Role of insertable cardiac monitors in anticoagulation therapy in patients with atrial fibrillation at high risk of bleeding

"Real-world" performance of the Confirm Rx™ SharpSense AF detection algorithm: UK Confirm Rx study

Introduction

The novel Confirm Rx™ implantable cardiac monitor (ICM) with SharpSense™ technology incorporates a new P-wave discriminator designed to improve AF detection. This study aimed to evaluate the diagnostic performance of the Confirm Rx™ ICM in detecting AF episodes of varying durations.

Methods

We conducted a multicenter retrospective analysis of consecutive patients implanted with a Confirm Rx™ ICM (v1.2) across nine UK hospitals, all with documented AF lasting at least 6 min. Electrocardiograms (ECGs) were manually adjudicated by cardiologists. To account for intra- and inter-reviewer variability, a random sample of 10% of ECGs underwent additional review. Disagreements were resolved by a third reviewer. Diagnostic performance was determined by calculating the gross and patient-averaged positive predictive value (PPV) for AF episodes of different duration. The source of false positive (FP) detection was also categorized.

Results

Overall, 16,230 individual ECGs from 232 patients were included. The median AF episode duration was 14 min. R-wave amplitude remained stable during follow-up (0.52 ± 0.27 mV [initial] vs. 0.54 ± 0.29 mV [end of follow-up], p = .10). The gross and patient-averaged PPV were 75.0% and 67.0%, respectively. Diagnostic performance (gross) increased with progressively longer AF episodes: 88.0% for ≥1 h, 97.3% for 6 h, and 100% for 24 h. The main source of FP during tachycardia was T-wave oversensing (54.2%), while in non-tachycardic episodes it was predominantly ectopy (71.2%). The AF burden precision was excellent (93.3%).

Conclusion

The Confirm Rx™ ICM diagnostic performance was modest for all AF episodes (75%), with accuracy increasing for longer AF episodes.

'Pill-in-the-pocket' Oral Anticoagulation Guided by Daily Rhythm Monitoring for Stroke Prevention in Patients with AF: A Systematic Review and Meta-analysis

Aims

In patients with a low AF burden and long periods of sinus rhythm, 'pill-in-the-pocket' oral anticoagulation (OAC) may, taken as needed in response to AF episodes, offer the same thromboembolic protection as continuous, life-long OAC, while reducing bleeding complications at the same time. The purpose of this study is to systematically summarise available evidence pertaining to the feasibility, safety and efficacy of pill-in-the-pocket OAC.

Methods

Medline and Embase were searched from inception to July 2022 for studies adopting a pill-in-the-pocket OAC strategy in AF patients guided by daily rhythm monitoring (PROSPERO/CRD42020209564). Outcomes of interest were extracted and event rates per patient-years of follow-up were calculated. A random effects model was used for pooled estimates.

Results

Eight studies were included (711 patients). Daily rhythm monitoring was continuous in six studies and intermittent in two (pulse checks or smartphone single-lead electrocardiograms were used). Anticoagulation criteria varied across studies, reflecting the uncertainty regarding the AF burden that warrants anticoagulation. The mean time from AF meeting OAC criteria to its initiation was not reported. Adopting pill-in-the-pocket OAC led to 390 (54.7%) patients stopping OAC, 85 (12.0%) patients taking pill-in-the-pocket OAC and 237 (33.3%) patients remaining on or returning to continuous OAC. Overall, annualised ischaemic stroke and major bleeding rates per patient-year of follow-up were low at 0.005 (95% CI [0.002-0.012]) and 0.024 (95% CI [0.013-0.043]), respectively.

Conclusion

Current evidence, although encouraging, is insufficient to inform practice. Additional studies are required to improve our understanding of the relationships between AF burden and thromboembolic risk to help define anticoagulation criteria and appropriate monitoring strategies.

Outpatient Initiation of Sotalol in Patients with Atrial Fibrillation: Utility of Cardiac Implantable Electronic Devices for Therapy Monitoring

Background

Antiarrhythmic drugs are often used in the management of patients with atrial fibrillation (AF). Sotalol is conventionally initiated in the inpatient setting for monitoring efficacy and adverse effects, including QTc interval prolongation and torsades de pointes (TdP) proarrhythmia.

Objective

We aimed to evaluate the efficacy and safety of outpatient initiation of sotalol for the treatment of AF in a select group of patients with cardiac implantable electronic devices (CIEDs): permanent pacemakers (PPMs), implantable cardioverter defibrillators (ICDs), and implantable loop recorders (ILRs) capable of continuous rhythm monitoring remotely.

Methods

We conducted our clinical study in a real-world practice setting with longitudinal follow-up of the study cohort. We included adult patients with symptomatic paroxysmal and persistent AF eligible for sotalol for rhythm control strategy and who had CIEDs in our study. Patients with a known contraindication to sotalol were excluded. After making a shared management decision with patients, sotalol was initiated as an outpatient, with regular clinical encounters with patients to assess the efficacy and safety of treatment, and monitoring cardiac rhythm and QTc intervals with CIEDs utilizing their remote monitoring platforms.

Results

The study cohort comprised 105 patients; 38 (36%) females, mean age ± standard deviation (SD) 73.9 ± 10.36 years, and with a CHA₂DS₂-VASc score of 3.26 ± 1.37 and left ventricular ejection fraction of 60.16 ± 9.10%. Twenty-six (24.8%) patients were implanted with PPMs, 10 (9.5%) with dual-chamber ICDs, and 69 (65.7%) with ILRs. Over a follow-up period of 23 ± 15 months, sotalol was continued at a steady median dose of 80 mg twice daily, 105 ± 42 mg (mean ± SD) in 77 (73%) patients who maintained sinus rhythm, and discontinued in 28 (27%) patients because of inefficacy or development of adverse effects. No adverse effects relating to QTc prolongation and TdP or mortality were observed during the study period.

Conclusions

Effective and safe outpatient initiation and maintenance of sotalol therapy is possible in select patients who have CIEDs for continuous remote monitoring and surveillance capabilities.

Outpatient initiation of dofetilide: insights from the complexities of atrial fibrillation management during the COVID-19 lockdown

Background

At peak COVID-19 lockdown, patients with symptomatic atrial fibrillation (AF) were faced with an equipoise between a palliative rate-control versus cautious rhythm-control strategy, including hospitalization for initiation of antiarrhythmic drug/s (AADs) and cardiac procedures which was impossible due to hospitalization restrictions.

Objectives

We aimed to evaluate the efficacy and safety of outpatient initiation of dofetilide in patients with AF using cardiac implantable electronic devices (CIEDs) for rhythm and QTc interval monitoring.

Methods

Adult patients with symptomatic AF with prior failure or intolerance to other AADs were enrolled if they were willing to in-office insertion of implantable loop recorders or already implanted with pacemakers or defibrillators capable of remote monitoring. Exclusion criteria were known medical contraindications of dofetilide and unable to provide consent. After making a shared management decision, dofetilide was initiated in a physician office, and rhythm and QTc intervals were monitored by ECGs and CIEDs. Patients were followed to assess the efficacy and safety of the treatment.

Results

The study cohort comprised of 30 patients, age 76 ± 7 years (mean ± standard deviation), 10 female (33%), CHA₂DS₂-VASc score 3.25 ± 1.3, ejection fraction 63.45% ± 8.52, and QTc interval 431.68 ± 45.09 ms. From 22 (73%) patients in AF at presentation, SR was restored in 14 (64%) patients after 4 doses of dofetilide. At 46 ± 59 days of follow-up, maintenance of SR in total 22 (73%) patients without cardiac adverse effects was accomplished.

Conclusion

Effective and safe outpatient initiation of dofetilide during the extenuating circumstance of COVID-19 lockdown was possible in patients with AF who had CIEDs.

Implantable loop recorders for cardiac dysrhythmia monitoring

Incorporation of technological advances in healthcare delivery has played a foundational role in development of modern healthcare. With the use of wireless transmission in conjunction with digitization of electrocardiography, continuous monitoring strategies have redefined our approach to dysrhythmia. These devices show promising results in evolving implantable loop recorder technology. In this review, we summarize the history of remote monitoring, indications for loop recorders, devices available, evidence for specific devices and anticipated studies.

Role of cardiovascular implantable electronic devices in delivering individualized disease-guided management of patients with non-valvular atrial fibrillation and high bleeding risk

BACKGROUND

Many patients with non-valvular atrial fibrillation (NVAF) with high risk for thromboembolic stroke and bleeding may not wish to continue long-term oral anticoagulants (OACs) to avoid bleeding complications. We aimed to investigate whether AF burden assessment by cardiovascular implantable electronic devices (CIEDs) would allow an individualised disease-guided approach for safe withdrawal of long-term OAC in high-risk patients.

METHODS AND RESULTS

We studied 145 patients (age 77.6 ± 10.6 years; 49.7% females) with NVAF, CHA₂DS₂-VASc score ≥2, HAS-BLED score ≥3, in whom CIEDs were implanted. These patients wished to stay off long-term OAC based on their previous adverse bleeding event/s or due to similar events witnessed in the family or friend circle. These patients were grouped into 'low AF burden' [n = 121 (83%)], or 'high AF burden' [n = 24 (17%)] defined as <24 hours or >24 hours cumulatively in 30 consecutive days respectively, and followed for 51.2 ± 29.8 months. All patients with 'low AF burden' were allowed to discontinue OAC, but OAC was resumed in 1 patient who experienced TIA. Bleeding events developed in 9 out of 24 (37.5%) patients with 'high AF burden' who were maintained on OAC, as compared to 3 out of 121 (2.47%) patients with 'low AF burden' who were off OAC (p <.05). There were 9 (6.2%) deaths unrelated to AF treatment approach.

CONCLUSIONS

In NVAF patients, AF burden assessment by CIEDs allows an individualised disease-guided approach to safe withdrawal of long-term OAC in patients with high bleeding risk who do not wish to continue long-term anticoagulation.

Implantable loop recorder in clinical practice

The implantable loop recorder (ILR), also known as insertable cardiac monitor (ICM) is a subcutaneous device used for diagnosing heart rhythm disorders. These devices have been strongly improved and miniaturized during the last years showing several reliable features along with the availability of remote monitoring which improves the diagnostic timing and the follow-up strategy with a potential reduction of costs for health care. The recent advent of injectable ILRs makes the procedure even easier and more tolerated by patients. ILR allows the investigation of unexplained recurrent syncope with uncertain diagnosis, revealing a possible relationship with cardiac arrhythmias. In addition, it has recently been equipped with sophisticated algorithms able to detect atrial fibrillation episodes. This new opportunity may provide to the physicians systematic heart rhythm screening with possible effects on patient antiarrhythmic and anticoagulant therapy management. The use of such devices will surely increase, since they may be helpful to diagnose a wide range of disorders and pathologies. Indeed, further studies should be performed in order to identify all the potentialities of these tools.

Long-term monitoring to detect atrial fibrillation with the indwelling implantable cardiac monitors

An increasing number of detection tools are available and several detection strategies have been described to pursue the diagnosis of atrial fibrillation to prevent ischemic stroke. Monitoring tools include standard electrocardiography, snapshot single-lead recordings with professional or personal devices (e.g. smartphone-based), Holter monitor, external devices with long-term recording capabilities, and cardiac implantable electronic devices, including pacemakers, implantable cardioverter defibrillators and insertable cardiac monitors. Insertable cardiac monitors have shown high sensitivity and specificity for the detection of atrial fibrillation, allow up to three years of continuous monitoring, do not require cooperation of the patient, are well tolerated, have a short device-related time delay between detection of atrial fibrillation and notification to the physician, provide information on atrial fibrillation burden and are minimally invasive. On the other hand, insertable cardiac monitors require a considerable use of resources to process the recordings and have a significant initial cost. Studies conducted with insertable cardiac monitors on patients with prior stroke and on patients with risk factors for stroke but no prior cerebrovascular events or atrial fibrillation have consistently shown a measurable incidence of atrial fibrillation at follow-up. However, the effectiveness of oral anticoagulations in reducing the incidence of ischemic stroke in patients with atrial fibrillation lasting less than 24 h, though reasonable, is currently unproven. The future of atrial fibrillation detection tools and atrial fibrillation detection strategies will be influenced by ongoing studies exploring whether oral anticoagulations reduce the incidence of stroke in patients with atrial fibrillation burden lower than 24 h.

Revisiting the Role of Antiarrhythmic Drugs in Prevention of Atrial Fibrillation Recurrence: A Single Center Retrospective Review

Background

We conducted a retrospective analysis to revisit the efficacy of four different commonly used antiarrhythmic drugs (AADs) in a single community hospital setting in the U.S. We used cardiac implantable electronic devices (CIEDs) to continuously monitor the patients for maintenance of sinus rhythm. The CIEDs in our study included insertable cardiac monitor (ICM), permanent pacemaker (PPM) and cardiac resynchronization therapy-defibrillator (CRT-D). The aim was to compare efficacy of commonly used AADs for maintenance of sinus rhythm in atrial fibrillation (AF) patients.

Methods

We conducted our retrospective study in a real world practice setting. We analyzed electronic medical records of 145 consecutive patients with paroxysmal and persistent AF who were treated with AADs for maintenance of sinus rhythm between the period of April 2014 and February 2018.

Results

Total 34 out of 145 patients (23.45%) had AF recurrence. The mean duration of first AF recurrence in total patient cohort was 18.01 ± 12 months. There was no major difference in efficacy in terms of prevention of first episode of AF recurrence among commonly used class III and class IC AADs.

Conclusions

Higher doses clearly seem to be more effective in preventing the recurrence of AF in class III AADs; sotalol and amiodarone. Use of CIEDs helps to continuously monitor patients for recurrence of AF and detects proarrhythmic effects of AADs.

When is Device-Detected Atrial Fibrillation Actionable?

Device-detected atrial high-rate episodes (AHREs) are frequently encountered in patients with no history of atrial fibrillation (AF) and represent a challenge for clinicians because patients with device-only documented AF have not been included in clinical trials of anticoagulants and other AF therapies. For patients with known history of AF, wireless continuous rhythm monitoring and rapidly acting oral anticoagulants offer the possibility of tailored anticoagulation in response to AHREs, with studies ongoing to evaluate the safety of this approach. This article provides an overview of current evidence on device-detected AHREs and evolving areas of investigation.

How and When to Screen for Atrial Fibrillation after Stroke: Insights from Insertable Cardiac Monitoring Devices

The introduction of insertable cardiac monitoring devices has dramatically altered our understanding of the role of intermittent atrial fibrillation in cryptogenic stroke. In this narrative review we discuss the incidence, timing and relationship between atrial fibrillation and cryptogenic stroke, how to select patients for monitoring and the value and limitations of different monitoring strategies. We also discuss the role of empirical anticoagulation, and atrial fibrillation burden as a means of tailoring anticoagulation in patients at high risk of bleeding.