Intensive heart rhythm monitoring to decrease ischemic stroke and systemic embolism-the Find-AF 2 study-rationale and design

Anticoagulation in patients with low-burden atrial fibrillation: new evidence focussing on device-detected AF

Stroke, one of the most severe complications of atrial fibrillation (AF), can be prevented by oral anticoagulants in patients with ECG-documented AF and clinical stroke risk factors. Recent controlled trials suggest that reducing the burden of AF, that is, the time spent in AF, can reduce the risk of stroke. Furthermore, stroke rate was slightly lower than anticipated in controlled trials of anticoagulation in screening-detected AF, and substantially lower than expected in patients with device-detected atrial fibrillation (DDAF) and after AF ablation. These data suggest that AF burden modulates the risk of stroke in patients with AF. Based on their high AF burden in observational datasets, anticoagulation remains the default therapy in patients with ECG-documented AF. However, AF burden reduction using rhythm-control therapies emerges as a new treatment strategy for stroke prevention, and there may be a group of patients with such a low burden of AF, for example, patients with DDAF, that the risks of current anticoagulation therapies outweigh their stroke-preventing effects. Patients with DDAF in the absence of ECG-documented AF and without vascular disease appear to be at low risk of thromboembolic events. In patients with DDAF, shared decision-making that considers the presence of vascular disease, potentially the burden of AF if it is very high, and patient preferences currently emerges as good clinical care. More data are needed to robustly define the complex relations between AF burden, phenotypes and stroke risk.

Low blood flow velocity in the left atrial appendage in sinus rhythm as a predictor of atrial fibrillation: results of a prospective cohort study with 3 years of follow-up

BACKGROUND

Atrial fibrillation (AF) is a common cause of cardioembolic stroke and can lead to severe and recurrent cerebrovascular events. Thus, identifying patients suffering from cardioembolic events caused by undetected AF is crucial. Previously, we found an association between increasing stroke severity and a decreasing left atrial appendage (LAA) blood flow velocity below 60 cm/s.

METHODS

This was a prospective single-center cohort study including hospitalized patients who underwent a transesophageal echocardiography (TEE) in sinus rhythm. The participants were divided into two groups (≥ 60 cm/s;<60 cm/s) based on their maximum LAA blood flow velocity. The results of the cardiovascular risk assessment and 24- to 72-hour ECG Holter were recorded. Follow-up appointments were scheduled at 3, 6, 12, 24 and 36 months. The primary endpoint was new-onset AF. The statistics included a Cox-proportional-hazard-model and a binary logistic regression. Numerical data or categorical data were analyzed with the Mann-Whitney U test or chi-square test.

RESULTS

A total of 166 patients were recruited. The median LAA blood flow velocity was 64 cm/s. New-onset AF was diagnosed in 22.9% of the patients. An LAA blood flow velocity ≤ 60 cm/s was associated with a threefold increased risk of new-onset AF (35.8% vs. 11.5%; HR3.56; CI95%1.70-7.46; p < 0.001), independently according to a multivariate analysis (p = 0.035). Furthermore, a decreasing LAA blood flow velocity was associated with an increased risk of new-onset AF (OR1.043; CI95%1.021-1.069; p < 0.001).

CONCLUSION

A low LAA blood flow velocity (≤ 60 cm/s) in sinus rhythm is prospectively associated with an increased risk of new-onset AF. Additional simple LAA-TEE examinations could help to identify patients who benefit from more accurate cardiac rhythm monitoring.

Factors associated with the detection of atrial fibrillation in patients with embolic stroke of undetermined source

BACKGROUND

Detection of atrial fibrillation (AF) in patients with embolic stroke of undetermined source (ESUS) is important for the secondary prevention of stroke. We investigated the factors associated with the detection of newly diagnosed AF in ESUS patients during follow-up.

METHODS

Patients with acute ischemic stroke classified as ESUS were included. All patients underwent transthoracic echocardiography and Holter to detect the source of embolism. Structural, electrophysiological markers of left atrial cardiopathy (i.e., left atrial enlargement [LAE], non-sustained tachycardia [NSAT]) as well as lesion patterns of ischemic stroke were examined. Implantable loop recorder (ILR) was implanted in selective patients. Sensitivity and positive predictive value analysis was used to assess the predictive value for AF detection.

RESULTS

Among 312 patients with ESUS, AF was detected in 24 (7.7%) patients during follow-up. Patients with AF had a higher prevalence of LAE, NSAT, and the imaging pattern of confluent plus additional lesions in a single vascular territory. Multivariable analysis showed that ILR implantation (hazards ratio 11.497 [95% confidence interval 3.795-34.818]), LAE (3.204 [1.096-9.370]), NSAT (4.070 [1.378-12.018]), and confluent plus additional lesions (4.977 [1.649-15.019]) were independent predictors of AF detection. The sensitivity of detecting AF in those with LAE, NSAT, or confluent plus additional lesions pattern was 91.7%. The positive predictive value of detecting AF in those with LAE, NSAT and confluent plus additional lesions pattern was 40.0%.

CONCLUSION

In conclusion, patients with LAE, NSAT, or confluent plus additional lesions may benefit from ILR monitoring detecting new AF.

Symmetric Dimethylarginine Predicts Previously Undetected Atrial Fibrillation in Patients With Ischemic Stroke

BACKGROUND

Atrial fibrillation (AF) is a stroke risk factor that often remains undetected at hospital admission. Long-term Holter monitoring helps to identify patients with previously unrecognized AF. Asymmetric (ADMA) and symmetric dimethylarginine (SDMA) are elevated in AF in cross-sectional studies. We analyzed ADMA, SDMA, and other L-arginine metabolites to assess their association with AF in the Find-AF trial.

METHODS AND RESULTS

We included 280 patients presenting with acute cerebral ischemia. Patients presenting in sinus rhythm received 7-day Holter-ECG. Biomarkers were quantified by ultra-performance liquid chromatography-tandem mass spectrometry. We also analyzed protein methylation and L-arginine-related metabolites in human induced pluripotent stem cell-derived cardiomyocytes in vitro. ADMA and SDMA were elevated in 44 patients who presented with AF. SDMA, but not ADMA, was significantly elevated in patients newly diagnosed with AF in Holter-ECG as compared with those in sinus rhythm. SDMA plasma concentration >0.571 μmol/L significantly predicted presence of AF in Holter-ECG (area under the curve=0.676 [0.530-0.822]; P=0.029; sensitivity 0.786, specificity 0.572). SDMA levels further increased in patients with AF during the first 24 hours in hospital, and ADMA levels remained stable. In vitro, induced pluripotent stem cell-derived cardiomyocytes showed increased symmetric protein methylation and elevated SDMA during rapid pacing (2.0 Hz versus 0.5 Hz), whereas asymmetric protein methylation and ADMA were unchanged.

CONCLUSIONS

SDMA at admission was significantly elevated in stroke patients presenting with AF and showed a moderate but significant prospective association with previously unrecognized AF. Thus, stroke patients with elevated SDMA concentration at admission may specifically benefit from extended Holter-ECG monitoring.

Anticoagulation in Patients With Device-Detected Atrial Fibrillation With and Without a Prior Stroke or Transient Ischemic Attack: The NOAH-AFNET 6 Trial

BACKGROUND

Short and rare episodes of atrial fibrillation (AF) are commonly detected using implanted devices (device-detected AF) in patients with prior stroke or transient ischemic attack (TIA). The effectiveness and safety of oral anticoagulation in patients with prior stroke or TIA and device-detected AF but with no ECG-documented AF is unclear.

METHODS AND RESULTS

This prespecified analysis of the NOAH-AFNET 6 (Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial High Rate Episodes) trial with post hoc elements assessed the effect of oral anticoagulation in patients with device-detected AF with and without a prior stroke or TIA in the randomized, double-blind, double-dummy NOAH-AFNET 6 trial. Outcomes were stroke, systemic embolism, and cardiovascular death (primary outcome) and major bleeding and death (safety outcome). A prior stroke or TIA was found in 253 patients with device-detected AF randomized in the NOAH-AFNET 6 (mean age, 78 years; 36.4% women). There was no treatment interaction with prior stroke or TIA for any of the primary and secondary time-to-event outcomes. In patients with a prior stroke or TIA, 14 out of 122 patients experienced a primary outcome event with anticoagulation (5.7% per patient-year). Without anticoagulation, there were 16 out of 131 patients with an event (6.3% per patient-year). The rate of stroke was lower than expected (anticoagulation: 4 out of 122 [1.6% per patient-year]; no anticoagulation: 6 out of 131 [2.3% per patient-year]). Numerically, there were more major bleeding events with anticoagulation in patients with prior stroke or TIA (8 out of 122 patients) than without anticoagulation (2 out of 131 patients).

CONCLUSIONS

Anticoagulation appears to have ambiguous effects in patients with device-detected AF and a prior stroke or TIA in this hypothesis-generating analysis of the NOAH-AFNET 6 in the absence of ECG-documented AF, partially due to a low rate of stroke without anticoagulation.

Atrial fibrillation burden: a new outcome predictor and therapeutic target

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is not a dichotomous disease trait. Technological innovations enable long-term rhythm monitoring in many patients and can estimate AF burden. These technologies are already used to detect and monitor AF. This review describes the relation between AF burden and outcomes and potential effects of AF burden reduction. A lower AF burden is associated with a lower risk of stroke and heart failure in patients with AF: stroke risk without anticoagulation is lower in patients with device-detected AF and a low AF burden (stroke rate 1%/year) than in patients with persistent and permanent AF (stroke rate 3%/year). Paroxysmal AF shows intermediate stroke rates (2%/year). Atrial fibrillation burden-reducing interventions can reduce cardiovascular outcomes in patients with AF: early rhythm control reduces cardiovascular events including stroke and heart failure in patients with recently diagnosed AF and cardiovascular conditions. In patients with heart failure and AF, early rhythm control and AF ablation, interventions that reduce AF burden, reduce mortality and heart failure events. Recent technological innovations allow to estimate AF burden in clinical care, creating opportunities and challenges. While evidence remains limited, the existing data already suggest that AF burden reduction could be a therapeutic goal. In addition to anticoagulation and treatment of cardiovascular conditions, AF burden reduction emerges as a therapeutic goal. Future research will define the AF burden that constitutes a relevant risk of stroke and heart failure. Technologies quantifying AF burden need careful validation to advance the field.

Impact of Helicobacter pylori and metabolic syndrome on mast cell activation-related pathophysiology and neurodegeneration

Both Helicobacter pylori (H. pylori) infection and metabolic syndrome (MetS) are highly prevalent worldwide. The emergence of relevant research suggesting a pathogenic linkage between H. pylori infection and MetS-related cardio-cerebrovascular diseases and neurodegenerative disorders, particularly through mechanisms involving brain pericyte deficiency, hyperhomocysteinemia, hyperfibrinogenemia, elevated lipoprotein-a, galectin-3 overexpression, atrial fibrillation, and gut dysbiosis, has raised stimulating questions regarding their pathophysiology and its translational implications for clinicians. An additional stimulating aspect refers to H. pylori and MetS-related activation of innate immune cells, mast cells (MC), which is an important, often early, event in systemic inflammatory pathologies and related brain disorders. Synoptically, MC degranulation may play a role in the pathogenesis of H. pylori and MetS-related obesity, adipokine effects, dyslipidemia, diabetes mellitus, insulin resistance, arterial hypertension, vascular dysfunction and arterial stiffness, an early indicator of atherosclerosis associated with cardio-cerebrovascular and neurodegenerative disorders. Meningeal MC can be activated by triggers including stress and toxins resulting in vascular changes and neurodegeneration. Likewise, H.pylori and MetS-related MC activation is linked with: (a) vasculitis and thromboembolic events that increase the risk of cardio-cerebrovascular and neurodegenerative disorders, and (b) gut dysbiosis-associated neurodegeneration, whereas modulation of gut microbiota and MC activation may promote neuroprotection. This narrative review investigates the intricate relationship between H. pylori infection, MetS, MC activation, and their collective impact on pathophysiological processes linked to neurodegeneration. Through a comprehensive search of current literature, we elucidate the mechanisms through which H. pylori and MetS contribute to MC activation, subsequently triggering cascades of inflammatory responses. This highlights the role of MC as key mediators in the pathogenesis of cardio-cerebrovascular and neurodegenerative disorders, emphasizing their involvement in neuroinflammation, vascular dysfunction and, ultimately, neuronal damage. Although further research is warranted, we provide a novel perspective on the pathophysiology and management of brain disorders by exploring potential therapeutic strategies targeting H. pylori eradication, MetS management, and modulation of MC to mitigate neurodegeneration risk while promoting neuroprotection.

The Role of Helicobacter pylori and Metabolic Syndrome-Related Mast Cell Activation Pathologies and Their Potential Impact on Pregnancy and Neonatal Outcomes

Helicobacter pylori infection, a significant global burden beyond the gastrointestinal tract, has long been implicated in various systemic pathologies. Rising evidence suggests that the bacterium's intricate relationship with the immune system and its potential to induce chronic inflammation impact diverse pathophysiological processes in pregnant women that may in turn affect the incidence of several adverse pregnancy and neonate outcomes. Helicobacter pylori infection, which has been linked to metabolic syndrome and other disorders by provoking pericyte dysfunction, hyperhomocysteinemia, galectin-3, atrial fibrillation, gut dysbiosis, and mast cell activation pathologies, may also contribute to adverse pregnancy and neonatal outcomes. Together with increasing our biological understanding of the individual and collective involvement of Helicobacter pylori infection-related metabolic syndrome and concurrent activation of mast cells in maternal, fetus, and neonatal health outcomes, the present narrative review may foster related research endeavors to offer novel therapeutic approaches and informed clinical practice interventions to mitigate relevant risks of this critical topic among pregnant women and their offspring.

Age-Dependent Detection of Atrial Fibrillation with Implantable Cardiac Monitors in Patients with Cryptogenic Stroke

Background  Continuous monitoring using implantable cardiac monitors (ICMs) results in atrial fibrillation (AF) detection rates of up to 30% in patients with cryptogenic stroke (CS). Although higher age is an independent risk factor for AF, there are no age-specific recommendations for the implantation of ICM. Objective  The aim of this study was to analyze age-related AF rates in patients with CS and continuous rhythm monitoring, to determine the rates of oral anticoagulation (OAC) and recurrent cerebrovascular events (stroke or transient ischemic attack) in patients with ICM-detected AF, and to describe the temporal relationship of AF detection and recurrent cerebrovascular events. Methods  In this observational study, patients with CS provided with ICMs were systematically followed. All patients underwent 72-hour electrocardiography monitoring, transcranial Doppler ultrasound, and transthoracic echocardiography prior to ICM insertion. Follow-up included a regular outpatient presentation every 3 months with medical history, physical examination, and interrogation of the ICM. Results  One-hundred eighty-six patients (mean age: 65 ± 12 years, 54% female) were included in this analysis. AF was detected in 6, 27, 56, and 65% ( p  < 0.001) of patients aged less than 60, 60 to 69, 70 to 79, and more than or equal to 80 years, respectively. All patients with AF under 60 years had an impaired left ventricular systolic function. OAC was initiated in 85% of the patients with AF. Recurrent cerebrovascular events occurred in 34 patients of whom 14 had a diagnosis of AF. In nine patients, AF was diagnosed before the occurrence of a recurrent cerebrovascular event. Conclusion  AF prevalence increased with age and was absent in CS patients younger than 60 years and with preserved left ventricular ejection fraction. The temporal relationship of AF and recurrent cerebrovascular events was weak.

Towards a new classification of atrial fibrillation detected after a stroke or a transient ischaemic attack

Globally, up to 1·5 million individuals with ischaemic stroke or transient ischaemic attack can be newly diagnosed with atrial fibrillation per year. In the past decade, evidence has accumulated supporting the notion that atrial fibrillation first detected after a stroke or transient ischaemic attack differs from atrial fibrillation known before the occurrence of as stroke. Atrial fibrillation detected after stroke is associated with a lower prevalence of risk factors, cardiovascular comorbidities, and atrial cardiomyopathy than atrial fibrillation known before stroke occurrence. These differences might explain why it is associated with a lower risk of recurrence of ischaemic stroke than known atrial fibrillation. Patients with ischaemic stroke or transient ischaemic attack can be classified in three categories: no atrial fibrillation, known atrial fibrillation before stroke occurrence, and atrial fibrillation detected after stroke. This classification could harmonise future research in the field and help to understand the role of prolonged cardiac monitoring for secondary stroke prevention with application of a personalised risk-based approach to the selection of patients for anticoagulation.