Economic evaluation of first-line cryoballoon ablation versus antiarrhythmic drug therapy for the treatment of paroxysmal atrial fibrillation from an English National Health Service perspective

INTRODUCTION

Three recent randomised controlled trials have demonstrated that pulmonary vein isolation as an initial rhythm control strategy with cryoablation reduces atrial arrhythmia recurrence in patients with symptomatic paroxysmal atrial fibrillation (PAF) compared with antiarrhythmic drug (AAD) therapy. The aim of this study was to evaluate the cost-effectiveness of first-line cryoablation compared with first-line AADs for treating symptomatic PAF in an English National Health Service (NHS) setting.

METHODS

Individual patient-level data from 703 participants with PAF enrolled into Cryo-FIRST (Catheter Cryoablation Versus Antiarrhythmic Drug as First-Line Therapy of Paroxysmal Atrial Fibrillation), STOP AF First (Cryoballoon Catheter Ablation in an Antiarrhythmic Drug Naive Paroxysmal Atrial Fibrillation) and EARLY-AF (Early Aggressive Invasive Intervention for Atrial Fibrillation) were used to derive the parameters applied in the cost-effectiveness model (CEM). The CEM comprised a hybrid decision tree and Markov structure. The decision tree had a 1-year time horizon and was used to inform the initial health state allocation in the first cycle of the Markov model (40-year time horizon; 3-month cycle length). Health benefits were expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3.5% per year. Model outcomes were generated using probabilistic sensitivity analysis.

RESULTS

The results estimated that cryoablation would yield more QALYs (+0.17) and higher costs (+£641) per patient over a lifetime than AADs. This produced an incremental cost-effectiveness ratio of £3783 per QALY gained. Independent of initial treatment, individuals were expected to receive ~1.2 ablations over a lifetime. There was a 45% relative reduction in time spent in AF health states for those initially treated with cryoablation.

DISCUSSION

AF rhythm control with first-line cryoablation is cost effective compared with first-line AADs in an English NHS setting.

Reactogenicity, pregnancy outcomes, and SARS-CoV-2 infection following COVID-19 vaccination during pregnancy in Canada: A national prospective cohort study

OBJECTIVE

To describe self-reported reactogenicity, pregnancy outcomes, and SARS-CoV-2 infection following COVID-19 vaccination during pregnancy.

DESIGN

National, prospective cohort study.

SETTING

Participants across Canada were enrolled from July 2021 until June 2022.

POPULATION

Individuals pregnant during the COVID-19 pandemic, regardless of vaccination status, were included.

METHODS

The Canadian COVID-19 Vaccine Registry for Pregnant and Lactating Individuals (COVERED) was advertised through traditional and social media. Surveys were administered at baseline, following each vaccine dose if vaccinated, pregnancy conclusion, and every two months for 14 months. Changes to pregnancy or vaccination status, SARS-CoV-2 infections, or significant health events were recorded.

MAIN OUTCOME MEASURES

Reactogenicity (local and systemic adverse events, and serious adverse events) within 1 week post-vaccination, pregnancy and neonatal outcomes, and subsequent SARS-CoV-2 infection.

RESULTS

Among 2868 participants who received 1-2 doses of a COVID-19 vaccine during pregnancy, adverse events described included: headache (19.5-33.9%), nausea (4.8-13.8%), fever (2.7-10.2%), and myalgia (33.4-42.2%). Reactogenicity was highest after the 2nd dose of vaccine in pregnancy. Compared to 1660 unvaccinated participants, there were no statistically significant differences in adverse pregnancy or infant outcomes, aside from an increased risk of NICU admission ≥ 24 h among the unvaccinated group. During follow-up, there was a higher rate of participant-reported SARS-CoV-2 infection in the unvaccinated compared to the vaccinated group (18[47.4%] vs. 786[27.3%]).

CONCLUSIONS

Participant-reported reactogenicity was similar to reports from non-pregnant adults. There was no increase in adverse pregnancy and birth outcomes among vaccinated vs. unvaccinated participants and lower rates of SARS-CoV-2 infection were reported in vaccinated participants.

TWEETABLE ABSTRACT

No significant increase in adverse pregnancy or infant outcomes among vaccinated versus unvaccinated pregnant women in Canada.

Motion Effects on Spatially Fractionated Lattice Therapy

PURPOSE/OBJECTIVE(S)

The practice of spatially fractionated radiation therapy (SFRT), such as grid and lattice, has been shown to be effective in managing large-size tumors for palliation or more recently for medium-sized tumors with definitive intents. The main feature that differentiates SFRT from standard radiation therapy is the deliberately high degree of dose heterogeneity in the gross tumor volume (GTV). The key parameter in assessing an SFRT plan is the valley-to-peak dose ratio (VPDR), which can be defined as a simple dose ratio between the low- and high-dose region in the tumor. The belief is that the healthy tissues in the low-dose regions of the tumor would serve as centers of tissue repair, while the high dose would kill the cancerous cells and induce the bystander effects. However, the compartments of low- and high-dose regions can be washed out due to motion, for example in cases when the disease is at or near the diaphragm. This work aims at examining motion effects on VPDR and equivalent uniform dose (EUD) in SFRT plans.

MATERIALS/METHODS

This work focuses on the effects of sinusoidal motion in lattice therapy, a 3D version of SFRT. A lattice VMAT plan with 6X was generated using the treatment planning system. Dose vertices were placed in a body-centered tetragonal lattice in a virtual water phantom. Each vertex was 1 cm3 and received 15 Gy to at least half of its volume. The volume ratio between the lattice and the GTV is about 3%. The distance between the two nearest vertice centers is 3 cm. A sinusoidal motion was introduced in the direction along the line connecting the two nearest neighbors and was binned into 10 phases with equal time intervals. The location of the phantom in each phase was determined by its average amplitude. The effect of the motion was assessed from the sum of all the plans in the 10 bins, each being scaled down by one-tenth of the prescribed dose. Dose coverage between the static and the sum plan is compared. Their difference in the VPDR and normal tissue damage with EUD are evaluated. The EUD was calculated based on Niemierko's formalism. The LQ model was used to estimate cell survival for normal tissues with a and b values of 0.366/Gy and 0.188 Gy2, respectively.

RESULTS

It is common to have the VPDR at around 1/3 or lower. Our study shows that it increases from 0.26 to 0.55 for the 1.5 cm motion and the EUD for normal tissue from 5 to 7 Gy. See Table 1 for more results. A large VPDR can reduce the ability of healthy tissues in the low-dose area for repair and a lower maximum dose in the vertices may diminish the bystander effects.

CONCLUSION

Motion may increase VPDR and normal tissue damage. Motion techniques such as gating or tracking can be used on disease sites subjected to respiratory motion.

Kidney function and the comparative effectiveness and safety of direct oral anticoagulants vs. warfarin in adults with atrial fibrillation: a multicenter observational study

AIMS

The aim of this study was to determine the comparative effectiveness and safety of direct oral anticoagulants (DOACs) and warfarin in adults with atrial fibrillation (AF) by level of kidney function.

METHODS AND RESULTS

We pooled findings from five retrospective cohorts (2011-18) across Australia and Canada of adults with; a new dispensation for a DOAC or warfarin, an AF diagnosis, and a measure of baseline estimated glomerular filtration rate (eGFR). The outcomes of interest, within 1 year from the cohort entry date, were: (1) the composite of all-cause death, first hospitalization for ischaemic stroke, or transient ischaemic attack (effectiveness), and (2) first hospitalization for major bleeding defined as an intracranial, upper or lower gastrointestinal, or other bleeding (safety). Cox models were used to examine the association of a DOAC vs. warfarin with outcomes, after 1:1 matching via a propensity score. Kidney function was categorized as eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m2. A total of 74 542 patients were included in the matched analysis. DOAC initiation was associated with greater or similar effectiveness compared with warfarin initiation across all eGFR categories [pooled HRs (95% CIs) for eGFR categories: 0.74(0.69-0.79), 0.76(0.54-1.07), 0.68(0.61-0.75) and 0.86(0.76-0.98)], respectively. DOAC initiation was associated with lower or similar risk of major bleeding than warfarin initiation [pooled HRs (95% CIs): 0.75(0.65-0.86), 0.81(0.65-1.01), 0.82(0.66-1.02), and 0.71(0.52-0.99), respectively). Associations between DOAC initiation, compared with warfarin initiation, and study outcomes were not modified by eGFR category.

CONCLUSION

DOAC use, compared with warfarin use, was associated with a lower or similar risk of all-cause death, ischaemic stroke, and transient ischaemic attack and also a lower or similar risk of major bleeding across all levels of kidney function.

Influence of monitoring and atrial arrhythmia burden on quality of life and health care utilization in patients undergoing pulsed field ablation: A secondary analysis of the PULSED AF trial

BACKGROUND

Freedom from atrial arrhythmia (AA) recurrence ≥30 seconds after pulsed field ablation (PFA) in patients with atrial fibrillation (AF) was reported in PULSED AF (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF; ClinialTrials.gov Identifier: NCT04198701). AA burden may be a more clinically meaningful endpoint.

OBJECTIVE

The purpose of this study was to determine the influence of monitoring strategies on AA detection and AA burden association with quality of life (QoL) and health care utilization (HCU) after PFA.

METHODS

Patients underwent 24-hour Holter monitoring at 6 and 12 months and weekly, and symptomatic transtelephonic monitoring (TTM). AA burden post-blanking was calculated as the greater of (1) percentage of AA on total Holter time; or (2) percentage of weeks with ≥1 TTM with AA out of all weeks with ≥1 TTM.

RESULTS

Freedom from all AAs varied by >20% when differing monitoring strategies were used. PFA resulted in zero burden in 69.4% of paroxysmal atrial fibrillation (PAF) and 62.2% of persistent atrial fibrillation (PsAF) patients. Median burden was low (<9%). Most PAF and PsAF patients had ≤1 week of AA detection on TTM (82.6% and 75.4%) and <30 minutes of AA per day of Holter monitoring (96.5% and 89.6%), respectively. Only PAF patients with <10% AA burden averaged a clinically meaningful (>19 point) QoL improvement. PsAF patients experienced clinically meaningful QoL improvements irrespective of burden. Repeat ablations and cardioversions significantly increased with higher AA burden (P <.01).

CONCLUSION

The ≥30-second AA endpoint is dependent on the monitoring protocol used. PFA resulted in low AA burden for most patients, which was associated with clinically relevant improvement in QoL and reduced AA-related HCU.

An economic evaluation of first-line cryoballoon ablation vs antiarrhythmic drug therapy for the treatment of paroxysmal atrial fibrillation from a U.S. Medicare perspective

Background

Three recent randomized controlled trials have demonstrated that, as an initial rhythm control strategy, first-line cryoballoon ablation (cryoablation) reduces atrial arrhythmia recurrence compared with antiarrhythmic drugs (AADs) in patients with symptomatic paroxysmal atrial fibrillation (PAF).

Objective

The study sought to evaluate the cost-effectiveness of first-line cryoablation compared with first-line AADs for treating symptomatic PAF from a U.S. Medicare payer perspective.

Methods

Individual patient-level data from 703 participants with PAF enrolled into the Cryo-FIRST (NCT01803438), STOP AF First (NCT03118518), and EARLY-AF (NCT02825979) trials were used to derive parameters for the cost-effectiveness model. The cost-effectiveness model used a hybrid decision tree and Markov structure. The decision tree had a 1-year time horizon and was used to inform the initial health state allocation in the first cycle of the Markov model. The Markov model used a 40-year time horizon (3-month cycle length). Health benefits were expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3% per year.

Results

Cryoablation was estimated to yield higher QALYs (+0.17) and higher costs (+$4274) per patient over a 40-year time horizon than AADs. Ultimately, this produced an average incremental cost-effectiveness ratio of $24,637 per QALY gained. Independent of initial treatment, individuals were expected to receive ∼1.2 ablations over a lifetime. There was a 45% relative reduction in time spent in atrial fibrillation health states for those initially treated with cryoablation compared with AADs.

Conclusion

Initial rhythm control with first-line cryoballoon ablation is highly cost-effective compared with first-line AADs from a U.S. Medicare payer perspective.

Canadian Cardiovascular Society-Canadian Heart Failure Society Focused Clinical Practice Update of Patients With Differing Heart Failure Phenotypes

A number of societies produce heart failure (HF) management guidelines, comprising official recommendations on the basis of recent research discoveries, but their applicability to specific situations encountered in daily practice might be difficult. In this clinical practice update we aim to provide responses to fundamental questions that face health care providers, like appropriate timing for the introduction and optimization of different classes of medication according to specific patient phenotypes, when second-line therapies and valvular interventions should be considered, and management of difficult clinical scenarios such as cardiorenal syndrome and frailty. A consensus-based methodology was used. Approaches to 5 different phenotypes are presented: (1) The wet HF phenotype is the easiest to manage, decongestion being performed alongside introduction of guideline-directed medical therapy (GDMT); (2) The de novo HF phenotype requires the introduction of the 4 pillars of GDMT, personalizing the order on the basis of the individuals' biological and physiological characteristics; (3) The worsening HF phenotype is a marker of poor prognosis, and therefore should motivate optimization of GDMT, start second-line therapies, and/or reevaluate goals of care/advanced HF therapies; (4) The cardiorenal phenotypes require correct volume assessment, because renal function usually improves with decongestion; and (5) The frail HF phenotype require special attention, careful drug titration, and consideration of cardiac rehabilitation programs. In conclusion, specific common HF phenotypes call for a personalized approach to improve adoption of the HF guidelines into clinical practice.

Safety and Effectiveness of Rivaroxaban Versus Warfarin Across GFR Levels in Atrial Fibrillation: A Population-Based Study in Australia and Canada

Rationale & Objective

The benefit-risk profile of rivaroxaban versus warfarin for atrial fibrillation (AF) in patients with chronic kidney disease is uncertain. We compared rivaroxaban with warfarin across the range of kidney function in adults with AF.

Study Design

Multicenter retrospective cohort.

Setting & Participants

Adults with AF and a measure of estimated glomerular filtration rate (eGFR); using administrative data from 5 jurisdictions across Australia and Canada (2011-2018). Kidney function was categorized as eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m². Patients receiving dialysis and kidney transplant recipients were excluded.

Exposures

New dispensation of either rivaroxaban or warfarin.

Outcomes

Composite (1) effectiveness outcome (all-cause death, ischemic stroke, or transient ischemic attack) and (2) major bleeding events (intracranial, gastrointestinal, or other) at 1 year.

Analytical Approach

Cox proportional hazards models accounting for propensity score matching were performed independently in each jurisdiction and then pooled using random-effects meta-analysis.

Results

55,568 patients (27,784 rivaroxaban-warfarin user matched pairs; mean age 74 years, 46% female, 33.5% with eGFR <60 mL/min/1.73 m²) experienced a total of 4,733 (8.5%) effectiveness and 1,144 (2.0%) bleeding events. Compared to warfarin, rivaroxaban was associated with greater or similar effectiveness across a broad range of kidney function (pooled HRs of 0.72 [95% CI, 0.66-0.78], 0.78 [95% CI, 0.58-1.06], 0.70 [95% CI, 0.57-0.87], and 0.78 [95% CI, 0.62-0.99]) for eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m², respectively). Rivaroxaban was also associated with similar risk of major bleeding across all eGFR categories (pooled HRs of 0.75 [95% CI, 0.56-1.00], 1.01 [95% CI, 0.79-1.30], 0.87 [95% CI, 0.66-1.15], and 0.63 [95% CI, 0.37-1.09], respectively).

Limitations

Unmeasured treatment selection bias and residual confounding.

Conclusions

In adults with AF, rivaroxaban compared with warfarin was associated with lower or similar risk of all-cause death, ischemic stroke and transient ischemic attack and similar risk of bleeding across a broad range of kidney function.

Plain-Language Summary

This real-world study involved a large cohort of 55,568 adults with atrial fibrillation from 5 jurisdictions across Australia and Canada. It showed that the favorable safety (bleeding) and effectiveness (stroke or death) profile of rivaroxaban compared with warfarin was consistent across different levels of kidney function. This study adds important safety data on the use of rivaroxaban in patients with reduced kidney function, including those with estimated glomerular filtration rate <30 mL/min/1.73 m² in whom the risks and benefits of rivaroxaban use is most uncertain. Overall, the study supports the use of rivaroxaban as a safe and effective alternative to warfarin for atrial fibrillation across differing levels of kidney function.

Early mortality after inpatient versus outpatient catheter ablation in patients with atrial fibrillation

BACKGROUND

Rates of early mortality and complications after catheter ablation (CA) of atrial fibrillation (AF) vary across health care settings.

OBJECTIVE

The purpose of this study was to identify the rate and predictors of early mortality (within 30 days) after CA in the inpatient and outpatient settings.

METHODS

Using the Medicare Fee for Service database, we analyzed 122,289 patients who underwent CA for treatment of AF between 2016 and 2019 to define 30-day mortality in both inpatients and outpatients. Odds of adjusted mortality were assessed with several methods, including inverse probability of treatment weighting.

RESULTS

Mean age was 71.9 ± 6.7 years, 44% were women, and mean CHA2DS2-VASc score was 3.2 ± 1.7. Overall, 82% underwent AF ablation as an outpatient. Mortality rate 30 days after CA was 0.6%, with inpatients accounting for 71.5% of deaths (P <.001). Early mortality rates were 0.2% for outpatient procedures and 2.4% for inpatient procedures. The prevalence of comorbidities was significantly higher in patients with early mortality. Patients with early mortality had significantly higher rates of postprocedural complications. After adjustment, inpatient ablation was significantly associated with early mortality (adjusted odds ratio [aOR] 3.81; 95% confidence interval [CI] 2.87-5.08; P <.001). Hospitals with high overall ablation volume had 31% lower odds of early mortality (highest vs lowest tertile: aOR 0.69; 95% CI 0.56-0.86; P <.001).

CONCLUSION

AF ablation conducted in the inpatient setting is associated with a higher rate of early mortality compared with outpatient AF ablation. Comorbidities are associated with enhanced risk of early mortality. High overall ablation volume is associated with a lower risk of early mortality.

Characterization of arrhythmia substrate to ablate persistent atrial fibrillation (COAST-AF): Randomized controlled trial design and rationale

BACKGROUND

Atrial low voltage area (LVA) catheter ablation has emerged as a promising strategy for ablation of persistent atrial fibrillation (AF). It is unclear if catheter ablation of atrial LVA increases treatment success rates in patients with persistent AF.

OBJECTIVE

The primary aim of this trial is to assess the potential benefit of adjunctive catheter ablation of atrial LVA in addition to pulmonary vein isolation (PVI) in patients with persistent AF, when compared to PVI alone. The secondary aims are to evaluate safety outcomes, the quality of life and the healthcare resource utilization.

METHODS/DESIGN

A multicenter, prospective, parallel-group, 2-arm, single-blinded randomized controlled trial is under way (NCT03347227). Patients who are candidates for catheter ablation for persistent AF will be randomly assigned (1:1) to either PVI alone or PVI + atrial LVA ablation. The primary outcome is 18-month documented event rate of atrial arrhythmia (AF, atrial tachycardia or atrial flutter) post catheter ablation. Secondary outcomes include procedure-related complications, freedom from atrial arrhythmia at 12 months, AF burden, need for emergency department visits/hospitalization, need for repeat ablation for atrial arrhythmia, quality of life at 12 and 18 months, ablation time, and procedure duration.

DISCUSSION

Characterization of Arrhythmia Mechanism to Ablate Atrial Fibrillation (COAST-AF) is a multicenter randomized trial evaluating ablation strategies for catheter ablation. We hypothesize that catheter ablation of atrial LVA in addition to PVI will result in higher procedural success rates when compared to PVI alone in patients with persistent AF.

Incidence of premature battery depletion in subcutaneous cardioverter-defibrillator patients. Insights from a multicenter registry

Funding Acknowledgements

Type of funding sources: None.

Introduction

A subset of more than 35,000 S-ICD is under FDA advisory, warning of the potential of premature battery depletion (PBD), caused by a faulty low-voltage capacitor. Based on internal data, the manufacturer projects the incidence at 3.7% after 5 years. Data independent from the manufacturer is sparse.

Methods

This study was a multicenter effort of 14 centers in Europe, the US, and Canada. Consecutive patients who received a S-ICD at the participating centers were included in this retrospective analysis. Patients with the 1010 S-ICD generator model, and those without available follow-up information were excluded. Data was collected and managed using REDCap electronic data capture tools hosted at the University Hospital Cologne.

The primary endpoint in this registry was device explantation, generator replacement, or generator failure. Reasons for explantation, replacement, or failure were collected. Device longevity was defined in months. It was calculated as the time from device insertion to the time of replacement, or explantation, or failure, where applicable. Premature battery depletion was defined as the occurrence of battery depletion requiring generator replacement after 60 months or less.

The study complies with the Declaration of Helsinki. Ethics committee approval was obtained. This study is registered with Clinicaltrials.gov.

Results

Data of n=1,102 S-ICD devices was analyzed. The registry comprised of S-ICD generators implanted between 03/2015 and 09/2021 (43.4% A209 model and 56.6% A219 model). Of these, 611 devices (55.4%) were identified by the Boston Scientific serial number lookup tool as affected by the advisory. The mean and median follow-up duration was 2.43±1.66 and 2.29 years, respectively.

During follow-up, 110 devices (10%) were explanted after 2.9±1.7 years. Battery depletion was the indication in 52. The endpoint of PBD (battery depletion after less than 5 years) was met in 37 devices (6% of the devices under advisory), after 4.1±0.6 years.

In 58 cases, the S-ICD was explanted for reasons other than battery depletion.

Infection (16), system upgrade (20), heart transplant or LVAD therapy (7), and inappropriate shocks or inappropriate sensing (7) were the most common indications.

Discussion

This registry provides a systematic and manufacturer independent analysis of premature battery depletion in S-ICD patients. In the affected devices, the incidence of premature battery occurred in 6%. This is higher than what is projected by the manufacturer. The rate of PBD increases notably around the 4-year mark.

Conclusion

S-ICD generators under advisory suffer from PBD at a higher incidence than previously reported. Patients equipped with these devices should be closely monitored.

Prevention and management of intra-operative pain during caesarean section under neuraxial anaesthesia: a technical and interpersonal approach

A woman who experiences pain during caesarean section under neuraxial anaesthesia is at risk of adverse psychological sequelae. Litigation arising from pain during caesarean section under neuraxial anaesthesia has replaced accidental awareness under general anaesthesia as the most common successful medicolegal claim against obstetric anaesthetists. Generic guidelines on caesarean section exist, but they do not provide specific recommendations for this area of anaesthetic practice. This guidance aims to offer pragmatic advice to support anaesthetists in caring for women during caesarean section. It emphasises the importance of non-technical skills, offers advice on best practice and aims to encourage standardisation. The guidance results from a collaborative effort by anaesthetists, psychologists and patients and has been developed to support clinicians and promote standardisation of practice in this area.

Representation of Females in Atrial Fibrillation Clinical Practice Guidelines

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia in males and females worldwide, and its prevalence is increasing. Management of AF is guided by evidence-based clinical practice guidelines which provide recommendations based on available evidence. The extent of sex-specific data in the AF literature used to provide guideline recommendations has not been investigated. Therefore, using the 2020 Canadian Cardiovascular Society (CCS) Atrial Fibrillation Management Guidelines as example, the purpose of this study was to review female representation and the reporting of sex-disaggregated data in the studies referenced in AF guidelines.

METHODS

Randomized controlled trials (RCTs), prospective and retrospective cohorts, were screened to calculate the proportion of study participants who were female and to establish whether studies provided sex disaggregated analyses. The participant prevalence ratio (PPR), a quotient of the female participant rate and the prevalence of females in the AF population, was calculated for each study.

RESULTS

A total of 885 studies included in the CCS guidelines were considered. Of those, 467 met the inclusion criteria. Overall, females represented 39.1% of the population in all studies and RCTs had the lowest proportions of females (33.8%, PPR: 0.70). Of studies with sex-disaggregated analyses (n=140 (29.9%)), single centered RCTs, and retrospective cohorts had the lowest and highest rate of sex-specific analyses respectively (11.5% vs 32.5%).

CONCLUSION

The evidence used to derive guideline recommendations may be inadequate for sex-specific recommendations. Until enough data can support female specific guidelines, increased inclusion of females in AF studies, may aid in the precision of recommendations.

Bayesian network meta-analysis comparing cryoablation, radiofrequency ablation, and antiarrhythmic drugs as initial therapies for atrial fibrillation

BACKGROUND

Antiarrhythmic drugs (AADs) and catheter ablation are first line treatments of paroxysmal atrial fibrillation (PAF), however, there exists a paucity of data regarding the potential benefit of different catheter ablation technologies versus AADs as an early rhythm strategy.

OBJECTIVE

To assess the safety and efficacy of cryoablation versus radiofrequency ablation (RFA) versus AADs as a first line therapy of PAF.

METHODS

MEDLINE, Embase, Scopus and CENTRAL were searched to retrieve randomized clinical trials (RCTs) comparing cryoablation, RFA or AADs to one another as first line therapies for atrial fibrillation (AF). The primary outcome was overall freedom from arrhythmia recurrence (AF, atrial flutter [AFL], atrial tachycardia). Secondary outcomes included freedom from symptomatic arrhythmia recurrence, hospitalization, and serious adverse events. A random-effects Bayesian network meta-analysis was used to calculate odds ratios (OR) and 95% credible intervals (CrI).

RESULTS

Six RCTs (N = 1212) met the inclusion criteria (605 AADs, 365 Cryoablation, and 245 RFA). Compared with AADs, overall recurrence was reduced with RFA (OR: 0.31; 95% CrI: 0.10-0.71) and cryoablation (OR: 0.39; 95% CrI: 0.16-1.00). Comparing ablation (cryoablation and RFA) with AADs in respect to freedom from symptomatic AF recurrence, neither cryoablation (OR: 0.35; 95% CrI: 0.06-1.96) nor RFA (OR: 0.34; 95% CrI: 0.07-1.27) resulted in statistically significant reductions individually compared to AADs, though pooled ablation with both technologies showed lower odds of arrhythmia recurrence (OR: 0.35; 95% CrI: 0.13-0.79). In terms of serious adverse events rates, neither cryoablation (OR: 0.77; 95% CrI: 0.44-1.39) nor RFA (OR: 1.45; 95% CrI: 0.67-3.23) were significantly different to AADs. RFA resulted in a statistically significant reduction in hospitalizations compared to AAD (OR: 0.08; 95% CrI: 0.01-0.99), whereas cryoablation did not (OR: 0.77; 95% CrI: 0.44-1.39). The surface under the cumulative ranking curve showed RFA to be the most effective treatment at reducing overall rates of recurrence, symptomatic recurrence and hospitalizations; whereas cryoablation was most likely to reduce serious adverse events.

CONCLUSION

Cryoablation and RFA are both effective and safe first line therapies for AF compared to AADs, with RFA being the most effective at reducing recurrences.

Magnetic resonance imaging in the evaluation of idiopathic frequent premature ventricular complexes with normal ventricular function

Background

The role of cardiac magnetic resonance (CMR) imaging in the diagnostic evaluation of patients with frequent premature ventricular complexes (PVCs) and normal left ventricular ejection fraction (LVEF) remains unclear. Existing data has been predominantly derived from highly selected populations, that may overestimate the true prevalence of abnormal findings on CMR in this patient population.

Purpose

The aim of this study was 2-fold: 1) to establish the prevalence of CMR imaging abnormalities in a cohort with normal LVEF and high PVC burden; 2) to identify predictors of CMR imaging abnormalities in patients with frequent PVCs and normal LVEF.

Methods

In this cohort study, 211 patients (age 53.2±19 years; 41% male) with frequent PVCs (≥5%/24 h), of normal LVEF (≥50% by echocardiography) and no known underlying structural heart disease were prospectively enrolled from 2016–2020. Of these, 166 (79%) patients were symptomatic from their PVCs in the form of palpitations, fatigue, chest pain, dizziness, and/or dyspnea. Patients underwent CMR imaging (1.5 Tesla) with a late gadolinium enhancement (LGE) protocol at the time of enrollment for the detection of scarring and/or fibrosis.

Results

Patients had a median baseline echocardiographic LVEF of 60% (± 5%) with 195 (92%) of patients having a normal native QRS morphology. Median PVC burden of the study cohort was 16% (± 14%). CMR LGE abnormalities were found in 19 (9%) patients including 17 scans with non-ischemic LGE and 2 with ischemic LGE. Age &gt;60 (odds ratio [OR]: 3.20, 95% confidence interval [CI]: 1.20–8.51, p=0.020), male sex (OR: 4.67, 95% CI: 1.61–13.50, p=0.004), history of hypertension (OR: 3.43, 95% CI: 1.31–8.97, p=0.012), native QRS duration (OR: 1.03, 95% CI: 1.00–1.05, p=0.031), and history of non-sustained ventricular tachycardia (OR: 2.81, 95% CI: 1.03–7.68, p=0.044) were significantly associated with the presence of imaging abnormalities on CMR. Dominant PVC origin from the left ventricle had a positive trend (OR: 2.60, 95% CI: 0.99–7.66, p=0.083) to association with CMR imaging abnormalities. On multivariate analysis, male sex (OR: 4.10, 95% CI: 1.40–12.04, p=0.010) and history of hypertension (OR: 2.89, 95% CI: 1.08–7.75, p=0.035) remained significantly associated with the presence of CMR abnormalities. There was no association between CMR imaging abnormalities and the burden of PVCs or the number of PVC morphologies.

Conclusion

In this cohort, only 9% of patients with apparently idiopathic frequent PVCs and normal LVEF had concealed myocardial abnormalities on CMR imaging. Male sex and history of hypertension were associated with a higher rate of CMR abnormalities.

Funding Acknowledgement

Type of funding sources: None.

Consolidation nivolumab and ipilimumab versus observation in limited-disease small-cell lung cancer after chemo-radiotherapy - results from the randomised phase II ETOP/IFCT 4-12 STIMULI trial

BACKGROUND

Concurrent chemotherapy and thoracic radiotherapy followed by prophylactic cranial irradiation (PCI) is the standard treatment in limited-disease small-cell lung cancer (LD-SCLC), with 5-year overall survival (OS) of only 25% to 33%.

PATIENTS AND METHODS

STIMULI is a 1:1 randomised phase II trial aiming to demonstrate superiority of consolidation combination immunotherapy versus observation after chemo-radiotherapy plus PCI (protocol amendment-1). Consolidation immunotherapy consisted of four cycles of nivolumab [1 mg/kg, every three weeks (Q3W)] plus ipilimumab (3 mg/kg, Q3W), followed by nivolumab monotherapy (240 mg, Q2W) for up to 12 months. Patient recruitment closed prematurely due to slow accrual and the statistical analyses plan was updated to address progression-free survival (PFS) as the only primary endpoint.

RESULTS

Of the 222 patients enrolled, 153 were randomised (78: experimental; 75: observation). Among the randomised patients, median age was 62 years, 60% males, 34%/65% current/former smokers, 31%/66% performance status (PS) 0/1. Up to 25 May 2020 (median follow-up 22.4 months), 40 PFS events were observed in the experimental arm, with median PFS 10.7 months [95% confidence interval (CI) 7.0-not estimable (NE)] versus 42 events and median 14.5 months (8.2-NE) in the observation, hazard ratio (HR) = 1.02 (0.66-1.58), two-sided P = 0.93. With updated follow-up (03 June 2021; median: 35 months), median OS was not reached in the experimental arm, while it was 32.1 months (26.1-NE) in observation, with HR = 0.95 (0.59-1.52), P = 0.82. In the experimental arm, median time-to-treatment-discontinuation was only 1.7 months. CTCAE v4 grade ≥3 adverse events were experienced by 62% of patients in the experimental and 25% in the observation arm, with 4 and 1 fatal, respectively.

CONCLUSIONS

The STIMULI trial did not meet its primary endpoint of improving PFS with nivolumab-ipilimumab consolidation after chemo-radiotherapy in LD-SCLC. A short period on active treatment related to toxicity and treatment discontinuation likely affected the efficacy results.

Catheter ablation as first-line treatment for paroxysmal atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of catheter ablation (CA) compared with antiarrhythmic drugs (AADs) as first-line treatment for symptomatic paroxysmal atrial fibrillation (AF).

METHODS

Systematic review and meta-analysis of randomised controlled trials identified using MEDLINE, Cochrane Library and Embase published between 01/01/2000 and 19/03/2021. The primary efficacy endpoint was the first documented recurrence of atrial arrhythmias following the blanking period. The primary safety endpoint was a composite of all serious adverse events (SAEs).

RESULTS

From 441 records, 6 studies met the inclusion criteria. 609 patients received CA, while 603 received AAD therapy. 212/609 patients in the CA group had a recurrence of atrial arrhythmias as compared with 318/603 in the AADs group resulting in a 36% relative risk reduction (risk ratio: 0.64, 95% CI 0.51 to 0.80, p<0.01). The risk of all SAEs was not statistically different between CA and AAD (0.87, 0.58 to 1.30, p=0.49); 107/609 SAE in the CA group vs 126/603 in the AAD group. Both recurrence of symptomatic atrial arrhythmias (109/505 vs 186/504) and healthcare utilisation (126/397 vs 185/394) were significantly lower in the CA group (0.53, 0.35 to 0.79 and 0.65, 0.48 to 0.89, respectively). There was a 79% reduction in the crossover rate during follow-up among patients randomised to CA compared with AAD (0.21, 0.13 to 0.32, p<0.01).

CONCLUSIONS

First-line treatment with CA is superior to AAD therapy in patients with symptomatic paroxysmal AF, as it significantly reduces the recurrence of any atrial arrhythmias and symptomatic atrial arrhythmias, and healthcare resource utilisation with comparable safety profile.

Whipping properties of recombined, additive-free creams

There is increasing industrial interest in the use of the milkfat globule membrane as a food ingredient. The objective of this research was to determine whether the aerosol whipping performance of cream separated into butter and buttermilk, and then recombined, would perform in a manner similar to untreated cream. Churning of cream tempered to different solid fat contents was used to separate butter from buttermilk, which were then recombined at the same ratios as the initial extraction yield, or with 25% extra buttermilk. Differences in milkfat globule size distributions among the recombined creams were apparent; however, their whipping behavior and overrun were similar. Importantly, all recombined creams did not yield properties similar to the original cream, indicating that the unique native milkfat globule membrane structure plays a role in cream performance well beyond its simple presence.

Incidence of accidental awareness during general anaesthesia in obstetrics: a multicentre, prospective cohort study

General anaesthesia for obstetric surgery has distinct characteristics that may contribute towards a higher risk of accidental awareness during general anaesthesia. The primary aim of this study was to investigate the incidence, experience and psychological implications of unintended conscious awareness during general anaesthesia in obstetric patients. From May 2017 to August 2018, 3115 consenting patients receiving general anaesthesia for obstetric surgery in 72 hospitals in England were recruited to the study. Patients received three repetitions of standardised questioning over 30 days, with responses indicating memories during general anaesthesia that were verified using interviews and record interrogation. A total of 12 patients had certain/probable or possible awareness, an incidence of 1 in 256 (95%CI 149-500) for all obstetric surgery. The incidence was 1 in 212 (95%CI 122-417) for caesarean section surgery. Distressing experiences were reported by seven (58.3%) patients, paralysis by five (41.7%) and paralysis with pain by two (16.7%). Accidental awareness occurred during induction and emergence in nine (75%) of the patients who reported awareness. Factors associated with accidental awareness during general anaesthesia were: high BMI (25-30 kg.m^-2 ); low BMI (<18.5 kg.m^-2 ); out-of-hours surgery; and use of ketamine or thiopental for induction. Standardised psychological impact scores at 30 days were significantly higher in awareness patients (median (IQR [range]) 15 (2.7-52.0 [2-56]) than in patients without awareness 3 (1-9 [0-64]), p = 0.010. Four patients had a provisional diagnosis of post-traumatic stress disorder. We conclude that direct postoperative questioning reveals high rates of accidental awareness during general anaesthesia for obstetric surgery, which has implications for anaesthetic practice, consent and follow-up.

Balance Right in Multiple Sclerosis (BRiMS): a feasibility randomised controlled trial of a falls prevention programme

Background

Balance, mobility impairments and falls are problematic for people with multiple sclerosis (MS). The “Balance Right in MS (BRiMS)” intervention, a 13-week home and group-based exercise and education programme, aims to improve balance and minimise falls. This study aimed to evaluate the feasibility of undertaking a multi-centre randomised controlled trial and to collect the necessary data to design a definitive trial.

Methods

This randomised controlled feasibility study recruited from four United Kingdom NHS clinical neurology services. Patients ≥ 18 years with secondary progressive MS (Expanded Disability Status Scale 4 to 7) reporting more than two falls in the preceding 6 months were recruited. Participants were block-randomised to either a manualised 13-week education and exercise programme (BRiMS) plus usual care, or usual care alone.

Feasibility assessment evaluated recruitment and retention rates, adherence to group assignment and data completeness. Proposed outcomes for the definitive trial (including impact of MS, mobility, quality of life and falls) and economic data were collected at baseline, 13 and 27 weeks, and participants completed daily paper falls diaries.

Results

Fifty-six participants (mean age 59.7 years, 66% female, median EDSS 6.0) were recruited in 5 months; 30 randomised to the intervention group. Ten (18%) participants withdrew, 7 from the intervention group. Two additional participants were lost to follow up at the final assessment point. Completion rates were > 98% for all outcomes apart from the falls diary (return rate 62%).

After adjusting for baseline score, mean intervention—usual care between-group differences for the potential primary outcomes at week 27 were MS Walking Scale-12v2: − 7.7 (95% confidence interval [CI] − 17.2 to 1.8) and MS Impact Scale-29v2: physical 0.6 (CI − 7.8 to 9), psychological − 0.4 (CI − 9.9 to 9). In total, 715 falls were reported, rate ratio (intervention:usual care) for falls 0.81 (0.41 to 2.26) and injurious falls 0.44 (0.41 to 2.23).

Conclusions

Procedures were practical, and retention, programme engagement and outcome completion rates satisfied a priori progression criteria. Challenges were experienced in completion and return of daily falls diaries. Refinement of methods for reporting falls is therefore required, but we consider a full trial to be feasible.

Trial registration

ISRCTN13587999

Date of registration: 29 September 2016

Thromboembolic risk stratification in atrial fibrillation-beyond clinical risk scores

Atrial fibrillation (AF) is the most common arrhythmia in the adult general population. As populations age, the global burden of AF is expected to rise. AF is associated with stroke and thromboembolic complications, which contribute to significant morbidity and mortality. As a result, it remains paramount to identify patients at elevated risk of thromboembolism and to determine who will benefit from thromboembolic prophylaxis. Conventional practice advocates the use of clinical risk scoring criteria to identify patients at risk of thromboembolic complications. These risk scores have modest discriminatory ability in many sub-populations of patients with AF, highlighting the need for improved risk stratification tools. New insights have been gained on the utility of biomarkers and imaging modalities, and there is emerging data on the importance of the identification and treatment of subclinical AF. Finally, the advent of wearable devices to detect cardiac arrhythmias pose a new and evolving challenge in the practice of cardiology. This review aims to address strategies to enhance thromboembolic risk stratification and identify challenges with current and future practice.

Machine learning for predicting AF ablation outcomes using daily heart rhythm data at baseline

Background

While numerous studies have shown that catheter ablation is superior to antiarrhythmic drug (AAD) in treating atrial fibrillation (AF), the long term outcomes have been limited by arrhythmia recurrence. Reliable data and methods to predict ablation outcomes will thus be valuable for treatment planning.

Objective

To evaluate the utility of machine learning and various types of input variables, viz. patient characteristics at baseline, and daily heart rhythm data recorded prior to ablation for outcome prediction.

Methods

We acquired permission to analyze data collected from a randomized clinical trial that recorded daily biomeasures from &gt;345 patients who were referred for first catheter ablation due to AF refractory to at least one AAD. After standardizing the dataset, each patient sample is characterized by a set of daily measures, viz. heart rate variability (HRV) and AF burden (AFB), which is the total minutes in AF per day. We next performed comparative analyses on 19 candidate model variants to evaluate each model's ability in identifying patients who were to experience at least one episode of AF recurrence during post-ablation period starting from day 91 up to day 365 post-ablation, per standard guidelines. We examined: i) use of a set of daily biomeasures jointly with baseline sex and age; and ii) observation lengths of the pre-ablation period. We also examined the use of baseline CHA2DS2-VASc scores, left-atrial volume (LAV), atrial diameter, medical history. We conducted multiple sets of 3-fold cross validation (CV) experiments, each fold independently trained a candidate model with 236 samples (two thirds of the dataset) and performed evaluation on the left-out samples. About 50% of cohort belongs to one class. Each fold scored a model and its input variables in terms of sensitivity (SEN), specificity (SPEC), area under receiver operating characteristic curve (AUC), etc. To circumvent risks of overfitting highly parameterized models to our training subset, we shortlisted 19 models that have few hyper-parameters, e.g. stepwise regression, random forest (RF), linear discriminant analysis (LDA).

Results

CV results demonstrated that LDA and RF gave comparable performances, with RF achieving highest AUC of 0.68±0.06 using 30 days of rhythm data prior to ablation (SEN of 65.9±7.82; SPEC of 66.3±0.57). When observation period extended to 90 days prior, AUC improved to 0.691±0.02. In contrast, use of LAV alone was not adequate to predict outcome (AUC∼0.5), and when combined with all aforementioned baseline variables, the best model achieved AUC of 0.58±0.05. Feature analyses from the trained models suggest that AFB had highest relevance in predicting outcome. Using only daily AFB, RF and LDA respectively achieved AUC of 0.608±0.04 and 0.652±0.04.

Conclusions

Our results suggest the value of pre-ablation rhythm data for improving outcome-prediction. Future work will validate these findings using large public datasets.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Huawei-Data Science Institute Research Program; Natural Sciences and Engineering Research Council of Canada (NSERC)

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multicentre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%).

Abstract WMP65: Prospective Validation of Predictive Features of Paroxysmal Atrial Fibrillation (PROPhecy): An Interim Analysis

Background: Atrial fibrillation (AF) has a distinct antithrombotic regimen for secondary stroke prevention. While 30-day cardiac monitoring has a greater detection rate for AF than 24-hour Holter, it is not widely accessible. Risk stratification may identify patients who could benefit most from prolonged monitoring. PROPhecy aims to prospectively validate predictive features for detection of AF found in EMBRACE, a trial using 30-day monitoring in individuals with an embolic stroke of undetermined source (ESUS).

Methods: Participants were > 55 years and within six months of ESUS, without evidence of AF/flutter on 24-hour Holter. All were given an event-triggered external loop recorder for 30 days. Primary outcome was detection of sustained ( > 30 sec) or non-sustained AF/flutter on 30-day monitoring.

Results: 150 of a planned 250 participants have completed long-term monitoring to date. Baseline characteristics are compared to EMBRACE (Table 1). Any AF/flutter was detected in 19.3% (EMBRACE, 16.1%). Burden of atrial premature beats in PROPhecy was low in comparison to EMBRACE and did not predict presence of AF on monitoring (Table 2). Left atrial volume index was a significant predictor of AF in both univariable and multivariable regression adjusted for age and sex (OR1.04 per mL/m 2 , 95% 1.01-1.08, p=0.02).

Conclusion: Recruitment is ongoing. AF was detected in ~1/5 participants. The burden of atrial ectopy in our cohort is much lower than in EMBRACE despite similar patient characteristics and AF burden. Further work is required to assess the nature of these differences. Left atrial volume index may be helpful for risk stratification.

164 Gonadotrophin-releasing hormone injection and colour flow Doppler ultrasound of the preovulatory follicle as a tool to increase pregnancy outcome after timed AI in beef cows

The aims of this study were to determine (1) the association between Doppler vascularisation scores (DVS) of the preovulatory follicle (POF) and fertility of beef cows submitted to timed AI (TAI) and (2) whether cows with low DVS benefit from a gonadotrophin-releasing hormone (GnRH) treatment at TAI. Multiparous lactating Nelore cows (Bos indicus; n=69) from a commercial beef farm in the state of Rondônia, Brazil, were enrolled in this study. Cows received 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogénesis Bagó) and an intravaginal progesterone-releasing device (1.9g of progesterone; controlled internal drug release, CIDR) to synchronise follicular wave emergence on Day 0. The CIDR device was removed and cows were treated with 150μg of D-cloprostenol intramuscularly (prostaglandin F2α analogue; Croniben), 1mg of oestradiol cypionate intramuscularly, and 300IU of equine chorionic gonadotrophin (Novormon) intramuscularly on Day 8. Cows were then painted with a tail chalk marker to identify those displaying oestrus. All cows were submitted to TAI 48h after CIDR removal. At TAI, occurrence of oestrus was recorded and all cows were examined using transrectal ultrasonography. Blood flow of the POF was evaluated using colour Doppler imaging. Colour Doppler signals present on the follicular wall were subjectively scored using a 1-to-4 scale (1=absence or very low blood flow, and 4=intense blood flow detected on most of the follicular wall surface) adapted from Ginther (2007Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography, pages 87-114). Then, cows were divided into three groups according their DVS of the POF: (1) high DVS (DVS ≥3; n=36), (2) low DVS (DVS &lt;3; n=16), and (3) low DVS (DVS &lt;3; n=17) plus a GnRH treatment at TAI. The diameter of the POF was analysed using analysis of variance (PROC GLIMMIX of SAS; SAS Institute Inc.), and the means were compared among groups using Tukey's test. The proportion of cows that displayed oestrus and pregnancy rates was analysed using chi-square test. Cows in the high-DVS group had a larger POF than cows in the low-DVS and low-DVS-GnRH groups (13.2±0.2, 11.7±0.5, and 12.2±0.4, respectively; P&lt;0.05). The proportion of cows that displayed oestrus was greater (P&lt;0.05) in the high-DVS group (72%, 26/36) than in the low-DVS (37.5%, 6/16) or low-DVS-GnRH (53%, 9/17) groups. Finally, greater (P&lt;0.05) pregnancy rates were observed in cows from the high-DVS (47.2%; 17/36) and low-DVS-GnRH (52.9%; 9/17) groups than in cows from the low-DVS group (18.7%; 3/16). The preliminary results from this study demonstrated that diameter of POF is positively associated with DVS. Moreover, cows that presented POF with higher DVS are more likely to become pregnant, and the administration of GnRH to females with low DVS can increase the fertility of beef cows submitted to TAI protocols. This study received funding support from Embrapa (MP1/PC3 project no. 01.03.14.011.00.00) and from CNPq (universal project no. 407307/2016-8).

P6536Implementation of a mass atrial fibrillation screening program in Canadian community practice

Background

Atrial fibrillation is the most common arrhythmia seen in clinical practice, and is an important cause of stroke. In up to 10% of patients, stroke is the first clinical manifestation of undiagnosed atrial fibrillation (AF). Early detection of AF is therefore desirable, as it would provide an opportunity to initiate appropriate stroke prevention with anticoagulation. While European guidelines recommend screening for AF as part of routine care in patients with risk factors, the optimal modality has not yet been determined. Smartphone enabled single lead ECG devices have been shown to be highly accurate and could prove to be an effective point of care tool for uncovering AF in the community and may facilitate implementation of screening recommendations.

Purpose

We sought to describe the integration of a smartphone enabled single lead ECG device into the practice of selected Canadian community-based physicians and its impact on patient care.

Methods

Canadian community-based physicians were provided with a smartphone enabled single lead ECG device for a period of six months. Physicians were instructed to perform a single 30 second ECG recording in patients over the age of 65 who present for a regular follow-up visit. Patients with previous AF diagnosis were excluded. Outcomes related to screening, and stroke prevention-treatment initiation were prospectively ascertained and documented using a patient flow tracker.

Results

Among 612 physicians who were invited to participate in the program, 315 (51%) agreed to track and report the use of the device that was provided to them. During this program, 315 physicians screened a total of 15,538 patients. AF was detected 1103 patients (7.1%). The majority of patients with a positive screen underwent a subsequent 12-lead ECG confirmatory exam (79%). AF could not be confirmed in 277 patients (31.7% of patients undergoing 12-lead ECG). A total of 677 patients were initiated on oral anticoagulation (OAC), with 262 patients (24%) being initiated on OAC prior to ECG confirmation.

Conclusion

Undiagnosed AF is common in patients >65 years of age in community practice. The results of this program indicate that single lead mobile ECG devices can be integrated into routine point of care use for Canadian physicians and, can be a valuable tool to detect previously undiagnosed AF. While this approach identified a large number of undiagnosed AF patients eligible for OAC therapy, undertreatment with OAC remains a concern.

Acknowledgement/Funding

Bristol-Myers Squibb/Pfizer Alliance

Outcomes of untreated frequent premature ventricular complexes with normal left ventricular function

Objective

The natural history of frequent premature ventricular complexes (PVCs) in association with preserved left ventricular ejection fraction (LVEF) is uncertain. The optimal management of this population is thus undefined. We studied the outcomes of untreated patients with frequent PVCs and preserved LVEF.

Methods

This cohort study prospectively evaluated consecutive patients from 2012 to 2017, with asymptomatic or minimally symptomatic frequent idiopathic PVCs (≥5% PVCs in 24 hours; normal LVEF; no cause identified on comprehensive evaluation). No suppressive therapy (ablation or antiarrhythmic drugs) were used and patients were followed with serial ambulatory ECG monitoring and echocardiography. The primary arrhythmic outcome was reduction in PVC burden to <1% on serial ambulatory monitoring. The primary echocardiographic outcome was a reduction of LVEF to <50%.

Results

One hundred patients met inclusion criteria (mean age 51.8 years, 57% female) with a median PVC burden of 18.4%. Reduction to <1% PVCs occurred in 44 of 100 patients (44.0%) at a median of 15.4 months (range 2.6 to 64.3). Recurrence was uncommon (4/44, 9.1%). Four patients (4.3%) with a persistently elevated PVC burden developed left ventricular dysfunction (LVEF <50%) during the follow-up period at a range of 53–71 months. The initial PVC burden did not predict subsequent resolution (HR 1.00(0.97, 1.03); p=0.86).

Conclusions

A strategy of active surveillance is appropriate for the majority of patients with frequent idiopathic PVCs in association with preserved LVEF, owing to the low risk of developing left ventricular systolic dysfunction and the high rate of spontaneous resolution.