Atrial high rate episodes detected by pacemaker diagnostics predict death and stroke: report of the Atrial Diagnostics Ancillary Study of the MOde Selection Trial (MOST)

Association of Burden of Atrial Fibrillation With Risk of Ischemic Stroke in Adults With Paroxysmal Atrial Fibrillation: The KP-RHYTHM Study

Importance

Atrial fibrillation is a potent risk factor for stroke, but whether the burden of atrial fibrillation in patients with paroxysmal atrial fibrillation independently influences the risk of thromboembolism remains controversial.

Objective

To determine if the burden of atrial fibrillation characterized using noninvasive, continuous ambulatory monitoring is associated with the risk of ischemic stroke or arterial thromboembolism in adults with paroxysmal atrial fibrillation.

Design, Setting, and Participants

This retrospective cohort study conducted from October 2011 and October 2016 at 2 large integrated health care delivery systems used an extended continuous cardiac monitoring system to identify adults who were found to have paroxysmal atrial fibrillation on 14-day continuous ambulatory electrocardiographic monitoring.

Exposures

The burden of atrial fibrillation was defined as the percentage of analyzable wear time in atrial fibrillation or flutter during the up to 14-day monitoring period.

Main Outcomes and Measures

Ischemic stroke and other arterial thromboembolic events occurring while patients were not taking anticoagulation were identified through November 2016 using electronic medical records and were validated by manual review. We evaluated the association of the burden of atrial fibrillation with thromboembolism while not taking anticoagulation after adjusting for the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) or CHA2DS2-VASc stroke risk scores.

Results

Among 1965 adults with paroxysmal atrial fibrillation, the mean (SD) age was 69 (11.8) years, 880 (45%) were women, 496 (25%) were persons of color, the median ATRIA stroke risk score was 4 (interquartile range [IQR], 2-7), and the median CHA2DS2-VASc score was 3 (IQR, 1-4). The median burden of atrial fibrillation was 4.4% (IQR ,1.1%-17.23%). Patients with a higher burden of atrial fibrillation were less likely to be women or of Hispanic ethnicity, but had more prior cardioversion attempts compared with those who had a lower burden. After adjusting for either ATRIA or CHA2DS2-VASc stroke risk scores, the highest tertile of atrial fibrillation burden (≥11.4%) was associated with a more than 3-fold higher adjusted rate of thromboembolism while not taking anticoagulants (adjusted hazard ratios, 3.13 [95% CI, 1.50-6.56] and 3.16 [95% CI, 1.51-6.62], respectively) compared with the combined lower 2 tertiles of atrial fibrillation burden. Results were consistent across demographic and clinical subgroups.

Conclusions and Relevance

A greater burden of atrial fibrillation is associated with a higher risk of ischemic stroke independent of known stroke risk factors in adults with paroxysmal atrial fibrillation.

Subclinical Atrial Fibrillation and Risk of Stroke: Past, Present and Future

Subclinical atrial fibrillation (SCAF) describes asymptomatic episodes of atrial fibrillation (AF) that are detected by cardiac implantable electronic devices (CIED). The increased utilization of CIEDs renders our understanding of SCAF important to clinical practice. Furthermore, 20% of AF present initially as a stroke event and prolonged cardiac monitoring of stroke patients is likely to uncover a significant prevalence of SCAF. New evidence has shown that implanting cardiac monitors into patients with no history of atrial fibrillation but with risk factors for stroke will yield an incidence of SCAF approaching 30–40% at around three years. Atrial high rate episodes lasting longer than five minutes are likely to represent SCAF. SCAF has been associated with an increased risk of stroke that is particularly significant when episodes of SCAF are greater than 23 h in duration. Longer episodes of SCAF are incrementally more likely to progress to episodes of SCAF >23 h as time progresses. While only around 30–40% of SCAF events are temporally related to stroke events, the presence of SCAF likely represents an important risk marker for stroke. Ongoing trials of anticoagulation in patients with SCAF durations less than 24 h will inform clinical practice and are highly anticipated. Further studies are needed to clarify the association between SCAF and clinical outcomes as well as the factors that modify this association.

Ultra-early continuous cardiac monitoring improves atrial fibrillation detection and prognosis of patients with cryptogenic stroke

BACKGROUND AND PURPOSE

Subclinical atrial fibrillation (AF) is known to underlie a number of cases of cryptogenic stroke (CrS). However, there is need to define the most effective strategy for AF detection. The diagnostic usefulness was analysed of a strategy based on ultra-early continuous monitoring in patients with CrS in terms of AF detection, oral anticoagulation treatment and stroke recurrence, in comparison to a standard outpatient strategy.

METHODS

Patients with ischaemic stroke of undetermined origin and confirmed to be cryptogenic after extensive work-up were searched for AF with (i) a conventional strategy (historical cohort, n = 101) with serial electrocardiograms and 24-h Holter monitoring or (ii) an ultra-early monitoring strategy with insertable cardiac monitor (ICM) implanted before discharge (prospective cohort, n = 90). AF episodes lasting >1 min, anticoagulant treatment and stroke recurrence were recorded.

RESULTS

During admission, AF was similarly detected in both cohorts (24% of patients). After discharge (mean follow-up 30 ± 10 months), AF detection rates were 17/80 (21.3%) and 38/65 (58.5%) for patients in the conventional versus the ultra-early ICM group (P < 0.001). Up to 41% of AF cases in the ICM cohort were detected within the first month. Oral anticoagulation was initiated in 37.6% versus 65.5% (P < 0.001) and stroke recurrence was recorded in 10.9% versus 3.3% (P 0.04) in the conventional versus the ICM cohort.

CONCLUSIONS

Pre-discharge ICM implant allows detection of AF during follow-up in up to 58% of selected patients with CrS. Compared to a conventional strategy, ultra-early ICM implant results in higher anticoagulation rates and a decrease in stroke recurrence.

Are atrial high rate episodes (AHREs) a precursor to atrial fibrillation?

Abstract

Atrial high rate episodes (AHREs), also termed, subclinical atrial tachyarrhythmias or subclinical atrial fibrillation (AF) are an important cardiovascular condition. Advancement in implantable cardiac devices such as pacemakers or internal cardiac defibrillators has enabled the continuous assessment of atrial tachyarrhythmias in patients with an atrial lead. Patients with device-detected AHREs are at an elevated risk of stroke and may have unmet anticoagulation needs. While the benefits of oral anticoagulation for stroke prevention in patients with clinical AF are well recognised, it is not known whether the same risk–benefit ratio exists for anticoagulation therapy in patients with AHREs. The occurrence and significance of AHRE are increasingly acknowledged but these events are still not often acted upon in patients presenting with stroke and TIA. Additionally, patients with AHRE show a significant risk for major adverse cardiovascular events (MACE) including acute heart failure, myocardial infarction, cardiovascular hospitalisation, ventricular tachycardia/fibrillation, which is dependent on AHRE burden. In this review, we present an overview of this relatively new entity, its associated thromboembolic risk and its management implications.

Graphic abstract

Subclinical and Asymptomatic Atrial Fibrillation: Current Evidence and Unsolved Questions in Clinical Practice

Atrial Fibrillation (AF) may be diagnosed due to symptoms, or it may be found as an incidental electrocardiogram (ECG) finding, or by implanted devices recordings in asymptomatic patients. While anticoagulation, according to individual risk profile, has proven definitely beneficial in terms of prognosis, rhythm control strategies only demonstrated consistent benefits in terms of quality of life. In fact, evidence collected by observational data showed significant benefits in terms of mortality, stroke incidence, and prevention of cognitive impairment for patients referred to AF catheter ablation compared to those medically treated, however randomized trials failed to confirm such results. The aims of this review are to summarize current evidence regarding the treatment specifically of subclinical and asymptomatic AF, to discuss potential benefits of rhythm control therapy, and to highlight unclear areas.

Subclinical atrial fibrillation detection with a floating atrial sensing dipole in single lead implantable cardioverter-defibrillator systems: Results of the SENSE trial

INTRODUCTION

Subclinical atrial fibrillation (AF), in the form of cardiac implantable device-detected atrial high rate episodes (AHREs), has been associated with increased thromboembolism. An implantable cardioverter-defibrillator (ICD) lead with a floating atrial dipole may permit a single lead (DX) ICD system to detect AHREs. We sought to assess the utility of the DX ICD system for subclinical AF detection in patients, with a prospective multicenter, cohort-controlled trial.

METHODS AND RESULTS

One hundred fifty patients without prior history of AF (age 59 ± 13 years; 108 [72%] male) were enrolled into the DX cohort and implanted with a Biotronik DX ICD system at eight centers. Age-, sex-, and left ventricular ejection fraction-matched single- and dual-chamber ICD cohorts were derived from a Cornell database and from the IMPACT trial, respectively. The primary endpoint were AHRE detection at 12 months. During median 12 months follow-up, AHREs were detected in 19 (13%) patients in the DX, 8 (5.3%) in the single-chamber, and 19 (13%) in the dual-chamber cohorts. The rate of AHRE detection was significantly higher in the DX cohort compared to the single-chamber cohort (P = .026), but not significantly different compared to the dual-chamber cohort. There were no inappropriate ICD therapies in the DX cohort. At 12 months, only 3.0% of patients in the DX cohort had sensed atrial amplitudes less than 1.0 mV.

CONCLUSION

Use of a DX ICD lead allows subclinical AF detection with a single lead DX system that is superior to that of a conventional single-chamber ICD system.

Pacemaker-detected atrial fibrillation burden and risk of ischemic stroke or thromboembolic events-A cohort study

BACKGROUND

Atrial fibrillation (AF) burden might link to increased risk of systemic embolism. Current scoring systems for evaluating stroke risks such as CHA₂DS₂-VASc do not incorporate AF burden partly because of the difficulty to assess these data. Patients with dual-chamber pacemakers implanted have opportunities to acquire incidence and duration of AF.

OBJECTIVES

We aimed to evaluate the AF burden and its association with thromboembolism in patients with dual-chamber pacemakers.

METHODS

This retrospective cohort study enrolled patients who underwent dual-chamber pacemaker implantation at our center between October 2003 and May 2017. We excluded patients with prior thromboembolism or receiving anticoagulants. The incidence and duration of pacemaker-detected AF were compared between patients with and without thromboembolic outcomes. Propensity score matching (1:1) was conducted based on clinical characteristics. Multivariate regressions were performed to determine the predictors of thromboembolic outcomes. Survival free from stroke and thromboembolism was assessed using Kaplan-Meier analysis in groups with different AF burden.

RESULTS

Among the 152 patients enrolled (43.4% women; age 73.2 ± 13.3 years), ten experienced thromboembolic events within a median follow-up of 67 months. Patients with thromboembolisms had higher CHA₂DS₂-VASc scores but not higher AF burden. Higher CHA₂DS₂-VASc score was associated with increased risk for systemic thromboembolism [hazard ratio (HR), 1.87; 95% confidence interval (CI), 1.07-3.24; P = 0.027). In the propensity score-matched cohort with comparable CHA₂DS₂-VASc score, patients with thromboembolism had higher AF burden. Pacemaker-detected AF was associated with increased risk for thromboembolism (propensity-adjusted HR, 9.33; 95% CI, 1.19-72.99; P = 0.033). Experiencing AF episodes lasting >6 min was a predictor of significantly higher risk of future stroke or thromboembolism (propensity-adjusted HR, 6.75; 95% CI, 1.30-35.11; P = 0.023).

CONCLUSION

In patients with dual-chamber pacemakers and comparable CHA₂DS₂-VASc score, pacemaker-detected AF burden is associated with elevated risk for thromboembolism. Further research is needed to clarify how pacemaker-detected AF burden could incorporate with CHA₂DS₂-VASc score variables and help to guide anticoagulation.

Thromboembolism in the Absence of Atrial Fibrillation

Atrial fibrillation (AF) is associated with thrombus formation in the left atrial appendage and systemic embolic events including ischemic stroke. Cardiogenic thromboembolism can also occur in the absence of clinical AF as a result of various pathological conditions affecting the endocardium. The inconsistent temporal relation between AF and ischemic events has stimulated exploration for factors other than clinical AF that contribute to thromboembolism. These include subclinical AF, a thrombogenic atrial cardiomyopathy, and left atrial appendage dysfunction and embolism from other sources. In conclusion, thromboembolism during normal sinus rhythm is likely multifactorial, involving intertwined pathologic processes. Patients at risk, if accurately identified, could theoretically benefit from anticoagulation.

Incidence of Previously Undiagnosed Atrial Fibrillation Using Insertable Cardiac Monitors in a High-Risk Population: The REVEAL AF Study

Importance

In approximately 20% of atrial fibrillation (AF)-related ischemic strokes, stroke is the first clinical manifestation of AF. Strategies are needed to identify and therapeutically address previously undetected AF.

Objective

To quantify the incidence of AF in patients at high risk for but without previously known AF using an insertable cardiac monitor.

Design, Setting, and Participants

This prospective, single-arm, multicenter study was conducted from November 2012 to January 2017. Visits took place at 57 centers in the United States and Europe. Patients with a CHADS2 score of 3 or greater (or 2 with at least 1 additional risk factor) were enrolled. Approximately 90% had nonspecific symptoms potentially compatible with AF, such as fatigue, dyspnea, and/or palpitations.

Exposures

Patients underwent monitoring with an insertable cardiac monitor for 18 to 30 months.

Main Outcomes and Measures

The primary end point was adjudicated AF lasting 6 or more minutes and was assessed at 18 months. Other analyses included detection rates at points from 30 days to 30 months and among CHADS2 score subgroups. Median time from insertion to detection and the percentage of patients subsequently prescribed oral anticoagulation therapy was also determined.

Results

A total of 446 patients were enrolled; 233 (52.2%) were male, and the mean (SD) age was 71.5 (9.9) years. A total of 385 patients (86.3%) received an insertable cardiac monitor, met the primary analysis cohort definition, and were observed for a mean (SD) period of 22.5 (7.7) months. The detection rate of AF lasting 6 or more minutes at 18 months was 29.3%. Detection rates at 30 days and 6, 12, 24, and 30 months were 6.2%, 20.4%, 27.1%, 33.6%, and 40.0%, respectively. At 18 months, AF incidence was similar among patients with CHADS2 scores of 2 (24.7%; 95% CI, 17.3-31.4), 3 (32.7%; 95% CI, 23.8-40.7), and 4 or greater (31.7%; 95% CI, 22.0-40.3) (P = .23). Median (interquartile) time from device insertion to first AF episode detection was 123 (41-330) days. Of patients meeting the primary end point, 13 (10.2%) had 1 or more episodes lasting 24 hours or longer, and oral anticoagulation therapy was prescribed for 72 patients (56.3%).

Conclusions and Relevance

The incidence of previously undiagnosed AF may be substantial in patients with risk factors for AF and stroke. Atrial fibrillation would have gone undetected in most patients had monitoring been limited to 30 days. Further trials regarding the value of detecting subclinical AF and of prophylactic therapies are warranted.

Trial Registration

clinicaltrials.gov Identifier: NCT01727297.

Practice Variation in Anticoagulation Prescription and Outcomes After Device-Detected Atrial Fibrillation

BACKGROUND

Device-detected atrial fibrillation (AF) is associated with increased risk of stroke; however, there are no clearly defined thresholds of AF burden at which to initiate oral anticoagulation (OAC). We sought to describe OAC prescription practice variation in response to new device-detected AF and the association with outcomes.

METHODS

We performed a retrospective cohort study using data from the Veterans Health Administration linked to remote monitoring data that included day-level AF burden. We included patients with cardiac implantable electronic devices and remote monitoring from 2011 to 2014, CHA2DS2-VASc score ≥2, and no prior stroke or OAC receipt in the preceding 2 years. We determined the proportion of patients prescribed OAC within 90 days after new device-detected AF across a range of AF thresholds (≥6 minutes to >24 hours) and examined site variation in OAC prescription. We used multivariable Cox proportional hazards regressions to determine the association of OAC prescription with stroke by device-detected AF burden.

RESULTS

Among 10 212 patients with cardiac implantable electronic devices, 4570 (45%), 3969 (39%), 3263 (32%), and 2469 (24%) had device-detected AF >6 minutes, >1 hour, >6 hours, and >24 hours, respectively. For device-detected AF >1 hour, 1712 patients met inclusion criteria (72±10 years; 1.5% female; CHA2DS2-VASc score 4.0±1.4; HAS-BLED score 2.6±1.1). The proportion receiving OAC varied based on device-detected AF burden (≥6 minutes: 272/2101 [13%]; >1 hour: 273/1712 [16%]; >6 hours: 263/1279 [21%]; >24 hours: 224/818 [27%]). Across 52 sites (N=1329 patients), there was substantial site-level variation in OAC prescription after device-detected AF >1 hour (median, 16%; range, 3%-67%; median odds ratio, 1.56 [95% credible interval, 1.49-1.71]). In adjusted models, OAC prescription after device-detected AF >24 hours was associated with reduced stroke risk (hazard ratio, 0.28; 95% CI, 0.10-0.81; P=0.02), although the propensity-adjusted model was significant when AF lasted at least 6 minutes.

CONCLUSIONS

Among veterans with cardiac implantable electronic devices, device-detected AF is common. There is large practice variation in 90-day OAC initiation after new device-detected AF, with low rates of treatment overall, even for episodes that last >24 hours. The strongest association of OAC with reduction in stroke was observed after device-detected AF >24 hours. Randomized trials are needed to confirm these observational findings.

Oral anticoagulation in patients with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 1: a current opinion of the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy and European Society of Cardiology Council on Stroke

Oral anticoagulation in patients presenting with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 1 (CHA2DS2-VASc of 2 in women) remains a challenging approach in clinical practice. Therapeutic decisions need to balance the individual benefit of reducing thromboembolic risk against the potential harm due to an increase in bleeding risk in this intermediate risk patient population. Within the current opinion statement of the European Society of Cardiology working group of cardiovascular pharmacotherapy and the European Society of Cardiology council on stroke the currently available evidence on the anti-thrombotic management in patients presenting with a CHA2DS2-VASc of 1 is summarized. Easily applicable tools for a personalized refinement of the individual thromboembolic risk in patients with atrial fibrillation and a CHA2DS2-VASc score of 1 that guide clinicians through the question whether to anticoagulate or not are provided.

Accuracy and Usability of a Novel Algorithm for Detection of Irregular Pulse Using a Smartwatch Among Older Adults: Observational Study

BACKGROUND

Atrial fibrillation (AF) is often paroxysmal and minimally symptomatic, hindering its diagnosis. Smartwatches may enhance AF care by facilitating long-term, noninvasive monitoring.

OBJECTIVE

This study aimed to examine the accuracy and usability of arrhythmia discrimination using a smartwatch.

METHODS

A total of 40 adults presenting to a cardiology clinic wore a smartwatch and Holter monitor and performed scripted movements to simulate activities of daily living (ADLs). Participants' clinical and sociodemographic characteristics were abstracted from medical records. Participants completed a questionnaire assessing different domains of the device's usability. Pulse recordings were analyzed blindly using a real-time realizable algorithm and compared with gold-standard Holter monitoring.

RESULTS

The average age of participants was 71 (SD 8) years; most participants had AF risk factors and 23% (9/39) were in AF. About half of the participants owned smartphones, but none owned smartwatches. Participants wore the smartwatch for 42 (SD 14) min while generating motion noise to simulate ADLs. The algorithm determined 53 of the 314 30-second noise-free pulse segments as consistent with AF. Compared with the gold standard, the algorithm demonstrated excellent sensitivity (98.2%), specificity (98.1%), and accuracy (98.1%) for identifying irregular pulse. Two-thirds of participants considered the smartwatch highly usable. Younger age and prior cardioversion were associated with greater overall comfort and comfort with data privacy with using a smartwatch for rhythm monitoring, respectively.

CONCLUSIONS

A real-time realizable algorithm analyzing smartwatch pulse recordings demonstrated high accuracy for identifying pulse irregularities among older participants. Despite advanced age, lack of smartwatch familiarity, and high burden of comorbidities, participants found the smartwatch to be highly acceptable.

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.

Are Older Adults Willing to Consider New Strategies to Reduce Stroke Risk?

Atrial fibrillation (AF) is a common arrhythmia that increases patients' risk of stroke, and determining an optimal prevention therapy is a preference-sensitive decision appropriate for shared decision making (SDM). Utilizing community-based focus groups, we explored beliefs and values around options for stroke prevention. Interview transcripts from five independent focus groups were qualitatively assessed and organized into themes. Most participants were taking a blood thinner (93%) and more than half of participants (64%) reported having AF. Few participants were familiar with newer therapies. Qualitative analysis revealed three themes: (a) fearing loss of self-control through debilitating stroke, (b) recognizing uncertainty in how to weigh risks and benefits of new treatments, and (c) needing mutual respect between clinicians and patients to consider new/alternative treatment regimens. These findings help direct future research efforts examining optimal timing for SDM and decision aids to promote mutual respect.

Atrial high rate episodes in patients with cardiac implantable electronic devices: implications for clinical outcomes

Background

Atrial high rate episodes (AHREs) detected by cardiac implantable electronic devices (CIEDs) are associated with an increased risk of stroke. However, the impact of AHRE on improving stroke risk stratification scheme remains uncertain.

Objective

The purpose of this study was to assess the impact of AHRE on prognosis in relation with cardiovascular events and risk stratification.

Methods

A total of 856 consecutive patients who had dual-chamber CIEDs implanted were retrospectively analyzed. To detect AHREs, they were monitored for 6 months after CIEDs’ implantation and were followed for a mean of 4.0 years for clinical outcomes such as thromboembolism or death.

Results

Overall, 125 (14.6%) of patients developed AHREs within the first 6 months (median age 72.0 years, 39.3% female). Patients with AHREs had a high rate of thromboembolism (2.6%/year) and mortality (3.0%/year). On multivariate analysis, AHRE was significantly associated with increased risk of thromboembolism [hazard ratio (HR) 3.40; 95% confidence interval (CI) 1.38–8.37, P = 0.01] and death (HR 3.47; 95% CI 1.51–7.95; P < 0.01). The predictive abilities of the CHADS₂ and CHA₂DS₂-VASc scores were modest, with no significant improvements by adding AHRE to those scores. However, the integrated discrimination improvement and net reclassification improvement showed that the addition of AHRE to the CHADS₂ and CHA₂DS₂-VASc scores statistically improved their predictive ability for the composite outcome.

Conclusions

AHRE was an independent factor associated with increased risk of clinical outcomes. The addition of AHRE to the clinical risk scores significantly improved discrimination for thromboembolism or death.

Electronic supplementary material

The online version of this article (10.1007/s00392-019-01432-y) contains supplementary material, which is available to authorized users.

Long-term rhythm monitoring with an implantable loop recorder in patients after the first clinical atrial fibrillation episode. Towards an individualized management

Although atrial fibrillation (AF) is an arrhythmia with a variable clinical profile (symptomatic and asymptomatic episodes), the first symptomatic episode leads to its initial diagnosis in most cases. Nowadays, continuous and remote long-term cardiac rhythm monitoring is feasible by the use of implantable loop recorders. The data concerning the AF recurrences and progression after the first electrocardiographic-documented clinical AF episode demonstrates that a high percentage of patients may not suffer any other AF recurrence, or may present a low recurrence rate of the arrhythmia in the future. The AF burden may play a key role in the management of the arrhythmia as far as the decision-making for anticoagulation, rate and/or rhythm control therapy is concerned. There is evidence that a higher AF burden is associated with a higher risk of ischemic stroke. Non-vitamin K antagonists (NOACs) anticoagulants are increasingly used in the management of AF, providing a more predictable effect with rapid onset and offset of their action. The use of these agents in combination with devices that provide a continuous remote rhythm monitoring capability has encouraged anticoagulation strategies based on the AF burden. Data from tailored anticoagulation studies in AF are in favor of the long-term rhythm monitoring, ensuring a patient-centered approach with a better evaluation and more individualized management of AF, especially in patients with intermediate thromboembolic risk and high bleeding risk. Further large randomized trials are needed, not only to evaluate such strategies but also to elucidate the long-term cardiac rhythm monitoring in the AF management.

Update on Bayés' syndrome: the association between an interatrial block and supraventricular arrhythmias

INTRODUCTION

The past few years have given rise to extensive research on an interatrial block and its clinical relevance, mainly its association with supraventricular arrhythmias. In 2015, the authors of this article reviewed the Bayes syndrome for the first time and after three years there has been so much evidence accumulated that it seems reasonable to rewrite an update, based fundamentally on the new findings. Focused on its relationship with cardioembolic strokes, today efforts are being targeted at understanding its pathophysiology, its diagnosis, and its prognostic implications, in order to learn if it should be treated. Areas covered: A non-systematic review of the literature was developed using the Pubmed and Cochrane databases, focusing on randomized clinical trials and large observational studies that evaluated new physiopathological and epidemiological aspects, new clinical scenarios in which it has been assessed and its association with dementia. Finally, those studies that proposed new possible treatments were reviewed. Expert commentary: Interatrial block is not only a predictor of supraventricular arrhythmias, is a subclinical disease that might be considered as a marker of risk for adverse outcomes. Although there is some evidence to suggest that early treatment may be beneficial, potential therapies have yet to be investigated.

The Relationship between Diffusion-Weighted Magnetic Resonance Imaging Lesions and 24-Hour Rhythm Holter Findings in Patients with Cryptogenic Stroke

BACKGROUND AND OBJECTIVES

Cranial magnetic resonance imaging findings of patients considered to be cryptogenic stroke may be useful in determining the clinical and prognostic significance of arrhythmias, such as atrial premature beats and atrial run attacks, that are frequently encountered in rhythm Holter analysis. This study was conducted to investigate the relationship between short atrial runs and frequent premature atrial contractions detected in Holter monitors and infarct distributions in cranial magnetic resonance imaging of patients diagnosed with cryptogenic stroke.

MATERIALS AND METHODS

We enrolled the patients with acute ischemic stroke whose etiology were undetermined. We divided the patients in two groups according to diffusion-weighted magnetic resonance imaging as single or multiple vascular territory acute infarcts. The demographic, clinical, laboratory, echocardiographic, and rhythm Holter analyses were compared.

RESULTS

The study investigated 106 patients diagnosed with cryptogenic stroke. Acute cerebral infarctions were detected in 31% of the investigated patients in multiple territories and in 69% in a single territory. In multivariate logistic regression analysis, the total premature atrial contraction count (OR = 1.002, 95% CI: 1.001⁻1.004, p = 0.001) and short atrial run count (OR = 1.086, 95% CI: 1.021⁻1.155, p = 0.008) were found as independent variables that could distinguish between infarctions in a single or in multiple vascular territories.

CONCLUSIONS

Rhythm Holter monitoring of patients with infarcts detected in multiple vascular territories showed significantly higher premature atrial contractions and short atrial run attacks. More effort should be devoted to the identification of cardioembolic etiology in cryptogenic stroke patients with concurrent acute infarcts in the multiple vascular territories of the brain.

Risk Assessment of Stroke in Patients with Atrial Fibrillation: Current Shortcomings and Future Directions

Atrial fibrillation is a well-known risk factor for cardioembolic stroke; a number of risk stratification scoring systems have been developed to help differentiate which patients would stand to benefit from anticoagulation. However, these scoring systems cannot be utilized in patients whose atrial fibrillation has not been diagnosed. As implantable cardiac monitors become more prevalent, it becomes possible to identify occult, subclinical atrial fibrillation. With this data, it is also possible to examine the relationship between episodes of paroxysmal atrial fibrillation and thromboembolism and the total burden of paroxysmal atrial fibrillation and thromboembolic risk. The data gleaned from these devices provides insight and raises questions regarding the underlying mechanism of thromboembolism in atrial fibrillation, and in doing so, exposes shortcomings in the present clinical use of current risk scoring systems, specifically, the inability to account for atrial fibrillation burden and to apply scores at all in subclinical atrial fibrillation.

Subclinical atrial fibrillation - what is the risk of stroke?

Atrial fibrillation is the most common arrhythmia and as such, it has become a significant public health issue due to its impact on patient morbidity and mortality. The prevalence of atrial fibrillation (AF) almost doubled in the last decade, being currently 2% in unselected patient populations. Its occurrence varies with age (present in almost 20% of octogenarians) and concomitant diseases. The most prevalent concomitant diseases are hypertension, diabetes, heart failure, renal failure, and cognitive decline. Cognitive decline or stroke may be actually the first manifestation of undiagnosed atrial fibrillation. In the majority of cases, atrial fibrillation is more of a syndrome than a disease in itself, with a multitude of etiologic factors and mechanisms. The risk of cardioembolic stroke increases with the number of comorbidities and age. The overall age-adjusted risk of stroke in patients with atrial fibrillation is 5 times higher than in the general population. Nowadays, the detection of asymptomatic episodes of atrial fibrillation by cardiac electronic implantable devices (CIED), referred to as device detected or subclinical atrial fibrillation, has opened new frontiers in AF management. The risk of stroke and subsequent need for anticoagulation treatment in this group of patients with device detected AF is however not clear. Here, we will review the literature to determine the association of subclinical atrial fibrillation with the risk of stroke.

Implantable Loop Recorders for Cryptogenic Stroke (Plus Real-World Atrial Fibrillation Detection Rate with Implantable Loop Recorders)

Cryptogenic stroke (CS) represents 10%-40% of ischemic strokes and is associated with significant morbidity and mortality and high risk of recurrence. Undetected atrial fibrillation is an important consideration in these patients. Tools for electrocardiographic monitoring range from 12-lead electrocardiogram to implantable loop recorders (ILRs). ILRs have become an important tool for long-term electrocardiogram monitoring in CS patients. Advancements in ILR technology are needed to ensure more robust connectivity and to help triage incoming data. An unresolved issue is what duration of AF indicates that the CS patient is at high risk for recurrent stroke and thus would benefit from initiation of anticoagulation.

Identification of paroxysmal atrial fibrillation subtypes in over 13,000 individuals

BACKGROUND

Paroxysmal atrial fibrillation (PAF) is broadly defined despite high variability in the occurrence and duration of PAF episodes.

OBJECTIVE

The purpose of this study was to identify rhythm patterns in a large cohort of individuals with PAF who wore an ambulatory single-lead electrocardiogram (ECG) patch sensor as part of standard clinical care.

METHODS

We performed a retrospective analysis of longitudinal rhythm data obtained from 13,293 individuals with PAF.

RESULTS

In this study, 7934 men and 5359 women with PAF wore an ambulatory single-lead ECG patch sensor for 11.4 days on average, experiencing 1,041,504 PAF episodes. The median daily rate of PAF was 1.21 episodes per day (interquartile range [IQR] 0.31-4.99), and the median maximum duration per individual was 7.5 hours (IQR 2.4-18.6 hours). There was an inverse relationship between the duration of PAF episodes and the frequency in which they occurred, which became pronounced at moderate and high overall burdens of AF. This produced a spectrum of PAF flanked by 2 distinct subtypes of the disease: the staccato subtype, characterized by many, short AF episodes; and the legato subtype, characterized by fewer, longer episodes. Longer but less frequent episodes became more common with increasing age. Only 49.4% of individuals experienced an episode in the first 24 hours of monitoring, increasing to 89.7% after 1 week of monitoring.

CONCLUSION

We identified subtypes of the disease that we labeled staccato and legato. Although further study is required, these subtypes may result from differing elements of pathophysiology and disease progression, and may confer differing stroke risks.

Left Atrial Appendage Occlusion in the Management of Stroke in Patients With Atrial Fibrillation

Atrial fibrillation (AF) is associated with a substantially higher risk of thromboembolism, particularly stroke events, resulting in significant morbidity and mortality. Oral anticoagulation (OAC), while effective in reducing embolic events in AF patients, is associated with an increased bleeding risk. Thus, not all patients with AF are candidates for OAC and some are only candidates for OAC in the short term. Of the available nonpharmacologic strategies for the management of AF, left atrial appendage occlusion (LAAO) has emerged as a potential approach for reducing the risk of systemic thromboembolism in AF patients eligible for OAC. LAAO can be achieved either surgically or percutaneously using an epicardial, endocardial, or a combined approach. Although available data are limited, currently available LAAO devices, and those being developed, have shown promise in reducing bleeding risk in AF patients because of the reduced overall need for anticoagulation, while maintaining efficacy in preventing thromboembolism. The optimal device will reduce both embolic and hemorrhagic strokes, and other bleeds, with a high implant success rate and a low complication rate. Until that time, anticoagulation remains the gold standard that these devices strive to surpass, and thus LAAO devices are currently indicated in patients with relative contraindication to OAC therapy.

Subclinical Atrial Fibrillation, Embolic Risk, and Anticoagulant Treatment

Professor Leonida Gherasim, MD, PhD, is a member of the Romanian Academy. We invited him to write the editorial review for this issue. The subject - how to treat the silent atrial fibrillation (that fibrillation discovered only by devices) and take the decision to anti coagulate or not - is a very important clinical judgement. Professor Gherasim was the editor of several editions of the Romanian Handbook of Internal Medicine - the Romanian equivalent of Harrison's, or Cecil and Loeb's Handbooks. He remains one of the most outstanding professors of internal medicine in Romania. In 2019, professor Leonida Gherasim will be 90 years old. Prof. Mircea Cinteza Chief Editor, MAEDICA J Clin Med.

2018 Korean Guideline of Atrial Fibrillation Management

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population. The Korean Heart Rhythm Society organized a Korean AF Management Guideline Committee and analyzed all available studies regarding the management of AF, including studies on Korean patients. This guideline is based on recent data of the Korean population and the recent guidelines of the European Society of Cardiology, European Association for Cardio-Thoracic Surgery, American Heart Association, and Asia Pacific Heart Rhythm Society. Expert consensus or guidelines for the optimal management of Korean patients with AF were achieved after a systematic review with intensive discussion. This article provides general principles for appropriate risk stratification and selection of anticoagulation therapy in Korean patients with AF. This guideline deals with optimal stroke prevention, screening, rate and rhythm control, risk factor management, and integrated management of AF.

Embolic and Other Adverse Outcomes in Symptomatic Versus Asymptomatic Patients With Atrial Fibrillation (from the ORBIT-AF Registry)

Asymptomatic atrial fibrillation (AF) is being increasingly diagnosed via implantable devices, screening, and inpatient telemetry. Management of asymptomatic AF is controversial, in part, because the associated risks have not been well described. We examined the incidence of major adverse outcomes in patients with asymptomatic versus symptomatic AF using Outcomes Registry for Better Informed Treatment of Atrial, a nationwide US registry of AF patients. We compared stroke and/or non-central nervous system (CNS) embolism, major adverse cardiovascular and neurologic events, bleeding, and death in 9,319 asymptomatic (defined by European Heart Rhythm Association score = 1 or "no symptoms") versus symptomatic patients. Overall, median (interquartile) age was 75 (67 to 82) years, 3,944 (42%) were women, and 38% versus 37% were asymptomatic based on physician versus patient-reported symptoms. Compared with those with symptoms, physician-defined asymptomatic patients were less likely to be woman (35%/47%) or be on an antiarrhythmic agent (22%/33%), but were more likely to have permanent and/or persistent AF (51%/40%). CHA₂DS₂-VASc scores did not vary by symptom status. After adjustment, risk of first stroke and/or non-CNS embolism (hazard ratio [HR] 0.85 [95% confidence interval {CI} 0.63 to 1.16], p = 0.32), major adverse cardiovascular and neurologic events (HR 0.88 [95% CI 0.76 to 1.03], p = 0.11), bleeding (HR 0.85 [95% CI 0.72 to 1.00], p = 0.05), and death (HR 0.99 [95% CI 0.87 to 1.13], p = 0.88) were similar in asymptomatic (European Heart Rhythm Association = 1) and symptomatic AF, respectively. Prospective, randomized studies are needed to further define associated adverse events and delineate optimal prophylactic therapies in patients with asymptomatic AF.

Role of the monocyte-to-high-density lipoprotein ratio in predicting atrial high-rate episodes detected by cardiac implantable electronic devices

OBJECTIVE:

Technological advances have allowed cardiac implantable electronic devices (CIEDs) to detect, analyze, and store atrial high-rate episodes (AHREs), which are surrogate for the term silent atrial fibrillation (AF). The association of AHREs with adverse clinical events has been demonstrated in several recent studies, implying that morbidity and mortality can be significantly prevented by prompt recognition and intervention. Inflammation and oxidative stress are among several mechanisms that contribute to the pathogenesis of AF. The monocyte-to-high-density lipoprotein ratio (M/H ratio) is a novel indicator of both inflammation and oxidative stress. In this study, we aimed to investigate the value of the M/H ratio for predicting AHREs detected by CIEDs.

METHODS:

A total of 203 patients (mean age: 57.5+9.1 years, 60.1% male) implanted with a dual pacemaker because of sick sinus syndrome were included. Blood samples were obtained from the patients after 12 h of fasting for the analysis of routine biochemistry tests and the lipid panel in the morning of device implantation. At a clinical visit 6 months after CIED implantation, the devices were interrogated to detect the occurrence of AHREs. AHREs were defined as atrial episodes faster than 220 bpm and lasting longer than 5 min. The patients were divided into two groups depending on the presence of AHREs during pacemaker interrogation: Group 1 (AHRE present) and Group 2 (AHRE absent).

RESULTS:

At the clinical visit 6 months after CIED implantation, 51 (25.1%) patients had at least one AHRE. The M/H ratio was significantly higher in patients in Group 1 (11.41±1.24) than in those in Group 2 (8.17±1.02) (p<0.01). On performing multivariate Cox regression analysis, the M/H ratio was found to be associated with the occurrence of AHREs in patients with CIEDs (OR: 22.813, 95% CI: 6.852–75.953, p<0.01).

CONCLUSION:

The M/H ratio is an indicator of inflammation and oxidative stress, both of which play an important role in the pathogenesis of AF. This ratio was found to be statically higher in patients with AHREs detected by CIEDs than in those without AHREs.

Newer technologies for detection of atrial fibrillation

Atrial fibrillation is a common arrhythmia that is associated with increased risk of stroke, which can be reduced with appropriate anticoagulation treatment. However, it remains underdiagnosed in contemporary clinical practice using conventional detection methods, resulting in missed opportunities to implement appropriate treatment. Newer technologies developed in recent years can potentially enhance the detection of atrial fibrillation and overcome certain limitations of the conventional methods. However, uncertainties remain about their use and the significance of atrial fibrillation detected by some of these newer technologies. This review examines the evidence supporting the use of some of these technologies and evaluates their applications in certain clinical scenarios.