Patricia M. Riccio

Diagnosis of atrial fibrillation after stroke and transient ischaemic attack: a systematic review and meta-analysis

BACKGROUND Among patients with atrial fibrillation, the risk of stroke is highest for those with a history of stroke; however, oral anticoagulants can lower the risk of recurrent stroke by two-thirds. No consensus has been reached about how atrial fibrillation should be investigated in patients with stroke, and its prevalence after a stroke remains uncertain. We did a systematic review and meta-analysis to estimate the proportion of patients newly diagnosed with atrial fibrillation after four sequential phases of cardiac monitoring after a stroke or transient ischaemic attack. METHODS We searched PubMed, Embase, and Scopus from 1980 to June 30, 2014. We included studies that provided the number of patients with ischaemic stroke or transient ischaemic attack who were newly diagnosed with atrial fibrillation. We stratified cardiac monitoring methods into four sequential phases of screening: phase 1 (emergency room) consisted of admission electrocardiogram (ECG); phase 2 (in hospital) comprised serial ECG, continuous inpatient ECG monitoring, continuous inpatient cardiac telemetry, and in-hospital Holter monitoring; phase 3 (first ambulatory period) consisted of ambulatory Holter; and phase 4 (second ambulatory period) consisted of mobile cardiac outpatient telemetry, external loop recording, and implantable loop recording. The primary endpoint was the proportion of patients newly diagnosed with atrial fibrillation for each method and each phase, and for the sequential combination of phases. For each method and each phase, we estimated the summary proportion of patients diagnosed with post-stroke atrial fibrillation using random-effects meta-analyses. FINDINGS Our systematic review returned 28,290 studies, of which 50 studies (comprising 11,658 patients) met the criteria for inclusion in the meta-analyses. The summary proportion of patients diagnosed with post-stroke atrial fibrillation was 7·7% (95% CI 5·0-10·8) in phase 1, 5·1% (3·8-6·5) in phase 2, 10·7% (5·6-17·2) in phase 3, and 16·9% (13·0-21·2) in phase 4. The overall atrial fibrillation detection yield after all phases of sequential cardiac monitoring was 23·7% (95% CI 17·2-31·0). INTERPRETATION By sequentially combining cardiac monitoring methods, atrial fibrillation might be newly detected in nearly a quarter of patients with stroke or transient ischaemic attack. The overall proportion of patients with stroke who are known to have atrial fibrillation seems to be higher than previously estimated. Accordingly, more patients could be treated with oral anticoagulants and more stroke recurrences prevented. FUNDING Heart and Stroke Foundation of Canada, and Natural Science and Engineering Research Council of Canada.

Newly Diagnosed Atrial Fibrillation after Acute Ischemic Stroke and Transient Ischemic Attack: Importance of Immediate and Prolonged Continuous Cardiac Monitoring

Atrial fibrillation (AF) is the major cause of cardioembolic stroke. It often remains occult when asymptomatic and paroxysmal. We hypothesized that the detection of AF after acute ischemic stroke (AIS) or transient ischemic attack (TIA) could be improved by using continuous cardiac monitoring (CCM) immediately after admission. We sought to determine the detection rate of AF by immediate in-hospital CCM after cryptogenic and noncryptogenic AIS or TIA in patients without a previous diagnosis of AF. We retrospectively studied a cohort of 155 patients with cryptogenic and noncryptogenic AIS or TIA without known AF. We compared the detection rates of newly diagnosed AF (NDAF) in patients admitted to areas with CCM and those never admitted to these areas. We developed a multiple logistic regression model for identifying predictors of NDAF. We characterized NDAF episodes and analyzed how the availability of CCM data changed secondary prevention strategies. We detected NDAF in 21 patients (13.5%). Diagnostic rates of NDAF in patients who underwent CCM and those who did not undergo CCM were 18.2% and 2.2%, respectively (P = .005). The median time from admission to recognition of NDAF was 2.0 days. Most NDAFs were paroxysmal (95.2%) and lasted less than 1 hour (85.7%). Diabetes mellitus and infarct size were predictors of NDAF. Detection of NDAF prompted the initiation of anticoagulation therapy in 8.2% of the patients admitted to areas with CCM availability. Our findings suggest that immediate and prolonged CCM significantly improves the detection of NDAF after cryptogenic and noncryptogenic AIS or TIA, and that diabetes mellitus and infarct size are significantly associated with NDAF.

Insular networks for emotional processing and social cognition: Comparison of two case reports with either cortical or subcortical involvement

INTRODUCTION The processing of the emotion of disgust is attributed to the insular cortex (IC), which is also responsible for social emotions and higher-cognitive functions. We distinguish the role of the IC from its connections in regard to these functions through the assessment of emotions and social cognition in a double case report. These subjects were very rare cases that included a focal IC lesion and a subcortical focal stroke affecting the connections of the IC with frontotemporal areas. MATERIALS & METHODS Both patients and a sample of 10 matched controls underwent neuropsychological and affective screening questionnaires, a battery of multimodal basic emotion recognition tests, an emotional inference disambiguation task using social contextual clues, an empathy task and a theory of mind task. RESULTS The insular lesion (IL) patient showed no impairments in emotion recognition and social emotions and presented with a pattern of delayed reaction times (RTs) in a subset of both groups of tasks. The subcortical lesion (SL) patient was impaired in multimodal aversive emotion recognition, including disgust, and exhibited delayed RTs and a heterogeneous pattern of impairments in subtasks of empathy and in the contextual inference of emotions. CONCLUSIONS Our results suggest that IC related networks, and not the IC itself, are related to negative emotional processing and social emotions. We discuss these results with respect to theoretical approaches of insular involvement in emotional and social processing and propose that IC connectivity with frontotemporal and subcortical regions might be relevant for contextual emotional processing and social cognition.

Poststroke atrial fibrillation: Cause or consequence? Critical review of current views

Poststroke atrial fibrillation (AF) represents up to 1 of 4 overall AF cases in acute ischemic stroke. Current guidelines recommend oral anticoagulation for every ischemic stroke patient in whom AF is diagnosed. However, in some cases, AF detected after acute ischemic stroke may be short-lasting and perhaps a nonrecurrent autonomic and inflammatory epiphenomena of stroke. The autonomic regulation of cardiac rhythm constitutes an integrated relay system. The highest level of control is exerted by the cerebral cortex, particularly the insula. The onset of AF may be associated with an imbalance of sympathetic and parasympathetic activity, a common consequence of insular infarctions. This autonomic imbalance and an interruption in the cerebral regulation of the intrinsic cardiac autonomic system constitute the most likely mechanisms responsible for the autonomic pathway. The role of inflammation in the genesis of AF within the first few days after ischemic stroke may occur through inflammatory mediators stimulating the intrinsic autonomic system and by direct damage to atrial myocardium. To what extent poststroke AF is the cause or a consequence remains uncertain.

Sex Differences in Stroke Incidence, Prevalence, Mortality and DALYs: Results from the Global Burden of Disease Study 2013

Background: Accurate information on stroke burden in men and women are important for evidence-based healthcare planning and resource allocation. Previously, limited research suggested that the absolute number of deaths from stroke in women was greater than in men, but the incidence and mortality rates were greater in men. However, sex differences in various metrics of stroke burden on a global scale have not been a subject of comprehensive and comparable assessment for most regions of the world, nor have sex differences in stroke burden been examined for trends over time. Methods: Stroke incidence, prevalence, mortality, disability-adjusted life years (DALYs) and healthy years lost due to disability were estimated as part of the Global Burden of Disease (GBD) 2013 Study. Data inputs included all available information on stroke incidence, prevalence and death and case fatality rates. Analysis was performed separately by sex and 5-year age categories for 188 countries. Statistical models were employed to produce globally comprehensive results over time. All rates were age-standardized to a global population and 95% uncertainty intervals (UIs) were computed. Findings: In 2013, global ischemic stroke (IS) and hemorrhagic stroke (HS) incidence (per 100,000) in men (IS 132.77 (95% UI 125.34-142.77); HS 64.89 (95% UI 59.82-68.85)) exceeded those of women (IS 98.85 (95% UI 92.11-106.62); HS 45.48 (95% UI 42.43-48.53)). IS incidence rates were lower in 2013 compared with 1990 rates for both sexes (1990 male IS incidence 147.40 (95% UI 137.87-157.66); 1990 female IS incidence 113.31 (95% UI 103.52-123.40)), but the only significant change in IS incidence was among women. Changes in global HS incidence were not statistically significant for males (1990 = 65.31 (95% UI 61.63-69.0), 2013 = 64.89 (95% UI 59.82-68.85)), but was significant for females (1990 = 64.892 (95% UI 59.82-68.85), 2013 = 45.48 (95% UI 42.427-48.53)). The number of DALYs related to IS rose from 1990 (male = 16.62 (95% UI 13.27-19.62), female = 17.53 (95% UI 14.08-20.33)) to 2013 (male = 25.22 (95% UI 20.57-29.13), female = 22.21 (95% UI 17.71-25.50)). The number of DALYs associated with HS also rose steadily and was higher than DALYs for IS at each time point (male 1990 = 29.91 (95% UI 25.66-34.54), male 2013 = 37.27 (95% UI 32.29-45.12); female 1990 = 26.05 (95% UI 21.70-30.90), female 2013 = 28.18 (95% UI 23.68-33.80)). Interpretation: Globally, men continue to have a higher incidence of IS than women while significant sex differences in the incidence of HS were not observed. The total health loss due to stroke as measured by DALYs was similar for men and women for both stroke subtypes in 2013, with HS higher than IS. Both IS and HS DALYs show an increasing trend for both men and women since 1990, which is statistically significant only for IS among men. Ongoing monitoring of sex differences in the burden of stroke will be needed to determine if disease rates among men and women continue to diverge. Sex disparities related to stroke will have important clinical and policy implications that can guide funding and resource allocation for national, regional and global health programs.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment: Results From the Gait and Brain Study

Importance Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. Objective To determine whether a dual-task gait test is associated with incident dementia in MCI. Design, Setting, and Participants The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Main Outcomes and Measures Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity – dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Results Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (<0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P = .05) while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Conclusions and Relevance Dual-task gait is associated with progression to dementia in patients with MCI. Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI. Trial Registration clinicaltrials.gov: NCT03020381.

Atrial Fibrillation Detected after Acute Ischemic Stroke: Evidence Supporting the Neurogenic Hypothesis

BACKGROUND It is unknown whether atrial fibrillation (AF) detected after acute ischemic stroke is caused by neurogenic or cardiogenic mechanisms. Based on the potential damage to the autonomic nervous system, neurogenic mechanisms could be implicated in the pathophysiology of newly diagnosed AF. To test this hypothesis, we developed a mechanistic approach by comparing a prespecified set of indicators in acute ischemic stroke patients with newly diagnosed AF, known AF, and sinus rhythm. METHODS We prospectively assessed every acute ischemic stroke patient undergoing continuous electrocardiographic monitoring from 2008 through 2011. We compared newly diagnosed AF, known AF, and sinus rhythm patients by using 20 indicators grouped in 4 domains: vascular risk factors, underlying cardiac disease, burden of neurological injury, and in-hospital outcome. RESULTS We studied 275 acute ischemic stroke patients, 23 with newly diagnosed AF, 64 with known AF, and 188 with sinus rhythm. Patients with newly diagnosed AF had a lower proportion of left atrial enlargement (60.9% versus 91.2%, P=.001), a smaller left atrial area (22.0 versus 26.0 cm2, P=.021), and a higher frequency of insular involvement (30.4% versus 9.5%, P=.017) than participants with known AF. Compared with patients in sinus rhythm, those with newly diagnosed AF had a higher proportion of brain infarcts of 15 mm or more (60.9% versus 37.2%, P=.029) and a higher frequency of insular involvement (30.4% versus 7.3%, P<.001). CONCLUSIONS The low frequency of underlying cardiac disease and the strikingly high proportion of concurrent strategic insular infarctions in patients with newly diagnosed AF provide additional evidence supporting the role of neurogenic mechanisms in a subset of AF detected after acute ischemic stroke.

Very short paroxysms account for more than half of the cases of atrial fibrillation detected after stroke and TIA: a systematic review and meta‐analysis

Background Guidelines suggest that only poststroke atrial fibrillation episodes lasting 30 s or longer should be considered for anticoagulation. However, little evidence supports this recommendation. Aims We performed a systematic review and meta-analysis to investigate the frequency of poststroke atrial fibrillation lasting less than 30 s in stroke and transient ischemic attack patients. Methods We searched PubMed, Embase, and Scopus from 1980 to June 30, 2014 for studies reporting the detection of poststroke atrial fibrillation of less than 30 s and of 30 s or longer. The primary endpoint was the proportion of screened patients diagnosed with poststroke atrial fibrillation lasting less than 30 s. The secondary endpoint was the proportion of patients diagnosed with poststroke atrial fibrillation shorter than 30 s among the overall number of patients in whom a poststroke atrial fibrillation was detected after stroke or transient ischemic attack. Results From 28 290 titles, we included nine studies in the random-effects meta-analysis. Among stroke and transient ischemic attack patients without a history of atrial fibrillation, 9·0% (95% confidence interval: 4·9–14·3) experienced episodes of poststroke atrial fibrillation shorter than 30 s. An additional 6·5% (95% confidence interval: 3·2–10·9) experienced episodes of poststroke atrial fibrillation longer than 30 s. Among all patients with poststroke atrial fibrillation, 56·3% (95% confidence interval: 37·7–74·0) had poststroke atrial fibrillation episodes shorter than 30 s during diagnostic evaluation. Conclusions The clinical and prognostic significance of poststroke atrial fibrillation episodes shorter than 30 s is unknown. The high frequency of poststroke atrial fibrillation episodes shorter than 30 s justify further investigation into the risk of stroke recurrence and the risk–benefit profile of anticoagulation for this patient population.

Newly diagnosed atrial fibrillation linked to wake-up stroke and TIA: Hypothetical implications

Background: Based on the higher frequency of paroxysmal atrial fibrillation during night and early morning hours, we sought to analyze the association between newly diagnosed atrial fibrillation and wake-up ischemic cerebrovascular events. Methods: We prospectively assessed every acute ischemic stroke and TIA patient admitted to our hospital between 2008 and 2011. We used a forward step-by-step multiple logistic regression analysis to assess the relationship between newly diagnosed atrial fibrillation and wake-up ischemic stroke or TIA, after adjusting for significant covariates. Results: The study population comprised 356 patients, 274 (77.0%) with a diagnosis of acute ischemic stroke and 82 (23.0%) with TIA. A total of 41 (11.5%) of these events occurred during night sleep. A newly diagnosed atrial fibrillation was detected in 27 patients of 272 without known atrial fibrillation (9.9%). We found an independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA (odds ratio 3.6, 95% confidence interval 1.2–7.7, p = 0.019). Conclusions: The odds of detecting a newly diagnosed atrial fibrillation were 3-fold higher among wake-up cerebrovascular events than among non–wake-up events. The significance of this independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA and the role of other comorbidities should be investigated in future studies.

Intraoperative hypotension, new onset atrial fibrillation, and adverse outcome after carotid endarterectomy

BACKGROUND Information regarding predisposing factors, frequency, and prognostic implications of new onset atrial fibrillation (NOAF) after carotid endarterectomy (CEA) is scarce. We assessed the frequency, risk factors, and the prognostic impact of NOAF after CEA. METHODS We assessed every patient undergoing CEA (n = 186) at our academic hospital between 2006 and 2009. Patients underwent continuous electrocardiographic monitoring during surgery and during the rest of hospital stay. We performed univariate and multivariate analyses for identifying variables associated with NOAF and for individualizing variables related to four perioperative adverse outcome measures: a) ischemic stroke; b) ischemic stroke and myocardial infarction, c) ischemic stroke and death, and d) ischemic stroke, myocardial infarction, and death. RESULTS The study cohort comprised 186 patients. Overall, NOAF was detected in 7 cases (3.8%). The only variable associated with NOAF was intraoperative hypotension (OR 9.6, 95% CI 1.9-47.4, P = .006). There were no perioperative deaths. NOAF was associated with perioperative ischemic stroke and with the combined outcome of ischemic stroke and myocardial infarction. CONCLUSIONS We found a low frequency of NOAF after CEA. Intraoperative hypotension was associated to a higher risk of NOAF. In turn, NOAF was related to adverse postoperative outcome. Further research is needed to clarify the pathophysiological relation between intraoperative hypotension, NOAF, and adverse CEA outcome.