Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device

Predictors of Paroxysmal Atrial Fibrillation in Patients With a Cryptogenic Stroke: Selecting Patients for Long-Term Rhythm Monitoring

BACKGROUND

After a cryptogenic stroke, patients will often require prolonged cardiac monitoring; however, the subset of patients who would benefit from long-term rhythm monitoring is not clearly defined.

OBJECTIVE

Using significant predictors of AF using age, sex, comorbidities, baseline 12-lead electrocardiogram, short term rhythm monitoring and echocardiogram data, we created a risk score and compared it to previously published risk scores.

METHODS

Patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or TIA who underwent long-term rhythm monitoring with an implantable cardiac monitor were retrospectively analyzed.

RESULTS

Variables positively associated with a diagnosis of clinically significant atrial fibrillation include age (p < 0.001), race (p = 0.022), diabetes status (p = 0.026), and COPD status (p = 0.012), the presence of atrial runs (p = 0.003), the number of atrial runs per 24 hours (p < 0.001), the total number of atrial run beats per 24 hours (p < 0.001) and the number of beats in the longest atrial run (p < 0.001), LA enlargement (p = 0.007) and at least mild mitral regurgitation (p = 0.009). We created a risk stratification score for our population, termed the "ACL score." The ACL score demonstrated superiority to the CHA2DS2-VASc score and comparability to the C2HEST score for predicting device-detected AF.

CONCLUSION

The ACL score enables clinicians to better predict which patients are more likely to be diagnosed with device-detected AF after a cryptogenic stroke.

Adherence to adhesive patch electrocardiographic monitoring among adults with disabilities

BACKGROUND

Individuals with developmental and/or intellectual disabilities (I/DD) are at a greater risk for atrial fibrillation (AF), the most common type of cardiac arrhythmia. AF is associated with heart failure, stroke, poor mental health, and reduced quality of life. Management and treatment decisions are based on the ability to detect AF; however, noninvasive, remote cardiac monitoring may not be tolerated by individuals with I/DD.

OBJECTIVE

To examine adherence to the placement of an ambulatory cardiac rhythm monitoring patch device by adult patients with I/DD.

METHODS

Investigators extracted chart data from a consecutive series of adult patients (18 years+) who received the patch device as part of standard treatment at an adult health center between November 1, 2015 and October 31, 2019.

RESULTS

A total of 95 patients were included in data analysis. Average age of subjects was 53.8 ± 13.9 years (range: 20.2-88.5); 66.7% were male. All subjects had intellectual disabilities as follows: mild, 37.9%; moderate, 29.5%; severe, 21.0%; and, profound, 11.6%. With a prescribed duration of 14 days, subjects wore the device a median (interquartile range [IQR]) of 12.2 days (4.1-14.0); total analysis time was a median of 9.5 days (3.4-13.5). A total of 29 subjects (30.5%) received cardiac diagnoses not previously identified (median = 1 new diagnosis; range: 1-5).

CONCLUSIONS

This pilot study suggests the possible utility of an ambulatory monitoring patch device in an adult population with I/DD. Investigators recommend larger studies to confirm such preliminary findings to ultimately improve clinical management and patient quality of life.

Low Utility of Short-Term Rhythm Assessment Before Long-Term Rhythm Monitoring in Patients With Cryptogenic Stroke

Implantable cardiac monitors are routinely placed for long-term monitoring (LTM) after a period of negative short-term monitoring (STM) to increase atrial fibrillation (AF) detection after a cryptogenic stroke or transient ischemic attack (TIA). Optimizing AF monitoring after a cryptogenic stroke is critical to improve outcomes and reduce costs. We sought to compare the diagnostic yield of STM versus LTM, assess the impact of routine STM on hospitalization length of stay, and perform a financial analysis comparing the current model to a theoretical model wherein patients can proceed directly to LTM. Our retrospective observational cohort study analyzed patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or TIA who underwent Holter device monitoring. Of 396 subjects, STM detected AF in 10 (2.5%) compared with a diagnostic yield of 14.6% for LTM (median time to diagnosis of 76 days). Of the 386 patients with negative STM, 130 (33.7%) received an implantable cardiac monitor while an inpatient, and 256 (66.3%) did not. We calculated a point estimate of 1.67 days delay of discharge attributable to the requirement for STM to precede LTM. Our model showed that the expected cost per patient in the STM-first paradigm is $28,615.33 versus $27,111.24 in the LTM-or-STM paradigm. Considering the relatively lower diagnostic yield of STM and its association with a longer length of stay and higher costs, it may be reasonable to proceed directly to LTM to optimize AF detection after a cryptogenic stroke or TIA.

Persistence to rivaroxaban therapy for stroke prevention in clinical practice in Italy: Rationale and design of the RITMUS-AF prospective observational cohort study

Background

Non-valvular atrial fibrillation (NVAF) is a cardiac rhythm disturbance that increases the risk of stroke and is highly prevalent in Europe and Italy, increasingly with advancing age. Oral anticoagulation is a key component of stroke prevention in patients with NVAF, yet withdrawal or interruption of anticoagulation may transiently increase the risk of embolic events. Treatment persistence to anticoagulation is an important metric but one that is not well studied in patients with NVAF in Italy. The RITMUS-AF study aims to evaluate the persistence with rivaroxaban treatment for stroke prevention in patients with NVAF in Italy.

Methods

RITMUS-AF is a prospective, observational cohort study of patients with NVAF in hospital cardiology departments with a non-vitamin K antagonist oral anticoagulant surveillance program across all 20 regions of Italy. The study population comprises consecutively screened, consenting patients with NVAF naïve to and newly treated with rivaroxaban for stroke prevention in routine clinical practice. The target enrollment is 800 patients; each patient will be followed for a maximum duration of 24 months. The primary endpoint is the proportion of patients who discontinue rivaroxaban treatment. Secondary endpoints are reasons for rivaroxaban discontinuation, dose changes and reasons for changes, switches to alternative therapies and the reasons for these decisions, and self-reported adherence. Data analyses will be exploratory and descriptive.

Conclusion

RITMUS-AF will help to address the limited data in Italian clinical practice on treatment persistence and reasons for drug interruptions in patients with NVAF on rivaroxaban.

Novel Technologies in the Detection of Atrial Fibrillation: Review of Literature and Comparison of Different Novel Technologies for Screening of Atrial Fibrillation

Atrial fibrillation (AF) is globally the most common arrhythmia associated with significant morbidity and mortality. It impairs the quality of the patient's life, imposing a remarkable burden on public health, and the healthcare budget. The detection of AF is important in the decision to initiate anticoagulation therapy to prevent thromboembolic events. Nonetheless, AF detection is still a major clinical challenge as AF is often paroxysmal and asymptomatic. AF screening recommendations include opportunistic or systematic screening in patients ≥65 years of age or in those individuals with other characteristics pointing to an increased risk of stroke. The popularities of well-being and taking personal responsibility for one's own health are reflected in the continuous development and growth of mobile health technologies. These novel mobile health technologies could provide a cost-effective solution for AF screening and an additional opportunity to detect AF, particularly its paroxysmal and asymptomatic forms.

Structural Cardiac Abnormalities in Patients with Atrial Fibrillation/Flutter and Myocardial Injury

BACKGROUND

High-sensitivity cardiac troponin (hs-cTnT) is often increased in patients with atrial fibrillation/flutter, portending a poor prognosis. The etiologies for these increases have not been systematically investigated. Our aim was to define prevalence/significance of structural cardiac abnormalities in patients with atrial fibrillation/flutter and high-sensitivity cardiac troponin T (hs-cTnT) increases.

METHODS

This is a retrospective observational cohort study of patients with atrial fibrillation/flutter diagnosis with hs-cTnT measurements, echocardiograms, and coronary angiograms. Myocardial injury was defined as hs-cTnT >10 ng/L for women and >15 ng/L for men. Cases with myocardial injury were adjudicated according to the Fourth Universal Definition of Myocardial Infarction.

RESULTS

Patients with definite causes for increased hs-cTnT (n = 875) were tabulated but not evaluated further; common diagnoses were type 1 myocardial infarction, critical illness, and known heart failure. Of the remaining 401, increased hs-cTnT was present in 336 (84%) patients. Of those, 78% had nonischemic myocardial injury, the remaining (n = 75, 22%) had type 2 myocardial infarction. Patients with elevated hs-cTnT had greater left ventricular mass index, left ventricular filling pressures, and right ventricular systolic pressure. They more frequently had significant coronary artery disease (47% vs 31%, P = .016), especially in type 2 myocardial infarction. With logistic regression, age, sex (F), diabetes, left ventricular mass index, e' medial velocity, and right ventricular systolic pressure were independent determinants of myocardial injury. One-year mortality was higher in patients with myocardial injury.

CONCLUSIONS

Structural heart abnormalities are common in patients with atrial fibrillation/flutter and increased hs-cTnT. Causes of myocardial injury should be elucidated in each patient to craft appropriate therapies.

Advantages of using a portable cardiac monitor in outpatients with paroxysmal atrial fibrillation

Aim. To study the advantages of using a portable electrocardiographic (ECG) monitor in outpatients with paroxysmal atrial fibrillation (AF).

Material and methods. We examined 88 patients (26 men, 62 women, mean age, 63 [57;68] years) with paroxysmal AF with an average frequency of arrhythmia episodes of 1,0 [0.3;3.75] per month. Forty three (49%) patients were included in the remote monitoring (RM) group using the ECG Dongle monitor, and 45 (51%) patients were included in the conventional monitoring (CM) group. Patients underwent scheduled examinations 2, 6 and 12 months after the start of therapy. Unscheduled consultations were carried out in case of AF recurrence. Patients from the RM group, using portable cardiac monitor, additionally self-registered ECG 1 time per week and in case of symptoms suggestive of AF. ECG strips were sent to the clinical investigator for analysis.

Results. With the help of portable cardiac monitor, 2477 ECG strips were collected and analyzed: 2159 (87,2%) — sinus rhythm, 318 (12,8%) — AF and atypical atrial flutter. Forty four episodes of AF in 3 patients were asymptomatic. In addition, 211 (8,5%) sinus rhythm ECG strips were recorded by 13 patients with symptoms suggestive of AF. In the RM group, 7 (16%) patients were hospitalized due to recurrent AF, while in the CM group, 20 (44%) patients (p=0,004). The total number of emergency hospitalizations was 8 and 29 in the RM and CM groups, respectively. The number of patients who called an ambulance was significantly lower in the RM group: in the CM group, 37 calls for an ambulance were made by 22 patients, while in the RM group — 12 patients made 15 calls (p=0,044). The proportion of calls followed by hospitalization (40 vs 70%, p=0,043) was significantly lower in the RM group.

Conclusion. Remote ECG monitoring using the ECG Dongle system is a useful way to monitor patients with paroxysmal AF, which make it possible to register asymptomatic AF episodes, differentiate the causes of palpitations, and significantly reduce the frequency of emergency calls and hospitalizations.

A Wireless Fully-Passive Acquisition of Biopotentials

Biopotential signals contain essential information for assessing the functionality of organs and diagnosing diseases. We present a flexible sensor, capable of measuring biopotentials, in real time, in a wireless and fully-passive manner. The flexible sensor collects and transmits biopotentials to an external reader without wire, battery, or harvesting/regulating element. The sensor is fabricated on a 90 μm-thick polyimide substrate with a footprint of 18 × 15 × 0.5 mm³. The wireless fully-passive acquisition of biopotentials is enabled by the RF (Radio Frequency) microwave backscattering effect where the biopotentials are modulated by an array of varactors with incoming RF carrier that is backscattered to the external reader. The flexile sensor is verified and validated by emulated signal and electrocardiogram (ECG), electromyogram (EMG), and electrooculogram (EOG), respectively. A deep learning algorithm analyzes the signal quality of wirelessly acquired data, along with the data from commercially available wired sensor counterparts. Wired and wireless data shows <3% discrepancy in deep learning testing accuracy for ECG and EMG up to the wireless distance of 240 mm. Wireless acquisition of EOG further demonstrates accurate tracking of horizontal eye movement with deep learning training and testing accuracy reaching up to 93.6% and 92.2%, respectively, indicating successful detection of biopotentials signal as low as 250 μV_PP. These findings support that the real-time wireless fully-passive acquisition of on-body biopotentials is indeed feasible and may find various uses for future clinical research.

Novel Predictor for New-Onset Atrial High-Rate Episode in Patients With a Dual-Chamber Pacemaker

Background: The incidence of new-onset atrial high-rate episode (AHRE) is higher among patients with cardiac implantable electronic devices (CIEDs) than in the general population. We sought to elucidate the clinical factors associated with AHRE in CIED patients, including P-wave dispersion (PWD) in sinus rhythm.

Methods and Results: In all, 101 patients with CIEDs newly implanted between 2010 and 2014 were included in the study. PWD was measured at the time of device implantation via a body-surface electrocardiogram. AHRE was defined as any episode of sustained atrial tachyarrhythmia (>170 beats/min) recorded in the device’s memory. Patients were divided into an AHRE (n=34) and non-AHRE (n=67) group based on the presence or absence of AHRE within 1 year of device implantation and compared. Mean (±SD) patient age was 75±11 years. A greater incidence of sick sinus syndrome (P=0.05) and longer PWD (62.6±13.1 vs. 38.2±13.9 ms; P<0.0001) were apparent in the AHRE than non-AHRE group. Multivariate analysis revealed that PWD was an independent predictor of new-onset AHRE (odds ratio 1.11; 95% confidence interval 1.06–1.17; P<0.0001). In logistic regression analysis, receiver-operating characteristic curve analysis (area under the curve 0.90; P<0.001) suggested the best cut-off value for PWD was 48 mm (sensitivity 73.8%, specificity 77.9%).

Conclusions: PWD is a simple but feasible predictor of new-onset AHRE in patients with CIEDs.

Impact of the Pattern of Atrial Fibrillation on Stroke Risk and Mortality

Thromboembolism is the most serious complication of AF, and oral anticoagulation is the mainstay therapy. Current guidelines place all AF types together in terms of anticoagulation with the major determinants being associated comorbidities translated into risk marker. Among patients in large clinical trials, those with non-paroxysmal AF appear to be at higher risk of stroke than those with paroxysmal AF. Higher complexity of the AF pattern is also associated with higher risk of mortality. Moreover, continuous monitoring of AF through cardiac implantable devices provided us with the concept of ‘AF burden’. Usually, the larger the AF burden, the higher the risk of stroke; however, the relationship is not well characterised with respect to the threshold value above which the risk increases. The picture is more complex than it appears: AF and underlying disorders must act synergically respecting the magnitude of its own characteristics, which are the amount of time a patient stays in AF and the severity of associated comorbidities.

Ambulatory External Electrocardiography Monitoring: Holter, Extended Holter, Mobile Cardiac Telemetry Monitoring

Ambulatory external electrocardiography (AECG) monitoring is effective as an evidence-based diagnostic tool when suspicion for cardiac arrhythmia is high. Multiple modalities of AECG monitoring exist, with unique advantages and limitations that predict effectiveness in a variety of clinical settings. Knowledge of these characteristics allows appropriate use of AECG, maximizing patient adherence, diagnostic yield, and cost-effectiveness. In addition, new technology has allowed the development of a modern generation of devices that offer increased efficacy and functionality compared with Holter monitors.

Biomarkers for Risk Assessment in Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with an increased risk of thromboembolism, which can be significantly reduced with anticoagulant treatment. Key goals in the clinical management of AF are the identification of patients at high risk for developing AF and accurate stratification of the risk of stroke and systemic embolic events (S/SEE) as well as treatment-related major bleeding.

CONTENT

In this review, we describe the expanding evidence regarding the use of circulating biomarkers for predicting the risks of both incident AF and its clinically important complications of S/SEE and treatment-related major bleeding. We also review emerging biomarker-based scores for assessing these risks.

SUMMARY

Patients with AF undergo progressive cardiac structural remodeling, which may precede the onset of the arrhythmia. Abnormal concentrations of circulating biomarkers reflecting the underlying pathophysiologic mechanisms of hemodynamic stress (i.e., natriuretic peptides), inflammation (i.e., C-reactive protein), and myocardial fibrosis identify patients at higher risk of developing AF. Circulating biomarkers can also be used to identify patients with AF who are at greatest risk for developing S/SEE or major bleeding. In particular, biomarkers of hemodynamic stress, myocardial injury (i.e., cardiac troponin), and coagulation activity (i.e., D-dimer) are key indicators of thromboembolic risk, and cardiac troponin and growth-differentiation factor-15 are strongly associated with risk of anticoagulant-related major bleeding. The biomarker-based age, biomarker, clinical history (ABC)-stroke and ABC-bleeding risk scores improve risk stratification for S/SEE and major bleeding, respectively, when compared with traditional clinical risk scores like the CHA2DS2-VASc and HAS-BLED scores.

Clinical Outcomes in Asymptomatic and Symptomatic Atrial Fibrillation Presentations in GARFIELD-AF: Implications for AF Screening

BACKGROUND

Asymptomatic atrial fibrillation is often detected incidentally. Prognosis and optimal therapy for asymptomatic compared with symptomatic atrial fibrillation is uncertain. This study compares clinical characteristics, treatment, and 2-year outcomes of asymptomatic and symptomatic atrial fibrillation presentations.

METHODS

Global Anticoagulant Registry in the Field-Atrial Fibrillation (GARFIELD-AF) is a global, prospective, observational study of newly diagnosed atrial fibrillation with ≥1 stroke risk factors (http://www.clinicaltrials.gov, unique identifier: NCT01090362). Patients were characterized by atrial fibrillation-related symptoms at presentation and the CHA₂DS₂-VASc score. Two-year follow-up recorded anticoagulation patterns (vitamin K antagonist, direct oral anticoagulants, parenteral therapy) and outcomes (stroke/systemic embolism, all-cause mortality, and bleeding).

RESULTS

At presentation, of 52,032 eligible patients, 25.4% were asymptomatic and 74.6% symptomatic. Asymptomatic patients were slightly older (72 vs 70 years), more often male (64.2% vs 52.9%), and more frequently initiated on anticoagulation ± antiplatelets (69.4% vs 66.0%). No difference in events (adjusted hazard ratios, 95% confidence interval) for nonhemorrhagic stroke/systemic embolism (1.19, 0.97-1.45), all-cause mortality (1.06, 0.94-1.20), or bleeding (1.02, 0.87-1.19) was observed. Anticoagulation was associated with comparable reduction in nonhemorrhagic stroke/systemic embolism (0.59, 0.43-0.82 vs 0.78, 0.65-0.93) and all-cause mortality (0.69, 0.59-0.81 vs 0.77, 0.71-0.85) in asymptomatic versus symptomatic, respectively.

CONCLUSIONS

Major outcomes do not differ between asymptomatic and symptomatic atrial fibrillation presentations and are comparably reduced by anticoagulation. Opportunistic screening-detected asymptomatic atrial fibrillation likely has the same prognosis as asymptomatic atrial fibrillation at presentation and likely responds similarly to anticoagulation thromboprophylaxis.

World Heart Federation Roadmap on Atrial Fibrillation - A 2020 Update

The World Heart Federation (WHF) commenced a Roadmap initiative in 2015 to reduce the global burden of cardiovascular disease and resultant burgeoning of healthcare costs. Roadmaps provide a blueprint for implementation of priority solutions for the principal cardiovascular diseases leading to death and disability. Atrial fibrillation (AF) is one of these conditions and is an increasing problem due to ageing of the world’s population and an increase in cardiovascular risk factors that predispose to AF. The goal of the AF roadmap was to provide guidance on priority interventions that are feasible in multiple countries, and to identify roadblocks and potential strategies to overcome them.

Since publication of the AF Roadmap in 2017, there have been many technological advances including devices and artificial intelligence for identification and prediction of unknown AF, better methods to achieve rhythm control, and widespread uptake of smartphones and apps that could facilitate new approaches to healthcare delivery and increasing community AF awareness. In addition, the World Health Organisation added the non-vitamin K antagonist oral anticoagulants (NOACs) to the Essential Medicines List, making it possible to increase advocacy for their widespread adoption as therapy to prevent stroke. These advances motivated the WHF to commission a 2020 AF Roadmap update. Three years after the original Roadmap publication, the identified barriers and solutions were judged still relevant, and progress has been slow.

This 2020 Roadmap update reviews the significant changes since 2017 and identifies priority areas for achieving the goals of reducing death and disability related to AF, particularly targeted at low-middle income countries. These include advocacy to increase appreciation of the scope of the problem; plugging gaps in guideline management and prevention through physician education, increasing patient health literacy, and novel ways to increase access to integrated healthcare including mHealth and digital transformations; and greater emphasis on achieving practical solutions to national and regional entrenched barriers. Despite the advances reviewed in this update, the task will not be easy, but the health rewards of implementing solutions that are both innovative and practical will be great.

Association Between Obesity-Mediated Atrial Fibrillation and Therapy With Sodium Channel Blocker Antiarrhythmic Drugs

Importance

The association between obesity, an established risk factor for atrial fibrillation (AF), and response to antiarrhythmic drugs (AADs) remains unclear.

Objective

To test the hypothesis that obesity differentially mediates response to AADs in patients with symptomatic AF and in mice with diet-induced obesity (DIO) and pacing induced AF.

Design, Setting, and Participants

An observational cohort study was conducted including 311 patients enrolled in a clinical-genetic registry. Mice fed a high-fat diet for 10 weeks were also evaluated. The study was conducted from January 1, 2018, to June 2, 2019.

Main Outcomes and Measures

Symptomatic response was defined as continuation of the same AAD for at least 3 months. Nonresponse was defined as discontinuation of the AAD within 3 months of initiation because of poor symptomatic control of AF necessitating alternative rhythm control therapy. Outcome measures in DIO mice were pacing-induced AF and suppression of AF after 2 weeks of treatment with flecainide acetate or sotalol hydrochloride.

Results

A total of 311 patients (mean [SD] age, 65 [12] years; 120 women [38.6%]) met the entry criteria and were treated with a class I or III AAD for symptomatic AF. Nonresponse to class I AADs in patients with obesity was less than in those without obesity (30% [obese] vs 6% [nonobese]; difference, 0.24; 95% CI, 0.11-0.37; P = .001). Both groups had similar symptomatic response to a potassium channel blocker AAD. On multivariate analysis, obesity, AAD class (class I vs III AAD [obese] odds ratio [OR], 4.54; 95% Wald CI, 1.84-11.20; P = .001), female vs male sex (OR, 2.31; 95% Wald CI, 1.07-4.99; P = .03), and hyperthyroidism (OR, 4.95; 95% Wald CI, 1.23-20.00; P = .02) were significant indicators of the probability of failure to respond to AADs. Pacing induced AF in 100% of DIO mice vs 30% (P < .001) in controls. Furthermore, DIO mice showed a greater reduction in AF burden when treated with sotalol compared with flecainide (85% vs 25%; P < .01).

Conclusions and Relevance

Results suggest that obesity differentially mediates response to AADs in patients and in mice with AF, possibly reducing the therapeutic effectiveness of sodium channel blockers. These findings may have implications for the management of AF in patients with obesity.

New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting and Long-Term Outcome: A Population-Based Nationwide Study From the SWEDEHEART Registry

Background

The long‐term impact of new‐onset postoperative atrial fibrillation (POAF) after coronary artery bypass grafting and the benefit of early‐initiated oral anticoagulation (OAC) in patients with POAF are uncertain.

Methods and Results

All patients who underwent coronary artery bypass grafting without preoperative atrial fibrillation in Sweden from 2007 to 2015 were included in a population‐based study using data from 4 national registries: SWEDEHEART (Swedish Web System for Enhancement and Development of Evidence‐based Care in Heart Disease Evaluated According to Recommended Therapies), National Patient Registry, Dispensed Drug Registry, and Cause of Death Registry. POAF was defined as any new‐onset atrial fibrillation during the first 30 postoperative days. Cox regression models (adjusted for age, sex, comorbidity, and medication) were used to assess long‐term outcome in patients with and without POAF, and potential associations between early‐initiated OAC and outcome. In a cohort of 24 523 patients with coronary artery bypass grafting, POAF occurred in 7368 patients (30.0%), and 1770 (24.0%) of them were prescribed OAC within 30 days after surgery. During follow‐up (median 4.5 years, range 0‒9 years), POAF was associated with increased risk of ischemic stroke (adjusted hazard ratio [aHR] 1.18 [95% CI, 1.05‒1.32]), any thromboembolism (ischemic stroke, transient ischemic attack, or peripheral arterial embolism) (aHR 1.16, 1.05‒1.28), heart failure hospitalization (aHR 1.35, 1.21‒1.51), and recurrent atrial fibrillation (aHR 4.16, 3.76‒4.60), but not with all‐cause mortality (aHR 1.08, 0.98‒1.18). Early initiation of OAC was not associated with reduced risk of ischemic stroke or any thromboembolism but with increased risk for major bleeding (aHR 1.40, 1.08‒1.82).

Conclusions

POAF after coronary artery bypass grafting is associated with negative prognostic impact. The role of early OAC therapy remains unclear. Studies aiming at reducing the occurrence of POAF and its consequences are warranted.

Left Ventricular Diastolic Dysfunction Is Associated With the Prevalence of Paroxysmal Atrial Fibrillation Determined on the Latest Echocardiographic Criteria

Background: The relationship between left ventricular diastolic dysfunction (LVDD) and paroxysmal atrial fibrillation (PAF) remains unclear because of a lack of standard measures to evaluate LVDD. Accordingly, we examined the association between the prevalence of PAF and each LVDD grade determined according to the latest American Society of Echocardiography guidelines.

Methods and Results: In all, 2,063 patients without persistent AF who underwent echocardiography at Saitama Municipal Hospital from July 2016 to June 2017 were included in the study. Patients were divided into LVDD 6 categories: No-LVDD (n=1,107), Borderline (n=392), Grade 1 (n=204), Indeterminate (n=62), Grade 2 (n=254), and Grade 3 (n=44). PAF was documented in 111 (10.0%), 81 (20.7%), 28 (13.7%), 6 (9.7%), 52 (20.5%), and 24 (54.5%) patients in the No-LVDD, Borderline, Grade 1, Indeterminate, Grade 2, and Grade 3 categories, respectively. PAF prevalence was higher in patients with Grade 3 LVDD across the whole study population. Subgroup analyses showed that the prevalence of PAF increased with increased LVDD grade in patients with reduced left ventricular ejection fraction. This relationship was significant in multivariate analysis including various patient characteristics.

Conclusions: LVDD severity determined on the basis of the latest echocardiographic criteria was associated with the prevalence of PAF. The present findings shed light on the development of new therapeutic markers for PAF.

Relationship between device-detected burden and duration of atrial fibrillation and risk of ischemic stroke

BACKGROUND

Wider availability of continuous rhythm monitoring has made feasible the incorporation of metrics of atrial fibrillation (AF) burden and duration into the decision to initiate anticoagulation. However, the relationship between thresholds of burden and duration and underlying risk factors at which anticoagulation should be considered remains unclear.

OBJECTIVE

The purpose of this study was to evaluate the relationships of these metrics with each other and the outcome of stroke/transient ischemic attack (TIA).

METHODS

We identified patients with cardiovascular implantable electronic devices (CIEDs) with atrial leads who had at least 1 interrogation in 2016 demonstrating nonpermanent AF and were not receiving oral anticoagulation (OAC). We evaluated the relationship between burden (ie, percentage of time spent in AF), the longest single episode of AF, and risk factors (ie, CHA₂DS₂-VASc score) in predicting risk of stroke/TIA.

RESULTS

The study included 384 patients with mean follow-up of 3.2 ± 0.8 years and incidence of stroke/TIA of 14.8% during follow-up (∼4.6% per year). The burden of AF and the duration of longest episode demonstrated a significant positive correlation to each other but not CHA₂DS₂-VASc score. Importantly, although the CHA₂DS₂-VASc score was predictive of stroke/TIA, neither burden nor duration was associated with stroke/TIA.

CONCLUSION

Among patients with CIED-detected AF not receiving OAC, the amount of AF (measured by either burden or duration) does not seem to significantly impact stroke risk, whereas CHA₂DS₂-VASc score does. These data suggest that among patients with CIED-detected AF, once AF occurs, stroke risk seems to be predominantly driven by underlying risk factors.

Postoperative Atrial Fibrillation in Lung Cancer Lobectomy-Analysis of Risk Factors and Prognosis

BACKGROUND

The incidence of postoperative atrial fibrillation (POAF) after pulmonary lobectomy ranges from 6.4 to 12.6%. This study aimed to analyze the postoperative risk factors and prognosis for POAF in lobectomy for lung cancer.

METHODS

Data were collected from patients undergoing pulmonary lobectomy from April 2010 to March 2019. We analyzed risk factors for POAF among perioperative factors and compared postoperative complications or overall survival between POAF and non-POAF groups. We classified POAF as either the temporary or non-temporary type and compared perioperative factors, postoperative complications, and overall survival.

RESULTS

POAF was identified in 49 (5.2%) of the 947 lobectomies. The POAF group included more males, patients with poor performance status (PS), history of paroxysmal atrial fibrillation (AF), chronic obstructive pulmonary disease (COPD), and intraoperative blood transfusions. Poor PS, COPD, previous paroxysmal AF, and intraoperative blood transfusion were independent risk factors for POAF in multivariate analysis. The POAF group had a poorer prognosis than the non-POAF group (p = 0.0045). POAF was divided into 29 temporary and 20 non-temporary types. The onset date of non-temporary-type POAF was significantly later than that of the transient type (P < 0.01), and diabetes mellitus was significantly higher in non-temporary-type POAF. Non-temporary-type POAF had a significantly poorer prognosis in terms of overall survival (p = 0.005).

CONCLUSIONS

Poor PS, COPD, history of PAF, and intraoperative blood transfusion were independent risk factors for POAF. Non-temporary-type POAF occurred significantly later than transient type and caused poorer prognosis after lobectomy for lung cancer.

Long-term clinical outcomes and prognostic indicators for focal impulse and rotor modulation guided ablation: A single-center observational study

BACKGROUND

Electrophysiologists have developed a computational mapping approach to localize sources that may perpetuate persistent atrial fibrillation (AF). Focal impulse and rotor modulation (FIRM)-guided ablation of these sources have produced variable results. The current study further assesses single-procedure success rates of FIRM-guided ablation for preventing AF or atrial tachyarrhythmia recurrence and analyzes different baseline characteristics as prognostic indicators for individuals experiencing these undesired outcomes.

METHODS

Seventy-one consecutive patients (mean age 64.58 ± 9.05 years and 36.6% female) with drug-refractory persistent AF with and without prior history of pulmonary vein antral isolation (PVAI) underwent FIRM-guided ablation. Patients without prior history of PVAI underwent FIRM-guided ablation in addition to de novo PVAI. Patients with prior history of PVAI had the pulmonary veins reassessed at the time of FIRM-guided ablation for reconnection as well as re-isolation, when necessary. These patients were then prospectively followed for AF and atrial tachyarrhythmia recurrence.

RESULTS

FIRM analysis revealed rotors in the right atrium in 66.2% (1.77 ± 1.53 mean rotors per patient) and in the left atrium in 85.9% (2.65 ± 1.52 mean rotors per patient) of patients analyzed in the current study. After a single FIRM-guided ablation procedure, AF and atrial tachyarrhythmia recurrence was demonstrated in 21.1% (15/71) and 33.8% (24/71) of patients, respectively. The entire cohort of patients were followed for a mean duration of 23.20 ± 8.38 months with the mean time to AF recurrence found to be 12.35 ± 10.44 months. Furthermore, valvular heart disease (i.e. moderate mitral or tricuspid regurgitation) was found to be a statistically significant independent predictor for AF recurrence following FIRM-guided ablation (p = .033).

CONCLUSIONS

FIRM-guided ablation in combination with PVAI is a suitable and effective approach for symptomatic individuals with drug-refractory persistent AF with and without prior history of PVAI. Randomized controlled studies are warranted.

Implantable loop recorders for cardiac dysrhythmia monitoring

Incorporation of technological advances in healthcare delivery has played a foundational role in development of modern healthcare. With the use of wireless transmission in conjunction with digitization of electrocardiography, continuous monitoring strategies have redefined our approach to dysrhythmia. These devices show promising results in evolving implantable loop recorder technology. In this review, we summarize the history of remote monitoring, indications for loop recorders, devices available, evidence for specific devices and anticipated studies.

Subclinical atrial fibrillation: when to give NAO?

Atrial fibrillation is defined as subclinical (SAF) when occurs without symptoms and is discovered only during the interrogation of permanent or temporary cardiac implantable devices. The significant interest in this condition derives from the fact that could easily be otherwise undiagnosed, portending to a potential serious neurological and cardiovascular consequences. The diagnosis of SAF is important for both the primary form and for patients after a stroke, and an appropriate management of antithrombotic treatment becomes a central instrument of prevention. Atrial fibrillation carries a five times increase in the thromboembolic risk. The subclinical asymptomatic forms of atrial tachyarrhythmias and fibrillation, diagnosed by interrogation of implantable cardiac devices, foretell a non-irrelevant risk of stroke, significantly higher than the one for patients without rhythm disturbances. Regardless the cause, the long-lasting asymptomatic arrhythmias, in patients with a significant risk profile, predict more important consequences and can justify anticoagulant treatment, also in primary prevention settings.

A Review of Atrial Fibrillation Detection Methods as a Service

Atrial Fibrillation (AF) is a common heart arrhythmia that often goes undetected, and even if it is detected, managing the condition may be challenging. In this paper, we review how the RR interval and Electrocardiogram (ECG) signals, incorporated into a monitoring system, can be useful to track AF events. Were such an automated system to be implemented, it could be used to help manage AF and thereby reduce patient morbidity and mortality. The main impetus behind the idea of developing a service is that a greater data volume analyzed can lead to better patient outcomes. Based on the literature review, which we present herein, we introduce the methods that can be used to detect AF efficiently and automatically via the RR interval and ECG signals. A cardiovascular disease monitoring service that incorporates one or multiple of these detection methods could extend event observation to all times, and could therefore become useful to establish any AF occurrence. The development of an automated and efficient method that monitors AF in real time would likely become a key component for meeting public health goals regarding the reduction of fatalities caused by the disease. Yet, at present, significant technological and regulatory obstacles remain, which prevent the development of any proposed system. Establishment of the scientific foundation for monitoring is important to provide effective service to patients and healthcare professionals.

Molecular Mechanisms, Diagnostic Aspects and Therapeutic Opportunities of Micro Ribonucleic Acids in Atrial Fibrillation

Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules responsible for regulation of gene expression. They are involved in many pathophysiological processes of a wide spectrum of diseases. Recent studies showed their involvement in atrial fibrillation. They seem to become potential screening biomarkers for atrial fibrillation and even treatment targets for this arrhythmia. The aim of this review article was to summarize the latest knowledge about miRNA and their molecular relation to the pathophysiology, diagnosis and treatment of atrial fibrillation.

Smartphone ECG Monitoring System Helps Lower Emergency Room and Clinic Visits in Post-Atrial Fibrillation Ablation Patients

Aim:

To evaluate the effectiveness of using a smartphone-based electrocardiography (ECG) monitoring device (ECG Check) on the frequency of clinic or emergency room visits in patients who underwent ablation of atrial fibrillation (AF).

Methods:

Two groups of patients were identified and compared: The conventional monitoring group (CM group) included patients who were prescribed conventional event monitoring or Holter monitoring systems. The ECG Check group (EC group) included patients who were prescribed the ECG Check device for continuous monitoring in addition to conventional event monitoring. The primary outcome was the number of patient visits to clinic or emergency room. The feasibility, accuracy, and detection rate of mobile ECG Check were also evaluated.

Results:

Ninety patients were studied (mean age: 66.2 ± 11 years, 64 males, mean CHA₂DS₂-VASc score: 2.6 ± 2). In the EC group, forty-five patients sent an average of 52.8 ± 6 ECG records for either routine monitoring or symptoms of potential AF during the follow-up period. The rhythm strips identified sinus rhythm (84.7%), sinus tachycardia (8.4%), AF (4.2%), and atrial flutter (0.9%). Forty-two EC transmissions (1.8%) were uninterpretable. Six patients (13%) in the EC group were seen in the clinic or emergency room over a 100-day study period versus 16 (33%) in the standard care arm (P value < 0.001).

Conclusions:

Use of smartphone-based ECG monitoring led to a significant reduction in AF-related visits to clinic or emergency department in the postablation period.

Lead-I ECG for detecting atrial fibrillation in patients with an irregular pulse using single time point testing: a systematic review and economic evaluation

BACKGROUND

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and is associated with an increased risk of stroke and congestive heart failure. Lead-I electrocardiogram (ECG) devices are handheld instruments that can be used to detect AF at a single time point in people who present with relevant signs or symptoms.

OBJECTIVE

To assess the diagnostic test accuracy, clinical impact and cost-effectiveness of using single time point lead-I ECG devices for the detection of AF in people presenting to primary care with relevant signs or symptoms, and who have an irregular pulse compared with using manual pulse palpation (MPP) followed by a 12-lead ECG in primary or secondary care.

DATA SOURCES

MEDLINE, MEDLINE Epub Ahead of Print and MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, PubMed, Cochrane Databases of Systematic Reviews, Cochrane Central Database of Controlled Trials, Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database.

METHODS

The systematic review methods followed published guidance. Two reviewers screened the search results (database inception to April 2018), extracted data and assessed the quality of the included studies. Summary estimates of diagnostic accuracy were calculated using bivariate models. An economic model consisting of a decision tree and two cohort Markov models was developed to evaluate the cost-effectiveness of lead-I ECG devices.

RESULTS

No studies were identified that evaluated the use of lead-I ECG devices for patients with signs or symptoms of AF. Therefore, the diagnostic accuracy and clinical impact results presented are derived from an asymptomatic population (used as a proxy for people with signs or symptoms of AF). The summary sensitivity of lead-I ECG devices was 93.9% [95% confidence interval (CI) 86.2% to 97.4%] and summary specificity was 96.5% (95% CI 90.4% to 98.8%). One study reported limited clinical outcome data. Acceptability of lead-I ECG devices was reported in four studies, with generally positive views. The de novo economic model yielded incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. The results of the pairwise analysis show that all lead-I ECG devices generated ICERs per QALY gained below the £20,000-30,000 threshold. Kardia Mobile (AliveCor Ltd, Mountain View, CA, USA) is the most cost-effective option in a full incremental analysis.

LIMITATIONS

No published data evaluating the diagnostic accuracy, clinical impact or cost-effectiveness of lead-I ECG devices for the population of interest are available.

CONCLUSIONS

Single time point lead-I ECG devices for the detection of AF in people with signs or symptoms of AF and an irregular pulse appear to be a cost-effective use of NHS resources compared with MPP followed by a 12-lead ECG in primary or secondary care, given the assumptions used in the base-case model.

FUTURE WORK

Studies assessing how the use of lead-I ECG devices in this population affects the number of people diagnosed with AF when compared with current practice would be useful.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018090375.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Rhythm monitoring strategies in patients at high risk for atrial fibrillation and stroke: A comparative analysis from the REVEAL AF study

BACKGROUND

Reducing atrial fibrillation (AF)-related stroke requires timely AF diagnosis, but the optimal monitoring strategy is unknown.

OBJECTIVE

We used insertable cardiac monitor (ICM) data from the REVEAL AF study to compare AF detection rates by various short-term continuous monitoring (STM) strategies.

METHODS AND RESULTS

Patients without known AF, but with CHADS₂ scores ≥3 (or = 2 with ≥1 additional AF risk factor) received an ICM for AF detection. One-time STM strategies were assessed by computing AF incidence at 1, 2, 7, 14, and 30 days post-ICM insertion. Repeated STM strategies (quarterly 24-hour, 48-hour, 7-day, or monthly 24-hour monitoring) were modeled by randomly selecting day(s) within a 30-day window around each nominal evaluation date over a 1-year period (simulated 10,000 times). Endpoints included AF ≥6 minutes, AF ≥1 hour, and daily AF burden ≥1 and ≥ 5.5 hours. The impact of compliance on AF detection was evaluated using daily compliance rates of 85%, 75%, 65% and 55% during follow-up months 1-3, 4-6, 7-9, and 9-12, respectively. Based on data from 385 patients (71.5 ± 9.9 years; CHADS₂ score 3.0 ± 1.0) the incidence of AF ≥6 minutes via ICM at 12 months was 27.1% (95% CI, 22.5-31.5%). This exceeded the range of estimated rates from all modeled one-time and repeated STM strategies (0.8% for 24-hour Holter monitoring to 10.6% for quarterly 7-day monitoring). Findings were similar for all AF endpoints. Modeled non-compliance reduced AF detection by 4.5% to 22.9%.

CONCLUSIONS

Most AF episodes detected via ICMs would go undetected via conventional STM strategies, thus preventing optimal prophylaxis for adverse consequences.

Catheter Ablation Versus Medical Therapy for Atrial Fibrillation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Despite the publication of several randomized clinical trials comparing catheter ablation (CA) with medical therapy (MT) in patients with atrial fibrillation (AF), the superiority of one strategy over another is still questioned by many. In this meta-analysis of randomized controlled trials, we compared the efficacy and safety of CA with MT for AF.

METHODS

We systematically searched MEDLINE, EMBASE, and other online sources for randomized controlled trials of AF patients that compared CA with MT. The primary outcome was all-cause mortality. Secondary outcomes included cardiovascular hospitalizations and recurrence of atrial arrhythmia. Subgroup analyses stratified by the presence of heart failure with reduced ejection fraction, type of AF, age, and sex were performed. Risk ratios (RRs) with 95% CIs were calculated using a random effects model, and Mantel-Haenszel method was used to pool RR.

RESULTS

Eighteen randomized controlled trials comprising 4464 patients (CA, n=2286; MT, n=2178) were included. CA resulted in a significant reduction in all-cause mortality (RR, 0.69; 95% CI, 0.54-0.88; P=0.003) that was driven by patients with AF and heart failure with reduced ejection fraction (RR, 0.52; 95% CI, 0.35-0.76; P=0.0009). CA resulted in significantly fewer cardiovascular hospitalizations (hazard ratio, 0.56; 95% CI, 0.39-0.81; P=0.002) and fewer recurrences of atrial arrhythmias (RR, 0.42; 95% CI, 0.33-0.53; P<0.00001). Subgroup analyses suggested that younger patients (age, <65 years) and men derived more benefit from CA compared with MT.

CONCLUSIONS

CA is associated with all-cause mortality benefit, that is driven by patients with AF and heart failure with reduced ejection fraction. CA reduces cardiovascular hospitalizations and recurrences of atrial arrhythmia for patients with AF. Younger patients and men appear to derive more benefit from CA.

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.

Advanced Cardiac Signal Recording

Implantable loop recorders allow prolonged and continuous single-lead electrocardiogram recording, with the pivotal addition of remote monitoring. They have significantly shortened time to electrocardiographic diagnosis and appropriate therapy of many bradyarrhythmias/tachyarrhythmias and proved helpful in arrhythmia burden definition, offering invaluable information in the diagnostic workup for syncope and atrial fibrillation. Advanced cardiac signal recording is also possible by transesophageal catheters. They have been used to orient diagnosis during wide and narrow QRS complex tachycardias and also to perform minimally invasive pacing. Intracardiac electrophysiologic study remains, however, essential for diagnosis of several arrhythmias in the perspective of curative catheter ablation.

A wireless fully-passive acquisition of biopotentials

Biopotential signals contain essential information for assessing functionality of organs and diagnosing diseases. We present a flexible sensor, capable of measuring biopotentials, in real time, in wireless and fully-passive manner. The flexible sensor collects and transmits biopotentials to an external reader without wire, battery, or harvesting/regulating element. The sensor is fabricated on a 90 μm-thick polyimide substrate with footprint of 18 × 15 × 0.5 mm³. The wireless fully-passive acquisition of biopotentials is enabled by the RF (Radio Frequency) microwave backscattering effect where the biopotentials are modulated by an array of varactors with incoming RF carrier that is backscattered to the external reader. The flexile sensor is verified and validated by emulated signal and Electrocardiogram (ECG), Electromyogram (EMG), and Electrooculogram (EOG), respectively. A deep learning algorithm analyzes the signal quality of wirelessly acquired data, along with the data from commercially-available wired sensor counterparts. Wired and wireless data shows <3% discrepancy in deep learning testing accuracy for ECG and EMG up to the wireless distance of 240 mm. Wireless acquisition of EOG further demonstrates accurate tracking of horizontal eye movement with deep learning training and testing accuracy reaching up to 93.6% and 92.2%, respectively, indicating successful detection of biopotentials signal as low as 250 μV_PP. These findings support that the real-time wireless fully-passive acquisition of on-body biopotentials is indeed feasible and may find various uses for future clinical research.

Arrhythmias in Patients with Implantable Devices

Pacemakers, cardioverter/defibrillators, and implantable loop recorders with their continuously improved diagnostic capabilities offer detailed information that can help interpreting a cardiac arrhythmia in implanted patients. Nevertheless, in some cases, analysis of the electrical signals stored in the device memory may not be easy. An accurate knowledge of the company-specific software and the meaning of the different markers used are necessary to correctly interpret the arrhythmia or diagnose an inappropriate device intervention due to under- or oversensing. This new technology does not replace the "old" surface electrocardiogram but supplements it to improve arrhythmia diagnosis.

[Visualisation and Radiofrequency Ablation of Sympathetic Innervation Loci in the Left Atrium in Patients with Paroxysmal Atrial Fibrillation]

INTRODUCTION

A novel cardiac gamma camera utilizes the radiopharmaceutical Iodine-123-Meta-iodobenzylguanidine (123I-MIBG) to visualize cardiac sympathetic innervation. Physiological accumulation of 123I-mIBG provides an anatomical quantitative determination of the structures of the autonomic nervous system (ANS) with discrete uptake areas (DUA) of sympathetic activity located in the left atrium (LA) corresponding to the main ganglionic plexi (GP) clusters that could not previously be visualized.

AIM

to visualize the DUA of the heart in patients with paroxysmal atrial fibrillation (AF) and to assess the effect of radiofrequency ablation (RFA) on DUA in LA.

MATERIALS AND METHODS

Computed tomography (CT) of the heart and radionuclide imaging with 123I-mIBG were performed in 15 patients with paroxysmal AF. The results of the study were combined with preliminary taken CT images to create a detailed anatomical map of the sympathetic activity of the heart. The processed images were combined with the 3D reconstruction of the LA, obtained with the navigation system (CARTO 3, CARTO RMT). In DUA, high-frequency stimulation (HFS) followed by RF ablation was performed using the current recommended parameters.

RESULTS

Forty-eight DUA (median 3 [3; 3]) were identified. Average activity of DUA was 1315 [1171; 1462] cnt / sec / ml. Positive response to HFS in the DUA was obtained in 8 (53.3 %) patients. Prior to ablation, no response was received to HFS in areas of LA outside the DUA. After ablation, there was no response to HFS in the DUA sites. At repeated scans 3 DUA (median 0 [0; 0]; p&lt;0.001 compared with preoperative data) were observed. Activity of DUA significantly decreased to 819 [684; 955] cnt / sec / ml (p&lt;0.001 as compared with preoperative data). Thirteen of 13 of 15 patients (87 %) had no AF / AT / AFL recurrences for 6 month follow up.

CONCLUSION

In patients with AF, the areas of sympathetic activity in LA can be visualized by physiological localized uptake of 123I-mIBG. Radiofrequency catheter ablation can target the identified sympathetic innervation structures in AF patients precisely and effectively.

Implantable loop recorder in clinical practice

The implantable loop recorder (ILR), also known as insertable cardiac monitor (ICM) is a subcutaneous device used for diagnosing heart rhythm disorders. These devices have been strongly improved and miniaturized during the last years showing several reliable features along with the availability of remote monitoring which improves the diagnostic timing and the follow-up strategy with a potential reduction of costs for health care. The recent advent of injectable ILRs makes the procedure even easier and more tolerated by patients. ILR allows the investigation of unexplained recurrent syncope with uncertain diagnosis, revealing a possible relationship with cardiac arrhythmias. In addition, it has recently been equipped with sophisticated algorithms able to detect atrial fibrillation episodes. This new opportunity may provide to the physicians systematic heart rhythm screening with possible effects on patient antiarrhythmic and anticoagulant therapy management. The use of such devices will surely increase, since they may be helpful to diagnose a wide range of disorders and pathologies. Indeed, further studies should be performed in order to identify all the potentialities of these tools.

Ocorrência de Fibrilação Atrial Subclínica no Acompanhamento de Pacientes Portadores de Marcapasso Cardíaco

Objetivo: O marcapasso cardíaco registra a fi brilação atrial (FA). Essa condição pode causar graves consequências hemodinâmicas aos pacientes, que devem ser assistidos por médico cardiologista. Este estudo objetivou documentar e investigar, em um hospital terciário, a prevalência de FA subclínica em portadores de marcapasso cardíaco. Métodos: Entre julho de 2015 e abril de 2016, foram atendidos 196 pacientes portadores de marcapasso em caráter ambulatorial. Desses, 60 apresentaram arritmias cardíacas registradas pelo marcapasso e foram convidados a participar do estudo. A coleta de dados foi feita por meio de entrevista estruturada contendo quatro questões: sexo, idade, acompanhamento com cardiologista e uso de anticoagulantes. Resultados:Foi registrada FA subclínica em 35 (17,8%) do total de 196 pacientes. Desses 35, 16 (45,7%) não realizavam acompanhamento regular em serviço de cardiologia e 29 (82,8%) não faziam uso de medicamento anticoagulante. Não foram encontradas relações estatisticamente signifi cativas entre idade, acompanhamento com cardiologista e presença ou ausência da FA subclínica nos pacientes estudados. Conclusão: Uma parcela signifi cativa dos pacientes portadores de marcapasso atendidos ambulatorialmente tem FA registrada pelo dispositivo. No entanto, ainda que essencial, quase metade desses não faz acompanhamento clínico com cardiologista e menos de um quinto com FA faz uso de terapia anticoagulante.

Occurrence of Subclinical Atrial Fibrillation in the Follow-up of Patients with Cardiac Pacemakers

Objective: Cardiac pacemaker records atrial fibrillation (AF). This condition can cause serious hemodynamic consequences to patients, who should be assisted by a cardiologist. This study aimed to document and investigate, in a tertiary hospital, the prevalence of subclinical AF in patients with a cardiac pacemaker. Methods: Between July 2015 and April 2016, 196 patients with pacemakers were attended on an outpatient basis. Of these, 60 had cardiac arrhythmias recorded by the pacemaker and were invited to participate in the study. Data collection was done through a structured interview containing four questions: gender, age, follow-up with cardiologist and use of anticoagulants. Results: Subclinical AF was recorded in 35 (17.8%) of the total of 196 patients. Of these 35, 16 (45.7%) did not follow a regular cardiology service and 29 (82.8%) did not use anticoagulant medication. No statistically significant relationships were found between age, follow up with a cardiologist, and presence or absence of subclinical AF in the patients studied. Conclusion: A significant portion of outpatient patients with pacemakers have AF recorded by the device. However, although essential, almost half of these do not proceed with the clinical follow-up with cardiologist and less than a fifth with AF makes use of anticoagulant therapy.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Rare truncating variants in the sarcomeric protein titin associate with familial and early-onset atrial fibrillation

A family history of atrial fibrillation constitutes a substantial risk of developing the disease, however, the pathogenesis of this complex disease is poorly understood. We perform whole-exome sequencing on 24 families with at least three family members diagnosed with atrial fibrillation (AF) and find that titin-truncating variants (TTNtv) are significantly enriched in these patients (P = 1.76 × 10⁻⁶). This finding is replicated in an independent cohort of early-onset lone AF patients (n = 399; odds ratio = 36.8; P = 4.13 × 10⁻⁶). A CRISPR/Cas9 modified zebrafish carrying a truncating variant of titin is used to investigate TTNtv effect in atrial development. We observe compromised assembly of the sarcomere in both atria and ventricle, longer PR interval, and heterozygous adult zebrafish have a higher degree of fibrosis in the atria, indicating that TTNtv are important risk factors for AF. This aligns with the early onset of the disease and adds an important dimension to the understanding of the molecular predisposition for AF.

Common genetic variants in structural proteins contribute to risk of atrial fibrillation (AF). Here, using whole-exome sequencing, the authors identify rare truncating variants in TTN that associate with familial and early-onset AF and show defects in cardiac sarcomere assembly in ttn.2-mutant zebrafish.

Association Between Family History and Early-Onset Atrial Fibrillation Across Racial and Ethnic Groups

Importance

There is a genetic predisposition to early-onset atrial fibrillation (EOAF) in European American individuals. However, the role of family history in the pathogenesis of EOAF in racial and ethnic minorities remains unclear.

Objective

To determine whether probands with EOAF across racial and ethnic groups have a higher rate of AF in first-degree family members than racially and ethnically matched control patients with non-early-onset AF (non-EOAF).

Design, Setting, and Participants

In this cohort study, patients prospectively enrolled in a clinical and genetic biorepository were administered baseline questionnaires that included questions about family history of AF. Early-onset AF was defined as AF occurring in probands aged 60 years or younger in the absence of structural heart disease. All other forms were categorized as non-EOAF. Recruitment took place from July 2015 to December 2017. Analysis was performed in January 2018.

Main Outcomes and Measures

Primary analysis of reported family history of AF in first-degree relatives with sensitivity analysis restricted to those in whom a family history was confirmed by medical record review and electrocardiogram.

Results

Of 664 patients enrolled (mean [SD] age, 62 [12] years; 407 [61%] male), 267 (40%) were European American; 258 (39%), African American; and 139 (21%), Hispanic/Latino. There was a family history of AF in 36 probands with EOAF (49%) compared with 128 patients with non-EOAF (22%) (difference, 27%; 95% CI, 14%-40%; P < .001). On multivariable analysis, the adjusted odds of a proband with EOAF who was of African descent (odds ratio [OR], 2.69; 95% CI, 1.06-6.91; P < .001) or Hispanic descent (OR, 9.25; 95% CI, 2.37-36.23; P = .002) having a first-degree relative with AF were greater than those of European descent (OR, 2.51; 95% CI, 1.29-4.87; P = .006). Overall, probands with EOAF were more likely to have a first-degree relative with AF compared with patients with non-EOAF (adjusted OR, 3.02; 95% CI, 1.82-4.95; P < .001) across the 3 racial and ethnic groups. Atrial fibrillation in a first-degree family member was confirmed in 32% of probands with EOAF vs 11% of those with non-EOAF (difference, 21%; 95% CI, 11%-33%; P < .001). Furthermore, African American (28% vs 5%; difference, 23%; 95% CI, 4%-43%; P = .001), European American (35% vs 20%; difference, 15%; 95% CI, 1%-30%; P = .03), and Hispanic/Latino (30% vs 5%; difference, 25%; 95% CI, 4%-54%; P = .02) probands with EOAF were more likely to have a first-degree relative with confirmed AF vs racially and ethnically matched control patients with non-EOAF. The positive and negative predictive values for a family history of confirmed AF were both 89%.

Conclusions and Relevance

Probands of African or Hispanic/Latino descent with EOAF were more likely to have a first-degree relative with AF when compared with European American individuals. These findings support genetic predisposition to EOAF across all 3 races.

The BioMonitor 2 insertable cardiac monitor: Clinical experience with a novel implantable cardiac monitor

INTRODUCTION

Implantable loop recorders (ILR) are leadless subcutaneous devices that allow cardiac monitoring for up to 3 years and are a valuable tool in the diagnosis of arrhythmias, cryptogenic stroke and unexplained syncope. The Biotronik BioMonitor 2 is a novel, insertable ILR allowing long-term continuous monitoring with wireless telemetry options.

METHODS

A single-center, prospective, observational study investigating the reliability of sensing quality and detection performance in the BioMonitor 2 ILR, as well as post-implantation patient satisfaction. R-wave amplitude was recorded immediately post implantation and 1 day post implantation, followed by extensive patient instruction. Follow-up was scheduled after 3 months, or after an event. Data from the ILR were retrieved, with documentation of all episodes, R-wave amplitude and noise burden. The anatomical position of the ILR was determined 1 day post implantation and after 3 months. A patient questionnaire was conducted after 3 months.

RESULTS

30 consecutive patients (mean age 71 ± 12 years, 56% male) were analyzed. Indications for ILR implantation were: unexplained syncope (n = 24, 80%), suspected atrial fibrillation (n = 4, 13%), cryptogenic stroke (n = 1, 3%) and palpitations (n = 1, 3%). Median time from skin cut to suture was 8 min. No complications occurred. Mean R-wave amplitude at implantation was 0.84 ± 0.32 mV, at day 1 post implantation 0.96 ± 0.31 mV, and after a mean follow-up of 85 ± 24 days 1.02 ± 0.47 mV (p = 0.01). The mean noise burden was 1.4 ± 2%.

CONCLUSION

Implantation of the novel BioMonitor 2 ILR is fast and uncomplicated. Initial sensing values are good and improve over time.