Rationale and design of a randomised trial of intravenous iron in patients with heart failure

OBJECTIVES

For patients with a reduced left ventricular ejection fraction (LVEF) heart failure with reduced ejection fraction (HFrEF) and iron deficiency, administration of intravenous iron improves symptoms, exercise capacity and may in the following 12 months, reduce hospitalisations for heart failure. The Effectiveness of Intravenous iron treatment versus standard care in patients with heart failure and iron deficiency (IRONMAN) trial evaluated whether the benefits of intravenous iron persist in the longer term and impact on morbidity and mortality.

METHODS

IRONMAN is a prospective, randomised, open-label, blinded endpoint (PROBE) event-driven trial. Patients aged ≥18 years with HFrEF (LVEF ≤45%) and evidence of iron deficiency (ferritin <100 µg/L and/or TSAT <20%) were enrolled if they had either a current or recent hospitalisation for heart failure or elevated plasma concentrations of a natriuretic peptide. Participants were randomised to receive, or not to receive, intravenous ferric derisomaltose in addition to guideline-recommended therapy for HFrEF. Every 4 months, intravenous iron was administered if either ferritin was <100 µg/L or, provided ferritin was ≤400 µg/L, TSAT was <25%. The primary endpoint is a composite of total hospitalisations for heart failure and cardiovascular death. Hospitalisation and deaths due to infection are safety endpoints.

RESULTS

Trial recruitment was completed across 70 UK hospital sites in October 2021. Participants were followed until the end of March 2022. We plan to report the results by November 2022.

CONCLUSIONS

IRONMAN will determine whether repeated doses of intravenous ferric derisomaltose are beneficial and safe for the long-term treatment of a broad range of patients with HFrEF and iron deficiency.

TRIAL REGISTRATION NUMBER

NCT02642562.

Transvenous or subcutaneous implantable cardioverter defibrillator: a review to aid decision-making

The implantable cardioverter-defibrillator (ICD) is a proven treatment for preventing sudden cardiac death. Transvenous leads are associated with significant mortality and morbidity, and the subcutaneous ICD (S-ICD) addresses this. However, it is not without limitations, in particular the absence of anti-tachycardia pacing. The decision of which device is most suitable for an individual patient is often complex. Here, we review the relative merits and weaknesses of both the transvenous and S-ICD. We summarise the available evidence for each device in particular patient cohorts, namely: ischaemic and non-ischaemic cardiomyopathy, idiopathic ventricular fibrillation, Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy.

Impact of Adenosine on Wavefront Propagation in Persistent Atrial Fibrillation: Insights From Global Noncontact Charge Density Mapping of the Left Atrium

Background

Adenosine shortens action potential duration and refractoriness and provokes atrial fibrillation. This study aimed to evaluate the effect of adenosine on mechanisms of wavefront propagation during atrial fibrillation.

Methods and Results

The study included 22 patients undergoing catheter ablation for persistent atrial fibrillation. Left atrial mapping was performed using the AcQMap charge density system before and after administration of intravenous adenosine at 1 or more of 3 time points during the procedure (before pulmonary vein isolation, after pulmonary vein isolation, and after nonpulmonary vein isolation ablation). Wave‐front propagation patterns were evaluated allowing identification and quantification of localized rotational activation (LRA), localized irregular activation, and focal firing. Additional signal processing was performed to identify phase singularities and calculate global atrial fibrillation cycle length and dominant frequency. A total of 35 paired maps were analyzed. Adenosine shortened mean atrial fibrillation cycle length from 181.7±14.3 to 165.1±16.3, (mean difference 16.6 ms; 95% CI, 11.3–21.9, P<0.0005) and increased dominant frequency from 6.0±0.7 Hz to 6.6±0.8 Hz (95% CI, 0.4–0.9, P<0.0005). This was associated with a 50% increase in the number of LRA occurrences (16.1±7.6–24.2±8.1; mean difference 8.1, 95% CI, 4.1–12, P<0.0005) as well as a 20% increase in the number of phase singularities detected (30.1±7.8–36.6±9.3; mean difference 6.5; 95% CI, 2.6–10.0, P=0.002). The percentage of left atrial surface area with LRA increased with adenosine and 42 of 70 zones (60%) with highest density of LRA coincided with high density LRA zones at baseline with only 28% stable across multiple maps.

Conclusions

Adenosine accelerates atrial fibrillation and promotes rotational activation patterns with no impact on focal activation. There is little evidence that rotational activation seen with adenosine represents promising targets for ablation aimed at sites of stable arrhythmogenic sources in the left atrium.

Patients’ perspective on a pill-in-the-pocket oral anticoagulation as an alternative stroke prevention strategy in atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Oral anticoagulation (OAC) decisions are binary: if atrial fibrillation (AF) is detected and additional risk factors are presented, lifelong continuous OAC is recommended regardless of AF burden or temporal patterns. AF-related stroke risk appears to be lower in patients with paroxysmal AF and, therefore, indefinite OAC may have limited benefit whilst exposing patients to a significant bleeding risk. ‘Pill-in-the-pocket’ OAC during and shortly after AF challenges this dichotomous approach to OAC and is being explored in several pilot studies as an alternative AF-related stroke prevention strategy.

Purpose

This patient questionnaire sought to examine patients’ perspective of ‘pill-in-the pocket’ OAC strategy.

Methods

An 8-question interactive survey was developed in collaboration with AF Association (UK based charity) and included a short description of implantable cardiac monitors main features, implant procedure and associated risks. The survey was available online on the AF Association website from 30/09/2020 to 2/11/2020.

Results

Overall, 321 participants with an underlying diagnosis of AF replied to the online survey over the course of four and half weeks. The majority (82%) were taking direct oral anticoagulants. Just over two thirds of patients had concerns regarding bleeding side-effects from taking OAC and, approximately, a quarter had experienced a bleeding event (1.5% major bleeding and 24.2% minor bleeding). When asked if it was shown to be safe to monitor their heart rhythm continuously and take anticoagulants only during an episode of AF and for a small number of days afterwards (i.e. ‘pill-in-the-pocket’), 53.7% of participants would use guided by an implantable cardiac monitored. Slightly lower number of patients (48%) would take pill-in-the-pocket oral anticoagulation guided by a wearable device. In the comments the main reasons not to pursue ‘pill-in-the-pocket’ were permanent AF, previous thromboembolic events and concerns regarding reliability of monitoring technologies. In contrast, those who were receptive to this alternative approach had previous bleeding episodes, had very infrequent AF episodes and wanted to reduce their medication burden.

Conclusion

Approximately half of patients with choose a ‘pill-in-the-pocket’ OAC guided by daily rhythm monitoring with an ICM if proven to be safe and effective at reducing thromboembolism.

Diagnostic accuracy of the Confirm-Rx atrial fibrillation detection algorithm in real-world patients

Funding Acknowledgements

Type of funding sources: None.

Introduction

Continuous rhythm monitoring with implantable cardiac monitors (ICMs) is commonly used to detect and characterise atrial fibrillation (AF) episodes. The Confirm Rx™ with SharpSense™ technology offers four new discriminators and second pass analysis aimed at enhancing detection and improving accuracy for cardiac arrhythmias. This study sought to investigate the diagnostic accuracy of the Confirm Rx™ AF detection algorithm in a UK cohort of ‘real-world’ patients.

Methods

This multicentre retrospective study included patients with Confirm Rx™ and at least one episode of AF&gt;6 minutes from August 2018 to August 2021 across 9 UK hospitals. Each episode had a corresponding 120-second electrogram (EGM) and heart rate scatterplot. One cardiologist manually adjudicated all EGMs as ‘True-AF’ or ‘False-positive. To assess for intra and inter-observer variability, 10% of the EGMs were reviewed. Diagnostic accuracy was determined by calculating the raw and patient-averaged positive predictive value (PPV) for AF episode of different durations and implant indications.

Results

During the study 232 patients met inclusion criteria with a total of 315 patient-years of follow-up. 16,320 individual AF episodes were adjudicated; intra- and interobserver variability was excellent (Cohen’s kappa 0.85 and 0.86, respectively). The rate of ‘True-AF’ detection was 3.19 episodes per month corresponding to a raw PPV of 74.5% for the whole cohort. The highest number of episodes per months was observed in patients with a Confirm-Rx for palpitations (5.1) and suspected AF (5.8) but only approximately half of these represented ‘True-AF’ episodes (Figure 1). Patients with known AF had the lowest rate of AF episodes (1.6 episodes per month) but the highest proportion of ‘True-AF’ episodes (PPV of 95.5%). A clear trend of improving diagnostic accuracy was seen with longer AF episodes (Table1). AF&gt;3 hours had a PPV above 94% and all episodes lasting longer than 24 hours were ‘True-AF’. For AF episode of short duration, the PPV varied with the population being monitored; however, for longer AF episodes the PPV increased significantly and irrespective of implant indication (Figure 2).

Conclusion

Overall, the Confirm Rx™ ICM diagnostic accuracy was modest for all AF episodes lasting longer than 6 minutes (74.5%) but improved considerably for longer AF episodes irrespective of implant indication.

Clinical utility of non-contact charge density 'SuperMap' algorithm for the mapping and ablation of organized atrial arrhythmias

AIMS

SuperMap is a novel non-contact algorithm for the mapping of organized atrial arrhythmias. We prospectively evaluated SuperMap during mapping and ablation of atrial tachycardias (ATs) and paced rhythms and compared to conventional high-density contact mapping.

METHODS AND RESULTS

Consecutive patients undergoing SuperMap guided ablation of pre-existing ATs or AT developed during atrial fibrillation ablation procedures were included together with maps obtained during pacing to assess block in linear lesions. The time taken to obtain diagnostic maps was measured together with the number of electrogram (EGM) points and accuracy compared to the arrhythmia diagnosis confirmed using a combination of map findings, entrainment, and response to ablation. In a subgroup of patients, concurrent contact mapping was performed with contact and SuperMap analysed by separate operators blinded to the other technique. The time taken to generate a diagnostic map, EGM number, and map accuracy was compared. Thirty-one patients (62 maps) were included with contact mapping performed in 19 [39 maps (33 for AT)]. SuperMap acquisition time was 314 s [interquartile range (IQR) 239-436]. The median number of EGM points used per map was 5399 (IQR 3279-8677). SuperMap was faster than contact mapping [394 ± 219 s vs. 611 ± 331 s; difference 217 s, 95% confidence interval (CI) 116-318, P < 0.0005]. The number of EGM points used per map was higher for SuperMap (7351 ± 5054 vs. 3620 ± 3211; difference 3731, 95% CI 2073-5388, P < 0.0005). SuperMap and contact mapping were accurate in 92% and 85% of maps, respectively, P = 0.4805.

CONCLUSION

SuperMap non-contact charge density mapping is a rapid and reliable approach to guide the ablation of complex atrial arrhythmias.

Long-term outcomes and periprocedural safety and efficacy of percutaneous left atrial appendage closure in a United Kingdom tertiary center: An 11-year experience

BACKGROUND

Left atrial appendage occlusion (LAAO) has been widely adopted as a strategy for stroke prevention in patients with atrial fibrillation ineligible for oral anticoagulation.

OBJECTIVE

The purpose of this study was to explore longer-term "real-world" safety and efficacy outcomes in patients undergoing LAAO given varied practices in antithrombotic regimens and adoption of same-day discharge.

METHODS

Analysis of acute procedural and long-term outcome data was performed for all patients undergoing LAAO implant in a United Kingdom tertiary center over an 11-year period. Rates of adverse events were calculated and compared to predicted rates in historical cohorts according to CHA₂DS₂-VASc and HAS-BLED scores.

RESULTS

Device implantation was attempted in 229 patients, with an acute procedural success rate of 98.2% and low rate of major procedural complications of 2.6% at 30 days, including 1.3% procedure-related mortality. In the last year of enrollment, 75% of patients were discharged on the same day of the procedure. A strategy of early cessation of antithrombotic therapy was adopted, with a low rate of device-related thrombus. Over total follow-up of 889 patient-years, there were low rates of thromboembolic events (2.2/100 patient-years) and of significant bleeding events (intracranial bleed 0.6/100 patient-years; nonprocedural major bleeding 2.3/100 patient-years).

CONCLUSION

LAAO with a same-day discharge strategy and early cessation of antiplatelet therapy seems to be safe and effective in reducing the risk of stroke and major bleeding over mean follow-up approaching 4 years. Although these data are reassuring, results from randomized trials with strict shorter periods of postprocedural antithrombotic therapy are eagerly awaited.

Periprocedural safety and efficacy after left atrial appendage closure in a large UK tertiary centre: 10-year experience

Funding Acknowledgements

Type of funding sources: None.

Introduction

Left atrial appendage (LAA) thrombus is responsible for up 90% of atrial fibrillation (AF) related ischaemic strokes. Mechanical closure of the LAA is an alternative stroke prevention strategy in patients with non-valvular AF who are at a high risk of bleeding. LAA morphology is highly variable which may affect acute procedural success rates.

Purpose

This study sought to examine the periprocedural safety and efficacy, and short-term outcomes in patients undergoing left atrial appendage occlusion (LAAO) device implantation in a large UK tertiary centre.

Methods

This retrospective study included all patients listed for a LAAO device in our institution from January 2010 to December 2020. Medical notes, procedural and imaging reports were reviewed and adverse event rates were calculated at discharge, 30 and 90 days. A Cox regression model was used for multivariable analysis with pre-specified covariates to assess outcomes at 90 days.

Results

Of 237 patients listed for a LAAO device, 8 (3.4%) had a LAA thrombus and the procedure was abandoned (4 had a successful implant at a later date). In 225 (94.9%) patients a LAAO device was implanted and 4 (1.7%) had unsuitable anatomy precluding device deployment. Seventy-two percent were male, age 74 ± 8 years, BMI 27 ± 6 kg/m2, CHA2DS2-VASc score 4.4 ± 1.2, HASBLED score 3.2 ± 0.8 and at high risk of stroke (98 ischaemic strokes and 129 haemorrhagic strokes) and bleeding (151 major or life-threatening bleeding episodes).  The mean procedural and fluoroscopy time were 52.5 ± 30.5 and 8.0 ± 5.9 minutes, respectively. Three different LAAO devices were used (136 Watchman, 54 Watchman FLX and 35 Amplatzer Cardiac Plug) with no significant difference in acute procedural success (97.8%, 98.2% and 94.4%, p = 0.41, respectively). Complete seal was achieved in 202 (92%) patients with only 1 (0.4%) moderate leak. Procedure-related mortality was 1.3% and non-fatal serious adverse events occurred in 5 (2.1%) patients. At 90 days, 28 patients experienced an adverse event (KM 12.5%; 95% CI, 8%-16.1%) and 16 patients suffered a serious adverse event (KM 7.1%; 95% CI, 3.7%-10.4%). In a covariate-adjusted Cox model, CHA2DS2-VASc score less than 4 had hazard ratio of 0.21 (95% CI, 0.06 -0.71, p = 0.01) for serious events at 90 days.

Conclusion

The acute procedural success rate was high (97%) with a low number of periprocedural complications. Serious adverse events at both 30 and 90-days were low in keeping with other published registries. Abstract Figure.

Caged-in: Successful percutaneous closure of left atrial appendage with Watchman-FLX in the presence of proximal thrombus

Percutaneous mechanical closure of the left atrial appendage (LAA) is a valuable stroke prevention strategy in patients with atrial fibrillation and contraindication to oral anticoagulation. LAA thrombus is a common finding in patients with atrial fibrillation and frequently fails to resolve despite therapeutic anticoagulation. In this scenario, LAA occlusion device implant is generally discouraged due to the high risk of thrombus dislodgement and embolization; however, alternative management options are limited. We report the first case of a successful LAA occlusion device (Watchman-FLX) implant in the presence of a proximal thrombus.

Individualized ablation strategy to treat persistent atrial fibrillation: Core-to-boundary approach guided by charge-density mapping

BACKGROUND

Noncontact charge-density mapping allows rapid real-time global mapping of atrial fibrillation (AF), offering the opportunity for a personalized ablation strategy.

OBJECTIVE

The purpose of this study was to compare the 2-year outcome of an individualized strategy consisting of pulmonary vein isolation (PVI) plus core-to-boundary ablation (targeting the conduction pattern core with an extension to the nearest nonconducting boundary) guided by charge-density mapping, with an empirical PVI plus posterior wall electrical isolation (PWI) strategy.

METHODS

Forty patients (age 62 ± 12 years; 29 male) with persistent AF (10 ± 5 months) prospectively underwent charge-density mapping-guided PVI, followed by core-to-boundary stepwise ablation until termination of AF or depletion of identified cores. Freedom from AF/atrial tachycardia (AT) at 24 months was compared with a propensity score-matched control group of 80 patients with empirical PVI + PWI guided by conventional contact mapping.

RESULTS

Acute AF termination occurred in 8 of 40 patients after charge-density mapping-guided PVI alone and in 21 of the remaining 32 patients after core-to-boundary ablation in the study cohort, compared with 8 of 80 (10%) in the control cohort (P <.001). On average, 2.2 ± 0.6 cores were ablated post-PVI before acute AF termination. At 24 months, freedom from AF/AT after a single procedure was 68% in the study group vs 46% in the control group (P = .043).

CONCLUSION

An individualized ablation strategy consisting of PVI plus core-to-boundary ablation guided by noncontact charge-density mapping is a feasible and effective strategy for treating persistent AF, with a favorable 24-month outcome.

P978Core to block: a new ablation strategy for treating persistent atrial fibrillation

Background

Ablation strategy targeting the core of atrial fibrillation (AF) rotors alone can lead to both stabilisation and destabilisation of rotational activity. Non-contact dipole density mapping system is designed to rapidly identify dynamic regional atrial activation patterns of interest (API) during AF.

Purpose

To assess the feasibility of an ablation strategy consisted of pulmonary vein isolation + targeting the core of APIs followed by linear ablation to the nearest non-conducting boundary to treat persistent AF.

Methods

The ablation strategy includes: 1. Antral pulmonary vein electrical isolation (APVI); 2. APIs (focal, localised rotational and localised irregular activation; Figure1) detection by dipole density mapping; 3. API core ablation followed by linear ablation to the nearest non-conduction barrier (APVI/mitral valve); 4. repeat step 2 and 3 in LA (RA, if necessary) until sinus rhythm is achieved.

Results

Consecutive 40 persistent AF patients (mean 62±12 years, 29 males, AF duration 10±4 months, LA diameter 42±9 mm) were included from 2 centres. An average of 2.0±0.7 APIs per patient were targeted post-APVI. Acute AF termination by ablation was achieved in 27/40 (68%) patients. The mean ablation time of APVI and “Core to block” was 33±12 mins and 31±22 mins, respectively. No major complication occurred. During a mean follow-up of 12±5 months, 32/40 patients (80%) maintained sinus rhythm.

Conclusion

APVI + “Core to block” guided by the dipole density mapping is feasible for treating persistent AF. A larger randomised study is needed to test the effectiveness of this ablation strategy.

Acknowledgement/Funding

None