Specific cardiological evaluation after focal cerebral ischemia

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.

[Contribution of Holter ECG in the etiologic diagnosis of the ischemic stroke in Brazzaville, Congo]

Déterminer la prévalence des troubles rythmiques au cours des infarctus cérébraux et identifier les facteurs prédictifs de la fibrillation atriale (FA) paroxystique. Il s'est agi d'une étude transversale, descriptive et analytique, menée à Brazzaville entre janvier 2012 et décembre 2016. Elle a porté sur une série consécutive de 267 patients victimes d'un accident vasculaire cérébral ischémique transitoire (n = 17) ou constitué (n = 250), documenté par un scanner cérébral. Tous ces patients ont bénéficié d'un enregistrement Holter ECG dès 24h, réalisé dans le cadre de la recherche étiologique. Les principales anomalies rythmiques enregistrées ont été répertoriées et la régression logistique a permis l'identification des facteurs prédictifs de survenue de la FA paroxystique. Il s'agissait de 164 hommes (61,4%) et 103 femmes (38,6%), âgés en moyenne de 60,2 ± 12,1 ans (extrêmes: 22 et 94 ans). Les principaux facteurs de risque cardiovasculaire identifiés étaient une hypertension artérielle (HTA) dans 214 cas (80,1%), un diabète sucré dans 36 cas (13,5%), et un tabagisme dans 18 cas (6,7%), avec un taux de cumul de 1,5 facteur par individu. L'examen Holter ECG, normal dans 216 cas (81%), était pathologique dans 51 cas (19%). Les principales anomalies enregistrées consistaient en des extrasystoles ventriculaires bénignes (n = 32), une FA paroxystique (n = 7), des extrasystoles supraventriculaires (n = 5), une tachycardie ventriculaire (TV) non soutenue (n = 4), une TV soutenue (n = 2) et un bloc auriculo-ventriculaire type Mobitz II (n = 1). La fréquence de la FA paroxystique était de 2,6%. En analyse bivariée, il n'a pas été noté de corrélation entre la FA paroxystique et le sexe (p = 0,890), l'HTA (p = 0,818), le diabète (p = 0,839), le tabac (p = 0,969). En analyse multivariée, seul l'âge était prédictif de la survenue d'une FA paroxystique au cours des infarctus cérébraux (OR = 1,11;p = 0,0134). Il ressort de cette étude préliminaire que les troubles du rythme emboligènes sont relativement rares au cours des infarctus cérébraux à Brazzaville. La FA paroxystique, quoique peu fréquente, reste essentiellement corrélée à l'âge. Sa recherche systématique chez les sujets âgés contribue à améliorer la prise en charge.

Atrial fibrillation detection using single lead portable electrocardiographic monitoring: a systematic review and meta-analysis

OBJECTIVES

Recent technology advances have allowed for heart rhythm monitoring using single-lead ECG monitoring devices, which can be used for early diagnosis of atrial fibrillation (AF). We sought to investigate the AF detection rate using portable ECG devices compared with Holter monitoring.

SETTING, PARTICIPANTS AND OUTCOME MEASURES

We searched the Medline, Embase and Scopus databases (conducted on 8 May 2017) using search terms related to AF screening and included studies with adults aged >18 years using portable ECG devices or Holter monitoring for AF detection. We excluded studies using implantable loop recorders and pacemakers. Using a random-effects model we calculated the overall AF detection rate. Meta-regression analysis was performed to explore potential sources for heterogeneity. Quality of reporting was assessed using the tool developed by Downs and Black.

RESULTS

Portable ECG monitoring was used in 18 studies (n=117 436) and Holter monitoring was used in 36 studies (n=8498). The AF detection rate using portable ECG monitoring was 1.7% (95% CI 1.4 to 2.1), with significant heterogeneity between studies (p<0.001). There was a moderate linear relationship between total monitoring time and AF detection rate (r=0.65, p=0.003), and meta-regression identified total monitoring time (p=0.005) and body mass index (p=0.01) as potential contributors to heterogeneity. The detection rate (4.8%, 95% CI 3.6% to 6.0%) in eight studies (n=10 199), which performed multiple ECG recordings was comparable to that with 24 hours Holter (4.6%, 95% CI 3.5% to 5.7%). Intermittent recordings for 19 min total produced similar AF detection to 24 hours Holter monitoring.

CONCLUSION

Portable ECG devices may offer an efficient screening option for AF compared with 24 hours Holter monitoring.

PROSPERO REGISTRATION NUMBER

CRD42017061021.

Current rare indications and future directions for implantable loop recorders

The scope of application for implantable loop recorders has shifted away from the evaluation of unclear palpitations and syncope episodes to more complex conditions. This article focuses on rare indications of growing importance such as rhythm monitoring after ablation of atrial fibrillation or after cryptogenic stroke. Furthermore, forthcoming applications in various clinical settings are described, e. g., arrhythmia detection after myocardial infarction, after catheter-based valve interventions, in heart failure, and in cardiomyopathies. Enhancement of the capabilities of implantable loop recorders could broaden their fields of use.

Secondary Stroke Prevention: Improving Diagnosis and Management with Newer Technologies

Treatment of hypertension, diabetes, high cholesterol, smoking cessation, and healthy lifestyle have all contributed to the decline in the incidence of vascular disease over the last several decades. Patients who suffer an acute stroke are at a high risk for recurrence. Introduction of newer technologies and their wider use allows for better identification of patients in whom the risk of recurrence following an acute stroke may be very high. Traditionally, the major focus for diagnosis and management has focused on patient history, examination, imaging for carotid stenosis/occlusion, and detection of AF and paroxysmal AF (PAF) with 24-48 h cardiac monitoring. This review focuses on the usefulness of three newer investigative tools that are becoming widely available and lead to better prevention. Continuous ambulatory blood pressure measurements for 24 h or longer and 3D Doppler measures of the carotid arteries provide key useful information on the state of vascular health and enhance our ability to monitor the response to preventive therapies. Furthermore, the detection of PAF can be significantly improved with prolonged cardiac monitoring for 3 weeks or longer, enabling the initiation of appropriate prevention therapy. This review will focus on the potential impact and importance of these emerging technologies on the prevention of recurrent stroke in high-risk patients.

Optimal Duration of Monitoring for Atrial Fibrillation in Cryptogenic Stroke: A Nonsystematic Review

Atrial fibrillation (AF) is the most common form of cardiac arrhythmias and an independent risk factor for stroke. Despite major advances in monitoring strategies, clinicians tend to miss the diagnoses of AF and especially paroxysmal AF due mainly to its asymptomatic presentation and the rather limited duration dedicated for monitoring for AF after a stroke, which is 24 hours as per the current recommended guidelines. Hence, determining the optimal duration of monitoring for paroxysmal atrial fibrillation after acute ischemic stroke remains a matter of debate. Multiple trials were published in regard to this matter using both invasive and noninvasive monitoring strategies for different monitoring periods. The data provided by these trials showcase strong evidence suggesting a longer monitoring strategy beyond 24 hours is associated with higher detection rates of AF, with the higher percentage of patients detected consequently receiving proper secondary stroke prevention with anticoagulation and thus justifying the cost-effectiveness of such measures. Overall, we thus conclude that increasing the monitoring duration for AF after a cryptogenic stroke to at least 72 hours will indeed enhance the detection rates, but the cost-effectiveness of this monitoring strategy compared to longer monitoring durations is yet to be established.

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.

Atrial fibrillation and stroke - Coexistence and attitude to preventive therapy on the basis of Szczecin and Szczecin region patients

Atrial fibrillation (AF) is an independent factor increasing the risk of an ischemic stroke (IS) fivefold. The objective of the study was to evaluate the frequency of coexistence of non-valvular AF and IS during the acute stroke and to analyze the attitude of AF patients to treatment. The study included 3712 successive patients presenting either an IS or a transient ischemic attack. The analysis revealed a significant increase in the rate of patients with AF and IS in the years 2010-2013 (31.9%) compared with 2002-2005 (20.2%). A rise in the proportion of AF and IS patients was recorded over the course of consecutive years in group II. The proportion of newly detected AF cases during hospital stay differed significantly between the groups (16.9% vs. 31.9%). Group I and II patients differed essentially with regards to hypertension incidence and female rates. Antiplatelet medications or OACs were taken by a significantly greater number of AF patients in group II. Low number of therapeutic levels of INR was recorded in both groups. IS and AF coexist more frequently than indicated by previous assessments and demographic data from other countries. Increase in the number of IS and AF patients may result from higher detectability of AF and older age of patients affected with stroke, women in particular. Despite a well grounded knowledge about the benefits of OACs use in the prophylaxis of thrombotic-embolic events in AF patients, they are rarely used. A surprisingly low proportion of patients taking OACs reaches a therapeutic INR level.

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.

Improved Detection of Silent Atrial Fibrillation Using 72-Hour Holter ECG in Patients With Ischemic Stroke

Background and Purpose—

Adequate diagnosis of atrial fibrillation (AF), including paroxysmal AF, is an important part of stroke workup. Prolonged ECG monitoring may improve the detection of paroxysmal, previously undiagnosed AF (unknown AF). Therefore, we evaluated systematic 72-hour Holter ECG monitoring to detect unknown AF for the workup of patients with stroke.

Methods—

Unselected survivors of a stroke or transient ischemic attack (TIA) without known AF were enrolled in a prospective, multicenter cohort study of 72-hour Holter ECG monitoring in 9 German secondary and tertiary stroke centers between May 2010 and January 2011. In addition to standardized workup of stroke pathogenesis according to the German Stroke Unit protocol, all patients underwent 72-hour Holter ECG monitoring directly after admission. All ECGs were centrally analyzed by 2 independent observers. We determined the proportion of unknown AF and compared the detection rates of 72- and 24-hour monitoring.

Results—

A total of 1135 patients were enrolled (mean age, 67 years [SD, 13.1 years], 45% women, 29% TIA). Unknown AF was detected in 49 out of 1135 patients (4.3%, [95% confidence interval, 3.4–5.2%]) by 72-hour ECG monitoring. Unknown AF was diagnosed in 29 patients (2.6%) within the first 24 hours of ECG monitoring, and in 20 more patients only by 72 hours of ECG monitoring. The number needed to screen by 72-hour ECG was 55 patients (95% confidence interval [35–123]) for each additional AF diagnosis. Patients with unknown AF were significantly older and had more often a history of previous stroke. Patients with unknown AF were equally distributed within categories of pathogenesis according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification.

Conclusions—

In unselected survivors of stroke or TIA, 72-hour ECG monitoring is feasible and improves the detection rate of silent paroxysmal AF.

[Detection of atrial fibrillation after stroke]

Approximately every fourth stroke results from cardiac embolism. Atrial fibrillation has been recognized as a common cause for thromboembolic stroke. Detection of unknown atrial fibrillation is an important clinical challenge, as anticoagulation may effectively reduce the risk of recurrent ischemic stroke. In all patients with a cryptogenic stroke 24-h Holter monitoring should be performed in addition to a standard ECG to detect paroxysmal atrial fibrillation. In addition, it is useful to pay attention to atrial fibrillation during continuous bedside ECG monitoring on the stroke unit and in pacemaker interrogation. The indication for longer ECG monitoring by implantable loop recorders may be considered individually based on the expected probability of atrial fibrillation. The potential benefit of these devices is currently being evaluated in clinical trials.

[Cardiologic diagnostics after stroke: what is really important?]

Patients with a stroke often exhibit similar risk factors compared to patients with coronary artery disease. The morbidity and mortality of patients surviving a stroke are strongly determined by cardiac co-morbidities. Moreover, ischemic stroke frequently results from cardiac embolism. Thus, for risk assessment and prevention of cardiovascular events patients should undergo cardiac evaluation after a stroke. Laboratory testing should include blood glucose, coagulation parameters, blood cell count and in the case of suspected acute coronary syndrome cardiac ischemic markers. Assessment of the lipid profile is useful to determine the overall cardiovascular risk. In all patients with a stroke an ECG should be recorded. In those with normal ECG and suspected thromboembolic stroke additional Holter is helpful to detect possible atrial fibrillation. Echocardiography should be performed in all patients with suspected cardioembolic stroke. Moreover, echocardiography may establish the diagnosis of structural heart disease, which has a major impact on prognosis in patients with a stroke.

Noninvasive Cardiac Monitoring for Detecting Paroxysmal Atrial Fibrillation or Flutter After Acute Ischemic Stroke

Background and Purpose— Identifying paroxysmal atrial fibrillation/flutter is an essential part of the etiological workup of patients with ischemic stroke. However, there is controversy in the literature regarding the use of noninvasive cardiac rhythm monitoring with previous reviews reporting a low detection rate with routine monitoring. We performed a systematic review to determine the frequency of occult atrial fibrillation/flutter detected by noninvasive methods of continuous cardiac monitoring after acute ischemic stroke or transient ischemic attack.

Methods— Studies were identified from comprehensive searches of PubMed, EMBASE, Science Citation Index, and bibliographies of relevant articles. Only English language articles were included. Randomized controlled trials and prospective cohort studies of consecutive patients with acute ischemic stroke that fulfilled predefined criteria were eligible. Two authors conducted searches and abstracted data from eligible studies independently.

Results— Sixty studies were deemed potentially eligible. After application of eligibility criteria, 5 studies (736 participants) were included in the analysis. All studies evaluated Holter monitoring; 2 also evaluated event loop recording. In studies that evaluated Holter monitoring (588 participants), new atrial fibrillation/flutter was detected in 4.6% (95% CI: 0% to 12.7%) of consecutive patients with ischemic stroke. Duration of monitoring ranged from 24 to 72 hours. Two studies (140 participants) evaluated event loop recorders after Holter monitoring. New atrial fibrillation/flutter was detected in 5.7% and 7.7% of consecutive patients in these 2 studies.

Conclusions— Screening consecutive patients with ischemic stroke with routine Holter monitoring will identify new atrial fibrillation/flutter in approximately one in 20 patients. Although based on limited data, extended duration of monitoring may improve the detection rate. Further research is required before definitive recommendations can be made.

Holter monitoring for 24 hours in patients with thromboembolic stroke and sinus rhythm diagnosed in the emergency department

It is well known that patients with ischemic stroke show ST-T abnormalities and various rhythm abnormalities on an electrocardiogram (ECG). The most commonly encountered rhythm abnormality is atrial fibrillation. It was recently shown that paroxysmal atrial fibrillation (PAF) is an important causative factor in patients with stroke. Detection of PAF is important in identifying the cause, prognosis, and treatment in patients with thromboembolic stroke. Investigators in the present study followed patients with thromboembolic stroke who had been admitted to the emergency department in sinus rhythm; 24-h Holter monitoring was used, and patients were assessed at referral and every 6 h for 24 h with ECG, which was used to detect rhythm disturbances, especially PAF. In 26 patients with stroke who came to the emergency department, acute thromboembolic stroke was diagnosed on the basis of magnetic resonance imaging; no rhythm abnormalities were noted on Holter monitoring. Eighteen patients were male and 8 were female (mean age: 66+/-13 y). Arrhythmia was identified on ECG in 3 patients (11%) and on 24-h Holter monitoring in 24 patients (92%). PAF was diagnosed in 3 patients (11%) on ECG and in 11 patients (42%) on Holter monitoring. In 2 patients, nonsustained ventricular tachycardia was detected only on Holter monitoring, which was found to be significantly superior to ECG for the detection of arrhythmias (P<.001). Investigators found no significant relationship between PAF and variables such as hypertension, diabetes, coronary artery disease, history of myocardial infarction, ST-T changes, and elevations in cardiac markers. However, a significant relationship (P<.01) was seen between nonsustained ventricular tachycardia and a history of myocardial infarction. No relationship was discerned between arrhythmia and stroke localization. Study results suggested that (1) PAF is a commonly diagnosed rhythm abnormality, and (2) Holter monitoring is superior to routine ECG for the detection of arrhythmias such as PAF in patients anticipated to have thromboembolic stroke with sinus rhythm.

Long-term continuous external electrocardiographic recording: a review

Ambulatory electrocardiographic (AECG) monitoring is an essential tool in the diagnostic evaluation of patients with cardiac arrhythmias. Recent advances in solid-state technology have improved the quality of the ECG signals and new dedicated algorithms have expanded the clinical application of software-based AECG analysis systems. These advances, in addition to the availability of inexpensive large storage capacities, and very long-term continuous high-quality AECG monitoring, have opened new potential uses for AECG. New digital recorders have the capability of multichannel simultaneous recordings (from 3 to 12 leads) and for telemetred signal transduction. These possibilities will expand the traditional uses of AECG for arrhythmia detection, as arrhythmia monitoring to assess drug and device efficacies has been further defined by new studies. The analysis of transient ST-segment deviation still remains controversial, but considerably more data are now available, especially about the prognostic value of detecting asymptomatic ischaemia. Heart rate variability analysis has shown promise for predicting mortality rates in cardiac patients at high risk. We review recent advances in this field of non-invasive cardiac testing.

Holter monitoring in the diagnosis of stroke mechanism

BACKGROUND

Atrial fibrillation (AF), an important and treatable cause of ischaemic stroke, can occur as a sustained or a paroxysmal arrhythmia. Continuous cardiac rhythm monitoring (Holter monitoring) is often performed in stroke patients to identify paroxysmal AF, which is an indication for warfarin anti-coagulation in this patient population.

AIM

The aim of this study was to assess the clinical utility of Holter monitoring in detecting occult AF in patients with possible cardioembolic stroke.

METHODS

The medical records of ischaemic stroke patients consecutively hospitalized at a single academic centre during a one-year period were reviewed. Data regarding patient demographics, stroke characteristics, electrocardiography and echocardiography results and duration and findings of Holter monitoring were abstracted. The primary outcome was yield of newly diagnosed AF on Holter monitoring.

RESULTS

Of 465 consecutive patients admitted with a diagnosis of new ischaemic stroke, 210 underwent Holter monitoring. The mean duration of monitoring was 22.8 +/- 4.0 h. Previously undiscovered AF was -identified in five cases (2.4%), all of which represented non-rheumatic AF. In three cases, the Holter test was negative despite AF documented on an admission electro-cardiogram.

CONCLUSIONS

Holter monitoring can identify occult paroxysmal AF, assisting targeted secondary prevention in patients with new ischaemic stroke. However, the standard 24-h duration of monitoring probably under-estimates the prevalence of paroxysmal AF in this population. Prospective studies are indicated to evaluate the value of longer monitoring periods in stroke populations.

Value of Routine Holter Monitoring for the Detection of Paroxysmal Atrial Fibrillation in Patients With Cerebral Ischemic Events

Background and Purpose— Holter monitoring for the detection of paroxysmal atrial fibrillation (PAF) is a routine procedure after cerebral ischemic events, although its value is unknown. The aim of this study was to evaluate the incidence of PAF and its impact on drug treatment modifications in this population.

Methods— Retrospective evaluation of all Holter ECGs in patients with cerebral ischemic events was done. Chart analysis with regard to drug treatment modification and cardiovascular drug therapy was performed in all patients.

Results— Between January 2000 and December 2002, 425 hospitalized patients (median age, 68 years) had routine Holter ECG after a cerebral ischemic event. PAF was diagnosed in 9 patients (2.1%): in 2, oral anticoagulation was contraindicated; 1 had severe carotid stenosis as an additional risk factor; 1 had PAF but was on oral anticoagulation for basilar thrombosis; 2 had had PAF before and were on aspirin; and 3 had a new diagnosis of PAF. The last 5 patients were put on oral anticoagulation. Thus, routine Holter ECG resulted in drug treatment modification in only 5 of 425 patients (1.2%).

Conclusions— PAF in cerebral ischemic event patients has a low incidence and, if diagnosed, rarely leads to drug modification. Therefore, routine Holter monitoring for PAF screening is not recommended in this patient population.

Diagnostic evaluation of stroke

Diagnostic testing in patients with ischemic stroke serves many purposes, including confirmation of the diagnosis and providing clues as to possible causes. Evaluation of the cerebral vasculature, the heart, the blood coagulation system, and selected other diagnostic tests may point to a mechanism of stroke which helps determine treatment and prognosis. With the recent advent of acute interventions for ischemic stroke, diagnostic testing is now an important component in the emergency management of stroke. In this article, the authors will review the standard approach to diagnostic testing for patients with ischemic stroke or transient ischemic attack, and new developments in neuro-imaging and their use in acute stroke assessment.

Use of ambulatory electrocardiography for the detection of paroxysmal atrial fibrillation in patients with stroke. Canadian Task Force on Preventive Health Care

BACKGROUND

Patients with stroke commonly undergo investigations to determine the underlying cause of stroke. These investigations often include ambulatory electrocardiography to detect paroxysmal atrial fibrillation. There is conflicting evidence in the literature regarding whether routine ambulatory electrocardiography should be performed in all or selected stroke patients. This paper reviews the available evidence on (1) the yield of ambulatory electrocardiography in detecting paroxysmal atrial fibrillation in patients with stroke or transient ischemic attack and (2) the effectiveness of anticoagulation in preventing recurrent stroke in patients with paroxysmal atrial fibrillation.

METHODS

A MEDLINE search for primary articles was performed, and the references were reviewed manually. In addition, citations were obtained from experts. The evidence was systematically reviewed using the evidence-based methodology of the Canadian Task Force on Preventive Health Care.

RESULTS

Ambulatory electrocardiography can detect atrial fibrillation not found on initial electrocardiogram in between 1% and 5% of people with stroke. Ambulatory electrocardiography is generally safe. The risk of recurrent stroke in the setting of paroxysmal atrial fibrillation is uncertain, but appears to be similar to that seen with chronic atrial fibrillation (about 12% per year). Therapy with warfarin may reduce this risk by about two-thirds as compared to placebo. The annual risk of major bleeding with warfarin therapy is between 1% and 3% but rates for individual patients depend on various specific risk factors.

INTERPRETATION

There is insufficient evidence to recommend for or against the use of ambulatory electrocardiography for the detection of paroxysmal atrial fibrillation in either selected or unselected patients with stroke (C Recommendation). There is fair evidence to recommend therapy with warfarin for patients with stroke and paroxysmal atrial fibrillation (B Recommendation).