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.

DOACs vs Vitamin K Antagonists During Cardiac Rhythm Device Surgery: A Multicenter Propensity-Matched Study

BACKGROUND

There is a paucity of data comparing vitamin K antagonists (VKAs) to direct oral anticoagulants (DOACs) at the time of cardiac implantable electronic device (CIED) surgery. Furthermore, the best management of DOACs (interruption vs continuation) is yet to be determined.

OBJECTIVES

This study aimed to compare the incidence of device-related bleeds and thrombotic events based on anticoagulant type (DOAC vs VKA) and regimen (interrupted vs uninterrupted).

METHODS

This was an observational multicenter study. We included patients on chronic oral anticoagulation undergoing CIED surgery. Patients were matched using propensity scoring.

RESULTS

We included 1,975 patients (age 73.8 ± 12.4 years). Among 1,326 patients on DOAC, this was interrupted presurgery in 78.2% (n = 1,039) and continued in 21.8% (n = 287). There were 649 patients on continued VKA. The matched population included 861 patients. The rate of any major bleeding was higher with continued DOAC (5.2%) compared to interrupted DOAC (1.7%) and continued VKA (2.1%) (P = 0.03). The rate of perioperative thromboembolism was 1.4% with interrupted DOAC, whereas no thromboembolic events occurred with DOAC or VKA continuation (P = 0.04). The use of dual antiplatelet therapy, DOAC continuation, and male sex were independent predictors of major bleeding on a multivariable analysis.

CONCLUSIONS

In this large real-world cohort, a continued DOAC strategy was associated with a higher bleeding risk compared to DOAC interruption or VKA continuation in patients undergoing CIED surgery. However, DOAC interruption was associated with increased thromboembolic risk. Concomitant dual antiplatelet therapy should be avoided whenever clinically possible. A bespoke approach is necessary, with a strategy of minimal DOAC interruption likely to represent the best compromise.

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.

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.

Early results of the novel radiofrequency balloon ablation catheter for pulmonary vein isolation

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein isolation (PVI) remains the cornerstone for treating of symptomatic atrial fibrillation (AF). Single-shot PVI technologies have evolved as a standard for first-time PVI. A novel radiofrequency balloon ablation catheter is now available to offer single-shot RF pulmonary vein isolation.

Purpose

To summarize the early experience using the novel RF balloon ablation catheter for patients undergoing PVI in two tertiary centres in Europe.

Methods

We prospectively assessed the first 38 consecutive patients undergoing PVI using RF balloon ablation catheter for paroxysmal or persistent AF in two high volume centres. Both centres used a standardised approach including ultrasound-guided vascular access, uninterrupted anticoagulation, transeptal puncture via the RF balloon sheath and a limited 3D mapping software-guided LA geometry created with a circular mapping catheter. Radiofrequency application for 60s to the anterior segments and 20s posteriorly was performed in all cases, phrenic pacing was employed for ablation of right PVs. BHS performed all procedures (except 2 cases due to high BMI and severe sleep apnea) under sedation, while all patients from UHZ underwent PVI procedures with general anaesthesia as per institutional protocol. All patients had an oesophageal temperature probe to assess oesophageal temperature during ablation (passed orally under sedation) and had uninterrupted oral anticoagulation throughout the periprocedural period.

Results

Overall, mean age was 64±8 years, 23 (61%) were male, 24 (63%) of patients had paroxysmal AF. The majority were de novo interventions (92%). There was no significant difference between the patients demographics in the two hospitals. All veins were isolated in both groups with a total of 144 applications (n = 73 in the sedation group, n = 71 in the GA population). Median fluoroscopy time was comparable (sedation group 1.1 minutes vs GA group 1.2 minutes; P = 0.58), but median procedure time was shorter in the sedation group (65 minute vs 106 minutes; P &lt; 0.001). The median number of RF ablation per patient (sedation group 7 vs GA group 9; P = 0.32) and time to isolation of each vein (sedation group 11 seconds vs GA group 10 seconds; P = 0.9) were similar. Number of acute reconnections requiring further ablations were not significantly different between groups (sedation group 11 [15%] vs GA group 14 [20%]; P = 0.96). One patient sustained transient phrenic nerve injury in the sedation group.

Conclusion

Our early experience shows the novel HS balloon ablation can be performed effectively, efficiently and safely under either GA or conscious sedition. The RF balloon ablation catheter paradigm lends itself to refined workflows, with low fluoroscopy requirements and a short learning curve even in initial cohorts.

Risk factors for developing pacing induced LV dysfunction: Experience from a tertiary centre in the UK

INTRODUCTION

The risk factors for developing pacing induced Left Ventricular dysfunction (LVD) in patients with high burden of right ventricular pacing (RVP) is poorly understood. Therefore, in the present study, we aimed to assess the determinants of pacing induced LVD.

METHODS

Our data were retrospectively collected from 146 patients with RVP > 40% who underwent generator change (GC) or cardiac resynchronisation therapy (CRT) upgrade between 2016-2019 who had left ventricular ejection fraction (EF) ≥50% at initial implant.

RESULTS

75 patients had CRT upgrade due to pacing induced LVD (EF<50%) and 71 patients with preserved LV function (EF ≥50%) had a GC. Primary indication for pacing in both groups was complete heart block. Male predominance (p = 0.008), prior myocardial infarction (MI) (p = 0.001), atrial fibrillation (AF) (p = 0.009), chronic kidney disease (CKD) (p = 0.005), and borderline low systolic function (BLSF) (EF 50-55%) (p = 0.04) were more prevalent in the CRT upgrade group. Presence of AF (OR = 3.05, 95% CI 1.42-6.58; p = 0.004), BLSF (OR = 3.8, 95% CI 1.22-11.8; p = 0.02) and male gender (OR = 2.41, 95% CI 1.14-5.08; p = 0.02) were independent predictors for RVP induced LVD. Age (OR = 1.08, 95% CI 1.02-1.14; p = 0.005) and BLSF (OR = 5.33, 95% CI 1.26-22.5; p = 0.023) were independent predictors of earlier development of LVD after implant.

CONCLUSIONS

Our results suggested that AF, BLSF and male gender are predictors for development of pacing induced LVD in patients with high RVP burden. LVD can occur at any time after pacemaker implant with BLSF and increasing age associated with earlier development of LVD. This article is protected by copyright. All rights reserved.

Incidence and Prognostic Impact of New-Onset Atrial Fibrillation in Patients with Severe Covid-19: A Retrospective Cohort Study

Background

Corona virus disease 2019 (COVID-19) contributes to cardiovascular complications including arrhythmias due to high inflammatory surge. Nevertheless, the common types of arrhythmia amongst severe COVID-19 is not well described. New onset atrial fibrillation(NOAF) is frequentlyseen in critically ill patients and therefore we aim to assess the incidence of NOAF in severe COVID -19and its association with prognosis.

Methods

This is a retrospective multicentre study including 109 consecutive patients admitted to intensive care units (ICU) with confirmed COVID-19 pneumonia and definitive outcome (death or discharge). The study period was between 11th March and 5th May 2020.

Results

Median age of our population was 59 years (IQR 53-65) and 83% were men. Nearly three-fourth of the population had two or more comorbidities. 14.6% developed NOAF during ICU stay with increased risk amongst older age and with underlying chronic heart failure and chronic kidney disease. NOAF developed earlier during the course of severe COVID-19 infection amongst non-survivors than those survived the illness andstrongly associated with increased in-hospital death (OR 5.4; 95% CI 1.7-17; p=0.004).

Conclusions

In our cohort with severe COVID-19, the incidence of new onset atrial fibrillation is comparatively lower than patients treated in ICU with severe sepsis in general. Presence of NOAF has shown to be a poor prognostic marker in this disease entity.

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.

Communication in the intensive care unit during COVID-19: early experience with the Nightingale Communication Method

Objective

To assess the utility and frequency of use of the Nightingale Communication Method, during the early operational phase of the Nightingale Hospital London (NHL) 4000-bed field hospital’s intensive care unit.

Design

Survey-based cross-sectional assessment.

Setting

The intensive care unit at the Nightingale London hospital.

Participants

Staff working in the clinical area and therefore requiring full personal protective equipment (PPE).

Intervention

Survey of all staff members sampled from a single shift at the Nightingale Hospital. This investigated perceived utility and actual use of identification methods (name and role labels on visors and gowns, coloured role identification tapes) and formal hand signals as an adjunctive communication method.

Main Outcome Measure

Self-reported frequency of use and perceived utility of each communication and personnel identification adjunct.

Results

Fifty valid responses were received (72% response rate), covering all clinical professional groups. Prominent name/role identifications and coloured role identification tapes were very frequently used and were perceived as being highly useful. Formal hand signals were infrequently used and not perceived as being beneficial, with respondents citing use of individual hand signals only in specific circumstances.

Conclusion

PPE is highly depersonalizing, and interpersonal identification aids are very useful. Despite being difficult, verbal communication is not completely prohibited, which could explain the low utility of formal hand signals. The methods developed at the Nightingale hospital have enhanced communication in the critical care, field hospital setting. There is potential for wider application to a variety of healthcare settings, in both the current situation and future pandemic scenarios.

Toward a uniform pathway in managing incidental lung nodules on computerised tomography [CT] coronary angiography; for a cost effective and safe outcome

Background

National Institute for Health and Care Excellence guidelines (NICE CG95) recommends computed tomography coronary angiography [CTCA] as the first line investigation for all patients with suspected typical or atypical angina irrespective of pre-test probability due to its excellent performance and cost effectiveness. However previous cost effectiveness analyses have not factored in the burden of lung nodules [LN] or extracardiac incidentalomas, which are commonly identified on CTCA.

Purpose

As we increasingly detect LN on CTCA scans, it is prudent that a uniform pathway is followed for surveillance of LN. The British Thoracic Society (BTS) has enabled evidence-based development of an algorithm for the management of LN which defines a cut off LN size of ≥5mm requiring further follow up. We aimed to assess the compliance of LN follow up in our patients according to radiology recommendation on CTCA reports and also to assess how well these recommendations adhere to BTS guidelines.

Method

117 patients who underwent CTCA as the initial diagnostic investigation were retrospectively identified from the rapid access chest pain clinic database. Data was collected during a 1 year period between January - December 2017. Data was analysed to determine whether appropriate surveillance pathway was followed for repeat imaging. According to BTS guidelines, nodules ≥5mm should have a systematic work up for surveillance and hence we have stratified our data based on the nodule size. In case of multiple nodules, the largest nodule size was considered.

Results

Out of 117 patients, 77% patients were female with average age 57.8±9.0 years. 40% patients were found to have incidental LN with an average size of 4.63±1.92mm; 44% had a history of cigarette smoking.

Among patient with nodules, 22 (19%) had CT thorax to assess interval change and interestingly 16 (73%) had persisting LN; whereas in 4 (18%), the LN resolved and only 2 (9%) showed increase in LN size. Repeat CT chest was advised for these 2 patients; 1 was advised to undergo biopsy which eventually ruled out malignancy. 6 patients (5%) from group 1 were recommended for repeat CT despite having LN size &lt;5mm.

In the remaining 25 patients (21%) with LN, 15 (60%) did not have further surveillance imaging even though this was recommended by the reporting radiologist. Of these only 3 (12%) had LN ≥5mm which qualified for surveillance CT.

Conclusion

CTCA frequently detects incidentalomas especially LN which cannot be overlooked and require further imaging irrespective of the primary presentation. Our findings also suggest a discrepancy on surveillance CT recommendation against the current BTS guidelines, with potential significant impact on the overall cost effectiveness of CTCA. A systematic approach to LN surveillance could be best achieved with a multidisciplinary team approach (e.g. referral pathway to nodule MDT) and adherence to a standard guideline.

Lung nodule surveillance following CTCA

Funding Acknowledgement

Type of funding source: None

Rare and challenging case of stroke as a manifestation of non bacterial thrombotic endocarditis in an underlying ovarian clear cell carcinoma

Non bacterial thrombotic endocarditis presenting as a stroke is a rare presentation as a result of an underlying occult ovarian clear cell adenocarcinoma. Embolic events secondary to non bacterial thrombotic endocarditis are potentially a life-threatening condition if not diagnosed and treated promptly. High clinical suspicion for an underlying neoplasm is one of the key elements to be considered in the management of non bacterial thrombotic endocarditis. Systemic anticoagulation will treat as well as prevent further thromboembolic events.

Bio-organic materials in the atmosphere and snow: measurement and characterization

Bio-organic chemicals are ubiquitous in the Earth's atmosphere and at air-snow interfaces, as well as in aerosols and in clouds. It has been known for centuries that airborne biological matter plays various roles in the transmission of disease in humans and in ecosystems. The implication of chemical compounds of biological origins in cloud condensation and in ice nucleation processes has also been studied during the last few decades, and implications have been suggested in the reduction of visibility, in the influence on oxidative potential of the atmosphere and transformation of compounds in the atmosphere, in the formation of haze, change of snow-ice albedo, in agricultural processes, and bio-hazards and bio-terrorism. In this review we critically examine existing observation data on bio-organic compounds in the atmosphere and in snow. We also review both conventional and cutting-edge analytical techniques and methods for measurement and characterisation of bio-organic compounds and specifically for microbial communities, in the atmosphere and snow. We also explore the link between biological compounds and nucleation processes. Due to increased interest in decreasing emissions of carbon-containing compounds, we also briefly review (in an Appendix) methods and techniques that are currently deployed for bio-organic remediation.