Delayed Detection of Atrial Fibrillation after Ischemic Stroke

Detecting atrial fibrillation in the polysomnography-derived electrocardiogram: a software validation study

PURPOSE

The present study validated a software-based electrocardiogram (ECG) analysis tool for detection of atrial fibrillation (AF) and risk for AF using polysomnography (PSG)-derived ECG recordings.

METHODS

The Stroke Risk Analysis® (SRA®) software was applied to 3-channel ECG tracings from diagnostic PSG performed in enrolled subjects including a subgroup of subjects with previously documented AF. No subjects used positive airway pressure therapy. All ECG recordings were visually analyzed by a blinded cardiologist.

RESULTS

Of subjects enrolled in the study, 93 had previously documented AF and 178 of 186 had an ECG that could be analyzed by either method. In subjects with known history of AF, automated analysis using SRA® classified 47 out of 87 ECG as either manifest AF or showing increased risk for paroxysmal AF (PAF) by SRA® (sensitivity 0.54, specificity 0.86). On visual analysis, 36/87 ECG showed manifest AF and 51/87 showed sinus rhythm. Among the latter subgroup, an increased risk for PAF was ascribed by SRA® in 11 cases (sensitivity 0.22, specificity 0.78) and by expert visual analysis in 5 cases (sensitivity 0.1, specificity 0.90). Among 36/178 ECG with manifest AF on visual analysis, 33 were correctly identified by the SRA® software (sensitivity and specificity 0.92).

CONCLUSION

Sleep studies provide a valuable source of ECG recordings that can be easily subjected to software-based analysis in order to identify manifest AF and automatically assess the risk of PAF. For optimal evaluability of data, multiple channel ECG tracings are desirable. For assessment of PAF risk, the SRA® analysis probably excels visual analysis, but sensitivity of both methods is low, reflecting that repeated ECG recording remains essential.

Atrial fibrillation detection in primary care during blood pressure measurements and using a smartphone cardiac monitor

Improved atrial fibrillation (AF) screening methods are required. We detected AF with pulse rate variability (PRV) parameters using a blood pressure device (BP+; Uscom, Sydney, Australia) and with a Kardia Mobile Cardiac Monitor (KMCM; AliveCor, Mountain View, CA). In 421 primary care patients (mean (range) age: 72 (31–99) years), we diagnosed AF (n = 133) from 12-lead electrocardiogram recordings, and performed PRV and KMCM measurements. PRV parameters detected AF with area under curve (AUC) values of up to 0.92. Using the mean of two sequential readings increased AUC to up to 0.94 and improved positive predictive value at a given sensitivity (by up to 18%). The KMCM detected AF with 83% sensitivity and 68% specificity. 89 KMCM recordings were “unclassified” or blank, and PRV detected AF in these with AUC values of up to 0.88. When non-AF arrhythmias (n = 56) were excluded, the KMCM device had increased specificity (73%) and PRV had higher discrimination performance (maximum AUC = 0.96). In decision curve analysis, all PRV parameters consistently achieved a positive net benefit across the range of clinical thresholds. In primary care, AF can be detected by PRV accurately and by KMCM, especially in the absence of non-AF arrhythmias or when combinations of measurements are used.

MR-imaging pattern is not a predictor of occult atrial fibrillation in patients with cryptogenic stroke

Background

To date, insertable cardiac monitors (ICMs) are the most effective method for the detection of occult atrial fibrillation (AF) in cryptogenic stroke. The overall detection rate after 12 months, however, is low and ranges between 12.4 and 33.3%, even if clinical predictors are considered. Ischemic stroke patients due to cardiogenic embolism present with particular lesion patterns. In patients with cryptogenic stroke, MR-imaging pattern may be a valuable predictor for AF.

Methods

This is an MRI-based, retrospective, observational, comparative, single-center study of 104 patients who underwent ICM implantation after cryptogenic stroke. The findings were compared to a reference group with related stroke etiology, i.e., 166 patients with embolic stroke due to AF detected for the first time by long-term ECG. Lesion patterns were evaluated with regard to affected territories, distribution (cortical, lacunar, scattered), lesion volume, and lesion size (diameter of the lesion size > 20 mm).

Results

The MR-imaging analysis of acute ischemic lesions yielded no association between AF and lesion size or volume, arterial vessel distribution, or the number of affected territories. There was no significant difference between the cohorts regarding ischemic patterns (cortical lesions, scattered lesions, and lacunar infarcts). An important clinical inference of our findings is that 10% (2 of 20) of cases in the ICM group in whom AF was detected had a lacunar infarct pattern. Similar results were shown in cases of ischemic stroke patients with AF detected for the first time by long-term ECG, with 10.9% (16 of 147) of them showing lacunar infarcts. The analysis of chronic MRI lesions revealed no differences between the groups in the rate of chronic lesions, arterial vessel distribution, or the number of affected territories. Left atrial size (LA size) and the presence of atrial runs in long-term ECG were independently associated with AF.

Conclusions

In this MRI-based analysis of patients with cryptogenic stroke who had received ICM implantation, the detection rate of AF in patients with ICM was not related to the imaging pattern. In addition, the lacunar infarct pattern should not be an exclusion criterion for ICM insertion in patients with cryptogenic stroke. ICM insertion in patients with cryptogenic stroke should not be evaluated solely on the basis of reference to infarct patterns.

Delayed diagnosis of atrial fibrillation after first-ever stroke increases recurrent stroke risk: a 5-year nationwide follow-up study

BACKGROUND

Delayed detection of atrial fibrillation (AF) is common in patients with stroke. However, it is not well known whether delayed identification of AF in patients with stroke affects the prognosis of patients.

AIMS

To evaluate the association between the timing of AF diagnosis after stroke and clinical outcomes.

METHODS

We identified a cohort of all patients admitted with a primary diagnosis of first-ever ischaemic stroke, which was categorised into three groups, namely, non-AF, AF presenting with stroke and delayed AF diagnosis groups. The study patients were individually followed for 5 years to evaluate the occurrence of recurrent stroke and death.

RESULTS

In total, 17 399 patients were hospitalised with first-ever ischemic stroke, of whom 16 261 constituted the non-AF group, 907 the AF presenting with stroke group and 231 the delayed AF diagnosis group. During the 5-year follow up, 2773 (17.1%), 175 (19.3%) and 68 (29.4%) patients in the non-AF, AF presenting with stroke and delayed AF diagnosis groups, respectively, were hospitalised for recurrent stroke. The delayed AF diagnosis group exhibited a 1.57-times higher risk of recurrent stroke than the AF presenting with stroke group, after adjustment for the CHA2DS2-VASc scores (adjusted hazard ratio (HR): 1.57; 95% confidence interval (CI) = 1.19-2.08; P = 0.002). In addition, delayed diagnosis of AF significantly increased the risk of recurrent stroke in men, but not in women, after adjustment for the CHA2DS2-VASc scores.

CONCLUSION

Delayed diagnosis of AF after stroke increased the risk of recurrent stroke, particularly in men.

Pulse rate variability predicts atrial fibrillation and cerebrovascular events in a large, population-based cohort

BACKGROUND

Many patients with atrial fibrillation (AF) present with stroke as their first clinical manifestation and since improved AF screening methods are thus required, we investigated whether pulse rate variability parameters predict future AF and cerebrovascular events.

METHODS

In an observational cohort study of 5000 community-resident adults (58% male; 50-84 years), the beat-to-beat variability of suprasystolic brachial blood pressure waveforms was measured with root mean square of successive differences (RMSSD) and irregularity index (IrrIx). Based on outcome-oriented and previously validated thresholds for detecting AF, RMSSD and IrrIx were dichotomised at 100 ms and 7.7%, respectively. Participants were followed up for 4.6 years (median), accruing 249 AF and 120 cerebrovascular events in the total sample (n = 5000), and 133 AF and 90 cerebrovascular events among those without prior AF diagnosis (n = 4296).

RESULTS

In multivariable-adjusted analyses, an elevated RMSSD (>100 ms) or IrrIx (>7.7%) was strongly associated with a higher risk of AF (hazard ratios (HRs) = 2.00-2.95) and cerebrovascular events (HRs = 1.91-2.28), even among people without prior AF diagnosis: HRs for AF = 1.70-2.05 and cerebrovascular events = 2.00-2.28. These associations were strongest in the highest RMSSD tertile >100 ms or IrrIx tertile >7.7%: HRs for AF = 2.32-4.47 and cerebrovascular events = 2.43-3.69. Among those without prior AF diagnosis, the highest categorical net reclassification improvement for 5-year cerebrovascular risk was 14% (95% confidence interval: 7-21%).

CONCLUSIONS

Elevated RMSSD or IrrIx values indicative of the presence of AF predict future AF and cerebrovascular events; more so with increasing pulse irregularity and even among those without prior AF diagnosis.

Atrial fibrillation trial to evaluate real-world procedures for their utility in helping to lower stroke events (AFTER-PULSE): Study protocol for a randomized controlled trial

Background

Enhancing detection of undiagnosed atrial fibrillation (AF) in hospitalized patients with a recent ischemic stroke is important because of the treatment implications; especially since presence of paroxysmal AF may not be picked up in a single 12-lead electrocardiogram (ECG) test. While several trials have shown improved detection of AF with prolonged ECG monitoring, this strategy is associated with relatively high cost, labor intensity, and patient inconvenience, thereby making it challenging to routinely implement in all hospitals. Fortunately, conventional 24-h Holter monitoring and repeated 12-lead ECGs are readily available to detect paroxysmal AF in all hospitals, but is unclear which is the better strategy for evaluating undiagnosed AF. The objective of his study is to conduct a randomized trial of serial 12-lead ECGs vs. 24-hour Holter monitoring in the detection of AF in ischemic stroke patients without known AF.

Methods and analysis

We plan to enroll 1200 participants from six hospitals in Taiwan. Patients will be eligible for enrollment if they are admitted for an acute ischemic stroke within 2 days, are ≥65 years of age, and have no known AF by history or on baseline ECG at admission. We will randomly assign participants in a 1:1 ratio to undergo daily 12-lead ECG once daily for 5 days (intervention group) or 24-h Holter monitoring (control group). Primary outcome is newly detected AF on a 12-lead ECG or AF lasting ≥30 s on Holter monitoring.

Trial registration number

ClinicalTrials.gov Identifier: NCT02578979.

Screening For Atrial Fibrillation In The Community Using A Novel ECG Recorder

Aims: MyDiagnostick (MDK) is a novel portable ECG recorder. We conducted this study to evaluate its role in screening for atrial fibrillation (AF). Methods: The device is a cylindrical rod with metallic electrodes at both ends recording electrocardiogram (ECG) when both electrodes are held. Individuals were requested to hold the device for approximately 15 s, the device was then connected to a laptop (with proprietary software downloaded) and analysed. Anonymised ECGs were stored for further analysis. A total of 855 ECGs were recorded and analysed offline by two arrhythmia specialists assessing ECG quality, in particular the level of noise. A noise score (NS) was devised regarding ECG quality. Results: Seven individuals were found with unknown AF (0,8%). In general ECG quality was good and rhythm diagnosis was certain with total interobserver agreement. Conclusion: The MDK provided a rapid and accurate rhythm analysis and has potential implications in preventing ischaemic cardio-embolic stroke.

The Evolution and Application of Cardiac Monitoring for Occult Atrial Fibrillation in Cryptogenic Stroke and TIA

OPINION STATEMENT

The evaluation of the stroke and transient ischemic attack (TIA) patient has been historically predominated by the initial evaluation in the hospital setting. As the etiology of stroke has eluded us in approximately one third of all acute events, the medical community has been eager to seek the answer to this mystery. In recent years, we have seen an explosion of innovations and trends allowing for a more detailed post stroke assessment strategy aimed at the identification of occult atrial fibrillation as the etiologic cause for the cryptogenic event. This has been achieved through the evolution and aggressive application and study of prolonged and advanced cardiac monitoring. This review is aimed to clarify and elucidate the standard and novel cardiac monitoring methods that have become available for use by the medical community and expected in the higher level care of cryptogenic stroke and TIA patients. These cardiac monitoring methods and devices are as heterogeneous as our patient population and have their own advantages and disadvantages. Many factors may be taken into consideration in choosing the appropriate cardiac monitoring method and are highlighted for consideration in this review. With a judicious approach to investigating the cryptogenic stroke population, and applying a wealth of novel treatment options, we may move forward into a new era of stroke prevention.

Significance and Management Strategies for Patients with Asymptomatic Atrial Fibrillation

Atrial fibrillation (AF) is a common and refractory arrhythmia. Prevalence of AF increases with age. Asymptomatic AF is a state of asymptomatic episodes of arrhythmia and its exact prevalence remains unknown. Ablation and therapy with antiarrhythmic agents may predispose to asymptomatic AF. Detection of silent AF is crucial for prevention of ischaemic stroke. Progress in continuous ECG monitoring by Holter ECG, telemetry methods or implantable devices can provide a useful tools for identifying silent AF. Simple screening procedures like pulse examination and ambulatory ECG may be helpful in arrhythmia detection and logically - ischemic stroke prevention.

Troponin-I is a predictor of a delayed diagnosis of atrial fibrillation in acute ischemic stroke and transient ischemic attack

BACKGROUND

Prolonged cardiac monitoring detects higher rates of atrial fibrillation (AF) in ischemic stroke and transient ischemic attack (TIA) but is costly and has practical implications. The use of admission troponin-I (TnI) level to identify patients at high risk of delayed AF detection was investigated.

METHODS

Consecutive ischemic stroke and TIA cases presenting to our institute over a 13-month period were identified from the Irish Stroke and TIA Register. Electronic databases and case notes were examined. "Delayed" AF was diagnosed after a sinus rhythm admission electrocardiogram and no documented history. Group comparisons were made by AF status. The association between TnI and AF was investigated using a multivariate regression model.

RESULTS

A total of 185 cases (130 ischemic stroke) were analyzed. Mean age (standard deviation) was 73.3 (13.9) years, 47% female. Sixty-two cases (33.5%) had AF. The first documented presentation of AF was found in 21 cases, on admission electrocardiogram (n = 11) or inpatient telemetry (delayed, n = 10). TnI was higher in those with delayed AF than in those without AF (W = 194; P = .036). A higher proportion of those with an elevated TnI (30%) than those with a normal TnI (6.1%) had delayed diagnosis of AF (χ(2) = 6.41, P = .011). Having an abnormal TnI was a significant independent predictor of delayed AF detection (odds ratio, 5.8; P = .037).

CONCLUSIONS

TnI elevation is associated with a higher likelihood of subsequent AF diagnosis. Identification of these higher risk stroke and TIA cases for more intensive cardiac monitoring may improve stroke secondary prevention practices.

Cryptogenic stroke and underlying atrial fibrillation

BACKGROUND

Current guidelines recommend at least 24 hours of electrocardiographic (ECG) monitoring after an ischemic stroke to rule out atrial fibrillation. However, the most effective duration and type of monitoring have not been established, and the cause of ischemic stroke remains uncertain despite a complete diagnostic evaluation in 20 to 40% of cases (cryptogenic stroke). Detection of atrial fibrillation after cryptogenic stroke has therapeutic implications.

METHODS

We conducted a randomized, controlled study of 441 patients to assess whether long-term monitoring with an insertable cardiac monitor (ICM) is more effective than conventional follow-up (control) for detecting atrial fibrillation in patients with cryptogenic stroke. Patients 40 years of age or older with no evidence of atrial fibrillation during at least 24 hours of ECG monitoring underwent randomization within 90 days after the index event. The primary end point was the time to first detection of atrial fibrillation (lasting >30 seconds) within 6 months. Among the secondary end points was the time to first detection of atrial fibrillation within 12 months. Data were analyzed according to the intention-to-treat principle.

RESULTS

By 6 months, atrial fibrillation had been detected in 8.9% of patients in the ICM group (19 patients) versus 1.4% of patients in the control group (3 patients) (hazard ratio, 6.4; 95% confidence interval [CI], 1.9 to 21.7; P<0.001). By 12 months, atrial fibrillation had been detected in 12.4% of patients in the ICM group (29 patients) versus 2.0% of patients in the control group (4 patients) (hazard ratio, 7.3; 95% CI, 2.6 to 20.8; P<0.001).

CONCLUSIONS

ECG monitoring with an ICM was superior to conventional follow-up for detecting atrial fibrillation after cryptogenic stroke. (Funded by Medtronic; CRYSTAL AF ClinicalTrials.gov number, NCT00924638.).

Documentation of atrial fibrillation prior to first-ever ischemic stroke

OBJECTIVES

We assessed the prevalence of atrial fibrillation (AF) prior to first-ever ischemic stroke by examining a comprehensive electronic ECG archive.

METHODS

The study sample comprised 336 consecutive stroke patients (median age 76 (IQ16) y, 200 men) enrolled in Lund Stroke Register from March 2001 to February 2002 and 336 age- and gender-matched controls without stroke history. AF prior to admission was studied using the regional electronic ECG database and record linkage with the National Swedish Hospital Discharge Register (SHDR). Medical records were reviewed for AF documentation and CHA2 DS2-VASc risk score.

RESULTS

Atrial fibrillation before or at stroke onset was detected in 109 (32.4%) stroke patients and 44 (13.1%) controls, P<0.001. Twenty-five of 109 stroke patients had AF detected only on previous ECG (n=14) or through the SHDR (n=11). The most prevalent type of AF in stroke group was non-permanent AF (59.6%). AF prevalence among patients admitted with sinus rhythm at hospital admission (n=266) was higher in those with CHA2 DS2 -VASc score≥6 (28.6%) than with CHA2 DS2-VASc score<6 (13.0%), P=0.043.

CONCLUSION

Comprehensive approach for AF screening allows detecting AF in one-third of patients admitted with first-ever ischemic stroke. Patients with high cardiovascular risk are more likely to have non-permanent AF.

Noninvasive cardiac event monitoring to detect atrial fibrillation after ischemic stroke: a randomized, controlled trial

BACKGROUND AND PURPOSE

Atrial fibrillation (AF) elevates risk of recurrent stroke but is incompletely identified by standard investigation after stroke, though detection rates correlate with monitoring duration. We hypothesized that 7 days of noninvasive cardiac-event monitoring early after stroke would accelerate detection of AF and thus uptake of effective therapy.

METHODS

We performed a pragmatic randomized trial with objective outcome assessment among patients presenting in sinus rhythm with no AF history, within 7 days of ischemic stroke symptom onset. Patients were randomized to standard practice investigations (SP) to detect AF, or SP plus additional monitoring (SP-AM). AM comprised 7 days of noninvasive cardiac-event monitoring reported by an accredited cardiac electrocardiology laboratory. Primary outcome was detection of AF at 14 days.

RESULTS

One-hundred patients were enrolled from 2 centers. Within 14 days of stroke, sustained paroxysms of AF were detected in 18% of patients undergoing SP-AM versus 2% undergoing SP (P<0.05). Paroxysms of any-duration were detected in 44% of patients undergoing SP-AM versus 4% undergoing SP (P<0.001). These differences persisted at 90 days. Anticoagulant therapy was commenced within 14 days in 16% of SP-AM patients versus none randomized to SP (P<0.01). This difference persisted to 90 days (22% versus 6%; P<0.05).

CONCLUSIONS

Routine noninvasive cardiac-event monitoring after acute stroke enhances detection of paroxysmal AF and early anticoagulation. Extended monitoring should be offered to all eligible patients soon after acute stroke. Guidelines on investigation for AF in stroke patients could be strengthened.

CLINICAL TRIAL REGISTRATION URL

http://www.controlled-trials.com/isrctn/. Unique identifier: ISRCTN97412358.

Insertable Cardiac Event Recorder in Detection of Atrial Fibrillation After Cryptogenic Stroke

Background and Purpose—

Atrial fibrillation (AF) is the most frequent risk factor in ischemic stroke but often remains undetected. We analyzed the value of insertable cardiac event recorder in detection of AF in a 1-year cohort of patients with cryptogenic ischemic stroke.

Methods—

All patients with cryptogenic stroke and eligibility for oral anticoagulation were offered the insertion of a cardiac event recorder. Regular follow-up for 1 year recorded the incidence of AF.

Results—

Of the 393 patients with ischemic stroke, 65 (16.5%) had a cryptogenic stroke, and in 22 eligible patients, an event recorder was inserted. After 1 year, in 6 of 22 patients (27.3%), AF was detected.

Conclusions—

These preliminary data show that insertion of cardiac event recorder was eligible in approximately one third of patients with cryptogenic stroke and detected in approximately one quarter of these patients new AF.

New onset of atrial fibrillation in the hospitalized patient

Atrial fibrillation (AF) is a common dysrhythmia that clinicians often encounter while caring for hospitalized patients. Although many patients will have carried a diagnosis of AF prior to hospital admission, this review will pertain to patients for whom a first documented episode of AF occurs during hospitalization.

Cardiac manifestations of neurologic disorders

The cardiac complications of certain neurologic diseases have been well recognized for over 50 years and are mostly evident for cerebrovascular accidents. Although these complications are frequent and in most circumstances benign, detrimental cardiac side effects, such as serious arrhythmias and myocardial infarctions, may occur. The link to most of these cardiac derangements is a transient or chronic autonomic dysfunction, depending on the specific neurologic disease. Myocardial infarcts, left ventricular dysfunction, and arrhythmias are well-recognized complications of subarachnoid hemorrhage, intracranial bleed, and ischemic strokes. Seizures may present with atonia or sudden death from asystole. Degenerative brain disorders, namely the synucleinopathies, may affect the central control areas or peripheral ganglia of the autonomic nervous system, causing autonomic dysfunction. In addition, cardiac conduction defects and cardiomyopathy are common in certain neuromuscular disorders, namely the dystrophies and mitochondrial myopathies.

Monitoring of medical complications after acute ischemic stroke in a neurological intensive care unit

BACKGROUND/AIMS

Post-stroke complications may influence prognosis, and may even become potentially life-threatening. The aim of this prospective study was to examine the frequency and timing of medical complications during the acute stage of critical ischemic stroke in patients treated in a neurological intensive care unit.

METHODS

Seventy acute ischemic stroke patients in a critical condition with morbid changes in organs other than the brain or with severe complications were admitted to a neurological intensive care unit and followed up with assessments of 15 specified complications during the first 2 weeks on days 2, 4, 7, and 14.

RESULTS

The most common complications within 2 weeks of onset were chest infection (90%), fever (64%), hypoalbuminemia (56%), arrhythmia (46%), irritable ulcer (44%), gastrointestinal dysfunction (39%), progression or recurrence of stroke (33%), and urinary tract infection (30%). The incidence of progression or recurrence of stroke and urinary tract infection peaked at day 2, and the incidence of arrhythmia, fever, chest infection, irritable ulcer, gastrointestinal dysfunction, and malnutrition peaked from 1 to 2 weeks.

CONCLUSION

Progression or recurrence of stroke, fever, and chest infection are common complications in the acute stage of critical ischemic stroke.

First-ever atrial fibrillation documented after hemorrhagic or ischemic stroke: the role of the CHADS(2) score at the time of stroke

BACKGROUND

The CHADS(2) score (C, congestive heart failure [CHF]; H, hypertension [HT]; A, age ≥75 y; D, diabetes mellitus; S(2) , prior stroke or transient ischemic attack) is used to assess the risk of ischemic stroke in patients with atrial fibrillation (AF). However, its role in patients without documented AF is not well explored.

HYPOTHESIS

The goal of the current study was to explore if the incidence of hospitalization with first-ever AF after stroke increased with increasing CHADS(2) score.

METHODS

We identified 57636 patients with nonfatal stroke and no documented AF in the Swedish Stroke Register (Riks-Stroke) during 2001-2004 and followed them for a mean of 2.2 years through record linkage to the Inpatient and Cause of Death registers. Cox regression hazard models were used to estimate the relative risk (RR) of new AF following stroke and its association with different CHADS(2) scores.

RESULTS

Overall, 2769 patients were hospitalized with new AF (4.8%, 21.7 per 1000 person-years). The incidence increased from 9.6 per 1000 person-years in CHADS(2) score 0 to 42.7 in CHADS(2) score 6, conferring a RR of 4.2 (95% confidence interval [CI]: 2.5-6.8). For CHADS(2) scores 3-5, the RRs were approximately 3 (vs CHADS(2) score 0). Adjusted RRs were 1.9 (95% CI: 1.7-2.1) for CHF, 1.4 (95% CI: 1.3-1.5) for HT, 2.1 (95% CI: 2.0-2.3) for age ≥75 years, 0.9 (95% CI: 0.8-1.0) for diabetes, and 1.0 (95% CI: 0.91-1.07) for previous stroke. The risk of AF was higher in ischemic than in hemorrhagic stroke.

CONCLUSIONS

In this retrospective register study, the incidence of AF following stroke was strongly influenced by higher CHADS(2) scores where age ≥75 years, CHF, and HT were the contributing CHADS(2) components.

National Stroke Association recommendations for systems of care for transient ischemic attack

Transient ischemic attacks (TIAs) are common and portend a high short-term risk of stroke. Evidence-based recommendations for the urgent evaluation and treatment of patients with TIA have been published. However, implementation of these recommendations reliably and consistently will require changes in the systems of care established for TIA. The National Stroke Association convened a multidisciplinary panel of experts to develop recommendations for the essential components of systems of care at hospitals to improve the quality of care provided to patients with TIA. The panel recommends that hospitals establish standardized protocols to assure rapid and complete evaluation and treatment for patients with TIA, with particular attention to urgency and close observation in patients at high risk of stroke.

Predictors of occult paroxysmal atrial fibrillation in cryptogenic strokes detected by long-term noninvasive cardiac monitoring

Background and Purpose. Paroxysmal Atrial fibrillation/Flutter (PAF) detection rates in cryptogenic strokes have been variable. We sought to determine the percentage of patients with cryptogenic stroke who had PAF on prolonged non-invasive cardiac monitoring. Methods and Results. Sixty-two consecutive patients with stroke and TIA in a single center with a mean age of 61 (+/− 14) years were analyzed. PAF was detected in 15 (24%) patients. Only one patient reported symptoms of shortness of breath during the episode of PAF while on monitoring, and 71 (97%) of these 73 episodes were asymptomatic. A regression analysis revealed that the presence of PVCs (ventricular premature beats) lasting more than 2 minutes (OR 6.3, 95% CI, 1.11–18.92; P = .042) and strokes (high signal on Diffusion Weighted Imaging) (OR 4.3, 95% CI, 5–36.3; P = .041) predicted PAF. Patients with multiple DWI signals were more likely than solitary signals to have PAF (OR 11.1, 95% CI, 2.5–48.5, P < .01). Conclusion. Occult PAF is common in cryptogenic strokes, and is often asymptomatic. Our data suggests that up to one in five patients with suspected cryptogenic strokes and TIAs have PAF, especially if they have PVCs and multiple high DWI signals on MRI.

A novel method for detection of the transition between atrial fibrillation and sinus rhythm

Automatic detection of atrial fibrillation (AF) for AF diagnosis, especially for AF monitoring, is necessarily desirable for clinical therapy. In this study, we proposed a novel method for detection of the transition between AF and sinus rhythm based on RR intervals. First, we obtained the delta RR interval distribution difference curve from the density histogram of delta RR intervals, and then detected its peaks, which represented the AF events. Once an AF event was detected, four successive steps were used to classify its type, and thus, determine the boundary of AF: 1) histogram analysis; 2) standard deviation analysis; 3) numbering aberrant rhythms recognition; and 4) Kolmogorov-Smirnov (K-S) test. A dataset of 24-h Holter ECG recordings (n = 433) and two MIT-BIH databases (MIT-BIH AF database and MIT-BIH normal sinus rhythm (NSR) database) were used for development and evaluation. Using the receiver operating characteristic curves for determining the threshold of the K-S test, we have achieved the highest performance of sensitivity and specificity (SP) (96.1% and 98.1%, respectively) for the MIT-BIH AF database, compared with other previously published algorithms. The SP was 97.9% for the MIT-BIH NSR database.

VISTA-Rehab: A Resource for Stroke Rehabilitation Trials

Background

Stroke rehabilitation is a complex intervention. Many factors influence the interaction between the patient and the elements of the intervention. Rehabilitation interventions are aimed at altering different domains of patient outcome including body functions, activity and participation. As a consequence, randomised clinical trials in this area are difficult to design. We developed an archive of stroke rehabilitation trials (VISTA-Rehab) to act as a resource to help trialists model and design future rehabilitation studies.

Methods

We developed specific eligibility criteria for the entry of stroke rehabilitation trials into the archive. We established a Steering Committee to oversee projects and publications and commenced the recruitment of rehabilitation trials into this resource.

Results

As of August 2009, VISTA-Rehab contains data from 23 stroke rehabilitation trials (>3400 patients). Demographic data, including age [median=73, interquartile range (63,79)], gender (male=53%) and initial dependency [median baseline Barthel index score=6, interquartile range ( 9 , 19 )], are available for all patients. Outcome measures include the modified Rankin Scale, Barthel Index, Rivermead Motor Assessment, Fugl-Meyer Assessment, General Health Questionnaire and Nottingham Extended Activities of Daily Living Scale.

Conclusion

VISTA-Rehab expands the Virtual International Stroke Trials Archive to include rehabilitation trials. Anonymised data can be used to examine questions specific to stroke rehabilitation and to generate novel hypotheses.

The Virtual International Stroke Trials Archive (VISTA): Results and Impact on Future Stroke Trials and Management of Stroke Patients

Background

The Virtual International Stroke Trials Archive was established to improve stroke care and trial design through the collation, categorization and potential access to data sets from clinical trials for the treatment of stroke.

Methods

Virtual International Stroke Trials Archive currently provides access to a combined data set of 29 anonymised acute stroke trials and one acute stroke registry with data on >27 500 patients aged between 18 and 103 (mean 71) years.

Results

Virtual International Stroke Trials Archive has facilitated research across a broad canvas. The prognosis was poor in patients with very high blood pressure at the time of admission or with a wide variability of systolic blood pressure during the acute phase. The late occurrence of hyperthermia following an ischaemic stroke worsens the prognosis. Stroke lateralisation is not an important predictor of cardiac adverse events or 90-day mortality. Haemorrhagic transformation is seen frequently in patients with cardio-embolic strokes and is associated with a poor prognosis when occurring after the acute phase. Virtual International Stroke Trials Archive has allowed various prognostic models for patients with ischaemic or haemorrhagic stroke to be established and validated. More direct outcomes such as lesion volume can be useful in phase II clinical trials for determining whether a phase III trial should be undertaken. New outcome measures such as ‘home time’ may also strengthen future trials. On a worldwide level, the prognosis of stroke patients differs considerably between various countries.

Conclusion

Virtual International Stroke Trials Archive provides an excellent opportunity for analysis of natural history data and prognosis. It has the potential to influence clinical trial design and implementation through exploratory data analyses.