Electrocardiographic Left Atrial Abnormality and Risk of Stroke: Northern Manhattan Study

Stroke Disparities: From Observations to Actions: Inaugural Edward J. Kenton Lecture 2020

Numerous epidemiological studies have demonstrated stroke disparities across race and ethnic groups. The goal of the NOMAS (Northern Manhattan Study) was to evaluate race and ethnic differences in stroke within a community with 3 different race-ethnic groups. Starting as a population-based incidence and case-control study, the study evolved into a cohort study. Results from NOMAS have demonstrated differences in stroke incidence, subtypes, risk factors, and outcomes. Disparities in ideal cardiovascular health can help explain many differences in stroke incidence and call for tailored risk factor modification through innovative portals to shift more diverse subjects to ideal cardiovascular health. The results of NOMAS and multiple other studies have provided foundational data to support interventions. Conceptual models to address health disparities have called for moving from detecting disparities in disease incidence, to determining the underlying causes of disparities and developing interventions, and then to testing interventions in human populations. Further actions to address race and ethnic stroke disparities are needed including innovative risk factor interventions, stroke awareness campaigns, quality improvement programs, workforce diversification, and accelerating policy changes.

Atrial fibrillation: villain or bystander in vascular brain injury

Atrial fibrillation (AF) and stroke are inextricably connected, with classical Virchow pathophysiology explaining thromboembolism through blood stasis in the fibrillating left atrium. This conceptualization has been reinforced by the remarkable efficacy of oral anticoagulant (OAC) for stroke prevention in AF. A number of observations showing that the presence of AF is neither necessary nor sufficient for stroke, cast doubt on the causal role of AF as a villain in vascular brain injury (VBI). The requirement for additional risk factors before AF increases stroke risk; temporal disconnect of AF from a stroke in patients with no AF for months before stroke during continuous ECG monitoring but manifesting AF only after stroke; and increasing recognition of the role of atrial cardiomyopathy and atrial substrate in AF-related stroke, and also stroke without AF, have led to rethinking the pathogenetic model of cardioembolic stroke. This is quite separate from recognition that in AF, shared cardiovascular risk factors can lead both to non-embolic stroke, or emboli from the aorta and carotid arteries. Meanwhile, VBI is now expanded to include dementia and cognitive decline: research is required to see if reduced by OAC. A changed conceptual model with less focus on the arrhythmia, and more on atrial substrate/cardiomyopathy causing VBI both in the presence or absence of AF, is required to allow us to better prevent AF-related VBI. It could direct focus towards prevention of the atrial cardiomyopathy though much work is required to better define this entity before the balance between AF as villain or bystander can be determined.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters.

METHODS

We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer.

RESULTS

Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster.

CONCLUSIONS

This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

Association between electrocardiographic and echocardiographic atrial abnormalities and prognosis in cryptogenic stroke

BACKGROUND AND PURPOSE

The role of atrial fibrillation in cryptogenic stroke (CS) is well known. However, the usefulness of left atrial (LA) electrical and morphological abnormalities to identify more disabling strokes in sinus rhythm patients is less studied. We evaluated the association between electrocardiographic P-wave abnormalities and echocardiographic LA measures with neurological disability in patients with cryptogenic stroke.

METHODS

In a retrospective cohort, we included all consecutive hospitalized patients with cryptogenic stroke. Patients were classified according to modified Rankin scale at hospital discharge and at 3 months. LA abnormalities were identified by electrocardiographic (ECG) P-wave, axis and LA enlargement criteria, and by bidimensional echocardiograph through left atrial diameter and volume index.

RESULTS

Among the 143 patients with CS (63.4 ± 14.2 years, 53% women), 70 patients were classified as non-disabling stroke (Rankin score < 2) and 73 patients as disabling stroke (Rankin score ≥ 2) at hospital discharge. On echocardiogram, more patients with disabling stroke presented with enlarged LA volume index (48% vs. 25%; p = 0.01). This difference remained significant after adjustment for age, gender, CHA₂DS₂-VASc and NIHSS scores (p = 0.02) and even when the LA volume index was analyzed as a continuous variable (p = 0.055). Also, enlarged LA volume index was more prevalent (52% vs. 25%; p = 0.03) among those with disabling stroke at 3 months after hospital discharge. Among ECG criteria, only the LA enlargement assessed by downward deflection was more prevalent in disabling stroke.

CONCLUSION

Our study demonstrated an association between left atrial enlargement, assessed by downward deflection from ECG and volume index from echocardiogram, and more disabling cryptogenic strokes. This information could help to identify patients with poorer prognosis, or a subgroup where atrial cardiopathy may play a role in cardioembolic pathway.

Atrial Myopathy Underlying Atrial Fibrillation

While AF most often occurs in the setting of atrial disease, current assessment and treatment of patients with AF does not focus on the extent of the atrial myopathy that serves as the substrate for this arrhythmia. Atrial myopathy, in particular atrial fibrosis, may initiate a vicious cycle in which atrial myopathy leads to AF, which in turn leads to a worsening myopathy. Various techniques, including ECG, plasma biomarkers, electroanatomical voltage mapping, echocardiography, and cardiac MRI, can help to identify and quantify aspects of the atrial myopathy. Current therapies, such as catheter ablation, do not directly address the underlying atrial myopathy. There is emerging research showing that by targeting this myopathy we can help decrease the occurrence and burden of AF.

Frontiers of Upstream Stroke Prevention and Reduced Stroke Inequity Through Predicting, Preventing, and Managing Hypertension and Atrial Fibrillation: A Call to Action From the Value in Healthcare Initiative's Predict & Prevent Learning Collaborative

Stroke is one of the leading causes of morbidity and mortality in the United States. While age-adjusted stroke mortality was falling, it has leveled off in recent years due in part to advances in medical technology, health care options, and population health interventions. In addition to adverse trends in stroke-related morbidity and mortality across the broader population, there are sociodemographic inequities in stroke risk. These challenges can be addressed by focusing on predicting and preventing modifiable upstream risk factors associated with stroke, but there is a need to develop a practical framework that health care organizations can use to accomplish this task across diverse settings. Accordingly, this article describes the efforts and vision of the multi-stakeholder Predict & Prevent Learning Collaborative of the Value in Healthcare Initiative, a collaboration of the American Heart Association and the Robert J. Margolis, MD, Center for Health Policy at Duke University. This article presents a framework of a potential upstream stroke prevention program with evidence-based implementation strategies for predicting, preventing, and managing stroke risk factors. It is meant to complement existing primary stroke prevention guidelines by identifying frontier strategies that can address gaps in knowledge or implementation. After considering a variety of upstream medical or behavioral risk factors, the group identified 2 risk factors with substantial direct links to stroke for focusing the framework: hypertension and atrial fibrillation. This article also highlights barriers to implementing program components into clinical practice and presents implementation strategies to overcome those barriers. A particular focus was identifying those strategies that could be implemented across many settings, especially lower-resource practices and community-based enterprises representing broad social, economic, and geographic diversity. The practical framework is designed to provide clinicians and health systems with effective upstream stroke prevention strategies that encourage scalability while allowing customization for their local context.

Electrocardiographic left atrial abnormality in patients presenting with ischemic stroke

BACKGROUND

P wave indices represent electrocardiographic marker of left atrial pathology. We hypothesized that P wave would be more abnormal in patients presenting with ischemic stroke than a comparable group without ischemic stroke.

METHODS

We compared P wave terminal force in V1 (PTFV1) between patients admitted with ischemic stroke (case) and patients followed in cardiology clinic (control) at a single medical center. Using logistic regression models, we tested for an association between abnormal PTFV1 (> 4000 µV ms) and ischemic stroke. We also defined several optimal cut-off values of PTFV1 using a LOESS plot and estimated odds ratio of ischemic stroke when moving from one cut-point level to the next higher-level.

RESULTS

A total of 297 patients (case 147, control 150) were included. PTFV1 was higher in patients with vs. those without ischemic stroke (median 4620 vs 3994 µV ms; p=0.006). PTFV1 was similar between cardioembolic/cryptogenic and other stroke subtypes. In multivariable analyses adjusting for sex, obesity, age, and hypertension, the association between abnormal PTFV1 and ischemic stroke ceased to be significant (OR 1.53 [0.95, 2.50], p=0.083). Increase to the next cutoff level of PTFV1 (900, 2000, 3000, 4000, 5000, and 6000 µV ms) was associated with 18% increase in odds of having ischemic stroke (vs. no ischemic stroke) (OR 1.18 [1.02, 1.36], p=0.026).

CONCLUSION

Patients presenting with acute ischemic stroke are more likely to have abnormal PTFV1. These findings from a real-world clinical setting support the results of cohort studies that left atrial pathology manifested as abnormal PTFV1 is associated with ischemic stroke.

Tailoring the Approach to Embolic Stroke of Undetermined Source: A Review

Importance

One-third of ischemic strokes have no identifiable cause after standard evaluation. In 2014, researchers termed these embolic strokes of undetermined source (ESUS) and argued that this entity would respond to anticoagulation. Two recent randomized clinical trials have not upheld this hypothesis, leading to questions about the ESUS concept.

Observations

This article proposes that ESUS remains a useful concept, the clinical effect of which can be enhanced by considering 2 subsets defined by their likelihood of responding to anticoagulation. Recent studies indicate that some ESUS cases result from subclinical atrial fibrillation, atrial cardiopathy, unrecognized myocardial infarction, patent foramen ovale, or cancer, while other cases result from nonstenosing large-artery atherosclerosis, aortic atherosclerosis, or nonatherosclerotic vasculopathies. Evidence suggests that anticoagulation will prove superior to antiplatelet therapy for cases in the first group of causative mechanisms but not those in the second group, suggesting the need for personalized therapy.

Conclusions and Relevance

Although the ESUS concept as currently constructed cannot guide treatment, efforts to better understand ESUS and develop therapies tailored to specific mechanisms are likely to help reduce the burden of stroke.

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

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

Potential Embolic Sources and Outcomes in Embolic Stroke of Undetermined Source in the NAVIGATE-ESUS Trial

Background and Purpose—

Emboli in embolic stroke of undetermined source (ESUS) may originate from various potential embolic sources (PES), some of which may respond better to anticoagulation, whereas others to antiplatelets. We analyzed whether rivaroxaban is associated with reduction of recurrent stroke compared with aspirin in patients with ESUS across different PES and by number of PES.

Methods—

We assessed the presence/absence of each PES (atrial cardiopathy, atrial fibrillation, arterial atherosclerosis, left ventricular dysfunction, cardiac valvulopathy, patent foramen ovale, cancer) in NAVIGATE-ESUS (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source) participants. Prevalence of each PES, as well as treatment effect and risk of event for each PES were determined. Results by number of PES were also determined. The outcomes were ischemic stroke, all-cause mortality, cardiovascular mortality, and myocardial infarction.

Results—

In 7213 patients (38% women, mean age 67years) followed for a median of 11 months, the 3 most prevalent PES were atrial cardiopathy (37%), left ventricular disease (36%), and arterial atherosclerosis (29%). Forty-one percent of all patients had multiple PES, with 15% having ≥3 PES. None or a single PES was present in 23% and 36%, respectively. Recurrent ischemic stroke risk was similar for rivaroxaban- and aspirin-assigned patients for each PES, except for those with cardiac valvular disease which was marginally higher in rivaroxaban-assigned patients (hazard ratio, 1.8 [95% CI, 1.0–3.0]). All-cause mortality risks were similar across treatment groups for each PES while too few myocardial infarctions and cardiovascular deaths occurred for meaningful assessment. Increasing number of PES was not associated with increased stroke recurrence nor all-cause mortality, and outcomes did not vary between rivaroxaban- and aspirin-assigned patients by number of PES.

Conclusions—

A large proportion of patients with ESUS had multiple PES which could explain the neutral results of NAVIGATE-ESUS. Recurrence rates between rivaroxaban- and aspirin-assigned patients were similar across the spectrum of PES.

Registration—

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02313909.

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

Background and aims

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

Methods

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

Results

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

Conclusions

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

Clinical trial registration

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

Measuring atrial stasis during sinus rhythm in patients with paroxysmal atrial fibrillation using 4 Dimensional flow imaging: 4D flow imaging of atrial stasis

BACKGROUND

Paroxysmal atrial fibrillation (PAF) is associated with cardioembolic risk, however events may occur during sinus rhythm (SR). 4D-flow cardiac magnetic resonance (CMR) imaging allows visualisation of left atrial blood flow, to determine the residence time distribution (RTD), an assessment of atrial transit time.

OBJECTIVE

To determine if atrial transit time is prolonged in PAF patients during SR, consistent with underlying atrial stasis.

METHOD

91 participants with PAF and 18 healthy volunteers underwent 4D flow analysis in SR. Velocity fields were produced RTDs, calculated by seeding virtual 'particles' at the right upper pulmonary vein and counting them exiting the mitral valve. An exponential decay curve quantified residence time of particles in the left atrium, and atrial stasis was expressed as the derived constant (RTD_TC) based on heartbeats. The RTD_TC was evaluated within the PAF group, and compared to healthy volunteers.

RESULTS

Patients with PAF (n = 91) had higher RTD_TC compared with gender-matched controls (n = 18) consistent with greater atrial stasis (1.68 ± 0.46 beats vs 1.51 ± 0.20 beats; p = .005). PAF patients with greater thromboembolic risk had greater atrial stasis (median RTD_TC of 1.72 beats in CHA₂DS₂-VASc≥2 vs 1.52 beats in CHA₂DS₂-VASc<2; p = .03), only female gender and left ventricular ejection fraction contributed significantly to the atrial RTD_TC (p = .006 and p = .023 respectively).

CONCLUSIONS

Atrial stasis quantified by 4D flow is greater in PAF, correlating with higher CHA₂DS₂-VASc scores. Female gender and systolic dysfunction are associated with atrial stasis. RTD offers an insight into atrial flow that may be developed to provide a personalised assessment of thromboembolic risk.

Increased Left Atrial Appendage Density on Computerized Tomography is Associated with Cardioembolic Stroke

BACKGROUND AND PURPOSE

While studies have stratified cardioembolic (CE) stroke risk by qualitative left atrial appendage (LAA) morphology and biomarkers of atrial dysfunction, the quantitative properties that underlie these observations are not well established. Accordingly, we hypothesized that LAA volume and contrast density (attenuation) on computerized tomography (CT) may capture the structural and hemodynamic processes that underlie CE stroke risk.

METHODS

Data were collected from a single center prospective ischemic stroke database over 18 months and included all patients with ischemic stroke who previously underwent routine, nongated, contrast enhanced thin-slice (≤2.5 mm) chest CT. Stroke subtype was determined based on the inpatient diagnostic evaluation. LAA volume and attenuation were determined from CT studies performed for various clinically appropriate indications. Univariate and multivariable analyses were performed to determine factors associated with ischemic stroke subtype, including known risk factors and biomarkers, as well as LAA density and morphologic measures.

RESULTS

We identified 311 patients with a qualifying chest CT (119 CE subtype, 109 Embolic Stroke of Undetermined Source (ESUS), and 83 non-CE). In unadjusted models, there was an association between CE (versus non-CE) stroke subtype and LAA volume (OR per mL increase 1.15, 95% CI 1.07-1.24, P < .001) and LAA density (4th quartile versus 1st quartile; OR 2.95, 95% CI 1.28-6.80, P = .011), but not with ESUS (versus non-CE) subtype. In adjusted models, only the association between LAA density and CE stroke subtype persisted (adjusted OR 3.71, 95% CI 1.37-10.08, P = .010).

CONCLUSION

The LAA volume and density values on chest CT are associated with CE stroke subtype but not ESUS subtype. Patients with ESUS and increased LAA volume or attenuation may be a subgroup where the mechanism is CE and anticoagulation can be tested for secondary stroke prevention.

Markers of endothelial pathology to support detection of atrial fibrillation in embolic stroke of undetermined source

A relevant part of embolic strokes of undetermined source (ESUS) is assumed to be cardiogenic. As shown previously, certain biomarkers of endothelial pathology are related to atrial fibrillation (AF). In this long-term follow-up study, we aimed to investigate whether these biomarkers are associated with subsequently diagnosed AF and with atrial cardiopathy. In 98 patients who suffered ischemic stroke of known and unknown origin L-arginine, Asymmetric (ADMA) and Symmetric Dimethylarginine (SDMA) have been measured on follow-up at least one year after index stroke. Stroke-diagnostics were available for all patients, including carotid Intima-Media-Thickness (CIMT) and comprehensive echocardiography studies. CIMT was larger in AF- compared with ESUS-patients (P < 0.001), independently from CHA2DS2VASC in the regression analysis (P = 0.004). SDMA-values were stable over time (P < 0.001; r = 0.788), whereas for ADMA moderate correlation with the initial values could be found (P = 0.007; r = 0.356). According to Kaplan-Meier-analyses, AF-detection rates were associated with CIMT (P = 0.003) and SDMA (P < 0.001). SDMA correlated with left atrial volume-index within the whole collective (P = 0.003, r = 0.322) and within the ESUS-subgroup (P = 0.003; r = 0.446). These associations were independent from CHA2DS2VASC and renal function in the regression analysis (P = 0.02 and P = 0.005, respectively). In conclusion, these results highlight SDMA and CIMT as potential markers of atrial cardiopathy and AF in ESUS-patients.

Association of Abnormal P-Wave Indices With Dementia and Cognitive Decline Over 25 Years: ARIC-NCS (The Atherosclerosis Risk in Communities Neurocognitive Study)

Background Abnormal P-wave indices (PWIs)-reflecting underlying left atrial abnormality-are associated with increased risk of stroke independent of atrial fibrillation. We assessed whether abnormal PWIs are associated with incident dementia and greater cognitive decline, independent of atrial fibrillation and ischemic stroke. Methods and Results We included 13 714 participants (mean age, 57±6 years; 56% women; 23% black) who were followed for dementia through the end of 2015. (Abnormal P-wave terminal force in lead V1, ≥4000 μV×ms), abnormal P-wave axis (>75° or <0°), prolonged P-wave duration (>120 ms), and advanced interatrial block were determined from ECGs at visits 2 to 4. Dementia was adjudicated by an expert panel using data from cognitive tests and hospitalization International Classification of Diseases codes. Cognitive function was measured longitudinally using 3 neuropsychological tests. Cox proportional hazards models were used to assess the association between time-dependent abnormal PWIs with incident dementia. Linear regression models were used to evaluate PWIs with cognitive function over time. At the conclusion of the study, 19%, 16%, 28%, and 1.9% of participants had abnormal P-wave terminal force in lead V1, abnormal P-wave axis, prolonged P-wave duration, and advanced interatrial block, respectively. During mean follow-up of 18 years, there were 1390 (10%) dementia cases. All abnormal PWIs except advanced interatrial block were associated with an increased risk of dementia even after adjustment for incident atrial fibrillation and stroke: multivariable hazard ratio of abnormal P wave terminal force in lead V1=1.60, 95% CI, 1.41 to 2.83; abnormal P-wave axis, hazard ratio =1.36, 95% CI, 1.17 to 2.57; prolonged P-wave duration, hazard ratio=1.60, 95% CI, 1.42 to 1.80. Only abnormal P-wave terminal force in lead V1 was associated with greater decline in global cognition. Conclusions Abnormal PWIs are independently associated with an increased risk of dementia. This novel finding should be replicated in other cohorts and the underlying mechanisms should be evaluated.

Searching for Atrial Fibrillation Poststroke: A White Paper of the AF-SCREEN International Collaboration

Cardiac thromboembolism attributed to atrial fibrillation (AF) is responsible for up to one-third of ischemic strokes. Stroke may be the first manifestation of previously undetected AF. Given the efficacy of oral anticoagulants in preventing AF-related ischemic strokes, strategies of searching for AF after a stroke using ECG monitoring followed by oral anticoagulation (OAC) treatment have been proposed to prevent recurrent cardioembolic strokes. This white paper by experts from the AF-SCREEN International Collaboration summarizes existing evidence and knowledge gaps on searching for AF after a stroke by using ECG monitoring. New AF can be detected by routine plus intensive ECG monitoring in approximately one-quarter of patients with ischemic stroke. It may be causal, a bystander, or neurogenically induced by the stroke. AF after a stroke is a risk factor for thromboembolism and a strong marker for atrial myopathy. After acute ischemic stroke, patients should undergo 72 hours of electrocardiographic monitoring to detect AF. The diagnosis requires an ECG of sufficient quality for confirmation by a health professional with ECG rhythm expertise. AF detection rate is a function of monitoring duration and quality of analysis, AF episode definition, interval from stroke to monitoring commencement, and patient characteristics including old age, certain ECG alterations, and stroke type. Markers of atrial myopathy (eg, imaging, atrial ectopy, natriuretic peptides) may increase AF yield from monitoring and could be used to guide patient selection for more intensive/prolonged poststroke ECG monitoring. Atrial myopathy without detected AF is not currently sufficient to initiate OAC. The concept of embolic stroke of unknown source is not proven to identify patients who have had a stroke benefitting from empiric OAC treatment. However, some embolic stroke of unknown source subgroups (eg, advanced age, atrial enlargement) might benefit more from non-vitamin K-dependent OAC therapy than aspirin. Fulfilling embolic stroke of unknown source criteria is an indication neither for empiric non-vitamin K-dependent OAC treatment nor for withholding prolonged ECG monitoring for AF. Clinically diagnosed AF after a stroke or a transient ischemic attack is associated with significantly increased risk of recurrent stroke or systemic embolism, in particular, with additional stroke risk factors, and requires OAC rather than antiplatelet therapy. The minimum subclinical AF duration required on ECG monitoring poststroke/transient ischemic attack to recommend OAC therapy is debated.

Association of Intracranial Hemorrhage Risk With Non-Vitamin K Antagonist Oral Anticoagulant Use vs Aspirin Use: A Systematic Review and Meta-analysis

Importance

Non-vitamin K antagonist oral anticoagulants (NOACs) might be an attractive choice for stroke prevention in people without atrial fibrillation who may harbor a potential source of cardiac emboli, but not if certain individual NOACs carry risks of intracranial hemorrhage that are heightened relative to aspirin.

Objective

To conduct a systematic review and meta-analysis of randomized clinical trials to assess the risk of intracranial hemorrhage with individual NOACs vs aspirin across all indications.

Data Sources

We searched PubMed, Embase, CENTRAL, and ClinicalTrials.gov from inception to May 28, 2018, with the terms novel oral anticoagulants, non-vitamin K antagonist oral anticoagulants, direct oral anticoagulants, dabigatran, rivaroxaban, apixaban, edoxaban, warfarin, Coumadin, vitamin K antagonist, aspirin, acetylsalicylic acid, or ASA, and major bleeding, fatal bleeding, or intracranial hemorrhage. We restricted our search to clinical trials on humans. There were no language restrictions.

Study Selection

Randomized clinical trials of 3 months or longer that included a comparison of the outcomes of NOAC use vs use of aspirin.

Data Extraction and Synthesis

Two investigators independently abstracted data from eligible studies. We computed a fixed-effect estimate based on the Mantel-Haenszel method.

Main Outcomes and Measures

Odds ratios (ORs) with 95% CI were used as a measure of the association of individual NOAC vs aspirin with the risk of intracranial hemorrhage. The hypothesis that intracranial hemorrhage risk would be higher with NOACs than aspirin was formulated during data collection.

Results

Our principal analysis included 5 randomized clinical trials comparing 1 or more NOACs with aspirin, with 39 398 individuals enrolled. Pooling the results from the fixed-effects model showed that a dose of 15 to 20 mg of rivaroxaban once daily was associated with an increased risk of intracranial hemorrhage (2 trials; OR, 3.31 [95% CI, 1.42 to 7.72]) compared with aspirin, while a 10-mg dose of rivaroxaban once daily or a 5-mg dose twice daily (3 trials; OR, 1.43 [95% CI, 0.93 to 2.21]) and a 5-mg dose of apixaban twice daily (1 trial; OR, 0.84 [95% CI, 0.38 to 1.88]) were not.

Conclusions and Relevance

A 15-mg to 20-mg dose of rivaroxaban once daily is associated with substantially increased risks of intracranial hemorrhage, while smaller daily doses of rivaroxaban and apixaban were not, implying that risk increase is dose dependent. It may be worthwhile to conduct randomized clinical trials comparing specific NOACs in specific doses (eg, apixaban, 5 mg twice daily) and aspirin in patients without atrial fibrillation, but with potential sources of cardiac emboli that could cause stroke.

Atrial Myopathy

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The authors discuss the concept of atrial myopathy; its relationship to aging, electrophysiological remodeling, and autonomic remodeling; the interplay between atrial myopathy, AF, and stroke; and suggest how to identify patients with atrial myopathy and how to incorporate atrial myopathy into decisions about anticoagulation.

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Atrial myopathy seen in animal models of AF and in patients with AF is the result of a combination of factors that lead to electrical and structural remodeling in the atrium. Although AF may lead to the initiation and/or progression of this myopathy, the presence of AF is by no means essential to the development or the maintenance of the atrial myopathic state.

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Methods to identify atrial myopathy include atrial electrograms, tissue biopsy, cardiac imaging, and certain serum biomarkers. A promising modality is 4-dimensional flow cardiac magnetic resonance. The concept of atrial myopathy may help guide oral anticoagulant therapy in selected groups of patients with AF, particularly those with low to intermediate risk of strokes and those who have undergone successful AF ablation. This review highlights the need for prospective randomized trials to test these hypotheses.

This paper discusses the evolving concept of atrial myopathy by presenting how it develops and how it affects the properties of the atria. It also reviews the complex relationships among atrial myopathy, atrial fibrillation (AF), and stroke. Finally, it discusses how to apply the concept of atrial myopathy in the clinical setting—to identify patients with atrial myopathy and to be more selective in anticoagulation in a subset of patients with AF. An apparent lack of a temporal relationship between episodes of paroxysmal AF and stroke in patients with cardiac implantable electronic devices has led investigators to search for additional factors that are responsible for AF-related strokes. Multiple animal models and human studies have revealed a close interplay of atrial myopathy, AF, and stroke via various mechanisms (e.g., aging, inflammation, oxidative stress, and stretch), which, in turn, lead to fibrosis, electrical and autonomic remodeling, and a pro-thrombotic state. The complex interplay among these mechanisms creates a vicious cycle of ever-worsening atrial myopathy and a higher risk of more sustained AF and strokes. By highlighting the importance of atrial myopathy and the risk of strokes independent of AF, this paper reviews the methods to identify patients with atrial myopathy and proposes a way to incorporate the concept of atrial myopathy to guide anticoagulation in patients with AF.

Left Atrial Volume Index Is Associated With Cardioembolic Stroke and Atrial Fibrillation Detection After Embolic Stroke of Undetermined Source

Background and Purpose- Left atrial enlargement has been shown to be associated with ischemic stroke, but the association with embolic stroke mechanisms remains unknown. We aim to study the associations between left atrial volume index (LAVI) and embolic stroke subtypes and atrial fibrillation (AF) detection on cardiac event monitoring in patients with embolic stroke of unknown source. Methods- Data were collected from a prospective cohort of consecutive patients with ischemic stroke admitted to a comprehensive stroke center over 18 months. Stroke subtype was classified into cardioembolic stroke, noncardioembolic stroke of determined mechanism (NCE), or embolic stroke of undetermined source (ESUS). Univariate and prespecified multivariable analyses were performed to assess associations between LAVI and stroke subtype and AF detection in patients with ESUS. Results- Of 1224 consecutive patients identified during the study period, 1020 (82.6%) underwent transthoracic echocardiography and had LAVI measurements. LAVI was greater in patients with cardioembolic stroke than NCE (41.4 mL/m²±18.0 versus 28.6 mL/m²±12.2; P<0.001) but not in ESUS versus NCE (28.9 mL/m²±12.6 versus 28.6 mL/m²±12.2; P=0.61). In multivariable logistic regression models, LAVI was greater in cardioembolic stroke versus NCE (adjusted odds ratio per mL/m², 1.07; 95% CI, 1.05-1.09; P<0.001) but not in ESUS versus NCE (adjusted odds ratio per mL/m², 1.00; 95% CI, 0.99-1.02; P=0.720). Among 99 patients with ESUS who underwent cardiac monitoring, 18.2% had AF detected; LAVI was independently associated with AF detection in ESUS (adjusted odds ratio per mL/m², 1.09; 95% CI, 1.02-1.15; P=0.007). Conclusions- LAVI is associated with cardioembolic stroke as well as AF detection in patients with ESUS, 2 subsets of ischemic stroke that benefit from anticoagulation therapy. Patients with increased LAVI may be a subgroup where anticoagulation may be tested for stroke prevention.

Atrial fibrillation and stroke: a practical guide

Neurologists and stroke physicians will be familiar with atrial fibrillation as a major cause of ischaemic stroke, and the role of anticoagulation in preventing cardioembolic stroke. However, making decisions about anticoagulation for individual patients remains a difficult area of clinical practice, balancing the serious risk of ischaemic stroke against that of major bleeding, particularly intracranial haemorrhage. Atrial fibrillation management requires interdisciplinary collaboration with colleagues in cardiology and haematology. Recent advances, especially the now-widespread availability of direct oral anticoagulants, have brought opportunities to improve stroke care while posing new challenges. This article gives an overview of the contemporary diagnosis and management of atrial fibrillation, and the associated evidence base. Where there is uncertainty, we describe our own approach to these areas, while highlighting ongoing research that will likely guide future practice.

Electrocardiographic criteria for the diagnosis of abnormal hypertensive cardiac phenotypes

This article compared the performance of 18 electrocardiographic (ECG) left ventricular hypertrophic (LVH) criteria and four P-wave indices for the diagnosis of echocardiographic (ECHO) LVH and left atrial enlargement (LAE), including the deepest S-wave amplitude added to the S-wave amplitude of lead V4 (SD +SV4 ) and P-wave terminal force in lead V1 (PTFV1 ). A total of 152 middle-aged hypertensive patients without evident cardiovascular diseases (CVDs) were enrolled. The gold standard for the diagnosis of LVH and LAE was ECHO left ventricular mass index (LVMI) and largest left atrial volume index (LAVI). For the detection of LVH, Sokolow-Lyon voltage, Cornell voltage, Cornell product, SD +SV4 , Manning, and R+S in any precordial lead had relatively higher sensitivity, especially SD +SV4 criteria. Their combination could further increase sensitivity (43% vs 29% [SD +SV4 ], P = 0.016). PTFV1 was the only criterion that had significant diagnostic value for ECHO LAE (AUC, 0.68; 95% CI: 0.54-0.73, P = 0.008). For middle-aged hypertensive patients without evident cardiovascular diseases, SD +SV4 had the highest sensitivity for the diagnosis of LVH and the combination of several ECG LVH criteria might further increase sensitivity. PTFV1 had significant diagnostic value for ECHO LAE.

Obstructive sleep apnea and electrocardiographic P-wave morphology

INTRODUCTION

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder with important cardiovascular implications. Left atrial abnormality can be identified by electrocardiographic P-wave morphology and is considered an important risk for atrial fibrillation (AF) and stroke, both of which have been associated with OSA. We hypothesized that severity of OSA would be associated with more abnormal electrocardiographic P-wave morphology as indicated by P-wave terminal force in V₁ (PTFV₁ ) and P-wave area in V₁ (PWAV₁ ).

METHODS

Patients who underwent clinically indicated polysomnography and had 12-lead ECG were identified through medical record review. Logistic regression was used to determine the associations between the measures of OSA severity (apnea hypopnea index [AHI] and mean nocturnal oxygen [O₂ ] saturation) and abnormal PTFV₁ and PWAV₁ (defined by >75% percentile value of the studied cohort) adjusting for age, sex, body mass index, and hypertension.

RESULTS

A total of 261 patients (mean age: 57 years old, male: 52%) were included in the study. Multivariate analysis showed that AHI was associated with abnormal PTFV₁ (>7,280 µV ms) and PWAV₁ (>1,000 µV ms; OR: 1.5; 95% CI [1.1, 2.0], p = 0.008; OR: 1.5 [1.1, 2.1], p = 0.005 per 1 SD increase in AHI, respectively). Mean O₂ saturation was associated with abnormal PWAV₁ (OR: 0.72 [0.54, 0.98], p = 0.03). Results remained unchanged after excluding patients taking AV nodal blocking agents.

CONCLUSION

In a sleep clinic cohort, there was significant association between OSA severity and ECG-defined left atrial abnormality.

The AtRial Cardiopathy and Antithrombotic Drugs In prevention After cryptogenic stroke randomized trial: Rationale and methods

RATIONALE

Recent data suggest that a thrombogenic atrial substrate can cause stroke in the absence of atrial fibrillation. Such an atrial cardiopathy may explain some proportion of cryptogenic strokes.

AIMS

The aim of the ARCADIA trial is to test the hypothesis that apixaban is superior to aspirin for the prevention of recurrent stroke in subjects with cryptogenic ischemic stroke and atrial cardiopathy.

SAMPLE SIZE ESTIMATE

1100 participants.

METHODS AND DESIGN

Biomarker-driven, randomized, double-blind, active-control, phase 3 clinical trial conducted at 120 U.S. centers participating in NIH StrokeNet.

POPULATION STUDIED

Patients ≥ 45 years of age with embolic stroke of undetermined source and evidence of atrial cardiopathy, defined as ≥ 1 of the following markers: P-wave terminal force >5000 µV × ms in ECG lead V1, serum NT-proBNP > 250 pg/mL, and left atrial diameter index ≥ 3 cm/m2 on echocardiogram. Exclusion criteria include any atrial fibrillation, a definite indication or contraindication to antiplatelet or anticoagulant therapy, or a clinically significant bleeding diathesis. Intervention: Apixaban 5 mg twice daily versus aspirin 81 mg once daily. Analysis: Survival analysis and the log-rank test will be used to compare treatment groups according to the intention-to-treat principle, including participants who require open-label anticoagulation for newly detected atrial fibrillation.

STUDY OUTCOMES

The primary efficacy outcome is recurrent stroke of any type. The primary safety outcomes are symptomatic intracranial hemorrhage and major hemorrhage other than intracranial hemorrhage.

DISCUSSION

ARCADIA is the first trial to test whether anticoagulant therapy reduces stroke recurrence in patients with atrial cardiopathy but no known atrial fibrillation.

Succinate links atrial dysfunction and cardioembolic stroke

OBJECTIVE

To determine whether altered metabolic profiles represent a link between atrial dysfunction and cardioembolic (CE) stroke, and thus whether underlying dysfunctional atrial substrate may contribute to thromboembolism risk in CE stroke.

METHODS

A total of 144 metabolites were measured using liquid chromatography-tandem mass spectrometry in plasma samples collected within 9 hours of stroke onset in 367 acute stroke patients. Stroke subtype was assigned using the Causative Classification of Stroke System, and CE stroke (n = 181) was compared to non-CE stroke (n = 186). Markers of left atrial dysfunction included abnormal atrial function (P-wave terminal force in lead V1, PTFV₁ >4,000 μV·ms), left atrial enlargement on echocardiography, and frank atrial fibrillation on ECG. Stroke recurrence risk was assessed using CHADS₂ and CHA₂DS₂-VASc scores. Associations between metabolites and CE stroke, atrial dysfunction, and stroke recurrence risk were evaluated using logistic regression models.

RESULTS

Three tricarboxylic acid metabolites-succinate (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.36-2.15, p = 1.37 × 10^-6), α-ketoglutarate (OR 1.62, 95% CI 1.29-2.04, p = 1.62 × 10^-5), and malate (OR 1.58, 95% CI 1.26-1.97, p = 2.57 × 10^-5)-were associated with CE stroke. Succinate (OR 1.36, 95% CI 1.31-1.98, p = 1.22 × 10^-6), α-ketoglutarate (OR 2.14, 95% CI 1.60-2.87, p = 2.08 × 10^-8), and malate (OR 2.02, 95% CI 1.53-2.66, p = 1.60 × 10^-7) were among metabolites also associated with subclinical atrial dysfunction. Of these, succinate was also associated with left atrial enlargement (OR 1.54, 95% CI 1.23-1.94, p = 1.06 × 10^-4) and stroke recurrence based on dichotomized CHADS₂ (OR 2.63, 95% CI 1.68-4.13, p = 3.00 × 10^-6) and CHA₂DS₂-VASc (OR 2.43, 95% CI 1.60-3.68, p = 4.25 × 10^-6) scores.

CONCLUSIONS

Metabolite profiling identified changes in succinate associated with CE stroke, atrial dysfunction, and stroke recurrence, revealing a putative underlying link between CE stroke and energy metabolism.

Electrocardiographic left atrial abnormality and silent vascular brain injury: The Northern Manhattan Study

Hypothesis

We hypothesized that P wave terminal Force in the V1 lead (PTFV₁) would be associated with leukoaraiosis and subclinical infarcts, especially cortical infarcts, in a population-based, multi-ethnic cohort.

Methods

PTFV₁ was collected manually from baseline electrocardiograms of clinically stroke-free Northern Manhattan Study participants. Investigators read brain MRIs for superficial infarcts, deep infarcts, and white matter hyperintensity volume (WMHV). WMHV was adjusted for head size and log transformed, achieving a normal distribution. Logistic regression models investigated the association of PTFV₁ with cortical and with all subclinical infarcts. Linear regression models examined logWMHV. Models were adjusted for demographics and risk factors.

Results

Among 1174 participants with PTFV₁ measurements, the mean age at MRI was 70 ± 9 years. Participants were 14.4% white, 17.6% black, and 65.8% Hispanic. Mean PTFV₁ was 3587.35 ± 2315.62 μV-ms. Of the 170 subclinical infarcts, 40 were cortical. PTFV₁ ≥ 5000 μV-ms was associated with WMHV in a fully adjusted model (mean difference in logWMHV 0.15, 95% confidence interval 0.01–0.28). PTFV₁ exhibited a trend toward an association with cortical infarcts (unadjusted OR per SD change logPTFV₁ 1.30, 95% CI 0.94–1.81), but not with all subclinical infarcts.

Conclusion

Electrocardiographic evidence of left atrial abnormality was associated with leukoaraiosis.

Relation of Electrocardiographic Left Atrial Abnormalities to Risk of Stroke in Patients with Atrial Fibrillation

The P-wave terminal force in lead V₁ (PTFV₁) on the 12-lead electrocardiogram (ECG) quantifies left atrial (LA) structural and electrophysiologic abnormalities. We aimed to evaluate the association between PTFV₁ and cerebrovascular accident (CVA) as well as LA structure and function in patients with atrial fibrillation (AF). We conducted a cross-sectional study of 229 patients with AF (60 ± 10years, 72% men) with (n = 21) and without (n = 208) a history of CVA, who underwent preablation ECG and cardiac magnetic resonance in sinus rhythm. PTFV₁ was defined as the duration (in milliseconds) of the downward deflection of the P wave in lead V₁ multiplied by the absolute value of its amplitude (in microvolts) on ECG. PTFV₁ is associated with LA minimum volume (V_min) and left ventricular ejection fraction but not associated with the extent of LA fibrosis quantified by cardiac magnetic resonance late gadolinium enhancement. In addition, PTFV₁ is associated with CVA independent of the CHA₂DS₂-VASc score and LA V_min (odds ratio 1.23; 95% confidence interval 1.08 to 1.40; p = 0.002). Furthermore, PTFV₁ has an incremental value over the CHA₂DS₂-VASc score as a marker of CVA (p <0.001). In conclusion, ECG-defined PTFV₁ is independent marker of stroke in patients with AF and reflects the underlying LA remodeling. Our findings suggest that evaluation of PTFV₁ can improve the current risk stratification of stroke.

Association between sleep disordered breathing and electrocardiographic markers of atrial abnormalities: the MESA study

Aims

Electrocardiographic (ECG) markers of left atrial (LA) abnormalities have been linked to increased risk of atrial fibrillation (AF). Sleep disordered breathing (SDB) has been associated with increased risk of AF. We aimed to examine the association of ECG markers of LA abnormalities with SDB.

Methods and results

1546 participants (mean age 67.2 years, 53.4% women, and 63.3% non-whites) from the Multi-Ethnic Study of Atherosclerosis Exam 5 Sleep ancillary study were included in this analysis. ECG markers of LA abnormalities (P wave terminal force in V1 (PTFV1), maximum P wave duration, PR interval and heart rate corrected PR interval) were measured from resting standard digital ECG tracings using standardized processing. Linear and logistic regression analyses were utilized to examine the cross-sectional associations of measures of SDB (apnea hypopnea index [AHI] and % time spent with oxygen saturation <90% [%SpO290]) with each ECG marker. In a multivariable analysis adjusting for demographics, cardiovascular risk factors, and comorbidities, AHI was associated with greater PTFV1 but not with other ECG markers of LA abnormalities. A 1-SD increase of AHI (16.6/hr) was associated with higher levels of PTFV1 (175.1 µV.ms, 95% confidence interval [95%CI] 75.4, 274.7) and higher odds of abnormally elevated PTFV1 (≥4000 µV.ms) (Odds Ratio: 1.21 [95%CI 1.05, 1.39]). No association was found between %SpO290 and ECG markers of LA abnormalities.

Conclusion

Severity of SDB, as measured by AHI, is associated with subclinical LA disease, as indicated by PTFV1. PTFV1 may be an important ECG marker linking SDB and AF.

Atrial Cardiopathy and the Risk of Ischemic Stroke in the CHS (Cardiovascular Health Study)

BACKGROUND AND PURPOSE

Emerging evidence suggests that an underlying atrial cardiopathy may result in thromboembolism before atrial fibrillation (AF) develops. We examined the association between various markers of atrial cardiopathy and the risk of ischemic stroke.

METHODS

The CHS (Cardiovascular Health Study) prospectively enrolled community-dwelling adults ≥65 years of age. For this study, we excluded participants diagnosed with stroke or AF before baseline. Exposures were several markers of atrial cardiopathy: baseline P-wave terminal force in ECG lead V1, left atrial dimension on echocardiogram, and N terminal pro B type natriuretic peptide (NT-proBNP), as well as incident AF. Incident AF was ascertained from 12-lead electrocardiograms at annual study visits for the first decade after study enrollment and from inpatient and outpatient Medicare data throughout follow-up. The primary outcome was incident ischemic stroke. We used Cox proportional hazards models that included all 4 atrial cardiopathy markers along with adjustment for demographic characteristics and established vascular risk factors.

RESULTS

Among 3723 participants who were free of stroke and AF at baseline and who had data on all atrial cardiopathy markers, 585 participants (15.7%) experienced an incident ischemic stroke during a median 12.9 years of follow-up. When all atrial cardiopathy markers were combined in 1 Cox model, we found significant associations with stroke for P-wave terminal force in ECG lead V1 (hazard ratio per 1000 μV*ms 1.04; 95% confidence interval, 1.001-1.08), log-transformed NT-proBNP (hazard ratio per doubling of NT-proBNP, 1.09; 95% confidence interval, 1.03-1.16), and incident AF (hazard ratio, 2.04; 95% confidence interval, 1.67-2.48) but not left atrial dimension (hazard ratio per cm, 0.96; 95% confidence interval, 0.84-1.10).

CONCLUSIONS

In addition to clinically apparent AF, other evidence of abnormal atrial substrate is associated with subsequent ischemic stroke. This finding is consistent with the hypothesis that thromboembolism from the left atrium may occur in the setting of several different manifestations of atrial disease.

[Bayes' syndrome in cardiac surgery: prevalence of interatrial block in patients younger than 65 years undergoing cardiac surgery and association with postoperative atrial fibrillation]

OBJECTIVE

Interatrial block (IAB) is a well-known entity that is associated with an increased risk of atrial fibrillation (AF). This association is called Bayes' syndrome. The aim of our study was to define the prevalence of IAB among patients younger than 65 years undergoing cardiac surgery and determine whether there is an association between the presence of interatrial conduction delay and postoperative atrial fibrillation (POAF).

METHOD

A total of 207 patients were enrolled. Partial IAB was defined as P-wave>120ms. Advanced IAB was defined as P-wave>120ms+biphasic morphology in the inferior leads. Ocurrence of POAF was assessed and a comparative analysis was conducted between patients that did and did not develop AF.

RESULTS

IAB prevalence was 78.3% (partial 66.2%, advanced 12.1%). POAF occurred in 28.5% of all patients, and was more frequent among patients with advanced IAB (44%) compared to 27.7% and 24.4% of POAF among patients with partial IAB and without IAB, respectively. Patients who developed POAF were significantly older, had significantly higher NTproBNP, higher prevalence of atrial enlargement and thyroid disease. After multivariate analysis, advanced IAB was found to be independently associated with POAF.

CONCLUSIONS

IAB is a frequent finding among patients undergoing cardiac surgery. According to our results, advanced IAB is independently associated with POAF in younger patients (<65 years) undergoing cardiac surgery.

ECG markers associated with ischemic stroke at young age - a case-control study

INTRODUCTION

Certain electrocardiographic (ECG) abnormalities are associated with ischemic stroke (IS), especially cardioembolic subtype. Besides atrial fibrillation, markers of left ventricular hypertrophy (LVH) or atrial pathology also reflect elevated risk. We studied the association of ECG markers with IS in young adults.

METHODS

We performed a case-control study including 567 consecutive IS patients aged 15-49 years (inclusion period: 1994-2007) and one or two age- and sex-matched control subjects enrolled during 1978-1980 (n = 1033), and investigated also the stroke aetiologic subgroups. We studied ECGs of all participants for markers of atrial abnormality, i.e. P-terminal force (PTF) on lead V1, interatrial blocks (IAB; P-wave duration ≥110 ms), and LVH. Conditional logistic regression analyses were used.

RESULTS

IAB (hazard ratio [HR]: 1.57, 95% confidence interval [CI]: 1.16-2.13) and PTF combined with LVH (HR: 6.83, 95% CI: 1.65-28.31), were independently associated with IS. LVH, abnormal P-wave (HR: 6.87, 95% CI: 1.97-135.29), PTF, IAB, and combinations of these P-wave abnormalities with LVH - were associated with cardioembolic subtype. Abnormal P-wave and IAB were associated with cryptogenic stroke subtype. In unadjusted analysis, LVH was associated with small-vessel disease subtype.

CONCLUSION

P-wave abnormalities on ECG were associated with cardioembolic but also with a cryptogenic subtype of IS. Key messages ECG patterns associated with atrial pathology are markers of increased risk of ischemic stroke in young adults. The ECG markers reflecting atrial pathology were seen in patients with cardioembolic and cryptogenic subtypes of ischemic stroke.

High prevalence of subclinical cerebral infarction in patients with heart failure with preserved ejection fraction

AIMS

Undetected atrial fibrillation (AF) may be common in the heart failure with preserved ejection fraction (HFpEF) population, and failure to detect this may lead to the missing of opportunities to prevent associated subclinical cerebral infarctions (SCIs) and cognitive decline.

METHODS AND RESULTS

We studied 1527 participants in the Atherosclerosis Risk in Communities (ARIC) Study, who underwent echocardiography, brain magnetic resonance imaging (MRI) and detailed cognitive assessment during 2011-13. Prevalences of SCI as detected by brain MRI were compared among the following groups: participants with no HFpEF/no AF; those with no HFpEF/AF; those with HFpEF/no AF, and those with HFpEF/AF. Cognitive scores were also compared. Prevalences of HFpEF and AF in this sample were 13.2% and 5.7%, respectively. Participants with HFpEF but no prior diagnosis of AF had a high prevalence of SCI by brain MRI (29.3%), which was similar to those in the no HFpEF/AF (24.5%) and HFpEF/AF (23.5%) groups, but higher than that in the no HFpEF/no AF subjects (17.3%). The odds of having SCI were higher in participants with HFpEF/no AF than in the no HFpEF/no AF group even after adjustment for potential confounders (odds ratio 1.56, 95% confidence interval 1.06-2.30). Individuals with HFpEF and SCI had lower cognitive scores than the reference (no HFpEF/no SCI) and HFpEF/no SCI groups.

CONCLUSIONS

Subclinical cerebral infarctions were prevalent in subjects in the ARIC cohort with HFpEF and no prior AF diagnosis and are associated with measurable cognitive deficits. Although other sources of emboli may be possible, these data suggest that paroxysmal AF may be underdiagnosed in this population. There may be a role for earlier anticoagulation in patients with HFpEF.

Electrocardiographic left atrial abnormalities and risk of incident stroke in hypertensive patients with electrocardiographic left ventricular hypertrophy

BACKGROUND

Recent findings in population-based studies suggest that abnormal P wave terminal force in lead V1 (PTFV1), a marker of left atrial abnormalities such as fibrosis, dilatation and elevated filling pressures, is associated with incident ischemic stroke, even in the absence of atrial fibrillation. However, whether PTFV1 predicts incident stroke in hypertensive patients during blood pressure lowering has not been examined.

METHODS

Risk of incident stroke was examined in relation to abnormal PTFV1 on a baseline ECG in 7778 hypertensive patients with ECG left ventricular hypertrophy, no history of atrial fibrillation, in sinus rhythm on their baseline ECG with no incident atrial fibrillation during follow-up, who were randomly assigned to losartan-based or atenolol-based treatment. Results focused on the subset of patients between 55 and 60 years old (n = 1879) because of a significant interaction between PTFV1 and age in Cox analyses. Abnormal PTFV1 was defined by the presence of a negative terminal P wave in lead V1 with amplitude × duration ≥ 4000 μV ms.

RESULTS

During mean follow-up of 4.8 ± 0.9 years, 364 patients (4.7%) of the overall study population and 45 patients (2.4%) in the subset of patients aged 60 years or less experienced a definite stroke. In the overall population, abnormal PTFV1 was not a significant predictor of incident stroke [hazard ratio 1.12, 95% confidence interval (CI) 0.91-1.38, P = 0.301], but there was a highly significant interaction of PTFV1 with age stratified at 60 (P = 0.009, hazard ratio 2.30, 95% CI 1.27-4.13, P = 0.006 for abnormal PTFV1 in the interaction model). Further analyses in the subset of patients aged 60 years or less revealed a higher incidence of stroke occurred in those with abnormal than normal baseline PTFV1: incidence rate per 1000 person-years, 7.8 (95% CI 5.2-11.4) vs 3.4 (95% CI 2.2-5.2; P = 0.004); a greater than two-fold increased risk of incident stroke (hazard ratio 2.31, 95% CI 1.28-4.16, P = 0.005) in univariate Cox analysis; and in multivariable Cox regression models that adjusted for other significant predictors of incident stroke in this population (sex, history of stroke or transient ischemic attack, ischemic heart disease or diabetes, baseline creatinine and in-treatment SBP), that abnormal PTFV1 remained associated with a greater than two-fold increased risk of incident stroke (hazard ratio 2.06; 95% CI 1.14-3.74, P = 0.017).

CONCLUSION

Abnormal PTFV1, a marker of left atrial abnormality, was strongly associated with incident stroke in hypertensive patients, independent of in-treatment SBP and other predictors of incident stroke. This association, in the absence of detectable atrial fibrillation, suggests that an underlying atrial cardiopathy may cause left atrial thrombus formation and a subsequent stroke without intervening clinically recognized atrial fibrillation.

Atrial cardiopathy: a mechanism of cryptogenic stroke

INTRODUCTION

Cryptogenic stroke accounts for approximately 30% of all ischemic strokes. Recently, atrial cardiopathy diagnosed by the presence of one of its serum, imaging, or electrocardiogram biomarkers has been shown to be associated with ischemic stroke, particularly of embolic subtypes. Areas covered: This paper aims to summarize data on occult atrial fibrillation and stroke, provide an overview on mechanisms, such as inflammation and fibrosis, of stroke in atrial cardiopathy, critically review data on biomarkers of atrial cardiopathy and their association with stroke, and suggest therapeutic implications, including directions for future research. Expert commentary: Atrial cardiopathy may constitute one of the mechanisms in cryptogenic stroke, and patients with evidence of atrial cardiopathy constitute a group of patients in whom clinical trials are warranted to test anticoagulation versus antiplatelet therapy to reduce stroke recurrence risk. In addition, more studies are needed to determine the degree of overlap between these atrial cardiopathy biomarkers and which one is more useful in predicting the risk of stroke and response to anticoagulation therapy.

P-Wave Terminal Force in Lead V1 Predicts Paroxysmal Atrial Fibrillation in Acute Ischemic Stroke

BACKGROUND

Detection of paroxysmal atrial fibrillation (PAF) in cryptogenic stroke is critical to selecting an antithrombotic therapy for preventing recurrent stroke. However, the predictor of PAF in patients with acute ischemic stroke is not well elucidated. P-wave terminal force in lead V₁ (PTFV₁) is a standard electrocardiogram marker of left atrial abnormality. In this study, we aimed to investigate the utility of PTFV₁ for the prediction of PAF in patients with acute ischemic stroke.

METHODS

The study included 295 consecutive patients who had acute ischemic stroke and were admitted to the hospital between September 2014 and August 2016. Patients with a known history of PAF, persistent atrial fibrillation, or cardiac pacemaker were excluded from the study. The clinical characteristics of patients with or without PAF were compared, and multiple logistic regression analysis was performed to assess the independent contribution of each variable.

RESULTS

Among 226 patients eligible for our analysis, 16 (7.1%) were diagnosed with PAF after admission. PTFV₁ was significantly higher in patients with PAF than those without PAF (.051 versus .027 mm⋅s; P < .001). Multivariate analysis showed that PTFV₁ per .01 mm⋅s increase was strongly associated with PAF (odds ratio, 1.61; 95% confidence interval, 1.24-2.09; P < .001). The optimal cutoff value of PTFV₁ for the prediction of PAF was .04 mm⋅s.

CONCLUSIONS

PTFV₁ is a strong predictor of PAF detection in acute ischemic stroke.

P-Wave Indices and Risk of Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Atrial cardiomyopathy is associated with an increased risk of ischemic stroke. P-wave terminal force in lead V₁, P-wave duration, and maximum P-wave area are electrocardiographic parameters that have been used to assess left atrial abnormalities related to developing atrial fibrillation. The aim of this systematic review and meta-analysis was to examine their values for predicting ischemic stroke risk.

METHODS

PubMed and EMBASE databases were searched until December 2016 for studies that evaluated the association between P-wave indices and stroke risk. Both fixed- and random-effects models were used to calculate the overall effect estimates.

RESULTS

Ten studies examining P-wave terminal force in lead V₁, P-wave duration, and maximum P-wave area were included. P-wave terminal force in lead V₁ was found to be an independent predictor of stroke as both a continuous variable (odds ratio [OR] per 1 SD change, 1.18; 95% confidence interval [CI], 1.12-1.25; P<0.0001) and categorical variable (OR, 1.59; 95% CI, 1.10-2.28; P=0.01). P-wave duration was a significant predictor of incident ischemic stroke when analyzed as a categorical variable (OR, 1.86; 95% CI, 1.37-2.52; P<0.0001) but not when analyzed as a continuous variable (OR, 1.05; 95% CI, 0.98-1.13; P=0.15). Maximum P-wave area also predicted the risk of incident ischemic stroke (OR per 1 SD change, 1.10; 95% CI, 1.04-1.17).

CONCLUSIONS

P-wave terminal force in lead V₁, P-wave duration, and maximum P-wave area are useful electrocardiographic markers that can be used to stratify the risk of incident ischemic stroke.

Cardioembolic Stroke

Cardiac embolism accounts for an increasing proportion of ischemic strokes and might multiply several-fold during the next decades. However, research points to several potential strategies to stem this expected rise in cardioembolic stroke. First, although one-third of strokes are of unclear cause, it is increasingly accepted that many of these cryptogenic strokes arise from a distant embolism rather than in situ cerebrovascular disease, leading to the recent formulation of embolic stroke of undetermined source as a distinct target for investigation. Second, recent clinical trials have indicated that embolic stroke of undetermined source may often stem from subclinical atrial fibrillation, which can be diagnosed with prolonged heart rhythm monitoring. Third, emerging evidence indicates that a thrombogenic atrial substrate can lead to atrial thromboembolism even in the absence of atrial fibrillation. Such an atrial cardiomyopathy may explain many cases of embolic stroke of undetermined source, and oral anticoagulant drugs may prove to reduce stroke risk from atrial cardiomyopathy given its parallels to atrial fibrillation. Non-vitamin K antagonist oral anticoagulant drugs have recently expanded therapeutic options for preventing cardioembolic stroke and are currently being tested for stroke prevention in patients with embolic stroke of undetermined source, including specifically those with atrial cardiomyopathy. Fourth, increasing appreciation of thrombogenic atrial substrate and the common coexistence of cardiac and extracardiac stroke risk factors suggest benefits from global vascular risk factor management in addition to anticoagulation. Finally, improved imaging of ventricular thrombus plus the availability of non-vitamin K antagonist oral anticoagulant drugs may lead to better prevention of stroke from acute myocardial infarction and heart failure.