Long-term detection of atrial fibrillation with insertable cardiac monitors in a real-world cryptogenic stroke population

The incidence of atrial fibrillation detected by implantable loop recorders: a comparison between patients with and without embolic stroke of undetermined source

Aims

Stroke is the most debilitating outcome of atrial fibrillation (AF). The use of implantable loop recorders increases the detection of AF episodes among patients with embolic stroke of undetermined source. The significance of device-detected AF, or subclinical AF, is unknown. This study aimed to compare the incidence of AF detected by implantable loop recorder in patients with and without embolic stroke of undetermined source.

Methods and results

We retrospectively studied all patients without known AF who were referred to our institution for implantable loop recorder implantation following embolic stroke of undetermined source, syncope, or palpitations from March 2009 to November 2019. The primary endpoint was any detection of AF or atrial flutter by implantable loop recorder. Seven hundred and fifty patients were included and followed up for a mean duration of 731 days (SD 443). An implantable loop recorder was implanted following embolic stroke of undetermined source in 323 and for assessment of syncope, palpitations, or another reason in 427 patients. The incidence of AF was significantly (P < 0.001) higher among patients with embolic stroke of undetermined source compared with the non-embolic stroke of undetermined source group; 48.6% vs. 13.8% (for any duration of AF) and 32.2% vs. 12.4% (for AF lasting ≥30 s) both P < 0.001. Kaplan-Meier analysis showed significantly higher incidence of AF for incremental durations of AF up to >5.5 h, but not >24 h. This was driven by longest AF durations of <6 min and between 5.5 h and 24 h, suggesting a bimodal distribution. In a multivariable Cox regression analysis, embolic stroke of undetermined source independently conferred an almost 5-fold increase in the hazard for any duration of AF.

Conclusion

The incidence of AF is significantly higher amongst embolic stroke of undetermined source vs. non-embolic stroke of undetermined source patients monitored constantly by an implantable loop recorder. A high number of embolic stroke of undetermined source survivors have short-duration AF episodes. Further work is needed to determine the optimal treatment strategy of these AF episodes in embolic stroke of undetermined source.

Multidisciplinary Approach to Patent Foramen Ovale Closure for Cryptogenic Stroke: Brain-Heart Board Experience

Background and Objectives

Patent foramen ovale (PFO) is present in approximately 25% of adult population. The prevalence of PFO is high in patients with cryptogenic stroke suggesting paradoxical embolism. PFO closure in carefully selected patients is an effective secondary preventive strategy in these patients. We report predictors of management recommendations by the multidisciplinary Board and their impact on outcomes.

Methods

Brain-Heart Board comprises vascular and interventional neurology and cardiology subspecialties (structural, electrophysiology, and cardiac imaging). Adult patients referred to the Board for consideration of PFO closure between October 2017 to March 2021 were included in this retrospective cohort analysis. Demographics, comorbid conditions, risk of paradoxical embolism (RoPE) score, event frequencies (transient ischemic attack [TIA] or stroke, intracranial hemorrhage [ICH], post-PFO closure cardiac arrhythmias), and modified Rankin Scale (mRS) at 1 year were compared between the groups (PFO closure vs medical management). Multivariable logistic regression was used to identify factors associated with management recommendation and chi-square tests to test differences in outcomes for patients according to management.

Results

Two hundred seventy patients (229 stroke; 41 TIA) were discussed by the Board for PFO closure. 119 (44.0%) patients were recommended for PFO closure of which 117 (98.3%) had evidence of ischemic infarct on imaging. In univariate analysis, age was similar (50 ± 11.9 vs 52 ± 12.8, p = 0.17), but RoPE score was higher in closure as compared with the medical management group (6 [IQR 5-7] vs 5 [IQR 4-7], p < 0.05). In multivariable analysis, TIA as the index event was an independent predictor of Board recommendation against PFO closure (OR 0.05, 95% CI 0.01-0.19, p < 0.05). Event frequency was low in both cohorts (5.9% vs 4.8%, p > 0.05) and comprised cardiac arrhythmias (6 cases of atrial fibrillation and 1 ICH in closure group; 1 TIA and 1 recurrent stroke in medical management group). Excellent functional outcome (mRS 0-1) was similar in both cohorts (66.3% vs 70.7%, p > 0.05) at 1 year.

Discussion

Multidisciplinary Brain-Heart Board provides a clinical practice model of collaborative care to ensure proper patient selection for PFO closure. TIA as the index event is associated with recommendation of medical management by the multidisciplinary Brain-Heart Board.

A Novel Heart Failure Diagnostic Risk Score Using a Minimally Invasive Subcutaneous Insertable Cardiac Monitor

BACKGROUND

The authors tested the hypothesis that physiological information from sensors within a minimally invasive, subcutaneous, insertable cardiac monitor (ICM) could be used to develop an ambulatory heart failure risk score (HFRS) to accurately identify heart failure (HF) patients, across the ejection fraction spectrum, at high risk of an impending worsening heart failure event (HFE).

OBJECTIVES

The purpose of this study was to examine performance of ICM-based, multiparameter, dynamic HFRS to predict HFEs in patients with NYHA functional class II/III HF.

METHODS

In 2 observational cohorts, HF patients were implanted with an ICM; subcutaneous impedance, respiratory rate, heart rate and variability, atrial fibrillation burden, ventricular rate during atrial fibrillation, and activity duration were combined into an HFRS to identify the probability of HFE within 30 days. Patients and providers were blinded to the data. HFRS sensitivity and unexplained detection rate were defined in 2 independent patient population data sets. HFEs were defined as hospitalization, observation unit, or emergency department visit with a primary diagnosis of HF, and intravenous diuretic treatment.

RESULTS

First data set (development): 42 patients had 19 HFE; second data set (validation): 94 patients had 19 HFE (mean age 66 ± 11 years, 63% men, 50% with LVEF ≥40%, 80% NYHA functional class III). Using a high-risk threshold = 7.5%, development and validation data sets: sensitivity was 73.7% and 68.4%; unexplained detection rate of 1.4 and 1.5 per patient-year; median 47 and 64 days early warning before HFE.

CONCLUSIONS

ICM-HFRS provides a multiparameter, integrated diagnostic method with the ability to identify when HF patients are at increased risk of heart failure events. (Reveal LINQ Evaluation of Fluid [REEF]; NCT02275923, Reveal LINQ Heart Failure [LINQ HF]; NCT02758301, Algorithm Using LINQ Sensors for Evaluation and Treatment of Heart Failure [ALLEVIATE-HF]; NCT04452149).

Improved diagnostic performance of insertable cardiac monitors by an artificial intelligence-based algorithm

AIMS

The increasing use of insertable cardiac monitors (ICM) produces a high rate of false positive (FP) diagnoses. Their verification results in a high workload for caregivers. We evaluated the performance of an artificial intelligence (AI)-based ILR-ECG Analyzer™ (ILR-ECG-A). This machine-learning algorithm reclassifies ICM-transmitted events to minimize the rate of FP diagnoses, while preserving device sensitivity.

METHODS AND RESULTS

We selected 546 recipients of ICM followed by the Implicity™ monitoring platform. To avoid clusterization, a single episode per ICM abnormal diagnosis (e.g. asystole, bradycardia, atrial tachycardia (AT)/atrial fibrillation (AF), ventricular tachycardia, artefact) was selected per patient, and analyzed by the ILR-ECG-A, applying the same diagnoses as the ICM. All episodes were reviewed by an adjudication committee (AC) and the results were compared. Among 879 episodes classified as abnormal by the ICM, 80 (9.1%) were adjudicated as 'Artefacts', 283 (32.2%) as FP, and 516 (58.7%) as 'abnormal' by the AC. The algorithm reclassified 215 of the 283 FP as normal (76.0%), and confirmed 509 of the 516 episodes as abnormal (98.6%). Seven undiagnosed false negatives were adjudicated as AT or non-specific abnormality. The overall diagnostic specificity was 76.0% and the sensitivity was 98.6%.

CONCLUSION

The new AI-based ILR-ECG-A lowered the rate of FP ICM diagnoses significantly while retaining a > 98% sensitivity. This will likely alleviate considerably the clinical burden represented by the review of ICM events.

Atrial fibrillation in embolic stroke of undetermined source: role of advanced imaging of left atrial function

AIMS

Atrial fibrillation (AF) is detected in over 30% of patients following an embolic stroke of undetermined source (ESUS) when monitored with an implantable loop recorder (ILR). Identifying AF in ESUS survivors has significant therapeutic implications, and AF risk is essential to guide screening with long-term monitoring. The present study aimed to establish the role of left atrial (LA) function in subsequent AF identification and develop a risk model for AF in ESUS.

METHODS AND RESULTS

We conducted a single-centre retrospective case-control study including all patients with ESUS referred to our institution for ILR implantation from December 2009 to September 2019. We recorded clinical variables at baseline and analysed transthoracic echocardiograms in sinus rhythm. Univariate and multivariable analyses were performed to inform variables associated with AF. Lasso regression analysis was used to develop a risk prediction model for AF. The risk model was internally validated using bootstrapping. Three hundred and twenty-three patients with ESUS underwent ILR implantation. In the ESUS population, 293 had a stroke, whereas 30 had suffered a transient ischaemic attack as adjudicated by a senior stroke physician. Atrial fibrillation of any duration was detected in 47.1%. The mean follow-up was 710 days. Following lasso regression with backwards elimination, we combined increasing lateral PA (the time interval from the beginning of the P wave on the surface electrocardiogram to the beginning of the A' wave on pulsed wave tissue Doppler of the lateral mitral annulus) [odds ratio (OR) 1.011], increasing Age (OR 1.035), higher Diastolic blood pressure (OR 1.027), and abnormal LA reservoir Strain (OR 0.973) into a new PADS score. The probability of identifying AF can be estimated using the formula. Model discrimination was good [area under the curve (AUC) 0.72]. The PADS score was internally validated using bootstrapping with 1000 samples of 150 patients showing consistent results with an AUC of 0.73.

CONCLUSION

The novel PADS score can identify the risk of AF on prolonged monitoring with ILR following ESUS and should be considered a dedicated risk stratification tool for decision-making regarding the screening strategy for AF in stroke.

Detection of atrial fibrillation using an implantable loop recorder in patients with previous cryptogenic stroke: the SPIDER-AF registry (Stroke Prevention by Increasing DEtection Rates of Atrial Fibrillation)

BACKGROUND

The use of implantable loop recorder (ILR) to detect atrial fibrillation (AF) in patients with a history of cryptogenic stroke (CS) has seldom been investigated in "real-world" settings.

OBJECTIVE

This study aimed to present the results of the Stroke Prevention by Increasing DEtection Rates of Atrial Fibrillation (SPIDER-AF) registry.

METHOD

SPIDER is a multicentric, observational registry, including 35 facilities all over Germany. It enrolled outpatients without AF history and with CS before ILR implantation.

RESULTS

We included 500 patients (mean age 63.1 ± 12.7 years), 304 (60.8%) were males, with previous stroke (72.6%) and TIA (27.4%). After inclusion, all were followed for at least 12 months. AF was detected in 133 (26.8%), 25.3% of patients with previous stroke and 29.9% with TIA (p = 0.30). AF was detected after a median of 121.5 days (IQR 40.5-223.0). AF was primarily paroxysmal (95.7% after stroke, 100% after TIA). In 19.5% (n = 26) anticoagulation was not administered after AF detection. Mean CHA2DS2-VASc score (OR 1.22; CI 1.01-1.49; p = 0.037) and age > 70 years (OR 0.41; CI 0.19-0.88; p = 0.0020) correlated with AF. Repeat cerebrovascular events at follow-up (28; 5.6%) correlated with AF (OR = 2.17; CI 1.00-4.72; p = 0.049). AF (p = 0.91) and recurrent events (p = 0.43) occurred similarly in females and males.

CONCLUSIONS

In the context of cryptogenic strokes ILRs are a valuable tool for early detection of AF. In a real-world scenario, the anticoagulation therapy remains inadequate despite diagnosed AF in a relevant subset of patients requiring optimization of patient management.

Left atrial appendage flow velocity predicts occult atrial fibrillation in cryptogenic stroke: a CRYPTON-ICM registry

BACKGROUND

An insertable cardiac monitor (ICM) and transesophageal echocardiography (TEE) are useful for investigating potential embolic sources in cryptogenic stroke, of which atrial fibrillation (AF) is a critical risk factor for stroke recurrence. The association of left atrial appendage flow velocity (LAA-FV) on TEE with ICM-detected AF is yet to be elucidated.

METHODS

CRYPTON-ICM (CRYPTOgenic stroke evaluation in Nippon using ICM) is a multicenter registry of cryptogenic stroke with ICM implantation, and patients whose LAA-FV was evaluated on TEE were enrolled. The primary outcome was the detection of AF (> 2 min) on ICM. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off of LAA-FV, and factors associated with ICM-detected AF were assessed.

RESULTS

A total of 307 patients (age 66.6 ± 12.3 years; 199 males) with median follow-up of 440 (interquartile range 169-726) days were enrolled; AF was detected in 101 patients. The lower-tertile LAA-FV group had older age, more history of congestive heart failure, and higher levels of B-type natriuretic peptide (BNP) or N-terminal proBNP (all P < 0.05). On ROC analysis, LAA-FV < 37.5 cm/s predicted ICM-detected AF with sensitivity of 26.7% and specificity of 92.2%. After adjustment for covariates, the lower tertile of LAA-FV (hazard ratio [HR], 1.753 [1.017-3.021], P = 0.043) and LAA-FV < 37.5 cm/s (HR 1.987 [1.240-3.184], P = 0.004) predicted ICM-detected AF.

CONCLUSIONS

LAA-FV < 37.5 cm/s predicts AF. TEE is useful not only to evaluate potential embolic sources, but also for long-term detection of AF on ICM by measuring LAA-FV in cryptogenic stroke. http://www.umin.ac.jp/ctr/ (UMIN000044366).

Diagnosis and Management of Atrial Fibrillation in Acute Ischemic Stroke in the Setting of Reperfusion Therapy: Insights and Strategies for Optimized Care

Reperfusion therapy in the form of intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT) has revolutionised the field of stroke medicine. Atrial fibrillation (AF) patients constitute a major portion of the overall stroke population; however, the prevalence of AF amongst acute ischemic stroke (AIS) patients receiving reperfusion therapy remains unclear. Limitations in our understanding of prevalence in this group of patients are exacerbated by difficulties in appropriately diagnosing AF. Additionally, the benefits of reperfusion therapy are not consistent across all subgroups of AIS patients. More specifically, AIS patients with AF often tend to have poor prognoses despite treatment relative to those without AF. This article aims to present an overview of the diagnostic and therapeutic management of AF and how it mediates outcomes following stroke, most specifically in AIS patients treated with reperfusion therapy. We provide unique insights into AF prevalence and outcomes that could allow healthcare professionals to optimise the treatment and prognosis for AIS patients with AF. Specific indications on acute neurovascular management and secondary stroke prevention in AIS patients with AF are also discussed.

Identifying Atrial Fibrillation With Sinus Rhythm Electrocardiogram in Embolic Stroke of Undetermined Source: A Validation Study With Insertable Cardiac Monitors

BACKGROUND AND OBJECTIVES

Paroxysmal atrial fibrillation (AF) is a major potential cause of embolic stroke of undetermined source (ESUS). However, identifying AF remains challenging because it occurs sporadically. Deep learning could be used to identify hidden AF based on the sinus rhythm (SR) electrocardiogram (ECG). We combined known AF risk factors and developed a deep learning algorithm (DLA) for predicting AF to optimize diagnostic performance in ESUS patients.

METHODS

A DLA was developed to identify AF using SR 12-lead ECG with the database consisting of AF patients and non-AF patients. The accuracy of the DLA was validated in 221 ESUS patients who underwent insertable cardiac monitor (ICM) insertion to identify AF.

RESULTS

A total of 44,085 ECGs from 12,666 patient were used for developing the DLA. The internal validation of the DLA revealed 0.862 (95% confidence interval, 0.850-0.873) area under the curve (AUC) in the receiver operating curve analysis. In external validation data from 221 ESUS patients, the diagnostic accuracy of DLA and AUC were 0.811 and 0.827, respectively, and DLA outperformed conventional predictive models, including CHARGE-AF, C2HEST, and HATCH. The combined model, comprising atrial ectopic burden, left atrial diameter and the DLA, showed excellent performance in AF prediction with AUC of 0.906.

CONCLUSIONS

The DLA accurately identified paroxysmal AF using 12-lead SR ECG in patients with ESUS and outperformed the conventional models. The DLA model along with the traditional AF risk factors could be a useful tool to identify paroxysmal AF in ESUS patients.

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.

Insertable cardiac monitoring results in higher rates of atrial fibrillation diagnosis and oral anticoagulation prescription after ischaemic stroke

AIMS

After an ischaemic stroke, atrial fibrillation (AF) detection allows for improved secondary prevention strategies. This study aimed to compare AF detection and oral anticoagulant (OAC) initiation in patients with an insertable cardiac monitor (ICM) vs. external cardiac monitor (ECM) after ischaemic stroke.

METHODS AND RESULTS

Medicare Fee-for-Service (FFS) insurance claims and Abbott Labs device registration data were used to identify patients hospitalized with an ischaemic stroke in 2017-2019 who received an ICM or ECM within 3 months. Patients with continuous Medicare FFS insurance and prescription drug enrolment in the prior year were included. Patients with prior AF, atrial flutter, cardiac devices, or OAC were excluded. Insertable cardiac monitor and ECM patients were propensity score matched 1:4 on demographics, comorbidities, and stroke hospitalization characteristics. The outcomes of interest were AF detection and OAC initiation evaluated with Kaplan-Meier and Cox proportional hazard regression analyses. A total of 5702 Medicare beneficiaries (ICM, n = 444; ECM, n = 5258) met inclusion criteria. The matched cohort consisted of 2210 Medicare beneficiaries (ICM, n = 442; ECM, n = 1768) with 53% female, mean age 75 years, and mean CHA₂DS₂-VASc score 4.6 (1.6). Insertable cardiac monitor use was associated with a higher probability of AF detection [(hazard ratio (HR) 2.88, 95% confidence interval (CI) (2.31, 3.59)] and OAC initiation [HR 2.91, CI (2.28, 3.72)] compared to patients monitored only with ECM.

CONCLUSION

Patients with an ischaemic stroke monitored with an ICM were almost three times more likely to be diagnosed with AF and to be prescribed OAC compared to patients who received ECM only.

Detection of Atrial Fibrillation after Ischemic Stroke with an Insertable Cardiac Monitor: A Systematic Review and Individual Patient Data Meta-Analysis of Randomized Clinical Trials

INTRODUCTION

We compared the use of insertable cardiac monitor (ICM) versus non-ICM methods of cardiac monitoring in ischemic stroke patients on the detection of atrial fibrillation (AF) and other clinical outcomes. Current guidelines recommend the routine use of 12-lead electrocardiography or Holter monitoring for AF detection after ischemic stroke. Recent randomized controlled trials have investigated the impact of ICM versus non-ICM methods of cardiac monitoring for AF detection in this population. However, precise recommendations for monitoring poststroke AF are lacking, including the optimal timing, duration, and method of electrocardiography monitoring.

METHODS

A systematic search was conducted on Embase and PubMed from database inception until October 27, 2022, to include randomized controlled trials that compared ICM with non-ICM methods of cardiac monitoring for poststroke AF detection. This yielded 3 randomized controlled trials with a combined cohort of 1,233 patients with a recent ischemic stroke. Individual patient data (IPD) were then reconstructed from Kaplan-Meier curves and analyzed using the shared-frailty Cox model. An aggregate data meta-analysis was conducted for 1,233 patients across all 3 studies for outcomes that could not be reconstructed using IPD.

RESULTS

One-stage meta-analysis demonstrated an increase in the hazard ratio (6.00 95% CI: 3.40-10.58; 195 p < 0.001) of AF detection in patients undergoing monitoring via ICM compared to standard care. The cumulative incidence curves of AF events in patients undergoing ICM and non-ICM separated significantly at 24 days. Aggregate data meta-analysis revealed a significant increase in initiation of anticoagulation (RR: 2.76, 95% CI: 1.89-4.02, p < 0.00001) in the ICM group. However, no significant differences in the incidence of recurrent ischemic stroke, transient ischemic attack, or death were found.

CONCLUSIONS

In this meta-analysis, we found that the use of ICM increased the detection rate of poststroke AF and the rate of anticoagulation initiation in ischemic stroke patients. However, this did not translate into a reduced incidence of recurrent ischemic stroke.

P-wave terminal force in lead V1 and atrial fibrillation burden in cryptogenic stroke with implantable loop recorders

Implantable loop recorders (ILRs) are useful for the detection of atrial fibrillation (AF) in patients with cryptogenic stroke (CS). P-wave terminal force in lead V₁ (PTFV₁) is associated with AF detection; however, data on the association between PTFV₁ and AF detection using ILRs in patients with CS are limited. Consecutive patients with CS with implanted ILRs from September 2016 to September 2020 at eight hospitals in Japan were studied. PTFV₁ was calculated by 12-lead ECG before ILRs implantation. An abnormal PTFV₁ was defined as ≥ 4.0 mV × ms. The AF burden was calculated as a proportion based on the duration of AF to the total monitoring period. The outcomes included AF detection and large AF burden, which was defined as ≥ 0.5% of the overall AF burden. Of 321 patients (median age, 71 years; male, 62%), AF was detected in 106 patients (33%) during the median follow-up period of 636 days (interquartile range [IQR], 436-860 days). The median time from ILRs implantation to AF detection was 73 days (IQR, 14-299 days). An abnormal PTFV₁ was independently associated with AF detection (adjusted hazard ratio, 1.71; 95% confidence interval [CI], 1.00-2.90). An abnormal PTFV₁ was also independently associated with a large AF burden (adjusted odds ratio, 4.70; 95% CI, 2.50-8.80). In patients with CS with implanted ILRs, an abnormal PTFV₁ is associated with both AF detection and a large AF burden.Clinical Trial Registration Information: UMIN Clinical Trials Registry 000044366.

Monitoring for atrial fibrillation prior to patent foramen ovale closure after cryptogenic stroke

BACKGROUND

Patients who had a cryptogenic stroke (CS) suspected to be causally related to a patent foramen ovale (PFO) are candidates for percutaneous PFO closure. In such patients, it is important to screen for atrial fibrillation (AF). Limited guidance is available regarding AF monitoring strategies in CS patients with PFO addressing optimal monitoring technology and duration.

AIM

To provide a narrative review of cardiac rhythm monitoring in CS patients considered for PFO closure, including current practices, stroke recurrences after CS, findings from monitoring studies in CS patients, and predictors for AF detection published in the literature. To propose a personalized strategy for cardiac monitoring in CS patients, accounting for aspects predicting AF detection.

SUMMARY OF REVIEW

AF detection in CS patients is predicted by age, left atrial enlargement, prolonged PR interval, frequent premature atrial contractions, interatrial conduction block, diabetes, prior brain infarctions, leukoaraiosis, elevated B-type natriuretic peptide (BNP)/N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, and a family history of AF, as well as composed scores (e.g. CHA₂DS₂-VASc, atrial fibrillation in embolic stroke of undetermined source (AF-ESUS)). The causal role of the PFO may be accounted for by the risk of paradoxical embolism (RoPE) score and/or the PFO-Associated Stroke Causal Likelihood (PASCAL) classification.

CONCLUSION

A personalized approach to AF detection in CS patients is proposed, accounting for the likelihood of AF detection and aimed at obtaining sufficient confidence regarding the absence of AF in patients considered for PFO closure. In addition, the impact of high-risk PFO features on the monitoring strategy is discussed.

Multiparametric identification of subclinical atrial fibrillation after an embolic stroke of undetermined source

BACKGROUND

Subclinical atrial fibrillation (SCAF) may represent a cause of embolic stroke of undetermined source (ESUS) and its detection has important implications for secondary prevention with anticoagulation. Indications to implantable cardiac monitors (ICM) include SCAF detection. The aims of this study were to (1) evaluate the frequency of ICM-detected SCAF; (2) determine predictors of SCAF; and (3) identify patients who would benefit most from ICM implantation.

METHODS

Between February 2017 and November 2020, all consecutive patients referred for ICM implantation after a diagnosis of ESUS and without previous history of atrial fibrillation or atrial flutter were included in this study. SCAF was diagnosed if the ICM electrogram demonstrated an episode of irregularly irregular rhythm without distinct P waves lasting > 2 min.

RESULTS

We enrolled 109 patients (age 66, SD = 13 years; 36% females). During a median follow-up of 19.2 (IQR 11.0-27.5) months, SCAF episodes were detected in 36 (33%) patients. Only abnormal P wave terminal force in lead V1, left atrial end-systolic indexed volume > 34 ml/m², and BMI > 25 kg/m² were independently associated with an increased risk of SCAF (HR 2.44, 95% CI 1.14-5.21, p = 0.021; HR 2.39, 95% CI 1.11-5.13, p = 0.026; and HR 2.64, 95% CI 1.06-6.49, p = 0.036 respectively). The ROC curve showed that the presence of all three parameters had the best accuracy (74%) to predict SCAF detection (sensitivity 39%, specificity 91%).

CONCLUSION

A multiparametric evaluation has the best accuracy to predict SCAF in ESUS patients and may help identifying those who would benefit most from ICM.

Remote Monitoring of Cardiac Implantable Electronic Devices: What is the Evidence?

PURPOSE OF REVIEW

This review offers an overview of the evidence in diagnostic and therapeutic applications of remote monitoring implantable devices.

RECENT FINDINGS

Remote monitoring of cardiac implantable devices has become more and more popular in recent years as healthcare is moving towards a more patient centralized system. For heart failure patients with an ICD or pacemaker, there is controversial evidence regarding improvements in the clinical outcome, e.g., reduction of hospitalization rates or overall mortality. New developments as hemodynamic remote monitoring via measurement of the pulmonary artery pressure are promising technical achievements showing encouraging results. In cardiac remote monitoring of syncope and arrhythmias, implantable loop recorder plays an important role in diagnostic algorithms. Although there is controversial evidence according to remote monitoring of implantable devices, its use is rapidly expanding, giving healthcare providers the opportunity to react promptly to worsening of their patients. Adequate evaluation of the data created by remote monitoring systems remains an unsolved challenge of contemporary healthcare services.

Diagnostic yield of an insertable cardiac monitor in a large patient population

Background

Insertable cardiac monitors (ICMs) are increasingly used for cardiac rhythm diagnosis with expanding indications. Little has been reported about their use and efficacy.

Objective

The study sought to evaluate the clinical utility of a novel ICM (Biotronik BIOMONITOR III) including the time to diagnosis in unselected patients with different ICM indications.

Methods

Patients from 2 prospective clinical studies were included to determine the diagnostic yield of the ICM. The primary endpoint was time to clinical diagnosis per implant indication or to the first change in atrial fibrillation (AF) therapy.

Results

A total of 632 patients were included with a mean follow-up of 233 ± 168 days. Of 384 patients with (pre)syncope, 34.2% had a diagnosis at 1 year. The most frequent therapy was permanent pacemaker implantation. Of 133 patients with cryptogenic stroke, 16.6% had an AF diagnosis at 1 year, resulting in oral anticoagulation. Of 49 patients with an indication for AF monitoring, 41.0% had a relevant change in AF therapy based on ICM data at 1 year. Of 66 patients with other indications, 35.4% received a rhythm diagnosis at 1 year. Moreover, 6.5% of the cohort had additional diagnoses: 26 of 384 patients with syncope, 8 of 133 patients with cryptogenic stroke, and 7 of 49 patients with AF monitoring.

Conclusion

In a large unselected patient population with heterogeneous ICM indications, the primary endpoint of rhythm diagnosis was achieved in ∼1 in 4, and additional clinically relevant findings was achieved in 6.5% of patients at short-term follow-up.

Molecular biomarkers predicting newly detected atrial fibrillation after ischaemic stroke or TIA: A systematic review

Background:

Several molecular biomarkers are available that predict newly detected atrial fibrillation (NDAF). We aimed to identify such biomarkers that predict NDAF after an Ischaemic stroke (IS)/Transient Ischaemic Attack (TIA) and evaluate their performance.

Methods:

A systematic review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies of patients with IS, TIA, or both, who underwent ECG monitoring for ⩾24 h, which reported molecular biomarkers and frequency of NDAF after electronic searches of multiple databases were included.

Results:

Twenty-one studies (76% IS, 24% IS and TIA) involving 4640 patients were included. Twelve biomarkers were identified, with cardiac biomarkers evaluated in the majority (75%) of patients. Performance measures were inconsistently reported. Among cohorts selecting high-risk individuals (12 studies), the most studied biomarkers were N-Terminal-Pro Brain Natriuretic Peptide (NT-ProBNP, five studies; C-statistics reported by three studies, 0.69–0.88) and Brain Natriuretic Peptide (BNP, two studies; C-statistics reported in two studies, 0.68–0.77). Among unselected cohorts (nine studies), the most studied biomarker was BNP (six studies; C-statistics reported in five studies, 0.75–0.88). Only BNP was externally validated (two studies) but using different thresholds to categorise risk of NDAF.

Conclusion:

Cardiac biomarkers appear to have modest to good discrimination for predicting NDAF, although most analyses were limited by small, heterogeneous study populations. Their clinical utility should be explored further, and this review supports the need to assess the role of molecular biomarkers in large prospective studies with standardised selection criteria, definition of clinically significant NDAF and laboratory assays.

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.

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.

Cost-Effectiveness of Monitoring Patients Post-Stroke With Mobile ECG During the Hospital Stay

Background

The effectiveness of a nurse‐led in‐hospital monitoring protocol with mobile ECG (iECG) was investigated for detecting atrial fibrillation in patients post‐ischemic stroke or post‐transient ischemic attack. The study aimed to assess the cost‐effectiveness of using iECG during the initial hospital stay compared with standard 24‐hour Holter monitoring.

Methods and Results

A Markov microsimulation model was constructed to simulate the lifetime health outcomes and costs. The rate of atrial fibrillation detection in iECG and Holter monitoring during the in‐hospital phase and characteristics of modeled population (ie, age, sex, CHA2DS2‐VASc) were informed by patient‐level data. Costs related to recurrent stroke, stroke management, medications (new oral anticoagulants), and rehabilitation were included. The cost‐effectiveness analysis outcome was calculated as an incremental cost per quality‐adjusted life‐year gained. As results, monitoring patients with iECG post‐stroke during the index hospitalization was associated with marginally higher costs (A$31 196) and greater benefits (6.70 quality‐adjusted life‐years) compared with 24‐hour Holter surveillance (A$31 095 and 6.66 quality‐adjusted life‐years) over a 20‐year time horizon, with an incremental cost‐effectiveness ratio of $3013/ quality‐adjusted life‐years. Monitoring patients with iECG also contributed to lower recurrence of stroke and stroke‐related deaths (140 recurrent strokes and 20 deaths avoided per 10 000 patients). The probabilistic sensitivity analyses suggested iECG is highly likely to be a cost‐effective intervention (100% probability).

Conclusions

A nurse‐led iECG monitoring protocol during the acute hospital stay was found to improve the rate of atrial fibrillation detection and contributed to slightly increased costs and improved health outcomes. Using iECG to monitor patients post‐stroke during initial hospitalization is recommended to complement routine care.

Atrial CARdiac Magnetic resonance imaging in patients with embolic stroke of unknown source without documented Atrial Fibrillation (CARM-AF): Study design and clinical protocol

Background

Initiation of anticoagulation therapy in ischemic stroke patients is contingent on a clinical diagnosis of atrial fibrillation (AF). Results from previous studies suggest thromboembolic risk may predate clinical manifestations of AF. Early identification of this cohort of patients may allow early initiation of anticoagulation and reduce the risk of secondary stroke.

Objective

This study aims to produce a substrate-based predictive model using cardiac magnetic resonance imaging (CMR) and baseline noninvasive electrocardiographic investigations to improve the identification of patients at risk of future thromboembolism.

Methods

CARM-AF is a prospective, multicenter, observational cohort study. Ninety-two patients will be recruited following an embolic stroke of unknown source (ESUS) and undergo atrial CMR followed by insertion of an implantable loop recorder (ILR) as per routine clinical care within 3 months of index stroke. Remote ILR follow-up will be used to allocate patients to a study or control group determined by the presence or absence of AF as defined by ILR monitoring.

Results

Baseline data collection, noninvasive electrocardiographic data analysis, and imaging postprocessing will be performed at the time of enrollment. Primary analysis will be performed following 12 months of continuous ILR monitoring, with interim and delayed analyses performed at 6 months and 2 and 3 years, respectively.

Conclusion

The CARM-AF Study will use atrial structural and electrocardiographic metrics to identify patients with AF, or at high risk of developing AF, who may benefit from early initiation of anticoagulation.

How should I treat patients with subclinical atrial fibrillation and atrial high-rate episodes? Current evidence and clinical importance

Long-term and continuous ECG monitoring using cardiac implantable electronic devices and insertable cardiac monitors has improved the capability of detecting subclinical atrial fibrillation (AF) and atrial high-rate episodes. Previous studies demonstrated a high prevalence (more than 20%) in patients with cardiac implantable electronic devices or insertable cardiac monitors. Subclinical AF and atrial high-rate episodes are often suspected as the cause of prior or potential future ischemic stroke. However, the clinical significance is still uncertain, and the evidence is limited. This review aims to present and discuss the current evidence on the clinical impact of subclinical AF and atrial high-rate episodes. It focuses particularly on the association between the duration of the episodes and major clinical outcomes like thromboembolic events. As subclinical AF and atrial high-rate episodes are presumed to be associated with ischemic strokes, detection will be particularly important in patients with cryptogenic stroke and in high-risk patients for thromboembolism. In this context, it is also interesting whether there is a temporal relationship between the detection of subclinical AF and atrial high-rate episodes and the occurrence of thromboembolic events. In addition, the review will examine the question whether there is a need for a therapy with oral anticoagulation.

Recurrent Stroke Incidence and Etiology in Patients with Embolic Stroke of Undetermined Source and Other Stroke Subtypes

AIMS

This study aimed at clarifying the incidence of recurrent stroke and its etiology in patients with embolic stroke of undetermined source (ESUS) and other stroke subtypes in both the acute and chronic periods.

METHODS

A total of 645 patients who were admitted with acute ischemic stroke (IS) between March 2015 and August 2019 were enrolled. Among them, 511 patients with ESUS, cardioembolism (CE), large artery atherosclerosis (LAA), or small vessel disease (SVD) were analyzed in this study. After discharge, 391 patients who visited the outpatient clinic were followed up until August 2020. The outcome was stroke recurrence.

RESULTS

In the acute admission, recurrence rates were 7.6%, 8.1%, 18.8%, and 2.2% in patients with ESUS, CE, LAA, and SVD, respectively, and there were significant differences between the groups. The subtype of recurrence was almost identical to that of the index stroke. In the outpatient clinic, the annual recurrence rates were 4.4%, 4.3%, 6.0%, and 2.9% in ESUS, CE, LAA, and SVD, respectively, and no difference was observed. Subtypes of recurrence in outpatients with ESUS included ESUS, intracerebral hemorrhage (ICH), and SVD. Patients with ESUS and SVD had a higher risk of ICH during follow-up.

CONCLUSIONS

Although the risk of recurrence was comparable between patients with ESUS and CE and intermediate between patients with LAA and SVD, in the acute admission unit, the risk in outpatients was similar among all subtypes. ESUS was the most recurrent stroke subtype in outpatients with ESUS. The risk of hemorrhagic stroke was significant in patients with SVD and ESUS.

Longitudinal Outcomes in Cryptogenic Stroke Patients With and Without Long-term Cardiac Monitoring for Atrial Fibrillation

Background

Guidelines recommend a confirmed diagnosis of atrial fibrillation (AF) to initiate oral anticoagulation in cryptogenic stroke (CS) patients. However, the intermittent nature of AF can make detection challenging with intermittent short-term cardiac monitoring.

Objective

The purpose of this retrospective cohort study was to examine post-CS utilization of cardiac monitoring and associated clinical outcomes.

Methods

Adults with incident hospitalization for CS were identified in the Optum® claims database and assessed for cardiac monitoring received poststroke. Patient were stratified into those with a long-term insertable cardiac monitor (ICM) vs external cardiac monitor (ECM) only. The timing of ICM placement poststroke was treated as a time-dependent covariate. The clinical outcomes of interest were time to AF diagnosis, oral anticoagulation usage, and all-cause mortality.

Results

A total of 12,994 patients met selection criteria for the analysis, of whom 1949 (15%) received an ICM and 11,045 (85%) received ECM only. In those who had received an ECM as their first monitoring modality, only 4.4% moved on to receive an ICM for longer-term monitoring. Use of ECM before ICM was associated with a longer time to AF diagnosis (median 336 vs 194 days). Compared to those with ECM only, ICM patients had a significantly lower rate of death (hazard ratio [HR] 0.70; P = .004), and faster time to AF diagnosis (HR 1.50; P <.0001) and anticoagulation initiation (HR 1.57; P <.0001) during follow-up of up to 5 years after CS.

Conclusion

In a real-world study of CS patients, prolonged cardiac monitoring was associated with higher rates of AF detection and treatment, and higher odds of survival.

ECG monitoring of post-stroke occurring arrhythmias: an observational study using 7-day Holter ECG

Post-stroke arrhythmias represent a risk factor for complications and worse prognosis after cerebrovascular events. The aims of the study were to detect the rate of atrial fibrillation (AF) and other cardiac arrhythmias after acute ischemic stroke, by using a 7-day Holter ECG which has proved to be superior to the standard 24-h recording, and to evaluate the possible association between brain lesions and arrhythmias. One hundred and twenty patients with cryptogenic ischemic stroke underwent clinical and neuroimaging assessment and were monitored with a 7-day Holter ECG. Analysis of the rhythm recorded over 7 days was compared to analysis limited at the first 24 h of monitoring. 7-day Holter ECG detected AF in 4% of patients, supraventricular extrasystole (SVEB) in 94%, ventricular extrasystole (VEB) in 88%, short supraventricular runs (SVRs) in 54%, supraventricular tachycardia in 20%, and bradycardia in 6%. Compared to the first 24 h of monitoring, 7-Holter ECG showed a significant higher detection for all arrhythmias (AF p = 0.02; bradycardia p = 0.03; tachycardia p = 0.0001; SVEB p = 0.0002; VEB p = 0.0001; SVRs p = 0.0001). Patients with SVRs and bradycardia were older (p = 0.0001; p = 0.035) and had higher CHA₂DS₂VASc scores (p = 0.004; p = 0.026) respectively, in the comparison with patients without these two arrhythmias. An association was found between SVEB and parietal (p = 0.013) and temporal (p = 0.013) lobe lesions, whereas VEB correlated with insular involvement (p = 0.002). 7-day Holter ECG monitoring proved to be superior as compared to 24-h recording for the detection of all arrhythmias, some of which (SVEB and VEB) were associated with specific brain areas involvement. Therefore, 7-day Holter ECG should be required as an effective first-line approach to improve both diagnosis and therapeutic management after stroke.

Embolic Stroke of Undetermined Source: Approaches in Risk Stratification for Cardioembolism

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Embolic stroke of undetermined source has been recently proposed to categorize nonlacunar ischemic strokes without confirmed etiology after adequate investigation with a likely embolic stroke mechanism. A strategy of empirical anticoagulation for embolic stroke of undetermined source patients is attractive but may only be beneficial in a select subset of patients. Strategies which would help identify the subset of embolic stroke of undetermined source patients most likely to have cardioembolic origin of stroke, and hence benefit from anticoagulation, are needed. This article will review current evidence which may be useful in the development of a risk stratification approach based on arrhythmia monitoring, cardiac imaging, and clinical risk stratification. This approach may be beneficial in clinical practice in improving patient outcomes and reducing stroke recurrence in this population; however, further work is required with active trials underway.

Detection of subclinical atrial fibrillation after cryptogenic stroke using implantable cardiac monitors

BACKGROUND

Implantable cardiac monitor (ICM) revealed subclinical atrial fibrillation (SCAF) in up to 30% of cryptogenic stroke (CS) patients in randomized trials. However, real world data are limited.

OBJECTIVES

We investigated SCAF occurrence, treatments, clinical outcomes and predictors of SCAF in a multicenter real-world population subjected to ICM after CS.

METHODS

From September 2016 to November 2019, 20 Italian centers collected data of consecutive patients receiving ICM after CS and followed with remote and outpatient follow-up according to clinical practice. All device-detected AF events were confirmed by the cardiologist to diagnose SCAF.

RESULTS

ICM was implanted in 334 CS patients (mean age±SD 67.4±11.5 years, 129 (38.6%) females, 242 (76.1%) with CHA₂DS₂-VASC score≥4). During a follow-up of 23.6 (IQR 14.6-31.5) months, SCAF was diagnosed in 92 (27.5%) patients. First episode was asymptomatic in 81 (88.1%). SCAF daily burden ≥5 minutes was 22.0%, 24.1% and 31.5% at 6, 12, and 24 months after ICM implantation. Median time to first day with AF was 60 (IQR 18-140) days. Female gender, age>69 years, PR interval>160 ms and cortical-subcortical infarct type at enrolment were independently associated with an increased risk of SCAF.

CONCLUSIONS

In a real-world population, ICM detected SCAF in more than a quarter of CS patients. This experience confirms the relevance of implanting CS patients, for maximizing the possibilities to detect AF, following failure of Holter monitoring, according to guidelines. However, there is need to demonstrate that shift to oral anticoagulation following SCAF detection is associated with reduced risk of recurrent stroke.

Predicting atrial fibrillation after cryptogenic stroke via a clinical risk score-a prospective observational study

Background and purpose

Atrial fibrillation (AF) often remains undiagnosed in cryptogenic stroke (CS), mostly because of limited availability of cardiac long‐term rhythm monitoring. There is an unmet need for a pre‐selection of CS patients benefitting from such work‐up. A clinical risk score was therefore developed for the prediction of AF after CS and its performance was evaluated over 1 year of follow‐up.

Methods

Our proposed risk score ranges from 0 to 16 points and comprises variables known to be associated with occult AF in CS patients including age, N‐terminal pro‐brain natriuretic peptide, electrocardiographic and echocardiographic features (supraventricular premature beats, atrial runs, atrial enlargement, left ventricular ejection fraction) and brain imaging markers (multi‐territory/prior cortical infarction). All CS patients admitted to our Stroke Unit between March 2018 and August 2019 were prospectively followed for AF detection over 1 year after discharge.

Results

During the 1‐year follow‐up, 24 (16%) out of 150 CS patients with AF (detected via electrocardiogram controls, n = 18; loop recorder monitoring, n = 6) were diagnosed. Our predefined AF Risk Score (cutoff ≥4 points; highest Youden's index) had a sensitivity of 92% and a specificity of 67% for 1‐year prediction of AF. Notably, only two CS patients with <4 score points were diagnosed with AF later on (negative predictive value 98%).

Conclusions

A clinical risk score for 1‐year prediction of AF in CS with high sensitivity, reasonable specificity and excellent negative predictive value is presented. Generalizability of our score needs to be tested in external cohorts with continuous cardiac rhythm monitoring.

Performance of implantable loop recorders. Role of R vector and detection algorithms

INTRODUCTION

We evaluated the performance of implantable loop recorders (ILRs) with different detection algorithms and looked for artifacts and therapeutic consequences and their dependence on patient factors.

METHODS AND RESULTS

586 RevealLinq™ ILRs (first generation (NT): n = 335; second generation with TruRhythm™ (TR): n = 251) were implanted during 2014-2021 (syncope n = 206; embolic stroke of unknown source (ESUS) n = 380). Automatically detected EGM episodes (n = 18,650) were classified as correct or incorrect for asystole (AS), atrial fibrillation (AF) or tachycardia (TA). Incorrect episodes were caused by loss of signal (LO), noise (NO), extrasystole (ES) and T-wave oversensing (TWO). Left directed R axes, lower R-amplitudes and older age were related to artifacts. Results were separated by indication. In ESUS patients TR reduced total median artifact episodes: 0.6 (0-7) vs 0 (0-5) (p < 0.03) and median artifact examination time: 0.3 (0-3.5) vs 0 (0-2.5) (p = 0.03) per patient-year. This benefit is caused by significant reductions in total AS and ES-AS artifacts. The total positive predictive value (PPV) improved only in syncope patients (45 vs 71%, p = 0.002). Accordingly in syncope patients with TR more therapeutic consequences could be established (log rank 0.003).

DISCUSSION

Patients R-axis and measured R-amplitudes during implantation predicted artifacts. This should be taken into account during ILR implantation. Total artifacts, AS artifacts and time spent for artifact analysis was reduced by the new TR detection algorithm in ESUS patients, whereas total artifacts remained unchanged in syncope patients despite reduction of AS artifacts. However TR had no effect on AF and TA episode detection and therefore has to be improved.

Real-world Adoption of Smartphone-based Remote Monitoring Using the Confirm Rx™ Insertable Cardiac Monitor

While previous generations of insertable cardiac monitors (ICMs) required a bedside monitor for remote monitoring (RM), the Confirm Rx™ ICM (Abbott, Chicago, IL, USA) utilizes Bluetooth^®, Wi-Fi/cellular technology, and a smart device to connect to the RM system. We aimed to characterize compliance, connectivity, and event transmission timing with the Confirm Rx™ ICM RM system. The study cohort included American patients who received the Confirm Rx™ ICM with SharpSense™ technology within three months of release (May–July 2019). Compliance with RM was quantified as the proportion of patients registering the patient app on their smart device and transmitting at least once. Connectivity was measured as the median number of days between consecutive transmissions per patient. Event transmission time was measured from episode detection to availability on the Merlin.net™ RM system (Abbott). Time from transmission until review by a clinician was examined. Values for device connectivity, episode transmission timing, and clinician view times were reported as median [first quartile, third quartile]. Of 5,666 patients who received a Confirm Rx™ ICM, 97% registered their patient app and 92% transmitted data at least once. Among those utilizing RM (aged 66 ± 15 years; 49% female), connectivity occurred every 1.5 [1.2, 2.4] days, or 4.7 times per week. Patient-reported symptoms were transmitted to Merlin.net™ within 2.9 [2.1, 3.8] minutes of event onset and viewed by the clinician within 0.9 [0.4, 3.1] days, while device-detected episodes without symptoms were transmitted within 18.5 [11.2, 36.5] hours and then viewed within 0.8 [0.3, 2.5] days. This real-world study demonstrated excellent patient compliance with the smartphone-based RM paradigm enabled by Confirm Rx™, suggesting the suitability of this technology for future cardiac implantable devices.

Cost-effectiveness of insertable cardiac monitors for diagnosis of atrial fibrillation in cryptogenic stroke in Australia

INTRODUCTION

Detection of atrial fibrillation (AF) is required to initiate oral anticoagulation (OAC) after cryptogenic stroke (CS). However, paroxysmal AF can be difficult to diagnose with short term cardiac monitoring. Taking an Australian payer perspective, we evaluated whether long-term continuous monitoring for 3 years with an insertable cardiac monitor (ICM) is cost-effective for preventing recurrent stroke in patients with CS.

METHODS

A lifetime Markov model was developed to simulate the follow-up of patients, comparing long-term continuous monitoring with an ICM to monitoring by conventional care. We used a linked evidence approach to estimate the rates of recurrent stroke when AF detection leads to initiation of OAC, as detected using ICM during the lifetime of the device or as detected using usual care. All diagnostic and patient management costs were modeled. Other model inputs were determined by literature review. Probabilistic sensitivity analysis (PSA) was undertaken to explore the effect of parameter uncertainty according to CHADS2 score and OAC treatment effect.

RESULTS

In the base-case analysis, the model predicted an incremental cost-effectiveness ratio (ICER) of A$29 570 per quality-adjusted life year (QALY). Among CHADS2 subgroups analyses, the ICER ranged from A$26 342/QALY (CHADS2 = 6) to A$42 967/QALY (CHADS2 = 2). PSA suggested that the probabilities of ICM strategy being cost-effective were 53.4% and 78.7%, at thresholds of $30 000 (highly cost-effective) and $50 000 per QALY (cost-effective), respectively.

CONCLUSIONS

Long-term continuous monitoring with an ICM is a cost-effective intervention to prevent recurrent stroke in patients following CS in the Australian context.

Atrial fibrillation in the elderly population: Challenges and management considerations

IMPORTANCE

Atrial fibrillation is the most clinically significant arrhythmia in humans when viewed both from a global and also a national perspective. In the United States, approximately 2.7-6.1 million people are estimated to have atrial fibrillation. With the aging of the population, this prevalence is on an increasing trend and remains an obstacle to cardiovascular health despite significant advancements specific to cardiovascular disease management.

OBSERVATION

In this specific group of patients, healthcare utilization is a concern from the public health perspective. Unfortunately, misconceptions dominate clinical decision making; for instance, the avoidance of safe and effective anticoagulation strategies in patients at the highest risk for embolic strokes continues to be widespread in clinical practice and is often based on a skewed assessment of risk versus benefit. Also, when there are contraindications to standard interventions for atrial fibrillation, a clear and nuanced understanding of second- and third-line interventions with proven benefit is often lacking.

CONCLUSIONS AND RELEVANCE

An individualized approach should be followed by physicians when managing atrial fibrillation in the elderly patient, taking into consideration the risk of complications, particularly the embolic stroke and the availability of treatment options for stroke prevention whether through pharmacological anticoagulation or left atrial appendage occluding devices. The following review sets out to clarify these issues.

Reexamination of the Embolic Stroke of Undetermined Source Concept

Occult atrial fibrillation (AF) is a leading cause of stroke of unclear cause. The optimal approach to secondary stroke prevention for these patients remains elusive. The term embolic stroke of undetermined source (ESUS) was coined to describe ischemic strokes in which the radiographic features demonstrate territorial infarcts resembling those seen in patients with confirmed sources of embolism but without a clear source of embolism detected. It was assumed that patients with ESUS had a high rate of occult AF and would benefit from treatment with direct oral anticoagulants, which are at least as effective as vitamin K antagonists for secondary stroke prevention in patients with AF, but with a much lower risk of intracerebral hemorrhage. Two recent large randomized trials failed to show superiority of direct oral anticoagulants over aspirin in ESUS patients. These findings prompt a reexamination of the ESUS concept, with the goal of improving specificity for detecting patients with a cardioembolic cause. Based on the negative trial results, there is renewed interest in the role of long-term cardiac monitoring for AF in patients who fit the current ESUS definition, as well as the clinical implication of detecting AF. Ongoing trials are exploring these questions. Current ESUS definitions do not accurately detect the patients who should be prescribed direct oral anticoagulants, potentially because occult AF is less common than expected in these patients and/or anticoagulants may be less beneficial in patients with ESUS but no AF than they are for patients with stroke with established AF. More specific criteria to identify patients who may be at higher risk for occult AF and reduce their risk of subsequent stroke have been developed and are being tested in ongoing clinical trials.

Use of echocardiography to stratify the risk of atrial fibrillation: comparison of left atrial and ventricular strain

AIMS

Although both left atrial (LA) and ventricular (LV) dysfunction has been accepted as an important risk factor of atrial fibrillation (AF), usefulness of LA and LV strain has not been fully compared for prediction of AF. The aims of this study were to clarify the associations of both LA and LV strain with AF and to compare their predictive values in the risk stratification for AF.

METHODS AND RESULTS

We evaluated 531 consecutive patients (median age 67 years, 56% male), with no history of AF who underwent echocardiography after cryptogenic stroke. Standard echocardiographic parameters were measured, and speckle-tracking was used to measure LA (reservoir, pump, and conduit strain) and LV strain (global longitudinal strain, GLS). The baseline clinical and echocardiographic parameters of the patients who developed AF and those who did not were compared. Median 36 months of follow-up, 61 patients (11%) had newly diagnosed AF. LA pump strain and GLS were significantly and independently associated with AF and provided incremental predictive value over clinical and standard echocardiographic parameters. Areas under the receiver-operating curves for GLS (0.841) were comparable to LA pump (0.825) and reservoir (0.851) strain. However, predictive value of both strains was different between patients with and without LA enlargement at the time of transthoracic echocardiography screening. LA strain was more useful than LV strain in patients with normal LA volumes, while LV strain was more useful than LA strain in patients with abnormal LA volumes.

CONCLUSION

Both LA and LV strain are significantly and independently associated with AF and provide incremental predictive value over clinical and standard echocardiographic parameters. However, priorities of strain assessment are different depends on patients' condition at the time of echocardiography.

Left Atrial Diameter and Atrial Ectopic Burden in Patients with Embolic Stroke of Undetermined Source: Risk Stratification of Atrial Fibrillation with Insertable Cardiac Monitor Analysis

Background and Purpose

An insertable cardiac monitor (ICM) has been demonstrated to be a useful tool for detecting subclinical atrial fibrillation (AF) in patients with embolic stroke of undetermined source (ESUS). This study aimed to identify the clinical predictors of AF in ESUS patients with ICMs.

Methods

We retrospectively selected consecutive patients with an ICM implanted for AF detection following ESUS. The primary endpoint was defined as any AF episode lasting for longer than 5 min. The atrial ectopic burden (AEB) was calculated as the percentage of the number of conducted QRS from atrial ectopy on Holter monitoring.

Results

This study included 136 patients. AF lasting ≥5 min was detected in 20 patients (14.7%) during a median follow-up period of 6.6 months (interquartile range, 3.3–10.8 months). AF patients had a higher AEB (0.20% vs. 0.02%, p<0.001) and a larger left atrial diameter (LAD, 41.0 mm vs. 35.3 mm, p<0.001) than those without AF. The areas under the receiver operating characteristic curves were 0.795 and 0.816 for the LAD and log-transformed AEB, respectively, for the best cutoff values of 38.5 mm for LAD and 0.050% for AEB. AF lasting ≥5 min was detected in 34.6% (9/26) of patients with LAD ≥38.5 mm and AEB ≥0.050%, and in 0% (0/65) of those with LAD <38.5 mm and AEB <0.050%.

Conclusions

AF was detected in a significant proportion of ESUS patients during a 6.6-month follow-up. The LAD and AEB are good predictors of AF and might be useful for AF risk stratification in ESUS patients.

Embolic Stroke of Undetermined Source and Patent Foramen Ovale: Risk of Paradoxical Embolism Score Validation and Atrial Fibrillation Prediction

[Figure: see text].

Insertable cardiac monitors for detection of atrial fibrillation after cryptogenic stroke: a meta-analysis

BACKGROUND

In recent years, the implantable cardiac monitors (ICM) have enhanced the recognition ability of atrial fibrillation (AF), which makes ICM have a new application in AF detection. We conducted a meta-analysis to determine the total incidence of newly found AF detected by ICM after cryptogenic stroke and to evaluate the factors related to the detection of AF.

METHODS

A literature search was conducted in the PubMed, EMBASE, Web of Science, and Cochrane library databases until March 1, 2020. Studies that reported the detection rate of AF using ICM in cryptogenic stroke patients with negative initial AF screening were analyzed.

RESULTS

A total of 23 studies were included. The overall proportion of AF detected by ICM in cryptogenic stroke patients was 25% (95% confidence interval [CI], 22-29%). The rate of AF detected by ICM was independently related to both cardiac monitoring time (coefficient = 0.0003; 95% CI, 0.0001-0.0005; P = 0.0001) and CHA₂DS₂-VASc score (coefficient = 0.0834; 95% CI, 0.0339-0.1329; P = 0.001). In subgroup analysis, we found a significant difference in the detection rate of AF for monitoring duration (< 6 months: 9.6% [95% CI, 4.4-16.4%]; ≥ 6 and ≤ 12 months: 19.3% [95% CI, 15.9-23.0%]; > 12 and ≤ 24 months: 23.6% [95% CI, 19.9-27.5%]; > 24 months and ≤ 36 months: 36.5% [95% CI, 24.2-49.9%]; P < 0.001), and continent (Europe: 26.5% [95% CI, 22.2-31.0%]; North America: 16.0% [95% CI, 10.3-22.6%]; Asia: 17.4% [95% CI, 12.4-23.0%]; P = 0.005).

CONCLUSIONS

The longer the time of ICM monitoring after cryptogenic stroke, the higher the detection rate of AF. Further research is still needed to determine the optimal duration of long-term cardiac monitoring.

Economic evaluation of extended electrocardiogram monitoring for atrial fibrillation in patients with cryptogenic stroke

BACKGROUND

Timely identification of occult atrial fibrillation following cryptogenic stroke facilitates consideration of oral anticoagulation therapy. Extended electrocardiography monitoring beyond 24 to 48 h Holter monitoring improves atrial fibrillation detection rates, yet uncertainty remains due to upfront costs and the projected long-term benefit. We sought to determine the cost-effectiveness of three electrocardiography monitoring strategies in detecting atrial fibrillation after cryptogenic stroke.

METHODS

A decision-analytic Markov model was used to project the costs and outcomes of three different electrocardiography monitoring strategies (i.e. 30-day electrocardiography monitoring, three-year implantable loop recorder monitoring, and conventional Holter monitoring) in acute stroke survivors without previously documented atrial fibrillation.

RESULTS

The lifetime discounted costs and quality-adjusted life years were $206,385 and 7.77 quality-adjusted life years for conventional monitoring, $207,080 and 7.79 quality-adjusted life years for 30-day extended electrocardiography monitoring, and $210,728 and 7.88 quality-adjusted life years for the implantable loop recorder strategy. Additional quality-adjusted life years could be attained at a more favorable incremental cost per quality-adjusted life year with the implantable loop recorder strategy, compared with the 30-day electrocardiography monitoring strategy, thereby eliminating the 30-day strategy by extended dominance. The implantable loop recorder strategy was associated with an incremental cost per quality-adjusted life year gained of $40,796 compared with conventional monitoring. One-way sensitivity analyses indicated that the model was most sensitive to the rate of recurrent ischemic stroke.

CONCLUSIONS

An implantable loop recorder strategy for detection of occult atrial fibrillation in patients with cryptogenic stroke is more economically attractive than 30-day electrocardiography monitoring compared to conventional monitoring and is associated with a cost per quality-adjusted life year gained in the range of other publicly funded therapies. The value proposition is improved when considering patients at the highest risk of recurrent ischemic stroke. However, the implantable loop recorder strategy is associated with increased health care costs, and the opportunity cost of wide scale implementation must be considered.

Clinical classification and the subclinical atrial fibrillation challenge: a position paper of the European Cardiac Arrhythmia Society

Symptomatic atrial fibrillation (AF) or clinical AF is associated with impaired quality of life, higher risk of stroke, heart failure, and increased mortality. Current clinical classification of AF is based on the duration of AF episodes and the recurrence over time. Appropriate management strategy should follow guidelines of Scientific Societies. The last decades have been marked by the advances in mechanism comprehension, better management of symptomatic AF, particularly regarding stroke prevention with the use of direct oral anticoagulants and a wider use of AF catheter or surgical ablations. The advent of new tools for detection of asymptomatic AF including continuous monitoring with implanted electronic devices and the use of implantable cardiac monitors and recently wearable devices or garments have identified what is called "subclinical AF" encompassing atrial high-rate episodes (AHREs). New concepts such as "AF burden" have resulted in new management challenges. Oral anticoagulation has proven to reduce substantially stroke risk in patients with symptomatic clinical AF but carries the risk of bleeding. Management of detected asymptomatic atrial arrhythmias and their relation to clinical AF and stroke risk is currently under evaluation. Based on a review of recent literature, the validity of current clinical classification has been reassessed and appropriate updates are proposed. Current evidence supporting the inclusion of subclinical AF within current clinical classification is discussed as well as the need for controlled trials which may provide responses to current therapeutic challenges particularly regarding the subsets of asymptomatic AF patients that might benefit from oral anticoagulation.

Nurse Led Smartphone Electrographic Monitoring for Atrial Fibrillation after Ischemic Stroke: SPOT-AF

BACKGROUND AND PURPOSE

Paroxysmal atrial fibrillation (PAF) underlying acute stroke frequently evades detection by standard practice, considered to be a combination of routine electrocardiogram (ECG) monitoring, and 24-hour Holter recordings. We hypothesized that nurse-led in-hospital intermittent monitoring approach would increase PAF detection rate.

METHODS

We recruited patients hospitalised for stroke/transient ischemic attack, without history of atrial fibrillation (AF), in a prospective multi-centre observational study. Patients were monitored using a smartphone-enabled handheld ECG (iECG) during routine nursing observations, and underwent 24-hour Holter monitoring according to local practice. The primary outcome was comparison of AF detection by nurse-led iECG versus Holter monitoring in patients who received both tests: secondary outcome was oral anticoagulant commencement at 3-month following PAF detection.

RESULTS

One thousand and seventy-nine patients underwent iECG monitoring: 294 had iECG and Holter monitoring. AF was detected in 25/294 (8.5%) by iECG, and 8/294 (2.8%) by 24-hour Holter recordings (P<0.001). Median duration from stroke onset to AF detection for iECG was 3 days (interquartile range [IQR], 2 to 6) compared with 7 days (IQR, 6 to 10) for Holter recordings (P=0.02). Of 25 patients with AF detected by iECG, 11 were commenced on oral anticoagulant, compared to 5/8 for Holter. AF was detected in 8.8% (69/785 patients) who underwent iECG recordings only (P=0.8 vs. those who had both iECG and 24-hour Holter).

CONCLUSIONS

Nurse-led in-hospital iECG surveillance after stroke is feasible and effective and detects more PAF earlier and more frequently than routine 24-hour Holter recordings. Screening with iECG could be incorporated into routine post-stroke nursing observations to increase diagnosis of PAF, and facilitate institution of guideline-recommended anticoagulation.

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.

Predictors of Atrial Fibrillation During Long-Term Implantable Cardiac Monitoring Following Cryptogenic Stroke

Background

Following cryptogenic stroke, guidelines recommend cardiac monitoring for occult atrial fibrillation (AF). We aimed to evaluate predictors of AF during long‐term implantable cardiac monitoring.

Methods and Results

We studied 293 consecutive patients who underwent implantable cardiac monitor implant (Medtronic LINQ) following hospitalization for cryptogenic stroke at the University of Rochester Medical Center from January 2013 to September 2018. Multivariable Cox proportional hazards regression modeling was used to identify predictors of AF during long‐term monitoring. At 36 months of follow‐up, the cumulative rate of implantable cardiac monitor–detected AF events was 32% in the total study population. Multivariable analysis identified age ≥70 years as the most powerful predictor of the development of AF events during follow‐up (hazard ratio, 2.28 [95% CI, 1.39–3.76]; P=0.001). Replacing age with the CHA₂DS₂‐VASc (congestive heart failure, hypertension, age, diabetes mellitus, stroke, vascular disease, age, sex category) score resulted in a weaker association, for which each 1‐point increment in the CHA₂DS₂‐VASC score was associated with an 18% increased risk of developing AF (95% CI, 1.00–1.38; P=0.047). Consistent results were shown using Kaplan–Meier analysis by age and by the CHA₂DS₂VASc score.

Conclusions

Cryptogenic stroke patients continue to develop AF episodes during 36 months of implantable cardiac monitoring following the index event. Age is the most powerful predictor of occult AF in this population.

Stroke

Stroke is a major cause of death and disability globally. Diagnosis depends on clinical features and brain imaging to differentiate between ischaemic stroke and intracerebral haemorrhage. Non-contrast CT can exclude haemorrhage, but the addition of CT perfusion imaging and angiography allows a positive diagnosis of ischaemic stroke versus mimics and can identify a large vessel occlusion target for endovascular thrombectomy. Management of ischaemic stroke has greatly advanced, with rapid reperfusion by use of intravenous thrombolysis and endovascular thrombectomy shown to reduce disability. These therapies can now be applied in selected patients who present late to medical care if there is imaging evidence of salvageable brain tissue. Both haemostatic agents and surgical interventions are investigational for intracerebral haemorrhage. Prevention of recurrent stroke requires an understanding of the mechanism of stroke to target interventions, such as carotid endarterectomy, anticoagulation for atrial fibrillation, and patent foramen ovale closure. However, interventions such as lowering blood pressure, smoking cessation, and lifestyle optimisation are common to all stroke subtypes.

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.

Diagnosis and Treatment for embolic stroke of undetermined source: Consensus statement from the Taiwan stroke society and Taiwan society of cardiology

Cryptogenic stroke comprises about one-quarter of ischemic strokes with high recurrence rate; however, studies specifically investigating the features and treatment of this stroke subtype are rare. The concept of 'embolic stroke of undetermined source' (ESUS) may facilitate the development of a standardized approach to diagnose cryptogenic stroke and improve clinical trials. Since recent large randomized control trials failed to demonstrate a reduction in stroke recurrence with anticoagulants, anti-platelet agents remain the first-line treatment for ESUS patients. Nevertheless, patients with high risk of stroke recurrence (e.g., those with repeated embolic infarcts despite aspirin treatment) require a more extensive survey of stroke etiology, including cardiac imaging and prolonged cardiac rhythm monitoring. Anticoagulant treatments may still benefit some subgroups of high-risk ESUS patients, such as those with multiple infarcts at different arterial territories without aortic atheroma, the elderly, or patients with high CHA₂D₂-VASc or HOVAC scores, atrial cardiopathy or patent foramen ovale. Several important ESUS clinical trials are ongoing, and the results are anticipated. With rapid progress in our understanding of ESUS pathophysiology, new subcategorizations of ESUS and assignment of optimal treatments for each ESUS subgroup are expected in the near future.

Identification of patients with embolic stroke of undetermined source and low risk of new incident atrial fibrillation: The AF-ESUS score

Background and aims

Only a minority of patients with Embolic Stroke of Undetermined Source (ESUS) receive prolonged cardiac monitoring despite current recommendations. The identification of ESUS patients who have low probability of new diagnosis of atrial fibrillation (AF) could potentially support a strategy of more individualized allocation of available resources and hence, increase their diagnostic yield. We aimed to develop a tool that can identify ESUS patients who have low probability of new incident AF.

Methods

We performed multivariate stepwise regression in a pooled dataset of consecutive ESUS patients from three prospective stroke registries to identify predictors of new incident AF. The coefficient of each independent covariate of the fitted multivariable model was used to generate an integer-based point scoring system.

Results

Among 839 patients (43.1% women, median age 67.0 years) followed-up for a median of 24.3 months (2999 patient-years), 125 (14.9%) had new incident AF. The proposed score assigns 3 points for age ≥ 60 years; 2 points for hypertension; −1 point for left ventricular hypertrophy reported at echocardiography; 2 points for left atrial diameter >40 mm; −3 points for left ventricular ejection fraction <35%; 1 point for the presence of any supraventricular extrasystole recorded during all available 12-lead standard electrocardiograms performed during hospitalization for the ESUS; −2 points for subcortical infarct; −3 points for the presence of non-stenotic carotid plaques. The rate of new incident AF during follow-up was 1.97% among the 42.3% of the cohort who had a score of ≤0, compared to 26.9% in patients with > 0 (relative risk: 13.7, 95%CI: 5.9--31.5). The area under the curve of the score was 84.8% (95%CI: 79.9--86.9%). The sensitivity and negative predictive value of a score of ≤0 for new incident AF during follow-up were 94.9% (95%CI: 89.3--98.1%) and 98.0% (95%CI: 95.8--99.3%), respectively.

Conclusions

The proposed AF-ESUS score has high sensitivity and high negative predictive value to identify ESUS patients who have low probability of new incident AF. Patients with a score of 1 or more may be better candidates for prolonged automated cardiac monitoring.

Clinical trial registration

URL: https://www.clinicaltrials.gov / Unique identifier: NCT02766205.

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.