER-CA) versus pharmacological rate control (RC). After trial completion, delayed selective catheter ablation (DS-CA) was performed where clinically indicated in the RC group. We hypothesized that ER-CA would result in a lower risk of cardiovascular hospitalization and death versus DS-CA in this population.

METHODS AND RESULTS

Overall, 102 patients were randomized (age 60 ± 11 years, left ventricular ejection fraction [LVEF] 31 ± 11%): 52 to ER-CA and 50 to RC. After 12 months, patients undergoing ER-CA had improved self-reported symptom scores, lower New York Heart Association class (i.e. better functional capacity), and higher LVEF compared to patients receiving RC alone. During a median follow-up of 7.8 (interquartile range 3.9-9.9) years, 27 (54%) patients in the RC group underwent DS-CA and 34 (33.3%) patients died, including 17 (32.7%) randomized to ER-CA and 17 (34.0%) randomized to RC. Compared with DS-CA, a strategy of ER-CA exhibited similar risk of all-cause mortality (adjusted hazard ratio [aHR] 0.89, 95% confidence interval [CI] 0.44-1.77, p = 0.731) and combined all-cause mortality or cardiovascular hospitalization (aHR 0.80, 95% CI 0.43-1.47, p = 0.467). However, analyses according to treatment received suggested an association between CA and improved outcomes versus RC (all-cause mortality: aHR 0.43, 95% CI 0.20-0.91, p = 0.028; all-cause mortality/cardiovascular hospitalization: aHR 0.48, 95% CI 0.24-0.94, p = 0.031).

CONCLUSIONS

In patients with persistent AF and HF, ER-CA produces similar long-term outcomes to a DS-CA strategy. The association between CA as a treatment received and improved outcomes means there is still a lack of clarity regarding the role of early CA in selected patients. Randomized trials are needed to clarify this question.

Cardiac implantable electronic device infections: prognostic value of the PADIT score and its cost-utility implications for antimicrobial envelope use in the United Kingdom

Background

The incidence of cardiac implantable electronic device (CIED) infections is rising.

Purpose

We examined the factors associated with CIED infection, assessed the prognostic power of the PADIT risk score, and modelled the cost-utility of selective TYRX antimicrobial envelope use for preventing CIED infections.

Methods

Data were extracted from 2016 to 2019, and included all de novo implants, generator changes and lead interventions for transvenous CIEDs at a high-volume UK centre. CIED infection was defined as hospitalisation for device infection within 12 months of a procedure. Cost-utility analysis was informed by standardised tariffs, and quality adjusted life year (QALY) and efficacy data was extrapolated from analysis of the WRAP-IT trial.

Results

6,035 patients underwent 7,383 procedures; CIED infection occurred in 59 individuals (0.8%). In addition to the constituents of the PADIT score, lead extraction (HR 3.3 (1.9–6.1), p&lt;0.0001), C-reactive protein &gt;50mg/l (HR 3.0 (1.4–6.4), p=0.005), re-intervention within two years (HR 10.1 (5.6–17.9), p&lt;0.0001), and procedure duration over two hours (HR 2.6 (1.6–4.1), p=0.001) were independent predictors of infection. Increased PADIT score was strongly associated with infection (AUC: 0.82, HR per point increase: 1.36 (1.27–1.47), p&lt;0.0001). A cost-utility model assigning TYRX envelopes to patients with PADIT scores ≥6 predicted a reduction in infections (number needed to treat: 72) and a cost per QALY gained within the UK's (NICE) cost-effectiveness threshold (£25,107).

Conclusions

The PADIT score was a powerful predictor of CIED infections in a heterogeneous population,and may facilitate cost-effective TYRX envelope allocation in selected high-risk patients.

Funding Acknowledgement

Type of funding sources: None.

Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Background

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP).

Purpose

We examined the associations of TSP-related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our centre from 2016–2020.

Methods

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinised to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT.

Results

3,239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP-related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above-median age (OR 2.4 (1.19–4.2), p=0.006) and those undergoing re-do procedures (OR 1.95 (1.29–3.43, p=0.042) were at higher risk of TRCT. Of the operator-dependent variables, choice of transseptal needle (Endrys vs Brockenbrough, p&gt;0.1) or puncture sheath (Swartz vs Mullins vs Agilis vs Vizigo vs Cryosheath, all p&gt;0.1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk (OR 4.42 (2.45–8.2), p=0.001), whilst top quartile operator experience (OR 0.4 (0.17–0.85, p=0.002), transoesophageal echocardiogram (TOE prevalence: 26%, OR 0.51 (0.11–0.94), p=0.023), and use of the SafeSept guidewire (OR 0.22 (0.08–0.62), p=0.001) reduced TRCT risk. An increase in SafeSept wire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R2=0.72, p&lt;0.001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the independent predictors of TRCT were patient age, re-do procedure, operator experience, unsuccessful first pass, TOE-guidance, and use of the SafeSept wire. A novel classification system for the causes of cardiac tamponade is proposed (table 1); this may be of interest to clinical trialists or auditors evaluating patient safety.

Funding Acknowledgement

Type of funding sources: None.

Coronary sinus electrogram characteristics predict termination of AF with ablation and long-term clinical outcome

INTRODUCTION

Markers predicting atrial fibrillation (AF) termination and freedom from AF/atrial tachycardia (AT) has been proposed. This study aimed to evaluate the role of novel coronary sinus (CS) electrogram characteristics in predicting the acute ablation response and freedom from AF/AT during follow-up.

METHODS

Patients undergoing ablation for persistent AF as part of the Stochastic Trajectory Analysis of Ranked signals mapping study were included. Novel CS electrogram characteristics including CS cycle length variability (CLV) and CS activation pattern stability (APS) and proportion of low voltage zones (LVZs) were reviewed as potential predictors for AF termination on ablation and freedom from AF/AT during follow-up. The relationship between localized driver characteristics and CS electrogram characteristics was also assessed.

RESULTS

Sixty-five patients were included. AF termination was achieved in 51 patients and 80% of patients were free from AF/AT during a follow-up of 29.5 ± 3.7 months. CS CLV of <30 ms, CS APS of ≥30% and proportion of LVZ < 30% showed high diagnostic accuracy in predicting AF termination on ablation and freedom from AF/AT during follow-up (CS CLV odds ratio [OR] 25.6, area under the curve [AUC] 0.91; CS APS OR 15.9, AUC 0.94; proportion of LVZs OR 21.4, AUC 0.88). These markers were independent predictors of AF termination on ablation and AF/AT recurrence during follow-up. Ablation of a smaller number of drivers that demonstrate greater dominance strongly correlate with greater CS organization.

CONCLUSION

Novel CS electrogram characteristics were independent predictors of AF termination and AF/AT recurrence during follow-up. These markers can potentially aid in predicting outcomes and guide ablation and follow-up strategies.

Driver characteristics associated with structurally and electrically remodeled atria in persistent atrial fibrillation

Background

Recent studies suggest persistent atrial fibrillation (AF) is maintained by localized focal or rotational electrical activations termed drivers.

Objective

The purpose of this study was to evaluate how left atrial (LA) dilation and time in AF impact persistent AF mechanisms.

Methods

Patients with persistent AF <2 years underwent electrocardiographic image mapping. Potential drivers (PDs) were defined as rotational wavefront activity ≥1.5 revolutions or focal activations. Distribution of PDs was recorded using an 18-segment model.

Results

One hundred patients were enrolled (age 61.3 ± 12.1 years). Of these patients, 47 were hypertensive, 14 had diabetes mellitus, and 10 had ischemic heart disease. AF duration was 8 [5-15] months. Median LA diameter was 39 [33-43] mm. Although LA dimensions did not correlate with overall PD burden or distribution, there was a modest correlation between increasing LA area (r = 0.235; P = .024) and LA volume (r = 0.216; P = .039) with proportion of PDs that were rotational. Although time in AF did not correlate with overall PD burden or distribution, there was a correlation between time in AF and the number of focal PDs (r = 0.203; P = .044). Female gender, increasing age, and hypertension also were associated with an increase in focal PDs.

Conclusion

This is the first study to demonstrate different AF mechanisms in patient subgroups. Greater understanding of patient-specific AF mechanisms may facilitate a tailored approach to AF mapping and ablation.

ECG-I Phenotyping of Persistent AF Based on Driver Burden and Distribution to Predict Response to Pulmonary Vein Isolation (PHENOTYPE-AF)

BACKGROUND

This prospective trial sought to phenotype persistent AF based on AF mechanisms using ECGI mapping to determine whether this would predict long term freedom from arrhythmia after pulmonary vein isolation (PVI).

METHODS

Patients with persistent AF of < 2 years duration underwent cryoballoon PVI. ECGI mapping was performed prior to PVI to determine potential drivers (PDs) defined as rotational activations completing ≥ 1.5 revolutions or focal activations. The co-primary end point was the association between (1) PD burden (defined as the number of PD occurrences) and (2) PD distribution (defined as the number of segments on an 18 segment model of the atria harbouring PDs) with freedom from arrhythmia at 1 year follow up.

RESULTS

Of 100 patients, 97 completed follow up and 52 (53.6%) remained in sinus rhythm off antiarrhythmic drugs. Neither PD burden nor PD distribution predicted freedom from arrhythmia (HR 1.01, 95% CI 0.99 - 1.03, p = 0.164; and HR 1.04, 95% CI 0.91 - 1.17, p = 0.591 respectively). Otherwise, the burden of rotational PDs, rotational stability, and the burden of PDs occurring at the pulmonary veins and posterior wall all failed to predict arrhythmia recurrence (all p > 0.10).

CONCLUSIONS

AF mechanisms as determined using ECGI mapping do not predict outcome after PVI for persistent AF. Further studies using different methodologies to characterise AF mechanisms are warranted. (NCT03394404) This article is protected by copyright. All rights reserved.

Iatrogenic cardiac perforation due to pacemaker and defibrillator leads: a contemporary multicentre experience

AIMS

To determine the incidence, clinical features, management, and outcomes of pacemaker (PM) and implantable cardioverter-defibrillator (ICD) lead cardiac perforation. Cardiac perforations due to PM and ICD leads are rare but serious complications. Clinical features vary widely and may cause diagnostic delay. Management strategies are non-guideline based due to paucity of data.

METHODS AND RESULTS

A multicentre retrospective series including 3 UK cardiac tertiary centres from 2016 to 2020. Patient, device, and lead characteristics were obtained including 6-month outcomes. Seventy cases of perforation were identified from 10 631 procedures; perforation rate was 0.50% for local implants. Thirty-nine (56%) patients were female, mean ( ± standard deviation) age 74 ( ± 13.8) years. Left ventricular ejection fraction 51 ( ± 13.2) %. Median time to diagnosis was 9 (range: 0-989) days. Computed tomography (CT) diagnosed perforation with 97% sensitivity. Lead parameter abnormalities were present in 86% (whole cohort) and 98.6% for perforations diagnosed >24 h. Chest pain was the commonest symptom, present in 46%. The management strategy was percutaneous in 98.6% with complete procedural success in 98.6%. Pericardial effusion with tamponade was present in 17% and was associated with significantly increased mortality and major complications. Anticoagulation status was associated with tamponade by multivariate analysis (odds ratio 21.7, 95% confidence interval: 1.7-275.5, P = 0.018).

CONCLUSIONS

Perforation was rare (0.50%) and managed successfully by a percutaneous strategy with good outcomes. Tamponade was associated with increased mortality and major complications. Anticoagulation status was an independent predictor of tamponade. Case complexity is highly variable and requires skilled operators with a multi-disciplinary approach to achieve good outcomes.

PolarX Cryoballoon metrics predicting successful pulmonary vein isolation: targets for ablation of atrial fibrillation

AIM

Evaluate the novel PolarX Cryoballoon in atrial fibrillation (AF) catheter ablation through a propensity-matched comparison with the Arctic Front Advance (AFA). The aim was also to identify cryoablation metrics that are predictive of successful pulmonary vein isolation (PVI) with the PolarX Cryoballoon.

METHODS AND RESULTS

This prospective multi-centre study included patients that underwent cryoablation for AF. All patients underwent PVI with reconnection assessed after a 30-min waiting period and adenosine. Safety, efficacy, and cryoablation metrics were compared between PolarX and a propensity-matched AFA cohort. Seventy patients were included with 278 veins treated. In total, 359 cryoablations were performed (1.3 ± 0.6 per vein) to achieve initial PVI with 205 (73.7%) veins isolating with a single cryoablation. Independent predictors for achieving initial PVI included temperature at 30 s [odds ratio (OR) 1.26; P = 0.003] and time to reach -40°C (OR 1.88; P < 0.001) with an optimal cut-off of ≤-38.5°C at 30 s [area under the curve (AUC) 0.79; P < 0.001] and ≤-40°C at ≤32.5 s (AUC 0.77; P < 0.001), respectively. Of the 278 veins, 46 (16.5%) veins showed acute reconnection. Temperature at 30 s (≤-39.5°C, OR 1.24; P = 0.002), nadir temperature (≤-53.5°C, OR 1.35; P = 0.003), and time to isolation (≤38.0 s, OR 1.18; P = 0.009) were independent predictors of sustained PVI. Combining two of these three targets was associated with reconnection in only 2-5% of PVs. Efficacy and safety of the PolarX Cryoballoon were comparable to AFA Cryoballoon, however, cryoablation metrics were significantly different.

CONCLUSIONS

The PolarX Cryoballoon has a different cryoablation profile to AFA Cryoballoon. Prospective testing of these proposed targets in large outcomes studies is required.

Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Aims

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP). We examined the associations of TSP‐related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our center from 2016 to 2020.

Methods and Results

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinized to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT. A total of 3239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP‐related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above‐median age [odds ratio (OR): 2.4 (1.19–4.2), p = .006] and those undergoing re‐do procedures [OR: 1.95 (1.29–3.43, p = .042] were at higher risk of TRCT. Of the operator‐dependent variables, choice of transseptal needle (Endrys vs. Brockenbrough, p > .1) or puncture sheath (Swartz vs. Mullins vs. Agilis vs. Vizigo vs. Cryosheath, all p > .1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk [OR: 4.42 (2.45–8.2), p = .001], whilst top quartile operator experience [OR: 0.4 (0.17–0.85), p = .002], transoesophageal echocardiogram [TOE prevalence: 26%, OR: 0.51 (0.11–0.94), p = .023], and use of the SafeSept transseptal guidewire [OR: 0.22 (0.08–0.62), p = .001] reduced TRCT risk. An increase in transseptal guidewire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R² = 0.72, p < .001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the risk of TRCT was reduced by operator experience, TOE‐guidance, and use of a transseptal guidewire, and was increased by patient age, re‐do procedures, and failure to cross the septum first pass.

Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility

Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel Na_V1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on Na_V1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings.

Remote Clinics and Investigations in Arrhythmia Services: What Have We Learnt During Coronavirus Disease 2019?

The coronavirus disease 2019 (COVID-19) pandemic has had a dramatic impact on the way that medical care is delivered. To minimise hospital attendance by both patients and staff, remote clinics, meetings and investigations have been used. Technologies including hand-held ECG monitoring using smartphones, patch ECG monitoring and sending out conventional Holter monitors have aided remote investigations. Platforms such as Google Meet and Zoom have allowed remote multidisciplinary meetings to be delivered effectively. The use of phone consultations has allowed outpatient care to continue despite the pandemic. The COVID-19 pandemic has resulted in a radical, and probably permanent, change in the way that outpatient care is delivered. Previous experience in remote review and the available technologies for monitoring have allowed the majority of outpatient care to be conducted without obviously compromising quality or safety.

ProGlide venous closure device facilitates early ambulation following cryoablation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Heart Foundation

Background

Same-day discharge following atrial fibrillation (AF) ablation is increasingly common. ProGlide device suture-mediated vascular closure (PD) offers a technique that may expedite mobilisation following large-bore (&gt;12F) venous access. The utility of PD closure following cryoablation of AF has not been reported.

Purpose

We sought to evaluate haemostasis and early ambulation outcomes in patients receiving the ProGlide compared with conventional techniques.

Methods

104 consecutive patients undergoing cryoballoon pulmonary vein isolation (PVI) for paroxysmal or persistent at a single high-volume institution were included. PVI was  performed via a standardised approach including sedation, ultrasound-guided vascular access for 14F Cryosheath and second 7F sheath, anticoagulation protocol, transeptal puncture, 28mm cryoballoon and nurse-led same-day discharge protocol. Haemostasis was achieved using the Perclose Proglide device (PD) in the 14F access point ("pre-closure" technique) plus 5 minutes manual pressure at the 7F sheath site. Alternatively, a figure-of-eight/Z-suture (ZS) was employed for closure according to operator preference. Protamine was used for heparin reversal in all patients. Safety outcomes of major bleeding, haematoma and minor bleeding were assessed. Time to ambulation (TTA), time to discharge (TTD), same-day discharge and complications at initial follow-up were measured.

Results

Overall, mean age was 64 ± 11 years, 65 (64%) were male and 52 (50%) of patients had paroxysmal AF, there were no significant differences between group demographics, with 31 patients (30%) in the PD group and 73 (70%) in the ZS group. All patients had uninterrupted oral anticoagulation throughout the periprocedural period. No major femoral bleeding complications requiring intervention occurred in either group. Haematomas occurred in none of the PD group compared with 2 (2.8%) in the ZS group. Incidence of minor bleeding was not significantly different between groups (PD: 3 [9.7%] vs ZS: 2 [2.7%], p = 0.155). Mean TTA was significantly shorter in the PD group (3.3 ± 1.1 vs 4.1 ± 1.7 hrs, p = 0.025). However, there was no significant difference in same-day discharge (PD: 25 [81%] vs ZS: 53 [73%], p = 0.386) and TTD (5.0 ± 3.6 vs 6.1 ± 4.2 hrs, p = 0.275) between groups. 1 patient complained of groin pain which delayed discharge in the ZS group not seen in the PD group. After a mean follow-up of 2.2 ± 1.4 months, there were no differences in major or minor complications.

Conclusion

Use of the Proglide closure device was associated with significant reductions in time to ambulation compared with Z-suture haemostasis following cryoablation of AF, and groin access complications were uncommon across groups.  PD closure may contribute to further streamlining patient pathways in day-case AF ablation.

Impact of adenosine on mechanisms sustaining persistent atrial fibrillation: Analysis of contact electrograms and non-invasive ECGI mapping data

BACKGROUND

We evaluated the effect of adenosine upon mechanisms sustaining persistent AF through analysis of contact electrograms and ECGI mapping.

METHODS

Persistent AF patients undergoing catheter ablation were included. ECGI maps and cycle length (CL) measurements were recorded in the left and right atrial appendages and repeated following boluses of 18 mg of intravenous adenosine. Potential drivers (PDs) were defined as focal or rotational activations completing ≥ 1.5 revolutions. Distribution of PDs was assessed using an 18 segment biatrial model.

RESULTS

46 patients were enrolled. Mean age was 63.4 ± 9.8 years with 33 (72%) being male. There was no significant difference in the number of PDs recorded at baseline compared to adenosine (42.1 ± 15.2 vs 40.4 ± 13.0; p = 0.417), nor in the number of segments harbouring PDs, (13 (11-14) vs 12 (10-14); p = 0.169). There was a significantly higher percentage of PDs that were focal in the adenosine maps (36.2 ± 15.2 vs 32.2 ± 14.4; p < 0.001). There was a significant shortening of CL in the adenosine maps compared to baseline which was more marked in the right atrium than left atrium (176.7 ± 34.7 vs 149.9 ± 27.7 ms; p < 0.001 and 165.6 ± 31.7 vs 148.3 ± 28.4 ms; p = 0.003).

CONCLUSION

Adenosine led to a small but significant shortening of CL which was more marked in the right than left atrium and may relate to shortening of refractory periods rather than an increase in driver burden or distribution. Registered on Clinicaltrials.gov: NCT03394404.

First experience of POLARx™ versus Arctic Front Advance™: An early technology comparison

INTRODUCTION

Cryoballoon ablation is an established technique to achieve pulmonary vein isolation in patients with atrial fibrillation (AF). Recently, a new manufacturer of cryoballoon achieved regulatory CE marking (POLARx™; Boston Scientific). We describe our early experience of using this new market entrant of the technology and describe procedural aspects in comparison to the incumbent Medtronic Arctic Front Advance™.

METHODS

We assessed the first 40 AF ablations performed with the POLARx catheter at the Barts Heart Centre. These patients were compared with a contemporaneous series of patients undergoing ablation by the same operators using the Arctic Front Advance. Procedural metrics were prospectively recorded.

RESULTS

A total of four operators undertook 40 cases using the POLARx catheter, compared with 40 cases using the Arctic Front Advance. Procedure times (60.0 vs. 60.0 min) were similar between the two technologies, however left atrial dwell time (35.0 vs 39.0 min) and fluoroscopy times (3.3 vs. 5.2 min) were higher with the POLARx. Measured nadir and isolation balloon temperatures were significantly lower with POLARx. Almost all veins were isolated with a median freezing time of 16.0 (POLARx) versus 15.0 (Arctic Front Advance) min. The rate of procedural complications was low in both groups.

CONCLUSION

The POLARx cryoballoon is effective for pulmonary vein isolation. Measured isolation and nadir temperatures are lower compared with the predicate Arctic Front Advance catheter. The technology appears similar in acute efficacy and has a short learning curve, but formal dosing studies may be required to prove equivalence of efficacy.

Long-term outcomes of index cryoballoon ablation or point-by-point radiofrequency ablation in patients with atrial fibrillation and systolic heart failure

Catheter ablation is an established effective approach for the treatment of atrial fibrillation (AF) in patients with heart failure, however, the role of cryoablation in this setting is unclear. Procedural success and left ventricular systolic dysfunction (LVEF) improvement in patients with LVEF ≤ 45% undergoing index catheter ablation with cryoablation were evaluated. Freedom from AF recurrence was seen in 43% rising to 59% following repeat procedure. There were significant improvements in LVEF and functional status at long-term follow-up. Results were comparable to a contemporaneous cohort of heart failure patients undergoing index ablation with radiofrequency ablation. Cryoablation is an effective first-line AF ablation approach in the setting of heart failure.

Ablation guided by STAR-mapping in addition to pulmonary vein isolation is superior to pulmonary vein isolation alone or in combination with CFAE/linear ablation for persistent AF

Introduction

The optimal ablation approach for persistent atrial fibrillation (AF) remains unclear.

Methods and Results

Objective was to compare the long‐term rates of freedom from AF/AT in patients that underwent STAR mapping guided ablation against outcomes of patients undergoing conventional ablation procedures.

Patients undergoing ablation for persistent AF as part of the Stochastic Trajectory Analysis of Ranked signals (STAR) mapping study were included. Outcomes following 'pulmonary vein isolation (PVI) plus STAR mapping guided ablation (STAR mapping cohort) were compared to patients undergoing PVI alone ablation during the same time period and also a propensity‐matched cohort undergoing PVI plus the addition of complex fractionated electrogram (CFAE) and/or linear ablation (“conventional ablation”). Rates of procedural AF termination and freedom from AF/AT during follow‐up were compared.

Sixty‐five patients were included in both the STAR cohort and propensity matched conventional ablation cohort. AF termination rates were significantly higher in the STAR cohort (51/65, 78.5%) than conventional ablation cohort (10/65, 15.4%) and PVI alone ablation cohort (13/50, 26.0%; STAR cohort vs. other 2 cohorts both p < .001). There was no significant difference in procedure time between the three cohorts. During ≥20 months follow‐up a lower proportion of patients had AF/AT recurrence in the STAR cohort (20.0%) compared with the conventional ablation cohort (50.8%) or the PVI alone ablation cohort (50.0%; both p < .05 compared to STAR cohort).

Conclusions

Outcomes of PVI plus STAR mapping guided ablation was superior to PVI alone or in combination with linear/CFAE ablation. A multicenter randomized controlled trial is planned to confirm these findings.

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms: results from a multicentre long-term registry

AIMS 

To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs).

METHODS AND RESULTS

Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03].

CONCLUSION 

Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences.

A Primary Prevention Clinical Risk Score Model for Patients With Brugada Syndrome (BRUGADA-RISK)

OBJECTIVES

The goal of this study was to develop a risk score model for patients with Brugada syndrome (BrS).

BACKGROUND

Risk stratification in BrS is a significant challenge due to the low event rates and conflicting evidence.

METHODS

A multicenter international cohort of patients with BrS and no previous cardiac arrest was used to evaluate the role of 16 proposed clinical or electrocardiogram (ECG) markers in predicting ventricular arrhythmias (VAs)/sudden cardiac death (SCD) during follow-up. Predictive markers were incorporated into a risk score model, and this model was validated by using out-of-sample cross-validation.

RESULTS

A total of 1,110 patients with BrS from 16 centers in 8 countries were included (mean age 51.8 ± 13.6 years; 71.8% male). Median follow-up was 5.33 years; 114 patients had VA/SCD (10.3%) with an annual event rate of 1.5%. Of the 16 proposed risk factors, probable arrhythmia-related syncope (hazard ratio [HR]: 3.71; p < 0.001), spontaneous type 1 ECG (HR: 3.80; p < 0.001), early repolarization (HR: 3.42; p < 0.001), and a type 1 Brugada ECG pattern in peripheral leads (HR: 2.33; p < 0.001) were associated with a higher risk of VA/SCD. A risk score model incorporating these factors revealed a sensitivity of 71.2% (95% confidence interval: 61.5% to 84.6%) and a specificity of 80.2% (95% confidence interval: 75.7% to 82.3%) in predicting VA/SCD at 5 years. Calibration plots showed a mean prediction error of 1.2%. The model was effectively validated by using out-of-sample cross-validation according to country.

CONCLUSIONS

This multicenter study identified 4 risk factors for VA/SCD in a primary prevention BrS population. A risk score model was generated to quantify risk of VA/SCD in BrS and inform implantable cardioverter-defibrillator prescription.

Prospective STAR-Guided Ablation in Persistent Atrial Fibrillation Using Sequential Mapping With Multipolar Catheters

BACKGROUND

A novel stochastic trajectory analysis of ranked signals (STAR) mapping approach to guide atrial fibrillation (AF) ablation using basket catheters recently showed high rates of AF termination and subsequent freedom from AF.

METHODS

This study aimed to determine whether STAR mapping using sequential recordings from conventional pulmonary vein mapping catheters could achieve similar results. Patients with persistent AF<2 years were included. Following pulmonary vein isolation AF drivers (AFDs) were identified on sequential STAR maps created with PentaRay, IntellaMap Orion, or Advisor HD Grid catheters. Patients had a minimum of 10 multipolar recordings of 30 seconds each. These were processed in real-time and AFDs were targeted with ablation. An ablation response was defined as AF termination or cycle length slowing ≥30 ms.

RESULTS

Thirty patients were included (62.4±7.8 years old, AF duration 14.1±4.3 months) of which 3 had AF terminated on pulmonary vein isolation, leaving 27 patients that underwent STAR-guided AFD ablation. Eighty-three potential AFDs were identified (3.1±1.1 per patient) of which 70 were targeted with ablation (2.6±1.2 per patient). An ablation response was seen at 54 AFDs (77.1% of AFDs; 21 AF termination and 33 cycle length slowing) and occurred in all 27 patients. No complications occurred. At 17.3±10.1 months, 22 out of 27 (81.5%) patients undergoing STAR-guided ablation were free from AF/atrial tachycardia off antiarrhythmic drugs.

CONCLUSIONS

STAR-guided AFD ablation through sequential mapping with a multipolar catheter effectively achieved an ablation response in all patients. AF terminated in a majority of patients, with a high freedom from AF/atrial tachycardia off antiarrhythmic drugs at long-term follow-up. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02950844.

With our powers combined: Does the pooled analysis of existing randomized data regarding treatment of atrial fibrillation in heart failure settle the case for catheter ablation?

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Use of a multi-electrode radiofrequency balloon catheter to achieve pulmonary vein isolation in patients with paroxysmal atrial fibrillation: 12-Month outcomes of the RADIANCE study

BACKGROUND

The RADIANCE first-in-man study evaluated acute (3-month) safety and design concept in terms of utility of a new multi-electrode radiofrequency (RF) balloon catheter (HELIOSTAR, Biosense Webster) to achieve pulmonary vein isolation (PVI). After study conclusion, a subset of patients was followed up to 12 months.

METHODS

Patients with drug refractory paroxysmal atrial fibrillation were enrolled. Neurological assessment, cardiac and cerebral magnetic resonance imagings were performed pre and post procedure. Ablation was delivered at 15 Watts to each PV for 60 seconds (electrodes adjacent to the posterior wall limited to 20 seconds). Adenosine or isoproterenol was administered to confirm PVI. Esophageal endoscopy was performed 48 hours post procedure. Patients were clinically followed up for 12 months.

RESULTS

Thirty-nine patients underwent catheter ablation from four centers. Mean age was 60.7 ± 10.0 years with 23 (57.5%) being male. Confirmation of PVI was performed in all PVs treated (152/152). Confirmation of isolation after one delivery was performed solely on 137 of 152 PVs of which 79.6% (109/137) achieved isolation with a single delivery of RF energy. Acute PV reconnection was seen in 4.6% (7/150) of PVs. Freedom from documented atrial arrhythmia at 12 months in those followed up was 86.4% (32/37). A total of 75.7% (28/37) of patients were free from atrial arrhythmia and off antiarrhythmic medications.

CONCLUSION

The HELIOSTAR RF balloon catheter allows for rapid and safe PVI with majority of PVs only requiring one application.

Drivers in AF colocate to sites of electrogram organization and rapidity: Potential synergy between spectral analysis and STAR mapping approaches in prioritizing drivers for ablation

INTRODUCTION

Stochastic trajectory analysis of ranked signals (STAR) mapping has recently been used to ablate persistent atrial fibrillation (AF) with high rates of AF termination and long-term freedom from AF in small, single-arm studies. We hypothesized that rapidity and organization markers would correlate with early sites of activation (ESA).

METHODS

Patients undergoing persistent AF ablation as part of the STAR mapping study were included. Five-minute unipolar basket recordings used to create STAR maps were used to determine the minimum-cycle length (Min-CL) and CL variability (CLV) at each electrode to identify the site of the fastest Min-CL and lowest CLV across the left atrium (LA). The location of ESA targeted with ablation was compared with these sites. Dominant frequency was assessed at ESA and compared with that of neighboring electrodes to assess for regional gradients.

RESULTS

Thirty-two patients were included with 83 ESA ablated, with an ablation response at 73 sites (24 AF termination and 49 CL slowing ≥30 ms). Out of these, 54 (74.0%) and 56 (76.7%) colocated to sites of fastest Min-CL and lowest CLV, respectively. Regional CL and frequency gradients were demonstrable at majority of ESA. ESA colocating to sites of fastest Min-CL and lowest CLV were more likely to terminate AF with ablation (odds ratio, 34 and 29, respectively, P = .02). These showed a moderate sensitivity (74.0% Min-CL and 75.3% CLV) and specificity (66.7% Min-CL and 76.9% CLV) in predicting ESA with an ablation response.

CONCLUSIONS

ESA correlate with rapidity and organization markers. Further work is needed to clarify any role for spectral analysis in prioritizing driver ablation.

Impact of pulmonary vein isolation on mechanisms sustaining persistent atrial fibrillation: Predicting the acute response

BACKGROUND

Noninvasive mapping identifies potential drivers (PDs) in atrial fibrillation (AF). We analyzed the impact of pulmonary vein isolation (PVI) on PDs and whether baseline PD pattern predicted termination of AF.

METHODS

Patients with persistent AF less than 2 years underwent electrocardiographic imaging mapping before and after cryoballoon PVI. We recorded the number of PD occurrences, characteristics (rotational wavefronts ≥ 1.5 revolutions or focal activations), and distribution using an 18-segment atrial model.

RESULTS

Of 100 patients recruited, PVI terminated AF in 15 patients; 21.3% ± 9.1% (8.7 ± 4.8) of PDs occurred at the pulmonary veins (PVs) and posterior wall. PVI had no impact on PD occurrences outside the PVs and posterior wall (33.2 ± 12.9 vs 31.6 ± 12.5; P = .164), distribution over the remaining 13 segments (9 [8-11] vs 9 [8-10]; P = .634), the proportion of PDs that was rotational (82.9% ± 9.7% vs 83.6% ± 10.1%; P = .496), or temporal stability (2.4 ± 0.4 vs 2.4 ± 0.5 rotations; P = .541). Fewer focal PDs (area under the curve, 0.683; 95% CI, 0.528-0.839; P = .024) but not rotational PDs (P = .626) predicted AF termination with PVI.

CONCLUSIONS

PVI did not have a global impact on PDs outside the PVs and posterior wall. Although fewer focal PDs predicted termination of AF with PVI, the burden of rotational PDs did not. It is accepted though not all PDs are necessarily real or important. Outcome data are needed to confirm whether noninvasive mapping can predict patients likely to respond to PVI.

Impact of Body Mass Index on the Outcomes of Catheter Ablation of Atrial Fibrillation: A European Observational Multicenter Study

Background Outcomes of catheter ablation of atrial fibrillation (AF) are variable and the predictors of success require further elucidation since the identification of correctable risk factors could help to optimize therapy. We aimed to assess the impact of body mass index (BMI) in the overall safety and efficacy of catheter ablation of AF, with emphasis on the use of cryoballoon ablation and novel oral anticoagulants. Methods and Results There were 2497 consecutive patients undergoing catheter ablation of AF in 7 European high volume centers were stratified according to BMI (normal weight <25 kg/m2, pre-obese 25-30 kg/m2, obesity 30-35 kg/m2, and morbid obesity ≥35 kg/m2) and comparisons of procedural outcomes evaluated. Pre-obese and obese patients presented more comorbidities (hypertension, diabetes mellitus, and sleep apnea), and had higher rates of non-paroxysmal AF ablation procedures. The rate of atrial 12-month arrhythmia relapse increased alongside with BMI (35.2%, 35.7%, 43.6%, and 48.0% P<0.001). During a median follow-up of 18.8 months (interquartile range 11-28), after adjusting for all baseline differences, BMI was an independent predictor of relapse (hazard ratio=1.01 per kg/m2; 95% CI 1.01-1.02; P=0.002), adding incremental predictive value to obstructive sleep apnea. BMI was not a predictor for any of the reported complications. Using novel oral anticoagulants and cryoballoon ablation was safe and efficacy was comparable with vitamin-K antagonists and radiofrequency ablation. Conclusions Obese patients present with a more adverse comorbidity profile, more advanced forms of AF, and have lower chances of being free from AF relapse after ablation. Use of novel oral anticoagulants and cryoballoon ablation may be an option in this patient group.

A Novel Mapping System for Panoramic Mapping of the Left Atrium: Application to Detect and Characterize Localized Sources Maintaining Atrial Fibrillation

Objectives

This study sought to use a novel panoramic mapping system (CARTOFINDER) to detect and characterize drivers in persistent atrial fibrillation (AF).

Background

Mechanisms sustaining persistent AF remain uncertain.

Methods

Patients undergoing catheter ablation for persistent AF were included. A 64-pole basket catheter was used to acquire unipolar signals, which were processed by the mapping system to generate wavefront propagation maps. The system was used to identify and characterize potential drivers in AF pre- and post-pulmonary vein (PV) isolation. The effect of ablation on drivers identified post-PV isolation was assessed.

Results

Twenty patients were included in the study with 112 CARTOFINDER maps created. Potential drivers were mapped in 19 of 20 patients with AF (damage to the basket and noise on electrograms was present in 1 patient). Thirty potential drivers were identified all of which were transient but repetitive; 19 were rotational and 11 focal. Twenty-six drivers were ablated with a predefined response in 22 of 26 drivers: AF terminated with 12 and cycle length slowed (≥30 ms) with 10. Drivers with rotational activation were predominantly mapped to sites of low-voltage zones (81.8%). PV isolation had no remarkable impact on the cycle length at the driver sites (138.4 ± 14.3 ms pre-PV isolation vs. 137.2 ± 15.2 ms post-PV isolation) and drivers that had also been identified on pre-PV isolation maps were more commonly associated with AF termination.

Conclusions

Drivers were identified in almost all patients in the form of intermittent but repetitive focal or rotational activation patterns. The mechanistic importance of these phenomena was confirmed by the response to ablation.

STAR mapping method to identify driving sites in persistent atrial fibrillation: Application through sequential mapping

INTRODUCTION

The optimal way to map localized drivers in persistent atrial fibrillation (AF) remains unclear. The objective of the study was to apply a novel vector mapping approach called Stochastic Trajectory Analysis of Ranked signals (STAR) in AF.

METHODS AND RESULTS

Patients having persistent AF ablation were included. Early sites of activation (ESA) identified on global STAR maps created with basket catheters were used to guide AF ablation post-pulmonary vein isolation (PVI). All patients also had sequential STAR maps created with ≥10 PentaRay recordings of 30 seconds. These were validated offline in their ability to identify the ESA targeted with a study-defined ablation response (AF termination or cycle length [CL] slowing of ≥30 ms). Thirty-two patients were included in whom 92 ESA were identified on the global STAR maps, with 73 of 83 targeted sites demonstrating an ablation response (24 AF termination and 49 CL slowing). Sixty-one out of 73 (83.6%) ESA were also identified on the sequential STAR maps. These showed greater consistency (P < .001), were seen pre- and post-PVI (P < .001) and were more likely to be associated with AF termination on ablation (P = .007). The sensitivity and specificity of sequential mapping for the detection of ESA with an ablation response was 84.9% (95% confidence interval [CI] = 74.6-92.2) and 90.0% (95% CI = 55.5-99.8), respectively. During a follow-up of 19.4 ± 3.7 months, 28 (80%) patients were free from AF/atrial tachycardia.

CONCLUSIONS

STAR mapping consistently identified ESA in all patients and the ablation response was compatible with ESA being driver sites. Mechanistically important ESA were successfully identified using sequential recordings.

P6586Brugada syndrome risk stratification - Evaluation of clinical and ECG risk markers in a multicenter international primary prevention cohort

Background

Risk stratification for sudden cardiac death (SCD) in Brugada syndrome (BrS) is a significant challenge.

Purpose

To evaluate the importance of clinical and ECG factors in the likelihood of developing significant ventricular arrhythmias (VAs)/SCD in BrS patients.

Methods

VA occurrence during follow-up were assessed and the role of 16 proposed clinical or ECG risk markers evaluated in a multicenter international study of BrS patients and no history of cardiac arrest. Markers with predictive power were identified and incorporated into a risk score model.

Results

Across 15 international centers, 1084 patients were included. During a follow-up of 5.3 years (IQR 2.7–9.0 years)- 110 patients had VA occurrence (10.1%) with an annual event rate of 1.7% (95% CI 1.4–2.0). Of the 16 proposed risk factors, diagnosis by family screening of sudden cardiac death (HR 4.65; p<0.001), probable arrhythmia related syncope (HR 3.88, p<0.001), type 1 spontaneous ECG (HR 3.56; p<0.001), Early Repolarisation (HR 3.15; p<0.001) and type 1 Brugada pattern in peripheral leads (HR 2.42; p<0.001) were associated with a higher VA occurrence risk during follow-up. These 5 variables were incorporated into a risk score model whereby each variable was allocated a point score based on the variable's predictive strength. The total points obtained from the model for a patient could then be translated into the predicted VA occurrence risk during follow-up (Figure 1). The model showed a sensitivity of 63.5% (95% CI 50.0–76.9) and specificity of 84.2% (95% CI 81.1–87.1) in predicting VA occurrence at 5-years follow-up. The model showed a greater discriminative power compared to an existing model (AUC 0.83 vs. 0.71; p<0.001).

Figure 1

Conclusions

This multicenter study with longest reported follow-up to date identified 5 risk markers for VA occurrence. Utilizing these markers in a risk score model can aid BrS risk stratification to enable individualized risk prediction and ICD prescription.

Ablation in Persistent Atrial Fibrillation Using Stochastic Trajectory Analysis of Ranked Signals (STAR) Mapping Method

OBJECTIVES

The aim of this study was to demonstrate that a stochastic vector-based mapping approach could guide ablation of atrial fibrillation (AF) drivers as evidenced by ablation response and long-term follow-up outcomes.

BACKGROUND

The optimal method for mapping and ablation of AF drivers is yet to be defined.

METHODS

Patients undergoing persistent AF ablation were recruited. Patients underwent pulmonary vein isolation (PVI) with further ablation guided by the stochastic trajectory analysis of ranked signals (STAR) mapping method. The proportion of the time an electrode's activation was seen to precede its neighboring electrodes activation was used to determine early sites of activation (ESA). A positive ablation response at ESA was defined as AF termination or cycle length slowing of ≥30 ms. Clinical outcome was defined as recurrence of AF/atrial tachycardia (AT) during a follow-up of 12 months.

RESULTS

Thirty-five patients were included (AF duration of 14.4 ± 5.3 months). After PVI, an average of 2.6 ± 0.8 ESA were ablated per patient with study-defined ablation response achieved in all patients. Of the 86 STAR maps created post-PVI, the same ESA was identified on 73.8 ± 26.1% of maps. ESA that resulted in AF termination were more likely to be identified on both pre- and post-PVI maps than those associated with cycle length slowing (23 of 24 vs. 16 of 49; p < 0.001). During a follow-up of 18.5 ± 3.7 months, 28 (80%) patients were free from AF/AT.

CONCLUSIONS

The ablation response at ESA suggests they may be drivers of AF. Ablation guided by STAR mapping produced a favorable clinical outcome and warrants testing through a randomized controlled trial. (Identification, Electro-mechanical Characterisation and Ablation of Driver Regions in Persistent Atrial Fibrillation [STAR MAPPING]; NCT02950844).

Development, in vitro validation and human application of a novel method to identify arrhythmia mechanisms: The stochastic trajectory analysis of ranked signals mapping method

Introduction

Methods and Results

Conclusions