A Structured Reading Algorithm Improves Telemetric Detection of Atrial Fibrillation After Acute Ischemic Stroke

A case report of successful rescue using veno-arterial extracorporeal membrane oxygenation: managing cerebral-cardiac syndrome

Introduction

The presence of cerebral-cardiac syndrome, wherein brain diseases coincide with heart dysfunction, significantly impacts patient prognosis. In severe instances, circulatory failure may ensue, posing a life-threatening scenario necessitating immediate life support measures, particularly effective circulatory support methods. The application of extracorporeal membrane oxygenation (ECMO) is extensively employed as a valuable modality for delivering circulatory and respiratory support in the care of individuals experiencing life-threatening circulatory and respiratory failure. This approach facilitates a critical temporal window for subsequent interventions. Consequently, ECMO has emerged as a potentially effective life support modality for patients experiencing severe circulatory failure in the context of cerebral-cardiac syndrome. However, the existing literature on this field of study remains limited.

Case description

In this paper, we present a case study of a patient experiencing a critical cerebral-cardiac syndrome. The individual successfully underwent veno-arterial-ECMO (VA-ECMO) therapy, and the patient not only survived, but also received rehabilitation treatment, demonstrating its efficacy as a life support intervention.

Conclusion

VA-ECMO could potentially serve as an efficacious life support modality for individuals experiencing severe circulatory failure attributable to cerebral-cardiac syndrome.

Cryptogenic Stroke and Embolic Stroke of Undetermined Source: Risk Factors and Approaches for Detection of Atrial Fibrillation

BACKGROUND

Stroke is a problem worldwide because of its high mortality and disability rates. Almost 90% of strokes are ischemic, and more than half of the deaths are caused by an ischemic stroke. Most risk factors for stroke are manageable so that it can be avoided with proper prevention. Despite the success in determining the causes of stroke in recent years, selectively, the "culprit" causing stroke remains unsolved. In such cases, a diagnosis of undetermined etiology (cryptogenic stroke) or embolic stroke of undetermined source (ESUS) is generated, resulting the prevention of a recurrent cerebrovascular occurrence impossible. Atrial fibrillation (AF) can be a cause of stroke by causing blood clots in the chambers of the heart.

PURPOSE

The aim was to determine the optimal method of heart rate monitoring in patients with ischemic stroke, as methods and approaches for detecting AF are very diverse, but there is still no single opinion, which would be universal.

PROCEDURES

In our review, we consider epidemiology, risk factors for the stroke of undetermined etiology, as well as analytical methods for detecting heart rhythm disturbances in this category of patients.

FINDINGS

Atrial fibrillation (AF) is detected by thorough monitoring of heart rate of patients with cryptogenic stroke and ESUS can be diagnosed in up to 46% of patients. .

CONCLUSION

After AF detection, consideration should be given to prescribing anticoagulants, instead of antiplatelet agents, for the secondary prevention of stroke.

Detection of Atrial Fibrillation on Stroke Units: Comparison of Manual versus Automatic Analysis of Continuous Telemetry

BACKGROUND

Detection of atrial fibrillation (AF) is one of the primary diagnostic goals for patients on a stroke unit. Physician-based manual analysis of continuous ECG monitoring is regarded as the gold standard for AF detection but requires considerable resources. Recently, automated computer-based analysis of RR intervals was established to simplify AF detection. The present prospective study analyzes both methods head to head regarding AF detection specificity, sensitivity, and overall effectiveness.

METHODS

Consecutive stroke patients without history of AF or proof of AF in the admission ECG were enrolled over the period of 7 months. All patients received continuous ECG telemetry during the complete stay on the stroke unit. All ECGs underwent automated analysis by a commercially available program. Blinded to these results, all ECG tracings were also assessed manually. Sensitivity, specificity, time consumption, costs per day, and cost-effectiveness were compared.

RESULTS

216 consecutive patients were enrolled (70.7 ± 14.1 years, 56% male) and 555 analysis days compared. AF was detected by manual ECG analysis on 37 days (6.7%) and automatically on 57 days (10.3%). Specificity of the automated algorithm was 94.6% and sensitivity 78.4% (28 [5.0%] false positive and 8 [1.4%] false negative). Patients with AF were older and had more often arterial hypertension, higher NIHSS at admission, more often left atrial dilatation, and a higher CHA2DS2-VASc score. Automation significantly reduced human resources but was more expensive compared to manual analysis alone.

CONCLUSION

Automatic AF detection is highly specific, but sensitivity is relatively low. Results of this study suggest that automated computer-based AF detection should be rather complementary to manual ECG analysis than replacing it.

The additional value of an algorithm for atrial fibrillation at the stroke unit

BACKGROUND AND PURPOSE

The rate of newly detected (paroxysmal) atrial fibrillation (AF) during inpatient cardiac telemetry is low. The objective of this study was to evaluate the additional diagnostic yield of an automated detection algorithm for AF on telemetric monitoring compared with routine detection by a stroke unit team in patients with recent ischemic stroke or TIA.

METHODS

Patients admitted to the stroke unit of Medisch Spectrum Twente with acute ischemic stroke or TIA and no history of AF were prospectively included. All patients had telemetry monitoring, routinely assessed by the stroke unit team. The ST segment and arrhythmia monitoring (ST/AR) algorithm was active, with deactivated AF alarms. After 24 h the detections were analyzed and compared with routine evaluation.

RESULTS

Five hundred and seven patients were included (52.5% male, mean age 70.2 ± 12.9 years). Median monitor duration was 24 (interquartile range 22-27) h. In 6 patients (1.2%) routine analysis by the stroke unit team concluded AF. In 24 patients (4.7%), the ST/AR Algorithm suggested AF. Interrater reliability was low (κ, 0.388, p < 0.001). Suggested AF by the algorithm turned out to be false positive in 11 patients. In 13 patients (2.6%) AF was correctly diagnosed by the algorithm. None of the cases detected by routine analysis were missed by the algorithm.

CONCLUSIONS

Automated AF detection during 24-h telemetry in ischemic stroke patients is of additional value to detect paroxysmal AF compared with routine analysis by the stroke unit team alone. Automated detections need to be carefully evaluated.

Electrocardiomatrix Facilitates Accurate Detection of Atrial Fibrillation in Stroke Patients

Background and Purpose- Cardiac telemetry is a routine part of inpatient ischemic stroke/transient ischemic attack evaluation to assess for atrial fibrillation (AF). Yet, tools to assist stroke clinicians in the evaluation of the large quantities of telemetry data are limited. The investigators developed a new method to evaluate electrocardiographic signals, electrocardiomatrix, that was applied to stroke unit telemetry data to determine its feasibility, validity, and usefulness. Electrocardiomatrix displays telemetry data in a 3-dimensional matrix that allows for more accurate and less time consuming P-wave analysis. Methods- In this single-center, prospective, observational study conducted in a stroke unit, all telemetry data from ischemic stroke and transient ischemic attack patients were collected (April 2017-January 2018) for examination facilitated by electrocardiomatrix. AF>30 seconds was identified through review of electrocardiomatrix-generated matrices by a nonphysician researcher. Electrocardiomatrix results were compared with the clinical team's medical record documentation of AF identified through telemetry. A study cardiologist reviewed the standard telemetry associated with all AF episodes identified by electrocardiomatrix and each case of disagreement. Results- Telemetry data (median 46 hours [interquartile range: 22-90]) were analyzed among 265 unique subjects (88% ischemic stroke). Electrocardiomatrix was successfully applied in 260 (98%) of cases. The positive predictive value of electrocardiomatrix compared with the clinical documentation was 86% overall and 100% among the subset with no prior history of AF. For the 5 false-positive and 5 false-negative cases, expert overview disagreed with the clinical documentation and confirmed the electrocardiomatrix-based diagnosis. Conclusions- The application of electrocardiomatrix to stroke unit-acquired telemetry data is feasible and appears to have superior accuracy compared with traditional monitor analysis by noncardiologists.

Detection of Atrial Fibrillation in Cryptogenic Stroke

PURPOSE OF REVIEW

To summarize the literature on the detection of atrial fibrillation (AF) in patients with "cryptogenic" stroke, a cohort including about 25% of all ischemic stroke patients and patients with embolic stroke of undetermined source (ESUS).

RECENT FINDINGS

A first episode of AF is detected in up to one third of cryptogenic stroke and in up to one fourth of ESUS patients during long-term monitoring. AF prevalence correlates to patient selection, duration, and quality of ECG monitoring. Higher rates of AF were reported in stroke patients with left atrial pathology, specific ECG alterations, or increased natriuretic peptides. While AF detection impacts on medical stroke prevention in the vast majority of patients, patient selection for prolonged monitoring is largely left at the physician's discretion. AF detection after cryptogenic stroke or ESUS is a frequent, potentially causal condition. Whether subsequent oral anticoagulation may improve outcome remains open.

Expert opinion paper on atrial fibrillation detection after ischemic stroke

This expert opinion paper on atrial fibrillation detection after ischemic stroke includes a statement of the "Heart and Brain" consortium of the German Cardiac Society and the German Stroke Society. This paper was endorsed by the Stroke Unit-Commission of the German Stroke Society and the German Atrial Fibrillation NETwork. In patients with ischemic stroke, detection of atrial fibrillation should usually lead to a change in secondary stroke prevention, since oral anticoagulation is superior to antiplatelet drugs. The detection of previously undiagnosed atrial fibrillation can be improved in patients with ischemic stroke to optimize stroke prevention. This paper summarizes the present knowledge on atrial fibrillation detection after ischemic stroke. We propose an interdisciplinary standard for a "structured analysis of ECG monitoring" on the stroke unit as well as a staged diagnostic scheme for the detection of atrial fibrillation. Since the optimal duration and mode of ECG monitoring has not yet been finally established, this paper is intended to give advice to physicians who are involved in stroke care. In line with the nature of an expert opinion paper, labeling of classes of recommendations is not provided, since many statements are based on the expert opinion, reported case series and clinical experience. Therefore, this paper is not intended as a guideline.

Nursing-Based Dysrhythmia Detection on a Dedicated Stroke Unit Using a Unit-Based Cardiac Telemetry Monitoring System

BACKGROUND

Acute stroke care includes cardiac rhythm monitoring in the first 24 hours. The method of monitoring varies, as do the reported findings. The nurses' role in this process can be intensive, including primary response and review of all data. Competency is critical as the acute stroke setting can be associated with life-threatening dysrhythmias as well as the detection of atrial fibrillation that affects therapy. Limited studies exist to evaluate the effectiveness of a unit-based cardiac monitoring system for which the bedside nurse has primary responsibility.

OBJECTIVE

The goal was to determine if a unit-based cardiac monitoring system for which the bedside nurse was responsible detected clinically significant dysrhythmias.

METHODS

Stroke unit nurses completed a mandatory education program on identifying common dysrhythmias and using the monitoring equipment along with a structured algorithm for cardiac dysrhythmia detection. The nurse was responsible for all alarms as well as review of their patients' data. Their findings were recorded and reviewed by a cardiology team after the 24-hour monitoring was completed. A total of 300 consecutive stokes, transient ischemic attack, and possible stroke patients were enrolled.

RESULTS

Nurses identified 96% of all significant dysrhythmias. Twenty-eight percent of the stroke patients had a dysrhythmia, of which 79% were atrial fibrillation/atrial flutter. The bedside nurses did identify all 8 new atrial fibrillation cases.

CONCLUSION

Stroke unit nurses who complete an educational program can identify dysrhythmias on their patients' unit-based cardiac monitoring systems and can improve patient outcomes.

Screening strategies for atrial fibrillation: a systematic review and cost-effectiveness analysis

Background

Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of thromboembolic events. Anticoagulation therapy to prevent AF-related stroke has been shown to be cost-effective. A national screening programme for AF may prevent AF-related events, but would involve a substantial investment of NHS resources.

Objectives

To conduct a systematic review of the diagnostic test accuracy (DTA) of screening tests for AF, update a systematic review of comparative studies evaluating screening strategies for AF, develop an economic model to compare the cost-effectiveness of different screening strategies and review observational studies of AF screening to provide inputs to the model.

Design

Systematic review, meta-analysis and cost-effectiveness analysis.

Setting

Primary care.

Participants

Adults.

Intervention

Screening strategies, defined by screening test, age at initial and final screens, screening interval and format of screening {systematic opportunistic screening [individuals offered screening if they consult with their general practitioner (GP)] or systematic population screening (when all eligible individuals are invited to screening)}.

Main outcome measures

Sensitivity, specificity and diagnostic odds ratios; the odds ratio of detecting new AF cases compared with no screening; and the mean incremental net benefit compared with no screening.

Review methods

Two reviewers screened the search results, extracted data and assessed the risk of bias. A DTA meta-analysis was perfomed, and a decision tree and Markov model was used to evaluate the cost-effectiveness of the screening strategies.

Results

Diagnostic test accuracy depended on the screening test and how it was interpreted. In general, the screening tests identified in our review had high sensitivity (> 0.9). Systematic population and systematic opportunistic screening strategies were found to be similarly effective, with an estimated 170 individuals needed to be screened to detect one additional AF case compared with no screening. Systematic opportunistic screening was more likely to be cost-effective than systematic population screening, as long as the uptake of opportunistic screening observed in randomised controlled trials translates to practice. Modified blood pressure monitors, photoplethysmography or nurse pulse palpation were more likely to be cost-effective than other screening tests. A screening strategy with an initial screening age of 65 years and repeated screens every 5 years until age 80 years was likely to be cost-effective, provided that compliance with treatment does not decline with increasing age.

Conclusions

A national screening programme for AF is likely to represent a cost-effective use of resources. Systematic opportunistic screening is more likely to be cost-effective than systematic population screening. Nurse pulse palpation or modified blood pressure monitors would be appropriate screening tests, with confirmation by diagnostic 12-lead electrocardiography interpreted by a trained GP, with referral to a specialist in the case of an unclear diagnosis. Implementation strategies to operationalise uptake of systematic opportunistic screening in primary care should accompany any screening recommendations.

Limitations

Many inputs for the economic model relied on a single trial [the Screening for Atrial Fibrillation in the Elderly (SAFE) study] and DTA results were based on a few studies at high risk of bias/of low applicability.

Future work

Comparative studies measuring long-term outcomes of screening strategies and DTA studies for new, emerging technologies and to replicate the results for photoplethysmography and GP interpretation of 12-lead electrocardiography in a screening population.

Study registration

This study is registered as PROSPERO CRD42014013739.

Funding

The National Institute for Health Research Health Technology Assessment programme.

Diagnostic value of prehospital ECG in acute stroke patients

Objective:

To investigate the diagnostic yield of prehospital ECG monitoring provided by emergency medical services in the case of suspected stroke.

Methods:

Consecutive patients with acute stroke admitted to our tertiary stroke center via emergency medical services and with available prehospital ECG were prospectively included during a 12-month study period. We assessed prehospital ECG recordings and compared the results to regular 12-lead ECG on admission and after continuous ECG monitoring at the stroke unit.

Results:

Overall, 259 patients with prehospital ECG recording were included in the study (90.3% ischemic stroke, 9.7% intracerebral hemorrhage). Atrial fibrillation (AF) was detected in 25.1% of patients, second-degree or greater atrioventricular block in 5.4%, significant ST-segment elevation in 5.0%, and ventricular ectopy in 9.7%. In 18 patients, a diagnosis of new-onset AF with direct clinical consequences for the evaluation and secondary prevention of stroke was established by the prehospital recordings. In 2 patients, the AF episodes were limited to the prehospital period and were not detected by ECG on admission or during subsequent monitoring at the stroke unit. Of 126 patients (48.6%) with relevant abnormalities in the prehospital ECG, 16.7% received medical antiarrhythmic therapy during transport to the hospital, and 6.4% were transferred to a cardiology unit within the first 24 hours in the hospital.

Conclusions:

In a selected cohort of patients with stroke, the in-field recordings of the ECG detected a relevant rate of cardiac arrhythmia. The results can add to the in-hospital evaluation and should be considered in prehospital care of acute stroke.

Cardiac diagnostic work-up for atrial fibrillation after transient ischaemic attacks in England and Wales: results from a cross-sectional survey

OBJECTIVES

Transient ischaemic attacks (TIAs) are an important precursor of stroke. Atrial fibrillation (AF) is among the most dangerous aetiologies shared between TIAs and strokes. Detection of AF after TIAs is essential for the initiation of oral anticoagulants. We aimed to identify variations in the use of cardiac investigations used to detect AF and cardiac pathology in patients with TIA in the UK.

SETTING

All TIA clinical leads in England and Wales received an invitation by email to participate in an online survey in February 2015. The questionnaire consisted of 36 multiple choice questions covering the domains: (1) general information about stroke units, (2) ECG diagnostics and cardiologic work-up and (3) management of AF.

RESULTS

146 survey invitations were sent. The response rate was 40% (n=59). Diagnosis of AF largely depends on medical history and 12-channel ECG which is performed in the vast majority of patients with TIA (>75%) in 94.1% of the TIA services. Many patients with TIA either do not receive 24-hour Holter recording (requested regularly in 42% of the services) or only after considerable delay (>2 weeks). Prolonged event recording is only rarely performed (16%). Only about half of patients with TIA undergo echocardiography. Cranial imaging in patients with TIA is mainly performed as CT (62%). The majority of TIA clinics rapidly initiate anticoagulation in TIA patients with AF (81.6%) preferably using new oral anticoagulants (75.5%).

CONCLUSIONS

Significant variation in the cardiac diagnostic work-up following TIA exists regarding the use of particular detection techniques and the duration of cardiac ECG monitoring. Only limited resources are allocated to cardiac evaluation. In addition to research establishing the optimal ECG technique for patients with TIA, healthcare delivery programmes are needed to ensure proper management to prevent strokes.

Cardiac monitoring for detection of atrial fibrillation after TIA: A systematic review and meta-analysis

Background and purpose

The detection rate of atrial fibrillation has not been studied specifically in transient ischemic attack (TIA) patients although extrapolation from ischemic stroke may be inadequate. We conducted a systematic review and meta-analysis to determine the rate of newly diagnosed atrial fibrillation using different methods of ECG monitoring in TIA.

Methods

A comprehensive literature search was performed following a pre-specified protocol the PRISMA statement. Prospective observational studies and randomized controlled trials were considered that included TIA patients who underwent cardiac monitoring for >12 h. Primary outcome was frequency of detection of atrial fibrillation ≥30 s. Analyses of subgroups and of duration and type of monitoring were performed.

Results

Seventeen studies enrolling 1163 patients were included. The pooled atrial fibrillation detection rate for all methods was 4% (95% CI: 2–7%). Yield of monitoring was higher in selected (higher age, more extensive testing for arrhythmias before enrolment, or presumed cardioembolic/cryptogenic cause) than in unselected cohorts (7% vs 3%). Pooled mean atrial fibrillation detection rates rose with duration of monitoring: 4% (24 h), 5% (24 h to 7 days) and 6% (>7 days), respectively. Yield of non-invasive was significantly lower than that of invasive monitoring (4% vs. 11%). Significant heterogeneity was observed among studies (I2=60.61%).

Conclusion

This first meta-analysis of atrial fibrillation detection in TIA patients finds a lower atrial fibrillation detection rate in TIA than reported for IS and TIA cohorts in previous meta-analyses. Prospective studies are needed to determine actual prevalence of atrial fibrillation and optimal diagnostic procedure for atrial fibrillation detection in TIA.

Detection of Atrial Fibrillation Among Patients With Stroke Due to Large or Small Vessel Disease: A Meta-Analysis

BACKGROUND

Recent trials have demonstrated that extended cardiac monitoring increases the yield of paroxysmal atrial fibrillation (AF) detection in patients with cryptogenic stroke. The utility of extended cardiac monitoring is uncertain among patients with stroke caused by small and large vessel disease. We conducted a meta-analysis to estimate the yield of AF detection in this population.

METHODS AND RESULTS

We searched PubMed, Cochrane, and SCOPUS databases for studies on AF detection in stroke patients and excluded studies restricted to patients with cryptogenic stroke or transient ischemic attack. We abstracted AF detection rates for 3 populations grouped by stroke etiology: large vessel stroke, small vessel stroke, and stroke of undefined etiology (a mixture of cryptogenic, small vessel, large vessel, and other stroke etiologies). Our search yielded 30 studies (n=5687). AF detection rates were similar in patients with large vessel (2.2%, 95% CI 0.3-5.5; n=830) and small vessel stroke (2.4%, 95% CI 0.4-6.1; n=520). No studies had a monitoring duration longer than 7 days. The yield of AF detection in the undefined stroke population was higher (9.2%; 95% CI 7.1-11.5) compared to small vessel stroke (P=0.02) and large vessel stroke (P=0.02) populations.

CONCLUSIONS

AF detection rate is similar in patients with small and large vessel strokes (2.2-2.4%). Because no studies reported on extended monitoring (>7 days) in these stroke populations, we could not estimate the yield of AF detection with long-term cardiac monitoring. Randomized controlled trials are needed to examine the utility of AF detection with long-term cardiac monitoring (>7 days) in this patient population.

Insular Cortex Lesions, Cardiac Troponin, and Detection of Previously Unknown Atrial Fibrillation in Acute Ischemic Stroke

Background and Purpose—

Detection rates of paroxysmal atrial fibrillation (AF) after acute ischemic stroke increase with duration of ECG monitoring. To date, it is unknown which patient group may benefit most from intensive monitoring strategies. Therefore, we aimed to identify predictors of previously unknown AF during in-hospital ECG monitoring.

Methods—

All consecutive patients with imaging-confirmed ischemic stroke admitted to our tertiary care hospital from February 2011 to December 2013 were registered prospectively. Patients received continuous bedside ECG monitoring for at least 24 hours. Detection of previously unknown AF during in-hospital ECG monitoring was obtained from medical records. Patients with AF on admission ECG or known history of AF were excluded from analysis.

Results—

Among 1228 patients (median age, 73 years; median National Institutes of Health Stroke Scale, 4; 43.4% women), previously unknown AF was detected in 114 (9.3%) during a median time of continuous ECG monitoring of 3 days (interquartile range, 2–4 days). Duration of monitoring ( P <0.01), older age ( P <0.01), history of hypertension ( P =0.03), insular cortex involvement ( P <0.01), and higher high-sensitivity cardiac troponin T ( P =0.04) on admission were independently associated with subsequent detection of AF in a multiple regression analysis. Addition of high-sensitivity cardiac troponin T, insular cortex stroke, or both to the CHADS2 score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke [2P]) significantly improved c -statistics from 0.63 to 0.68 ( P =0.01), 0.70 ( P <0.01), and 0.72 ( P <0.001), respectively.

Conclusions—

Insular cortex involvement, higher admission high-sensitivity cardiac troponin T, older age, hypertension, and longer monitoring are associated with new detection of AF during in-hospital ECG monitoring. Patients with higher high-sensitivity cardiac troponin T or insular cortex involvement may be candidates for prolonged ECG monitoring.

Detection of occult atrial fibrillation in patients with embolic stroke of uncertain source: a work in progress

Atrial fibrillation accounts for a substantial proportion of ischemic strokes of known etiology and may be responsible for an additional subset of the 25–40% of strokes of unknown cause (so-called cryptogenic). Oral anticoagulation is significantly more effective than antiplatelet therapy in the secondary prevention of atrial fibrillation-related strokes, providing justification for developing more sensitive approaches to detecting occult paroxysms of atrial fibrillation. In this article, we summarize the current state of knowledge regarding the value of in-hospital and out-patient monitoring for detecting atrial fibrillation in the context of cryptogenic stroke. We review the evidence for and against screening with standard Holter monitors, external loop recorders, the newer real-time continuous attended cardiac monitoring systems, cardiac implantable electronic devices, and insertable loop recorders. We review key questions regarding prolonged cardiac arrhythmia monitoring, including the relationship between duration of the atrial fibrillation episode and risk of thromboembolism, frequency of monitoring and its impact on the diagnostic yield in detecting occult or subclinical atrial fibrillation, and the temporal proximity of device-detected atrial fibrillation to stroke events. We conclude by proposing avenues for further research.

Electrocardiographic monitoring for detecting atrial fibrillation after ischemic stroke or transient ischemic attack: systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a major cause of stroke. Although standard investigations after an event include electrocardiographic monitoring, the optimal duration to detect AF is unclear. We performed a systematic review and meta-analysis to determine whether the duration of electrocardiographic monitoring after an ischemic event is related to the detection of AF.

METHODS AND RESULTS

Prospective studies that reported the proportion of new AF diagnosed using electrocardiographic monitoring for > 12 hours in patients with recent stroke or transient ischemic attack were analyzed. Studies were excluded if the stroke was hemorrhagic or AF was previously diagnosed. A total of 31 articles met inclusion criteria. Longer duration of monitoring was associated with an increased detection of AF when examining monitoring time as a continuous variable (P < 0.001 for metaregression analysis). When dichotomizing studies based on monitoring duration, studies with monitoring lasting ≤ 72 hours detected AF in 5.1%, whereas monitoring lasting ≥ 7 days detected AF in 15%. The proportion of new diagnosis increased to 29.15% with extended monitoring for 3 months. Significant heterogeneity within studies was detected for both groups (≤ 72 hours, I(2) = 91.3%; ≥ 7 days, I(2) =7 5.8). When assessing the odds of AF detection in the 3 randomized controlled trial, there was a 7.26 increased odds of AF with long-term monitoring (95% confidence intervals [3.99-12.83]; P value < 0.001).

CONCLUSIONS

Longer duration of electrocardiographic monitoring after cryptogenic stroke is associated with a greater detection of AF. Future investigation is needed to determine the optimal duration of long-term monitoring.

Reliability and limitations of automated arrhythmia detection in telemetric monitoring after stroke

BACKGROUND AND PURPOSE

Guidelines recommend continuous ECG monitoring in patients with cerebrovascular events. Studies on intensive care units (ICU) demonstrated high sensitivity but high rates of false alarms of monitoring systems resulting in desensitization of medical personnel potentially endangering patient safety. Data on patients with acute stroke are lacking.

METHODS

One-hundred fifty-one consecutive patients with acute cerebrovascular events were prospectively included. Automatically identified arrhythmia events were analyzed by manual ECG analysis. Muting of alarms was registered. Sensitivity was evaluated by beat-to-beat analysis of the entire recorded ECG data in a subset of patients. Ethics approval was obtained by University of Erlangen-Nuremberg.

RESULTS

A total of 4809.5 hours of ECG registration and 22 509 alarms were analyzed. The automated detection algorithm missed no events but the overall rate of false alarms was 27.4%. Only 0.6% of all alarms indicated acute life-threatening events and 91.4% of these alarms were incorrect. Transient muting of acoustic alarms was observed in 20.5% patients.

CONCLUSIONS

Continuous ECG monitoring using automated arrhythmia detection is highly sensitive in acute stroke. However, high rates of false alarms and alarms without direct therapeutic consequence cause desensitization of personnel. Therefore, acoustic alarms may be limited to life-threatening events but standardized manual evaluation of all alarms should complement automated systems to identify clinically relevant arrhythmias.

Detection of atrial fibrillation after ischemic stroke or transient ischemic attack: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Atrial fibrillation (AF) confers a high risk of recurrent stroke, although detection methods and definitions of paroxysmal AF during screening vary. We therefore undertook a systematic review and meta-analysis to determine the frequency of newly detected AF using noninvasive or invasive cardiac monitoring after ischemic stroke or transient ischemic attack.

METHODS

Prospective observational studies or randomized controlled trials of patients with ischemic stroke, transient ischemic attack, or both, who underwent any cardiac monitoring for a minimum of 12 hours, were included after electronic searches of multiple databases. The primary outcome was detection of any new AF during the monitoring period. We prespecified subgroup analysis of selected (prescreened or cryptogenic) versus unselected patients and according to duration of monitoring.

RESULTS

A total of 32 studies were analyzed. The overall detection rate of any AF was 11.5% (95% confidence interval, 8.9%-14.3%), although the timing, duration, method of monitoring, and reporting of diagnostic criteria used for paroxysmal AF varied. Detection rates were higher in selected (13.4%; 95% confidence interval, 9.0%-18.4%) than in unselected patients (6.2%; 95% confidence interval, 4.4%-8.3%). There was substantial heterogeneity even within specified subgroups.

CONCLUSIONS

Detection of AF was highly variable, and the review was limited by small sample sizes and marked heterogeneity. Further studies are required to inform patient selection, optimal timing, methods, and duration of monitoring for detection of AF/paroxysmal AF.

Performance of an external transtelephonic loop recorder for automated detection of paroxysmal atrial fibrillation

BACKGROUND

Although atrial fibrillation (AF) is the most commonly encountered arrhythmia, some of the properties make its detection challenging. In daily practice, underdiagnosis can lead to less effective treatment in prevention of stroke. Based on data from studies on treatment of AF, more intensive follow-up strategies, including 7-day Holter recording, 30-day event recording, and even implantable cardiac monitoring devices, are suggested. The study purpose is to evaluate the performance of a continuous single-channel loop recorder with automatic AF detection and transtelephonic electrocardiogram (ECG) transmission capabilities.

METHODS AND RESULTS

A consecutive cohort of 153 patients admitted to the stroke unit with a presumptive diagnosis of ischemic cerebrovascular accident was screened for AF. Twenty-four-hour rhythm observation was performed using a single-channel external loop recorder (ELR) configured for automated AF detection. A total of 45 patients with a known history of AF, AF on the admission ECG, or incomplete registrations were excluded. Extensive additional frequency-based settings were used to establish a reference registration. In total, 2923 recordings were transmitted. We evaluated all events, of which 1190 were designated by the device as AF. The sensitivity, specificity, PPV, and NPV for identifying AF using the ELR were, respectively, 93%, 51%, 5%, and 99%.

CONCLUSIONS

In this ELR validation study, the dedicated AF detection algorithm showed to be highly sensitive but not specific for AF. Applicability of an ELR might be limited for efficacious detection of AF, as manual verification is mandatory for a vast amount of recordings.

Serious Cardiac Arrhythmias After Stroke

Background and Purpose—

Patients with acute cerebrovascular events are susceptible to serious cardiac arrhythmias, but data on the time course and the determinants of their onset are scarce.

Methods—

The prospective Stroke-Arrhythmia-Monitoring-Database (SAMBA) assessed cardiac arrhythmias with need for urgent evaluation and treatment in 501 acute neurovascular patients during the first 72 hours after admission to a monitored stroke unit. Arrhythmias were systematically detected by structured processing of telemetric data. Time of arrhythmia onset and predisposing factors were investigated.

Results—

Significant cardiac arrhythmias occurred in 25.1% of all patients. Incidence was highest during the first 24 hours after admission. Serious arrhythmic tachycardia (ventricular or supraventricular >130 beats/min) was more frequent than bradycardic arrhythmia (sinus-node dysfunction, bradyarrhythmia, or atrioventricular block °II and °III). Arrhythmias were independently associated with higher age and severer neurological deficits as measured by the National Institutes of Health Stroke Scale on admission.

Conclusions—

The risk for significant cardiac arrhythmia after an acute cerebrovascular event is highest during the first 24 hours of care and declines with time during the first 3 days. Along with established vascular risk factors, the National Institutes of Health Stroke Scale may be considered for a stratified allocation of monitoring capabilities.

Clinical Trial Registration—

URL: www.clinicaltrials.gov . Unique identifier: NCT01177748.