A Comparison of Atrial Fibrillation Monitoring Strategies After Cryptogenic Stroke (from the Cryptogenic Stroke and Underlying AF Trial)

Evaluation of the safety, efficacy, effectiveness and cost-effectiveness of implantable Holter for prolonged monitoring in patients with previous stroke: a systematic review

Background

Atrial fibrillation (AF), which is associated with cryptogenic stroke, is the most common sustained arrhythmia in the general population. Because AF is asymptomatic and intermittent, its detection rate increases with the duration of monitoring. The objective of this study is to review the available evidence on the safety, efficacy, effectiveness and cost-effectiveness of AF diagnosis by prolonged monitoring with an implantable Holter monitor in adult patients with idiopathic or cryptogenic stroke of suspected cardioembolic origin, compared to conventional monitoring.

Methods

Two independent reviewers performed a systematic review of the literature, identifying relevant studies through a structured search of Medline (Ovid), EMBASE, Web of Science and Cochrane Library and the databases of national and international health technology assessment agencies. The quality of the included studies was assessed with AGREE-II, AMSTAR-2 and CHEC. GRADE criteria were used to summarise the evidence.

Results

Four of the 211 papers identified were included: 1 clinical practice guideline, 2 systematic reviews, and 1 economic evaluation. The quality of the evidence reviewed was low. An implantable Holter monitor might be more effective in detecting AF than conventional monitoring. Serious adverse events were similar in both groups. The economic evaluation suggests that the technology is cost-effective.

Conclusions

The available evidence suggests the diagnostic superiority of the implantable Holter monitor over the traditional Holter monitor. Due to the low quality of the evidence, further and higher quality studies on these technologies are needed before solid conclusions can be drawn.

Atrial fibrillation: focus on monitoring strategies after cryptogenic stroke

Atrial fibrillation (AF) is responsible for up to one-third of ischemic strokes, with stroke potentially being the first manifestation of a previously undetected AF. Given the efficacy of oral anticoagulants in preventing AF-related ischemic events, searching for unknown AF after stroke requires a comprehensive diagnostic workup. Prospective data have demonstrated the benefits of long-term cardiac monitoring to identify AF in association with cryptogenic stroke, as most strokes are presumed to result from AF. However, strategies of empirical anticoagulation using oral anticoagulants following cryptogenic stroke failed to improve outcomes. We herein summarize contemporary evidence and knowledge gaps on searching for AF after a stroke and the potential secondary prevention strategies to prevent further recurrences.

Long-Term Cardiac Monitoring After Embolic Stroke of Undetermined Source: Search Longer, Look Harder

Embolic stroke of undetermined source (ESUS) represents a heterogeneous subgroup of patients with cryptogenic stroke, in which despite an extensive diagnostic workup the cause of stroke remains uncertain. Identifying covert atrial fibrillation among patients with ESUS remains challenging. The increasing use of cardiac implanted electronic devices (CIED), such as pacemakers, implantable defibrillators, and implantable loop recorders (ILR), has provided important information on the burden of subclinical atrial fibrillation. Accumulating evidence indicate that long-term continuous monitoring, especially in selected patients with ESUS, significantly increases the possibility of atrial fibrillation detection, suggesting it may be a cost-effective tool in secondary stroke prevention. This review summarizes available evidence related to the use of long-term cardiac monitoring and the use of implantable cardiac monitoring devices in patients with ESUS.

Detection of hidden atrial fibrillation in primary care using a long-term band-based ECG registration system: The DESCUUBRE-FA study

OBJECTIVE

To assess whether the use of a band-based electrocardiographic (ECG) monitoring system improves the diagnostic accuracy of traditional diagnostic methods for the detection of atrial fibrillation (AF).

METHODS

Multicenter and observational study of primary care patients at risk of AF. To be included, patients had to be aged ≥70 years, with no known AF, and have at least 1 major criterion (obesity, hyperthyroidism, heart failure) or 2 minor criteria (hypertension, diabetes, female sex, ischemic stroke, transient ischemic attack or systemic embolism, COPD, dyslipidemia, ischemic heart disease, peripheral artery disease). All patients were monitored using the Nuubo™ system for a single 2-week period.

RESULTS

A total of 600 patients were included (median age 77 years; 70% women; 84.3% hypertension, 27.2% diabetes, 9.2% prior stroke). The global rate of diagnosis of new AF in the overall population was 2.83%. All patients with AF were anticoagulated. In numerical terms, patients with AF (vs no AF) had a higher number of supraventricular extrasystoles and episodes of supraventricular tachycardia, as well as longer P wave duration; however, these differences did not reach statistical significance. Overall, participants were very satisfied with the device, and no relevant limitations in daily activities were observed during the 2-week study period.

CONCLUSIONS

In an elderly population at risk of AF, a band-based ECG monitoring approach applied for only 2 weeks detected approximately 3% of new cases of AF, leading to a change in antithrombotic therapy. Most participants considered the device easy to use and comfortable.

Prediction of occult atrial fibrillation in patients after cryptogenic stroke and transient ischaemic attack: PROACTIA

AIMS

Studies with implantable cardiac monitors (ICMs) show that one-third of patients with cryptogenic stroke/transient ischaemic attack (TIA) have episodes of subclinical atrial fibrillation (SCAF) and benefit switching from antiplatelet- to anticoagulant therapy. However, ICMs are costly and resource demanding. We aimed to build a score based on participant's baseline characteristics that could assess individual risk of SCAF.

METHODS AND RESULTS

In a prospective study, 236 eligible patients with a final diagnosis of cryptogenic stroke/TIA had an ICM implantated during the index hospitalization. Pre-specified evaluated variables were: CHA2DS2-VASc, P-wave duration, P-wave morphology, premature atrial beats (PAC)/24 h, supraventricular tachycardia/24 h, left atrial end-systolic volume index (LAVI), Troponin-T, NT-proBNP, and D-dimer. SCAF was detected in 84 patients (36%). All pre-specified variables were significantly associated with SCAF detection in univariate analysis. P-wave duration, followed by PAC/24 h, NT-proBNP, and LAVI, had the largest ratio of SCAF prevalence between its upper and lower quartiles (3.3, vs. 3.2, vs. 3.1 vs. 2.8, respectively). However, in a multivariate analysis, only PAC/24t, P-wave duration, P-wave morphology, and LAVIs remained significant predictors and were included in the PROACTIA score. Subclinical atrial fibrillation prevalence was 75% in the highest vs. 10% in the lowest quartile of the PROACTIA score with a 10-fold higher number of patients with an atrial fibrillation burden >6 h in the highest vs. the lowest quartile.

CONCLUSION

The PROACTIA score can identify patients with cryptogenic stroke/TIA at risk of subsequent SCAF detection. The large difference in SCAF prevalence between groups may provide a basis for future tailored therapy.

CLINICAL TRIAL REGISTRATION

Clinical Trial Registration: ClinicalTrials.gov; NCT02725944.

Diagnostic sensitivity and cost per diagnosis of ambulatory cardiac monitoring strategies in unexplained syncope patients

Diagnosing cardiac pauses that could produce syncopal episodes is important to guide appropriate therapy. However, the infrequent nature of these episodes can make detection challenging with conventional monitoring (CM) strategies with short-term ECG monitors. Insertable cardiac monitors (ICMs) continuously monitor for arrhythmias but present a higher up-front cost. It is not well understood whether these higher costs are offset by the costs of repeat evaluation in CM strategies. We simulated the likelihood of diagnostic success and cost-per-diagnosis of pause arrhythmias with CM strategies compared to ICM monitoring. ICM device data from syncope patients diagnosed with pause arrhythmias was utilized to simulate patient pathways and diagnostic success with CM. We assumed that detected true pause episodes (≥5 seconds) were symptomatic and prompted a hospital encounter and further evaluation with CM. Subsequent true pause episodes in yet-undiagnosed patients triggered additional rounds of CM. Costs of monitoring were accrued at each encounter and represent the U.S. payer perspective. Cost per diagnosed patient was calculated as the total costs accrued for all patients divided by the number of patients diagnosed, across 1,000 simulations. During a mean 505±333 days of monitoring ICM detected 2.4±2.7 pause events per patient, with an average of 109±94 days until the first event. CM was projected to diagnose between 13.8% (24-hour Holter) and 30.2% (two 30-day monitors) of the ICM-diagnosed patients. Total diagnostic costs per ICM-diagnosed patient averaged $7,847, whereas in the CM strategies average cost-per-diagnosis ranged from $12,950±2,589 with 24-hour Holter to $32,977±14,749 for two 30-day monitors. Relative to patients diagnosed with pause arrhythmias via ICM, CM strategies diagnose fewer patients and incur higher costs per diagnosed patient.

A systematic review and meta-analysis on the impact of pre-existing and new-onset atrial fibrillation on outcomes before and after liver transplantation

BACKGROUND AND AIMS

Atrial Fibrillation (AF) is the most commonly diagnosed cardiac arrhythmia. It is associated with significant morbidity and mortality, as it is a major risk factor for cerebral vascular accidents (CVA). Our aim was to determine the prevalence of pre-existing and new-onset AF among patients undergoing liver transplantation (LT) and its impact on post-transplant outcomes.

METHODS

Medline and Embase were searched. Single-arm analysis was conducted using the generalized linear mixed model to determine the prevalence of pre-existing and new-onset AF. Logistic regression was performed to analyze risk factors. Comparative meta-analysis in odds ratio was conducted for binary outcomes.

RESULTS

Twenty articles were included, with 17 studies on pre-existing AF, and 7 including data on new-onset AF post-LT. The prevalence of pre-existing AF was 3.3% (CI 2.3-4.7) (14 studies, 45,070 patients) in pooled analysis. Significantly higher prevalence of pre-existing AF patients from North America was noted when compared to Europe (4.5%, CI 3.4-5.8 vs 1.5%, CI 0.8-2.7; p = 0.001). Body mass index (BMI), history of hypertension, diabetes, coronary artery disease (CAD), and cerebrovascular accidents (CVA) were risk factors for pre-existing AF. Pre-existing AF was significantly associated with major adverse cardiac or cerebrovascular events (MACCE) postoperatively (OR 8.02, 95%CI 5.40-11.90, p < 0.001). New-onset AF post-LT had an incidence of 6.8% (CI 4.9-9.3), and was associated with increased risk of mortality (OR 2.31, 95% CI 1.76-3.02, p < 0.001) and graft failure (OR 2.98, CI 1.99-4.47, p < 0.001).

CONCLUSION

AF is relatively more common among patients undergoing LT compared to the general non-transplant population. Additionally, it is associated with adverse outcomes including MACCE, thus warranting clinical attention. Thorough cardiac assessment, and close surveillance of post-operative AF may be clinically prudent.

Mobile health technology in atrial fibrillation

INTRODUCTION

Mobile health (mHealth) solutions in atrial fibrillation (AF) are becoming widespread, thanks to everyday life devices such as smartphones. Their use is validated both in monitoring and in screening scenarios. In the published literature, the diagnostic accuracy of mHealth solutions wide differs, and their current clinical use is not well established in principal guidelines.

AREAS COVERED

mHealth solutions have progressively built an AF-detection chain to guide patients from the device's alert signal to the health care practitioners' (HCPs) attention. This review aims to critically evaluate the latest evidence regarding mHealth devices and the future possible patient's uses in everyday life.

EXPERT OPINION

The patients are the first to be informed of the rhythm anomaly, leading to the urgency of increasing the patients' AF self-management. Furthermore, HCPs need to update themselves about mHealth devices use in clinical practice. Nevertheless, these are promising instruments in specific populations, such as post-stroke patients, to promote an early arrhythmia diagnosis in the post-ablation/cardioversion period, allowing checks on the efficacy of the treatment or intervention.

Clinical Implications of Atrial Fibrillation Detection Using Wearable Devices in Patients With Cryptogenic Stroke (CANDLE-AF) Trial: Design and Rationale

Background

Although many electrocardiography wearable devices have been released recently for the detection of atrial fibrillation (AF), there are few studies reporting prospective data for wearable devices compared to the strategy of the existing guidelines in the detection of atrial fibrillation (AF) after cryptogenic stroke. A tiny single-patch monitor is more convenient than a conventional Holter monitor recording device and, therefore, longer duration of monitoring may be acceptable.

Methods and Design

The CANDLE-AF study is a multicenter, prospective, randomized controlled trial. Patients with transient ischemic attack or ischemic stroke without any history of AF will be enrolled. The superiority of the 72-h single-patch monitor to standard strategy and non-inferiority of the 72-h single-patch monitor to an event-recorder-type device will be investigated. Single-patch monitor arm will repeat monitoring at 1, 3, 6, and 12 months, event-recorder-type arm will repeat monitoring twice daily for 12 months. The enrollment goal is a total of 600 patients, and the primary outcome is the detection of AF which continues at least 30 s during study period. The secondary outcome is the rate of changes from antiplatelet to anticoagulant and major adverse cardiac and cerebrovascular events within 1 year.

Conclusions

The results of CANDLE-AF will clarify the role of a single-lead patch ECG for the early detection of AF in patients with acute ischemic stroke. In addition, the secondary outcome will be analyzed to determine whether more sensitive AF detection can affect the prognosis and if further device development is meaningful. (cris.nih.go.kr KCT0005592).

Use of Prolonged Cardiac Rhythm Monitoring to Identify Atrial Fibrillation After Cryptogenic Stroke

PURPOSE OF REVIEW

Prolonged cardiac monitoring (PCM) improves detection of atrial fibrillation (AF) after cryptogenic stroke. We summarize current research supporting the use of PCM as part of the cryptogenic stroke evaluation, while highlighting areas that require more investigation.

RECENT FINDINGS

Despite increased AF detection with longer durations of PCM, more definitive research is needed to demonstrate how PCM improves clinical outcomes. The optimal type, timing, and length of cardiac monitoring after cryptogenic stoke remains unknown. Clinical calculators will be important to risk stratify which cryptogenic stroke patients are most likely to benefit from PCM. Currently, AF detection after cryptogenic stroke should prompt consideration of anticoagulation, but it is unclear if all durations and timing of AF after stroke should be treated the same. PCM remains an important part of the cryptogenic stroke work up, and detection of AF allows for anticoagulation initiation. Additional research is needed to further refine our application of PCM to cryptogenic stroke.

Two Cases of Multiple Thromboembolism With Asymptomatic Atrial Fibrillation

A 70-year-old woman was brought to our hospital by ambulance due to syncope and hemiparalysis. Brain magnetic resonance imaging (MRI) and an electrocardiogram (ECG) showed the cerebral infarction and ST elevation without chest pain. The neurological findings were improved at the emergency outpatient service, therefore an emergency coronary angiography and aspiration for the thrombus was performed for acute myocardial infarction. An electrocardiogram monitor revealed asymptomatic and paroxysmal atrial fibrillation (AF) on the third day. In the other case, an 88-year-old woman was admitted to ambulatory care for abdominal pain, and the abdominal ultrasound showed findings of splenic infarction. Although there were no chest symptoms, AF was observed on the electrocardiogram at the time of admission. And endoscopic ultrasonography and brain MRI during hospitalization showed splenic infarction and multiple infarctions. Here, we report two cases with multiple thromboembolic complications associated with asymptomatic AF.

Estimated incidence of previously undetected atrial fibrillation on a 14-day continuous electrocardiographic monitor and associated risk of stroke

Aims

There is uncertainty about whether and how to perform screening for atrial fibrillation (AF). To estimate the incidence of previously undetected AF that would be captured using a continuous 14-day ECG monitor and the associated risk of stroke.

Methods and results

We analysed data from a cohort of patients &gt;65 years old with hypertension and a pacemaker, but without known AF. For each participant, we simulated 1000 ECG monitors by randomly selecting 14-day windows in the 6 months following enrolment and calculated the average AF burden (total time in AF). We used Cox proportional hazards models adjusted for CHA2DS2-VASc score to estimate the risk of subsequent ischaemic stroke or systemic embolism (SSE) associated with burdens of AF &gt; and &lt;6 min. Among 2470 participants, the median CHA2DS2-VASc score was 4.0, and 44 patients experienced SSE after 6 months following enrolment. The proportion of participants with an AF burden &gt;6 min was 3.10% (95% CI 2.53–3.72). This was consistent across strata of age and CHA2DS2-VASc scores. Over a mean follow-up of 2.4 years, the rate of SSE among patients with &lt;6 min of AF was 0.70%/year, compared to 2.18%/year (adjusted HR 3.02; 95% CI 1.39–6.56) in those with &gt;6 min of AF.

Conclusions

Approximately 3% of individuals aged &gt;65 years with hypertension may have more than 6 min of AF detected by a 14-day ECG monitor. This is associated with a stroke risk of over 2% per year. Whether oral anticoagulation will reduce stroke in these patients is unknown.

Mobile Health for Arrhythmia Diagnosis and Management

Palpitations are a common symptom managed by general practitioners and cardiologists; atrial fibrillation (AF) is the most common arrhythmia in adults. The recent commercial availability of smartphone-based devices and wearable technologies with arrhythmia detection capabilities has revolutionized the diagnosis and management of these common medical issues, as it has placed the power of arrhythmia detection into the hands of the patient. Numerous mobile health (mHealth) devices that can detect, record, and automatically interpret irregularities in heart rhythm and abrupt changes in heart rate using photoplethysmography (PPG)- and electrocardiogram-based technologies are now commercially available. As opposed to prescription-based external rhythm monitoring approaches, these devices are more inexpensive and allow for longer-term monitoring, thus increasing sensitivity for arrhythmia detection, particularly for patients with infrequent symptoms possibly due to cardiac arrhythmias. These devices can be used to correlate symptoms with cardiac arrhythmias, assess efficacy and toxicities of arrhythmia therapies, and screen the population for serious rhythm disturbances such as AF. Although several devices have received clearance for AF detection from the United States Food & Drug Administration, limitations include the need for ECG confirmation for arrhythmias detected by PPG alone, false positives, false negatives, charging requirements for the battery, and financial cost. In summary, the growth of commercially available devices for remote, patient-facing rhythm monitoring represents an exciting new opportunity in the care of patients with palpitations and known or suspected dysrhythmias. Physicians should be familiar with the evidence that underlies their added value to patient care and, importantly, their current limitations.

Smartphone electrocardiogram for detecting atrial fibrillation after a cerebral ischaemic event: a multicentre randomized controlled trial

AIMS

Atrial fibrillation (AF) is a preventable cause of ischaemic stroke but it is often undiagnosed and undertreated. The utility of smartphone electrocardiogram (ECG) for the detection of AF after ischaemic stroke is unknown. The aim of this study is to determine the diagnostic yield of 30-day smartphone ECG recording compared with 24-h Holter monitoring for detecting AF ≥30 s.

METHODS AND RESULTS

In this multicentre, open-label study, we randomly assigned 203 participants to undergo one additional 24-h Holter monitoring (control group, n = 98) vs. 30-day smartphone ECG monitoring (intervention group, n = 105) using KardiaMobile (AliveCor®, Mountain View, CA, USA). Major inclusion criteria included age ≥55 years old, without known AF, and ischaemic stroke or transient ischaemic attack (TIA) within the preceding 12 months. Baseline characteristics were similar between the two groups. The index event was ischaemic stroke in 88.5% in the intervention group and 88.8% in the control group (P = 0.852). AF lasting ≥30 s was detected in 10 of 105 patients in the intervention group and 2 of 98 patients in the control group (9.5% vs. 2.0%; absolute difference 7.5%; P = 0.024). The number needed to screen to detect one AF was 13. After the 30-day smartphone monitoring, there was a significantly higher proportion of patients on oral anticoagulation therapy at 3 months compared with baseline in the intervention group (9.5% vs. 0%, P = 0.002).

CONCLUSIONS

Among patients ≥55 years of age with a recent cryptogenic stroke or TIA, 30-day smartphone ECG recording significantly improved the detection of AF when compared with the standard repeat 24-h Holter monitoring.

Smartwatch monitoring for atrial fibrillation after stroke—The Pulsewatch Study: Protocol for a multiphase randomized controlled trial

Background

Atrial fibrillation (AF) is a common heart rhythm disorder that elevates stroke risk. Stroke survivors undergo routine heart rhythm monitoring for AF. Smartwatches are capable of AF detection and potentially can replace traditional cardiac monitoring in stroke patients.

Objective

The goal of Pulsewatch is to assess the accuracy, usability, and adherence of a smartwatch-based AF detection system in stroke patients.

Methods

The study will consist of two parts. Part I will have 6 focus groups with stroke patients, caretakers, and physicians, and a Hack-a-thon, to inform development of the Pulsewatch system. Part II is a randomized clinical trial with 2 phases designed to assess the accuracy and usability in the first phase (14 days) and adherence in the second phase (30 days). Participants will be randomized in a 3:1 ratio (intervention to control) for the first phase, and both arms will receive gold-standard electrocardiographic (ECG) monitoring. The intervention group additionally will receive a smartphone/smartwatch dyad with the Pulsewatch applications. Upon completion of 14 days, participants will be re-randomized in a 1:1 ratio. The intervention group will receive the Pulsewatch system and a handheld ECG device, while the control group will be passively monitored. Participants will complete questionnaires at enrollment and at 14- and 44-day follow-up visits to assess various psychosocial measures and health behaviors.

Results

Part I was completed in August 2019. Enrollment for Part II began September 2019, with expected completion by the end of 2021.

Conclusion

Pulsewatch aims to demonstrate that a smartwatch can be accurate for real-time AF detection, and that older stroke patients will find the system usable and will adhere to monitoring.

Detection of occult atrial fibrillation with 24-hour ECG after cryptogenic acute stroke or transient ischaemic attack: A retrospective cross-sectional study in a primary care database in Israel

Background

Ischaemic stroke or cerebrovascular accident (CVA) due to occult atrial fibrillation (AF) may cause severe morbidity and mortality. Diagnosing occult AF can be challenging and there is no consensus regarding the optimal duration of screening. A 24-hour Holter electrocardiogram (ECG) is frequently employed to detect occult AF following ischaemic CVA.

Objectives

Demonstration of occult AF detection rate using a 24-hour Holter ECG in a primary care setting with descriptive analyses of independent variables to compare AF detected and non-detected patients.

Methods

This retrospective cross-sectional study utilised primary care data and included patients 50 years and older with a new CVA or transient ischaemic attack (TIA) diagnosis followed by a 24-hour Holter examination within 6 months, between 01 January 2013 and 01 June 2019. The analyses included descriptive statistics comparing demographics and clinical characteristics in patients who had AF or Atrial Flutter (AFL) detection to those who did not.

Results

Out of 5015 eligible patients, 66 (1.3%) were diagnosed with AF/AFL, with a number needed to screen of 88.5. Compared with those without AF/AFL detection, those diagnosed were older (75.42 ± 7.89 vs. 69.89 ± 9.88, p = 0.050), had a higher prevalence of hypertension (80.3% vs. 66.8%, p = 0.021) and chronic kidney disease (CKD) (71.2% vs. 44.2%, p < 0.001).

Conclusion

24-hour Holter has a low AF/AFL detection rate. Older persons and those with hypertension or CKD are more likely to be detected with AF/AFL using this method.

JAK 2 positive myeloproliferative neoplasm presenting as stroke, recurrent TIA and isolated third nerve palsy

A man in his early 40s with no significant vascular risk factors was managed within a period of 6 months for recurrent vascular events: ischaemic stroke, transient ischaemic attack and isolated third nerve palsy. He was extensively investigated throughout the course of illness. The only potential aetiological factor identified was a positive janus kinase 2 (JAK 2) mutation after screening on account of mildly elevated platelet count noted during his most recent admission. Bone marrow aspiration confirmed essential thrombocythaemia. He was started on hydroxycarbamide and has remained relatively symptom free since then.This case reiterates the known associations between thrombosis and JAK 2 mutation even without overt myeloproliferative neoplasms. It also highlights the need for specialists in stroke to consider screening for JAK 2 mutation in a young patient with cryptogenic stroke with or without polycythemia or thrombocytosis.

Atrial fibrillation and atrial cardiomyopathies

Atrial fibrillation (AF) is the most common arrhythmia among adults. While there have been incredible advances in the management of AF and its clinical sequelae, investigation of atrial cardiomyopathies (ACMs) is becoming increasingly more prominent. ACM refers to the electromechanical changes-appreciated subclinically and/or clinically-that underlie atrial dysfunction and create an environment ripe for the development of clinically apparent AF. There are several subtypes of ACM, distinguished by histologic features. Recent progress in cardiovascular imaging, including echocardiography with speckle-tracking (e.g., strain analysis), cardiovascular magnetic resonance imaging (CMR), and atrial 4-D flow CMR, has enabled increased recognition of ACM. Identification of ACM and its features carry clinical implications, including elevating a patient's risk for development of AF, as well as associations with outcomes related to catheter-based and surgical AF ablation. In this review, we explore the definition and classifications of ACM, its complex relationship with clinical AF, imaging modalities, and clinical implications. We propose next steps for a more unified approach to ACM recognition that can direct further research into this complex field.

Implantable cardiac monitors to detect atrial fibrillation after cryptogenic stroke: a systematic review and economic evaluation

BACKGROUND

Cryptogenic stroke is a stroke for which no cause is identified after standard diagnostic tests. Long-term implantable cardiac monitors may be better at diagnosing atrial fibrillation and provide an opportunity to reduce the risk of stroke recurrence with anticoagulants.

OBJECTIVES

The objectives were to assess the diagnostic test accuracy, clinical effectiveness and cost-effectiveness of three implantable monitors [BioMonitor 2-AF™ (Biotronik SE & Co. KG, Berlin, Germany), Confirm Rx™ (Abbott Laboratories, Lake Bluff, IL, USA) and Reveal LINQ™ (Medtronic plc, Minneapolis, MN, USA)] in patients who have had a cryptogenic stroke and for whom no atrial fibrillation is detected after 24 hours of external electrocardiographic monitoring.

DATA SOURCES

MEDLINE, EMBASE, The Cochrane Library, Database of Abstracts of Reviews of Effects and Health Technology Assessment databases were searched from inception until September 2018.

REVIEW METHODS

A systematic review was undertaken. Two reviewers agreed on studies for inclusion and performed quality assessment using the Cochrane Risk of Bias 2.0 tool. Results were discussed narratively because there were insufficient data for synthesis. A two-stage de novo economic model was developed: (1) a short-term patient flow model to identify cryptogenic stroke patients who have had atrial fibrillation detected and been prescribed anticoagulation treatment (rather than remaining on antiplatelet treatment) and (2) a long-term Markov model that captured the lifetime costs and benefits of patients on either anticoagulation or antiplatelet treatment.

RESULTS

One randomised controlled trial, Cryptogenic Stroke and underlying Atrial Fibrillation (CRYSTAL-AF) (Sanna T, Diener HC, Passman RS, Di Lazzaro V, Bernstein RA, Morillo CA, et al. Cryptogenic stroke and underlying atrial fibrillation. N Engl J Med 2014;370:2478-86), was identified, and no diagnostic test accuracy study was identified. The CRYSTAL-AF trial compared the Reveal™ XT (a Reveal LINQ predecessor) (Medtronic plc) monitor with standard of care monitoring. Twenty-six single-arm observational studies for the Reveal devices were also identified. The only data for BioMonitor 2-AF or Confirm Rx were from mixed population studies supplied by the companies. Atrial fibrillation detection in the CRYSTAL-AF trial was higher with the Reveal XT than with standard monitoring at all time points. By 36 months, atrial fibrillation was detected in 19% of patients with an implantable cardiac monitor and in 2.3% of patients receiving conventional follow-up. The 26 observational studies demonstrated that, even in a cryptogenic stroke population, atrial fibrillation detection rates are highly variable and most cases are asymptomatic; therefore, they probably would not have been picked up without an implantable cardiac monitor. Device-related adverse events, such as pain and infection, were low in all studies. The de novo economic model produced incremental cost effectiveness ratios comparing implantable cardiac monitors with standard of care monitoring to detect atrial fibrillation in cryptogenic stroke patients based on data for the Reveal XT device, which can be related to Reveal LINQ. The BioMonitor 2-AF and Confirm RX were included in the analysis by making a strong assumption of equivalence with Reveal LINQ. The results indicate that implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold. When each device is compared incrementally, BioMonitor 2-AF dominates Reveal LINQ and Confirm RX.

LIMITATIONS

The cost-effectiveness analysis for implantable cardiac monitors is based on a strong assumption of clinical equivalence and should be interpreted with caution.

CONCLUSIONS

All three implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold, compared with standard of care monitoring, for cryptogenic stroke patients with no atrial fibrillation detected after 24 hours of external electrocardiographic monitoring; however, further clinical studies are required to confirm their efficacy in cryptogenic stroke patients.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018109216.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 5. See the NIHR Journals Library website for further project information.

Prediction of Paroxysmal Atrial Fibrillation From Complexity Analysis of the Sinus Rhythm ECG: A Retrospective Case/Control Pilot Study

Paroxysmal atrial fibrillation (PAF) is the most common cardiac arrhythmia, conveying a stroke risk comparable to persistent AF. It poses a significant diagnostic challenge given its intermittency and potential brevity, and absence of symptoms in most patients. This pilot study introduces a novel biomarker for early PAF detection, based upon analysis of sinus rhythm ECG waveform complexity. Sinus rhythm ECG recordings were made from 52 patients with (n = 28) or without (n = 24) a subsequent diagnosis of PAF. Subjects used a handheld ECG monitor to record 28-second periods, twice-daily for at least 3 weeks. Two independent ECG complexity indices were calculated using a Lempel-Ziv algorithm: R-wave interval variability (beat detection, BD) and complexity of the entire ECG waveform (threshold crossing, TC). TC, but not BD, complexity scores were significantly greater in PAF patients, but TC complexity alone did not identify satisfactorily individual PAF cases. However, a composite complexity score (h-score) based on within-patient BD and TC variability scores was devised. The h-score allowed correct identification of PAF patients with 85% sensitivity and 83% specificity. This powerful but simple approach to identify PAF sufferers from analysis of brief periods of sinus-rhythm ECGs using hand-held monitors should enable easy and low-cost screening for PAF with the potential to reduce stroke occurrence.

Cost-effectiveness of an insertable cardiac monitor to detect atrial fibrillation in patients with cryptogenic stroke

Background: We assessed cost-effectiveness of insertable cardiac monitors (ICMs) in a US cryptogenic stroke population. Materials & methods: We modelled lifetime costs and quality-adjusted life years for three monitoring strategies post cryptogenic stroke: ICM starting immediately, ICM starting after Holter monitoring (delayed ICM) and standard of care involving intermittent ECG and Holter monitoring. Patient characteristics and detection efficacy were based on the CRYSTAL-AF trial. AF detection altered the modelled anticoagulation therapy and subsequent stroke and bleed risks. Results & conclusion: Immediate ICM was found to be cost-effective versus standard of care and cost-saving versus delayed ICM. Results were robust to sensitivity analyses. ICMs are a cost-effective diagnostic tool for the prevention of recurrent stroke in a US cryptogenic stroke population.

Predictors of atrial fibrillation detection and features of recurrent strokes in patients after cryptogenic stroke

BACKGROUND AND PURPOSE

Use of implantable cardiac monitors (ICMs) has increased diagnosis of atrial fibrillation (AF) in cryptogenic stroke (CS) patients. Identifying AF predictors may enhance the yield of AF detection. Recurrent strokes after CS are not well described. We aimed to assess the predictors for AF detection and the characteristics of recurrent strokes in patients after CS.

METHODS

We reviewed electronic medical records of CS patients who were admitted between February 2014 and September 2017 and underwent ICM placement with minimum one-year follow-up. Patient demographics, stroke characteristics, pre-defined risk factors as well as recurrent strokes were compared between patients with and without AF detection.

RESULTS

389 patients with median follow-up of 548 days were studied. AF was detected in 102 patients (26.2%). Age (per decade increase, OR 2.10, CI 1.64-2.68, with vs. without AF) and left atrium diameter (per 5 mm increase, OR 1.91, CI 1.33-2.74) were identified as AF predictors. Intracranial large vessel stenosis >50% irrelevant to the index strokes was associated with AF detection within 30 days (OR 0.24, CI 0.09-0.69, >30 vs. <30 days). Recurrent strokes occurred in 14% patients with median follow-up about 2.5 years. Topography of these strokes resembled embolic pattern and was comparable between patients with and without AF. Among recurrent strokes in patients with AF, the median time to AF detection was much shorter (90 vs. 251 days), and the median time to first stroke recurrence was much longer (422 vs. 76 days) in patients whose strokes recurred after AF detection than those before AF detection.

CONCLUSIONS

Older age and enlarged left atrium are predictors for AF detection in CS patients. Intracranial atherosclerosis is more prevalent in patients with early AF detection within 30 days. Recurrent strokes follow the embolic pattern, and early AF detection could delay the stroke recurrence.

Detection of arrhythmia using an implantable cardiac monitor following a cryptogenic stroke: a single-center observational study

Background

Detection of atrial fibrillation (AF) after cryptogenic stroke (CS) has therapeutic implications, but the most effective type and optimal duration of monitoring have still to be defined. This study that involved patients with CS or transient ischemic attack (TIA), all of whom carried an implantable cardiac monitor (ICM), sought to assess the incidence of AF and other arrhythmia detected using tele-monitoring or interval-based follow-up by an internal cardiologist at the university medical center of Rostock (UMR) or an external cardiologist.

Methods

The ICM implantation was performed during the inpatient stay in the neurology department, with inclusion and exclusion criteria jointly determined by the neurology and cardiology departments. Cardiologists programmed individual threshold values during ICM implantation, which were designed to instantly trigger an episode being recording and an alarm message being sent out. Outpatient care consisted of tele-monitoring of implants or interval-based follow-up care.

Results

The indication for ICM implantation was made for 102 patients, 88 of whom underwent ICM implantation, with full documentation available for these 88 study patients. Within a median observation period of 21.5 months, AF occurred in 19 patients, with a median observation time to the event of 7 months. In all cases, AF detection was followed by immediate medical intervention. Comparing patients with and without AF revealed that the median age of the AF group exceeded by 10 years that of the other patients. Stroke recurrence was recorded in five patients, with a median observation time to the event of 9 months. Comparing patients with and without stroke recurrence revealed that the median age in the stroke recurrence group tended to be higher by 14 years. No statistically significant between-group differences were found with regard to integration into tele-monitoring, nor were there any differences identified between outpatient care at the UMR or in the outpatient sector.

Conclusions

This study confirmed the feasibility of using an interdisciplinary and intersectoral therapeutic approach for monitoring CS patients with implanted ICMs. Further randomized studies are warranted to confirm these encouraging data. An open discussion concerning optimal care forms and opportunities for introducing digitizing care pathways appears warranted.

Characteristics of aged ischemic stroke patients indicative of cardioembolism

The treatment of ischemic stroke has recently witnessed dramatic developments. However, there are limited data on ischemic stroke characteristics in aged patients. As part of the South Tochigi Acute Ischemic Stroke Registry, we prospectively enrolled 636 consecutive acute ischemic stroke patients (within 7 days after the onset) who were ≥ 60 years of age and who were admitted to two independent institutes from April 1, 2016 to February 28, 2019. We analyzed three groups divided by age: early-aged (60-69 years), middle-aged (70-79 years), and oldest-aged (≥ 80 years). From the 636 subjects, 194 were early-aged, 215 were middle-aged, and 227 were oldest-aged. There were significant differences in the ischemic stroke subtypes in each aging group (p < 0.01). The proportion of cardioembolism was 22.2% in early-aged, 27.4% in middle-aged, and 41.4% in the oldest-aged patients. The proportion of patients with a modified Rankin Scale of 0-2 at 1 year after onset decreased to 42.2% in middle-aged and 17.8% in oldest-aged with cardioembolic ischemic stroke. The proportion of patients receiving anticoagulation therapy before admission was 25.6% (36.7% of atrial fibrillation [AF]) in early-aged, 39.0% (52.3% of AF) in middle-aged, and 18.1% (21.0% of AF) in oldest-aged patients (p < 0.001). Our study reports characteristics of clinical ischemic stroke in an aging population. The assessment of cardiogenic embolism is important for an aging population.

Implantable loop recorder monitoring in patients with cryptogenic stroke - Detection and treatment of different clinically relevant arrhythmias

AIMS

Implantable loop recorders (ILR) are recommended to detect atrial fibrillation (AF) in cases of cryptogenic stroke. However, real life data besides controlled trials are rare. Aim of the study was the detection of atrial fibrillation with a special focus on other arrhythmias according to criteria defined in earlier clinical trials.

METHODS

We performed a retrospective analysis of 64 patients with cryptogenic stroke who underwent ILR implantation between 4/2014 and 1/2018. The primary endpoint was the detection of atrial fibrillation, significant bradycardia (<40 bpm) or tachycardia (>150 bpm). ILR interrogation was performed after implantation and 6, 12 and 24 months thereafter.

RESULTS

Mean patients age was 65.4 ± 12 years, 50% were male. Mean follow-up duration was 419.2 ± 309 days. One death occurred during follow-up. 23 patients (35.9%) experienced a symptomatic clinical neurological or cardiac event during follow-up. Overall rate of detected arrhythmias was 35% (23/64). The most frequent arrhythmia was atrial fibrillation which was observed in 16 patients (25%). 6 of 16 patients presenting with atrial fibrillation had no clinical symptoms. Bradycardias requiring subsequent pacemaker implantations were detected in 9.4%. A ventricular tachycardia was observed in one patient (1.6%).

CONCLUSION

In this group of patients with cryptogenic stroke the rate of arrhythmic events was high. Besides a high rate of atrial fibrillation (25%), an unexpectedly high rate of bradyarrhythmias (9.4%) occurred in our patient collective. Since many of those episodes were clinically asymptomatic, the ILR helps to detect and treat those clinically silent arrhythmias.

Cryptogenic stroke and atrial fibrillation in a real-world population: the role of insertable cardiac monitors

The incidence of atrial fibrillation (AF) in cryptogenic stroke (CS) patients has been studied in carefully controlled clinical trials, but real-world data are limited. We investigated the incidence of AF in clinical practice among CS patients with an insertable cardiac monitor (ICM) placed for AF detection. Patients with CS admitted to our Stroke Unit were included in the study; they received an ICM and were monitored for up to 3 years for AF detection. All detected AF episodes of at least 120 sec were considered. From March 2016 to March 2019, 58 patients (mean age 68.1 ± 9.3 years, 67% male) received an ICM to detect AF after a CS. No patients were lost to follow-up. AF was detected in 24 patients (41%, AF group mean age 70.8 ± 9.4 years, 62% male) after a mean time of 6 months from ICM (ranging from 2 days to 2 years) and 8 months after CS (ranging from 1 month to 2 years). In these AF patients, anticoagulant treatment was prescribed and nobody had a further stroke. In conclusion, AF episodes were detected via continuous monitoring with ICMs in 41% of implanted CS patients. AF in CS patients is asymptomatic and difficult to diagnose by strategies based on intermittent short-term recordings. Therefore, we suggest that ICMs should be part of daily practice in the evaluation of CS patients.

Cryptogenic Stroke: Anatomy of the Stroke Work-Up

Despite advances in understanding the cause of ischemic stroke, cryptogenic stroke remains a diagnostic and therapeutic challenge for clinicians. Approximately 15% to 40% of all ischemic strokes have no identifiable cause. CS is a diagnosis of exclusion after completing the standard stroke work-up. Further investigation needs to be tailored individually according to results of the clinical evaluation so appropriate secondary prevention strategies can be applied.

Rhythm monitoring strategies in patients at high risk for atrial fibrillation and stroke: A comparative analysis from the REVEAL AF study

BACKGROUND

Reducing atrial fibrillation (AF)-related stroke requires timely AF diagnosis, but the optimal monitoring strategy is unknown.

OBJECTIVE

We used insertable cardiac monitor (ICM) data from the REVEAL AF study to compare AF detection rates by various short-term continuous monitoring (STM) strategies.

METHODS AND RESULTS

Patients without known AF, but with CHADS₂ scores ≥3 (or = 2 with ≥1 additional AF risk factor) received an ICM for AF detection. One-time STM strategies were assessed by computing AF incidence at 1, 2, 7, 14, and 30 days post-ICM insertion. Repeated STM strategies (quarterly 24-hour, 48-hour, 7-day, or monthly 24-hour monitoring) were modeled by randomly selecting day(s) within a 30-day window around each nominal evaluation date over a 1-year period (simulated 10,000 times). Endpoints included AF ≥6 minutes, AF ≥1 hour, and daily AF burden ≥1 and ≥ 5.5 hours. The impact of compliance on AF detection was evaluated using daily compliance rates of 85%, 75%, 65% and 55% during follow-up months 1-3, 4-6, 7-9, and 9-12, respectively. Based on data from 385 patients (71.5 ± 9.9 years; CHADS₂ score 3.0 ± 1.0) the incidence of AF ≥6 minutes via ICM at 12 months was 27.1% (95% CI, 22.5-31.5%). This exceeded the range of estimated rates from all modeled one-time and repeated STM strategies (0.8% for 24-hour Holter monitoring to 10.6% for quarterly 7-day monitoring). Findings were similar for all AF endpoints. Modeled non-compliance reduced AF detection by 4.5% to 22.9%.

CONCLUSIONS

Most AF episodes detected via ICMs would go undetected via conventional STM strategies, thus preventing optimal prophylaxis for adverse consequences.

Potential Utility of Neurosonology in Paroxysmal Atrial Fibrillation Detection in Patients with Cryptogenic Stroke

Background: Occult paroxysmal atrial fibrillation (PAF) is a common and potential treatable cause of cryptogenic stroke (CS). We sought to prospectively identify independent predictors of atrial fibrillation (AF) detection in patients with CS and sinus rhythm on baseline electrocardiogram (ECG), without prior AF history. We had hypothesized that cardiac arrhythmia detection during neurosonology examinations (Carotid Duplex (CDU) and Transcranial Doppler (TCD)) may be associated with higher likelihood of AF detection. Methods: Consecutive CS patients were prospectively evaluated over a six-year period. Demographics, clinical and imaging characteristics of cerebral ischemia were documented. The presence of arrhythmia during spectral waveform analysis of CDU/TCD was recorded. Left atrial enlargement was documented during echocardiography using standard definitions. The outcome event of interest included PAF detection on outpatient 24-h Holter ECG recordings. Statistical analyses were performed using univariate and multivariate logistic regression models. Results: A total of 373 patients with CS were evaluated (mean age 60 ± 11 years, 67% men, median NIHSS-score 4 points). The rate of PAF detection of any duration on Holter ECG recordings was 11% (95% CI 8%–14%). The following three variables were independently associated with the likelihood of AF detection on 24-h Holter-ECG recordings in both multivariate analyses adjusting for potential confounders: age (OR per 10-year increase: 1.68; 95% CI: 1.19–2.37; p = 0.003), moderate or severe left atrial enlargement (OR: 4.81; 95% CI: 1.77–13.03; p = 0.002) and arrhythmia detection during neurosonology evaluations (OR: 3.09; 95% CI: 1.47–6.48; p = 0.003). Conclusion: Our findings underline the potential utility of neurosonology in improving the detection rate of PAF in patients with CS.

Use of insertable cardiac monitors for the detection of atrial fibrillation in patients with cryptogenic stroke in the United States is cost-effective

Objectives: Atrial fibrillation (AF) is the most common arrhythmia and a major marker of ischemic stroke risk. Early detection is crucial and, once diagnosed, anticoagulation therapy can be initiated to reduce stroke risk. The aim of this study was to assess the cost-effectiveness of employing an insertable cardiac monitor (ICM), BIOMONITOR, for the detection of AF compared to standard of care (SoC) ECG and Holter monitoring in patients with cryptogenic stroke, that is, stroke of unknown origin and where paroxysmal, silent AF is suspected. Materials and methods: A Markov model was developed which consisted of five main health states reflecting the potential lifetime evolution of the AF disease: post cryptogenic stroke (index event), subsequent mild, moderate and severe stroke, and death. Sub-states were included to track a patient's AF diagnostic status and the use of antiplatelet or anticoagulant therapy. AF detection was assumed to result in a treatment switch from aspirin to anticoagulants, except among those with a history of major bleeding. Detection yield and accuracy, clinical actions and treatment effects were derived from the literature and validated by an expert clinician. All relevant costs from a US Medicare perspective were included. Results and conclusions: An ICM-based strategy was associated with a reduction of 37 secondary ischemic strokes per 1000 patients monitored compared with SoC. Total per-patient costs with an ICM were higher (US$90,052 vs. US$85,157) although stroke-related costs were reduced. The use of an ICM was associated with a base-case incremental cost-effectiveness ratio of US$18,487 per life year gained compared with SoC and US$25,098 per quality-adjusted life year gained, below established willingness-to-pay thresholds. The conclusions were found to be robust over a range of input values. From a US Medicare perspective the use of a BIOMONITOR ICM represents a cost-effective diagnostic strategy for patients with cryptogenic stroke and suspected AF.

Transcatheter closure of patent foramen ovale in patients older than 60 years of age with cryptogenic embolism

INTRODUCTION AND OBJECTIVES

Randomized trials have shown the efficacy of transcatheter closure of patent foramen ovale (PFO) in patients aged ≤ 60 years with cryptogenic embolism. We aimed to assess the long-term safety and efficacy of PFO closure in patients aged> 60 years.

METHODS

Of 475 consecutive patients with cryptogenic embolism who underwent PFO closure, 90 older patients aged> 60 years (mean, 66±5 years) were compared with 385 younger patients aged ≤ 60 years (mean, 44±10 years).

RESULTS

Older patients had a higher prevalence of cardiovascular risk factors (CVRF) (hypertension, dyslipidemia, diabetes; P <.01 for all vs younger patients). There were no differences in periprocedural complications between the 2 groups. During a median follow-up of 8 (4-12) years, there were a total of 17 deaths, all from noncardiovascular causes (7.8% and 2.6% in the older and younger patient groups, respectively; HR, 4.12; 95%CI, 1.56-10.89). Four patients had a recurrent stroke (2.2% and 0.5% in the older and younger patient groups, respectively; HR, 5.08; 95%CI, 0.71-36.2), and 12 patients had a transient ischemic attack (TIA) (3.3% and 2.3% in the older and younger patient groups, respectively; HR, 1.71; 95%CI, 0.46-6.39). There was a trend toward a higher rate of the composite of stroke/TIA in older patients (5.5% vs 2.6%; HR, 2.62; 95%CI, 0.89-7.75; P=.081), which did not persist after adjustment for CVRF (HR, 1.97; 95%CI, 0.59-6.56; P=.269).

CONCLUSIONS

In older patients with cryptogenic embolism, PFO closure was safe and associated with a low rate of ischemic events at long-term. However, older patients exhibited a tendency toward a higher incidence of recurrent stroke/TIA compared with younger patients, likely related to a higher burden of CVRF.

Exploring the experiences of individuals with an insertable cardiac monitor: Making the decision for device insertion

BACKGROUND

Little is known about the decision-making process for insertable cardiac monitors (ICM) in those with suspected arrhythmias.

OBJECTIVE

The purpose of this qualitative study was to describe how individuals make a decision to insert an ICM.

METHODS

A qualitative descriptive design was used. Data were analyzed using content analysis and constant comparison. NVivo 10 was used for data grouping and patterns.

RESULTS

Participants (N = 12) ranged in age from 41to 95. Most (n = 7) had the device inserted because of syncope or atrial fibrillation (AF), and others (n = 5) for cryptogenic stroke. Three categories emerged: pre-decision, definitive decision, and deliberated decision. Event symptoms, including physical, cognitive and emotional, and trust emerged as factors in decision-making.

CONCLUSIONS

Those who perceived their experience as life-threatening, trusted the healthcare provider and assented to the ICM insertion. Conversely, those who perceived symptoms as episodic, used other strategies to resolve symptoms prior to making the decision for insertion.

Incidence of atrial fibrillation among patients with an embolic stroke of undetermined source: Insights from insertable cardiac monitors

Background

Prophylactic use of direct oral anticoagulants for recurrent stroke prevention in patients with embolic strokes of undetermined source is currently being investigated. It is uncertain whether the bleeding risks associated with prophylactic direct oral anticoagulants use will outweigh any stroke prevention benefit in embolic strokes of undetermined source patients who lack underlying atrial fibrillation.

Methods

We determined the proportion of cryptogenic stroke patients in the CRYSTAL atrial fibrillation trial who met inclusion criteria for the NAVIGATE embolic stroke of undetermined source and RE-SPECT embolic stroke of undetermined source trials and their atrial fibrillation incidence. Both embolic strokes of undetermined source trials impose requirements on age, modified Rankin Score, antiplatelet use, and type of infarction. Insertable cardiac monitors were used to determine the atrial fibrillation detection rates at 30 days and 3 years using Kaplan–Meier’s estimates.

Results

Among 441 patients enrolled in the CRYSTAL atrial fibrillation trial, 189 (42.9%) and 236 (53.5%) met the inclusion criteria of the NAVIGATE embolic stroke of undetermined source and RE-SPECT embolic stroke of undetermined source trials, respectively. Atrial fibrillation detection rates at 3 years among insertable cardiac monitors patients eligible for the NAVIGATE embolic stroke of undetermined source and RE-SPECT embolic stroke of undetermined source trials were 35.8% and 33.6% while detection rates at 30 days were 5.6% and 3.5%, respectively.

Conclusion

Only half of cryptogenic stroke patients in CRYSTAL atrial fibrillation met the inclusion criteria for the ongoing embolic strokes of undetermined source trials. Approximately, two-thirds of patients with embolic strokes of undetermined source do not have any atrial fibrillation despite continuous rhythm monitoring for up to three years. The benefits of prophylactic use of direct oral anticoagulants in the absence of atrial fibrillation is unknown and therefore embolic strokes of undetermined source patients could benefit from prolonged atrial fibrillation monitoring until more robust data are available.

ClinicalTrials.gov Registration

NCT00924638. https://clinicaltrials.gov/ct2/show/NCT00924638 .

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.

Trends in stroke subtypes and vascular risk factors in a stroke center in China over 10 years

Rapid economic development in China has caused marked changes in people’s lifestyles and medical technology. Exploration of stroke subtype trends is necessary to provide physicians with vital insight for early diagnosis and treatment. We included stroke patients admitted from 2006 to 2015. Trends in stroke subtypes and vascular risk factors were investigated. There were 5521 patients, including 4534 (82.1%) ischemic stroke (IS), 813 (14.7%) intracerebral hemorrhage (ICH) and 174 (3.2%) subarachnoid hemorrhage (SAH) patients. The proportion of IS was increasing and proportions of ICH and SAH were decreasing (P < 0.001). Onset age and hypertension remained stable in stroke subtypes. In IS patients, large artery atherosclerosis (LAA) strokes increased from 17.0% to 30.8% in the first 7 years and ultimately decreased to 24.1%. Small vessel disease (SVD) strokes increased from 15.5% to 39.6%, undetermined etiology (UE) strokes decreased from 52.7% to 26.0%, others remained stable. The levels of low-density lipoprotein declined significantly, and an increased number of patients underwent intracranial artery examinations (P < 0.001). In conclusion, proportions of stroke subtypes changed significantly. Anti-hypertension therapy needs to be reinforced to control ICH, SAH and SVD ischemic stroke incidences. The etiologic detection of IS increased and lipid-lowing therapy was effective, cardioembolism detections should be reinforced.

Detection and management of atrial fibrillation after cryptogenic stroke or embolic stroke of undetermined source

Cryptogenic stroke (CS) and embolic stroke of unknown source (ESUS) represent a major challenge to healthcare systems worldwide. Atrial fibrillation (AF) is commonly found after CS or ESUS. Independent of the mechanism of the index CS or ESUS, detection of AF in these patients offers the opportunity to reduce the risk of stroke recurrence by prescribing an anticoagulant instead of aspirin. The detection of AF may be pursued with different monitoring strategies. Comparison of monitoring strategies should take into account that AF detection rates reported in published studies, and then pooled in meta-analyses, are not only a function of the monitoring strategy itself, but also depend on patient-related, device-related, and study design-related factors. Once AF is found, the decision to anticoagulate a patient should be made on the basis of AF burden and the baseline risk of the patient. Empirical anticoagulation in patients with ESUS and no evidence of AF is an intriguing but still-unproven strategy and therefore should not be adopted outside of randomized clinical trials.

The complexity of atrial fibrillation newly diagnosed after ischemic stroke and transient ischemic attack: advances and uncertainties

Purpose of review

Atrial fibrillation is being increasingly diagnosed after ischemic stroke and transient ischemic attack (TIA). Patient characteristics, frequency and duration of paroxysms, and the risk of recurrent ischemic stroke associated with atrial fibrillation detected after stroke and TIA (AFDAS) may differ from atrial fibrillation already known before stroke occurrence. We aim to summarize major recent advances in the field, in the context of prior evidence, and to identify areas of uncertainty to be addressed in future research.

Recent findings

Half of all atrial fibrillations in ischemic stroke and TIA patients are AFDAS, and most of them are asymptomatic. Over 50% of AFDAS paroxysms last less than 30 s. The rapid initiation of cardiac monitoring and its duration are crucial for its timely and effective detection. AFDAS comprises a heterogeneous mix of atrial fibrillation, possibly including cardiogenic and neurogenic types, and a mix of both. Over 25 single markers and at least 10 scores have been proposed as predictors of AFDAS. However, there are considerable inconsistencies across studies. The role of AFDAS burden and its associated risk of stroke recurrence have not yet been investigated.

Summary

AFDAS may differ from atrial fibrillation known before stroke in several clinical dimensions, which are important for optimal patient care strategies. Many questions remain unanswered. Neurogenic and cardiogenic AFDAS need to be characterized, as it may be possible to avoid some neurogenic cases by initiating timely preventive treatments. AFDAS burden may differ in ischemic stroke and TIA patients, with distinctive diagnostic and treatment implications. The prognosis of AFDAS and its risk of recurrent stroke are still unknown; therefore, it is uncertain whether AFDAS patients should be treated with oral anticoagulants.

Atrial fibrillation variability on long-term monitoring of implantable cardiac rhythm management devices

BACKGROUND

Atrial fibrillation (AF) burden and duration are predictors of thromboembolic events. The random nature of these measures may affect clinical decision making. The objective of this study was to determine temporal changes in AF burden as detected by continuous monitoring.

HYPOTHESIS

AF burden changes over time when detected by continuous monitoring.

METHODS

A post hoc analysis of patients enrolled in the TRENDS (A Prospective Study of the Clinical Significance of Atrial Arrhythmias Detected by Implanted Device Diagnostics) study with ≥1 stroke risk factor(s) who were implanted with a dual-chamber cardiac rhythm management device (CRMD) and had AF burden data available for ≥2 years was performed. AF burden was defined as no AF, low AF (<5.5 hours on any given day), or high AF burden (≥5.5 hours in a day), and was first assessed over the initial 30 days following enrollment and then reassessed at 6-month intervals for 2 years.

RESULTS

Among 394 patients included, the average age was 70.2 ± 10.9 years, 71% were male, and mean CHA2 DS2- VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or TIA, vascular disease, age 65-74 years, sex category) score was 3.7 ± 1.6. In the 30-day baseline period, 75.1% of patients had no AF, 11.2% had low AF, and 13.7% had high AF. Over the subsequent 2 years, 40.0% of patients initially classified as no AF or low AF experienced periods with high AF, whereas 59.3% of patients initially classified as high AF experienced ≥6 consecutive months with no AF or low AF. Advanced age was the sole predictor of AF progression.

CONCLUSIONS

Significant temporal variability in AF burden exists when measured continuously with an implantable CRMD.

Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE-AF) randomized trial: Design and rationale

BACKGROUND

Approximately 20% of ischemic strokes are associated with clinically apparent atrial fibrillation (AF). Regardless of stroke etiology, detection of AF in patients with ischemic strokes often changes antithrombotic treatment from anti-platelet to oral anticoagulation therapy. The role and the optimum duration of cardiac monitoring to detect AF in patients with strokes presumed due to large vessel atherosclerosis or small vessel disease is unknown. This manuscript describes the design and rationale of the STROKE-AF trial.

STUDY DESIGN

STROKE-AF is a randomized, controlled, open-label, post-market clinical trial. Detection of AF will be evaluated using continuous arrhythmia monitoring with an insertable cardiac monitor (ICM) compared with standard of care follow-up in patients with stroke (within the prior 10 days) that is presumed due to large vessel cervical or intracranial atherosclerosis, or to small vessel disease. Approximately 500 patients will be enrolled at approximately 40 centers in the United States. Patients will be randomized 1:1 to arrhythmia monitoring with an ICM (continuous monitoring arm) or standard of care follow-up (control arm). Subjects will be followed for ≥12 months and up to 3 years.

OUTCOMES

The primary objective is to compare the incidence rate of detected AF through 12 months of follow-up between the two arms.

CONCLUSION

This trial will provide information on the value of ICMs to detect subclinical AF in patients with stroke presumed due to large vessel atherosclerosis or small vessel disease, which will have implications for guiding treatment with oral anticoagulation for secondary stroke prevention.