Duration Of Atrial Fibrillation Episodes Research Articles

Left atrial and left ventricular positive and negative remodeling after catheter ablation of atrial fibrillation

Abstract Introduction Atrial fibrillation (AF) is associated with negative remodeling of left atrium (LA) and in later stages of diseases with negative remodeling of left ventricle (LV). Can radiofrequency ablation (RFA) of pulmonary veins cure AF and retain progression of arrhythmia? Purpose This study evaluated positive and negative remodeling of LA and LV after RFA of pulmonary veins and a 7-year follow-up. The patients were divided into 4 groups on the basis of Pulmonary Vein Isolation Outcome Degree (PVIOD 1-4), a new measure for the efficacy of catheter ablation of AF. Methods One hundred seventeen patients with symptomatic drug-refractory paroxysmal and persistent AF were treated with RFA. At baseline and after a 7 years of follow-up, 2-dimensional echocardiography was performed to assess LA diameter, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD) and left ventricular ejection fraction (LVEF). Results After a 7-year follow-up 32.5% patients with successful single RFA of AF (PVIOD 1) showed significant positive LA and LV remodeling: LA diameter 39.3±0.6 vs 36.5±0.6 mm, p=0.0007; LVEDD 53.1±0.6 vs 50.9±0.7 mm, p=0.008; LVESD 34.7±0.8 vs 32.0±0.1 mm, p=0.005 and LVEF 56.8±0.8 vs 62.1±1.1 %, p=0.000008. In 29.1% of patients with success after multiple procedures (PVIOD 2) occurred significant reverse LA remodeling: LA diameter 41.9±0.7 vs 40.2±0.6 mm, p=0.04. Clinical success (PVIOD 3) after RFA was defined as a significant reduction in the number and duration of AF episodes with or without previously ineffective antiarrhythmic drugs (AAD) class I and III. In 14.5% of subjects with long-term clinical success (PVIOD 3 and baseline LA diameter 43.2±1.0 mm) remodeling of LA and LV was not occurred. In 23.9% of patients with procedural and clinical failure after RFA (PVIOD 4) long-term follow-up showed significant negative remodeling of LA and LV: LA diameter 44.7±0.7 vs 47.4±0.7 mm, p=0.006; LVEDD 52.8±0.9 vs 57.1±0.6 mm, p=0.0006; LVESD 36.5±1.1 vs 40.7±1.2 mm, p=0.006 and LVEF 50.7±1.7 vs 43.8±1.8 %, p=0.004. Conclusions Single successful RFA of pulmonary veins in early stage of AF with normal LA diameter cure arrhythmia, which was proved with LA and LV positive remodeling after a 7-year follow-up. With increase of LA diameter, the success of RFA decrease. The multiple procedures slow the progression of AF, but are less effective because of long periods of time between them. Clinical success and role of AAD therapy are also important in AF management. If AF is not treated with RFA properly on time it becomes progressive disease.

Incidence of atrial fibrillation detected by an insertable cardiac monitor in a large real-world cohort of heart failure patients with reduced and preserved ejection fraction

Abstract Background Subcutaneous implantable cardiac monitors (ICM) have the capability to detect atrial fibrillation (AF) episodes with high degree of accuracy [1]. Objective We investigated the incidence of AF in patients implanted with an ICM and a clinical history of heart failure (HF) with reduced or preserved left ventricular ejection fraction (LVEF). Methods Patients with history of HF admissions who were implanted with an ICM were identified from the aggregated and de-identified electronic health record (EHR) database during 2007-2021. The device collected data were merged with the EHR data to create a de-identified database of real-world patients. Patients were included if they had ≥180 days of device follow-up. ICMs detect AF based on incoherence of RR intervals and absence of single p-wave between two R-waves [1]. All ICM detected AF episodes stored with at least 30 seconds of ECG at onset were adjudicated using an artificial intelligence (AI) model. The AI model was previously trained and validated using over 60K manually adjudicated episodes and was shown to have an accuracy of over 97% [2]. ICM detected AF episodes with AI model based true probability of AF ≥ 0.9 was analyzed. The Kaplan-Meier incidence curves for AF incidence as a function of episode duration, clinical history of AF, and LVEF are reported. Results A total of 1020 LINQ ICM patients with history of HF admission prior to implant were identified from the deidentified real-world dataset. LVEF was available in 889 (87%) patients, of whom 394 (44%) had EF <50%, and 495 (56%) had EF≥50%. NYHA class was available in 296 (29%) patients, of whom 39 (13%) were class I, 126 (43%) were class II, 112 (38%) were class III, and 19 (6%) were class IV. Patients had an average age of 68±13 years with 52% being males and had clinical history of hypertension in 95%, diabetes in 56%, coronary artery disease in 75%, AF in 57%, stroke/TIA in 51%, and renal dysfunction in 53%. A total of 911 patients with ≥180 days of follow-up (average follow-up of 25.8 months) were included. A total of 8407 episodes from 358 patients were classified by the AI model as true AF. The incidence of AF as a function of episode duration, clinical history of AF and reduced vs preserved LVEF are shown in Figures A, B, and C respectively. Incidence of AF, as detected by an ICM over 42 months of follow-up, was estimated to be 38% to 46% depending on AF episode duration. Estimated 42-month AF incidence was 23% in patients with no clinical history of AF. The 42-month AF incidence was 44% vs 47% in HF patients with reduced versus preserved LVEF. Conclusion Incidence of AF, as detected by an ICM over 3 years of follow-up, was estimated to be in close to half of ICM patients with history of HF events. Close to one fourth of the patients with no prior clinical history of AF had newly detected AF. AF incidence was similar in HF patients with preserved versus reduced LVEF in this real-world cohort.

Symptoms and atrial fibrillation burden measured by an insertable cardiac monitor in endurance athletes

Abstract Background Atrial fibrillation (AF) is the most common cardiac arrhythmia in athletes, but knowledge regarding AF burden, symptoms and quality of life (QoL) in endurance athletes with AF is limited. Purpose To study AF burden by continuous monitoring using insertable cardiac monitor (ICM), AF symptoms and QoL in endurance athletes with paroxysmal AF. Methods In endurance athletes diagnosed with paroxysmal AF who reported ≥2 episodes of AF, of which ≥1 during the past six months, we continuously monitored AF using ICM. Episodes recognized as AF by ICM were validated by a cardiologist. We defined AF burden as the cumulative duration of AF episodes lasting ≥30 secs divided by the total duration of monitoring. AF symptoms were assessed using the 21-item Atrial Fibrillation Effect on QualiTy-of-Life Questionnaire (AFEQT). AFEQT produces a summary score and three subscale scores (symptoms, daily activities, treatment concerns), ranging from 0 (complete AF-related disability) to 100 (no AF-related disability). We defined any score <80 as clinically relevant AF symptoms. We classified athletes according to the modified European Heart Rhythm Association (mEHRA) classification. Sport participation was obtained by questionnaires. Height and weight were measured and physical fitness was examined during cardiopulmonary exercise testing. Results A total of 38 athletes (3 female, 8%) were included. Table 1 shows their characteristics. Eight of the athletes (21%) had recurrent AF after previous AF ablation therapy. ICM recordings were available in 30 athletes who were monitored for an average of 53±21 days (mean±SD). Eighteen athletes (60%) had ≥1 AF episode, the median number of AF episodes was 2 (interquartile range 8.75), and the mean AF burden was 1.4±2.5%. The mean AFEQT summary score was 84±12 and 11 athletes (29%) had an AFEQT summary score <80. The mean AFEQT symptom subscale score was 78±18). While 21 athletes (55%) had a symptom subscale score <80, indicating clinically relevant symptomatic AF, 9 (24%) scored <60, indicating more severely symptomatic AF. Figure 1 shows ICM-detected AF burden across categories of mEHRA classes and categories of the AFEQT summary score. The AF burden corresponded to both AFEQT scores and mEHRA categories, with a higher AF burden associated with more symptomatic AF (Figure 1). AF burden was numerically lower in athletes with recurrent AF after previous AF ablation therapy, compared to athletes previously not treated with AF ablation (0.6% vs. 1.7%, p= 0.66), but previously ablated athletes were more symptomatic (AFEQT symptom subscale score 68 vs. 80, p= 0.04). Conclusions Despite a relatively low AF burden during continuous monitoring with ICM, a majority of the athletes had clinically relevant symptomatic AF. Athletes with recurrent AF after previous ablation therapy had a numerically lower AF burden, but were more symptomatic compared to athletes with paroxysmal AF not previously treated with AF ablation.

Spontaneous fluctuation in atrial fibrillation burden and duration in patients with implantable loop monitors.

Most studies of device-detected atrial fibrillation (AF) have recommended indefinite anticoagulation once a patient crosses a particular threshold for AF duration or burden. However, durations and burdens are known to fluctuate over time, but little is known about the magnitude of spontaneous fluctuations and the potential impact on anticoagulation decisions. To quantify spontaneous fluctuations in AF duration and burden in patients with implantable loop recorders (ILRs) METHODS: We reviewed all ILR interrogations for patients with non-permanent AF at our institution from 2018 to 2023. We excluded patients treated with rhythm control. The duration of longest AF episode at each interrogation was classified as<6, 6-24, and>24h, and the AF burden reported at each interrogation was classified as<2%, 2%-11.4%, and>11.4%. Out of 156 patients, the mean age at ILR implant was 70.9±12.5 years, CHA2DS2-VASc score was 4.2±1.8, duration of ILR follow-up was 23.4±11.2 months, and number of ILR interrogations per patient was 18.0±8.9. The duration of longest AF episode at any point during follow-up was<6, 6-24, and>24h in 110, 30, and 16 patients, respectively. Among the 30 patients with a longest AF episode of 6-24h at some point during follow-up, out of 594 total ILR interrogations, only 75 (12%) showed a longest episode of 6-24h. In the remaining 519 interrogations, the longest episode was<6h. In patients with a longest episode of>24h at any point during follow-up (n=16), only 47 out of 320 total ILR interrogations (15%) showed an episode of>24h. When evaluating AF burden, 96, 38, and 22 patients had maximum reported AF burdens of<2%, 2%-11.4%, and>11.4% at any point during ILR follow-up. Among those with a maximum burden of 2%-11.4% at some point during follow-up (n=38), out of 707 ILR interrogations, only 76 (11%) showed a burden of 2%-11.4%. In the remaining 631 interrogations, the burden was<2%. In the 22 patients with a burden>11.4% at some point during follow-up, only 80 out of 480 interrogations (17%) showed a burden of>11.4%. In 65% of interrogations, the burden was<2%. Significant, spontaneous fluctuations in AF burden and duration are common in patients with ILRs. Even in patients with AF episodes of 6-24h or>24h at some point during follow-up, the vast majority of interrogations show episodes of<6h. Similarly, in patients with burdens of 2%-11.4% or>11.4% at some point during follow-up, the vast majority of interrogations show burdens of<2%. More data are needed to determine whether crossing an AF burden or duration threshold once is sufficient to merit lifelong anticoagulation or whether spontaneous fluctuations in AF burden and duration should impact anticoagulation decisions.

Discordant Treatment Goals for PatientsWith Atrial Fibrillation and Clinical Trials Metrics.

Most clinical trials define successful atrial fibrillation (AF) treatment as no AF episodes longer than 30 seconds. Yet, there has been minimal study of how patients define successful treatment and whether their perspectives align with trial outcomes. Survey patients with AF to identify: 1) what aspect of AF is most important to address (frequency, duration, or severity of AF episodes); 2) what AF burden would be considered acceptable to consider treatment successful; and 3) to establish patient preferences for successful treatment thresholds for a validated patient-reported outcome (PRO) score. We surveyed patients receiving active care for AF at a single tertiary care center modeled after the Toronto AF Severity Scale (AFSS). The survey consisted of current and "successful treatment" AF frequency, burden, and symptom domains; and baseline socioeconomic information. Of 7,000 invitations, 852 individuals completed the survey (12% response) with a mean age of 65 ± 13 years, 36.5% were female, and they had a mean CHA2DS2-VAsc score of 2.9 ± 1.9. Overall, 114 (13%) selected a decrease in AF episode duration as their top treatment priority, 505 (59%) episode frequency, and 230 (27%) episode severity. Overall, 207 (24%) patients would only consider a treatment successful if they never had AF again, whereas 645 (76%) patients considered success to be fewer AF episodes. A total of 341 (40%) patients would only consider a treatment successful if AF episodes lasted less than a few minutes, whereas 509 (60%) patients would accept AF episodes lasting >30minutes. An AFSS symptom score≤5 was considered a good outcome by 80% of respondents. Patients prioritize decreased AF frequency over improvements in severity or duration, and an AFSS≤5 would be a reasonable outcome of AF treatment. Most patients would consider treatment successful if they had more than 1 AF episode lasting longer than 30 seconds. Future clinical trial design should consider patients' perspectives when designing outcomes.

Targeting Nrf2/HO-1 and NF-κB/TNF-α signaling pathways with empagliflozin protects against atrial fibrillation-induced acute kidney injury in rats

A bidirectional relationship exists between atrial fibrillation (AF) and kidney function. Uncontrolled AF may lead to kidney injury, whereas renal dysfunction may contribute to AF initiation and maintenance. This study aimed to investigate the protective effect of the sodium glucose cotransporter-2 inhibitor empagliflozin (EMPA) on acute kidney injury (AKI) associated with AF induced by acetylcholine and calcium chloride (ACh/CaCl2) in rats and elucidate the potential underlying mechanism. Rats were randomly divided as follows: control (CTRL) group: administered vehicles only; AF group: intravenously injected 1 ml/kg of an ACh/CaCl2 mixture for seven days to induce AF; EMPA group: orally administered EMPA (30 mg/kg) for seven days; AF+EMPA10 and AF+EMPA30 groups: co-administered the induction mixture and EMPA (10 and 30 mg/kg, respectively) for seven days. Our results showed that EMPA (10 and 30 mg/kg) effectively maintained kidney function and demonstrated a significant antioxidant potential. EMPA also suppressed AF-induced renal tubulointerstitial injury and fibrotic changes concurrently with reducing renal levels of the pro-inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-6, as well as the pro-fibrotic marker transforming growth factor beta-1 and collagen type I. Mechanistically, EMPA boosted nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) renal tissue expression while repressing nuclear factor kappa B (NF-κB) activation. In addition, these beneficial effects of EMPA on kidneys were concurrent with its ability to effectively inhibit AF-related electrocardiographic changes, reduce incidence and duration of AF episodes, and markedly suppress serum B-type natriuretic peptide and C-reactive protein levels. In conclusion, EMPA protected against AKI associated with AF induced by ACh/CaCl2 in rats through simultaneous modulation of the Nrf2/HO-1 and the NF-κB/TNF-α signaling pathways, exerting antioxidant, anti-inflammatory, and anti-fibrotic effects.

Screening for atrial fibrillation: the role of CHA2DS2-VASc and atrial fibrillation burden.

Individuals with subclinical atrial fibrillation (AF) face an increased risk of thromboembolic events, which may potentially be mitigated through AF screening and subsequent anticoagulation. However, data from randomized clinical trials (RCTs) indicate a lower stroke risk in subclinical AF compared with the clinical phenotype. This-along with the inherent bleeding risk related to anticoagulation-seems to render the net clinical benefit of AF screening less evident. Further, current guidelines recommend consideration of CHA2DS2-VASc score and AF episode duration to guide screening and treatment. These recommendations, in general, lack support and seem questionable in view of the limited RCT data. More evidence is warranted to provide insights into the potential benefits of screening and treatment of screen-detected AF in specific population subgroups and AF phenotypes.

Healthcare utilisation and quality of life according to atrial fibrillation burden, episode frequency and duration

BackgroundWe aimed to evaluate the association between atrial fibrillation (AF) burden, duration and number of episodes with healthcare utilisation and quality of life in patients with early paroxysmal AF without...

The Incidence of Atrial Fibrillation After Percutaneous Patent Foramen Ovale Closure Detected by Implantable Loop Recorders

BackgroundPatent foramen ovale (PFO) is seen in 25% of the general population but in up to 50% of patients ≤60 years old with cryptogenic strokes. Trials have shown that PFO closure vs medical therapy reduces the risk of future strokes. PFO closure may cause atrial fibrillation (AF), with prior trials reporting an incidence of 2% to 11.9%. However, the true incidence of AF after PFO closure is unknown due to limitations in prior studies for long-term monitoring. MethodsThis is a retrospective observational study at a single center. Patients who underwent PFO closure and had an implantable loop recorder prior to PFO closure were included. The final review included 38 patients who had at least 2 months of implantable loop recorder data post-PFO closure. ResultsTen out of 38 (26%) patients developed AF post-PFO closure. The median time to the first episode of AF was 3.95 weeks, with 40% having their first AF episode after 3 months. Median duration of AF episodes was 1 hour. One hundred percent had spontaneous termination of AF. Of the AF patients, 70% were started on oral anticoagulant therapy. ConclusionsOur review shows a higher incidence of AF post-PFO closure as compared with most reported prior studies. We recommend larger prospective studies to explore the true incidence of AF post-PFO closure, its clinical impact, and subsequent stroke risk.

Prevalence of atrial fibrillation on a 24-hour Holter in adult Indians

ObjectiveTo evaluate paroxysmal atrial fibrillation (AF) prevalence in Indian adults who completed 24-Hour Holter monitoring. MethodsA total of 23,847 patients (36.9 % women) were analyzed for AF duration using a software algorithm. ResultsAF was diagnosed in 4153 (17.4 %) patients with a median AF duration of 13 min and 55 s. ConclusionAF prevalence was high and largely untreated. The short duration of AF episodes indicates a low likelihood of detection during clinical visits, highlighting its potential underestimation in Indian healthcare.

Spontaneous atrial fibrillation occurrence following transesophageal atrial burst pacing in rats

Abstract Purpose Animal models play a crucial role in elucidating the complex pathophysiology of atrial fibrillation (AF) and in identifying and testing novel antiarrhythmic strategies. We aimed to develop and characterize a new experimental rat model of AF, induced by long-term transesophageal atrial electrical stimulation, and to investigate whether the "AF begets AF" concept applies to small rodent hearts. Method Twelve adult male Wistar rats were randomized into two groups: Sham (n = 5) and AF (n = 7). All rats were implanted at the beginning of the study with ECG radiotelemetry devices and underwent continuous ECG monitoring throughout the study. To induce AF, the rats in the AF group underwent atrial pacing for 10 consecutive days (15 successive cycles of stimulation/day, 20 s each, with a free interval of 5 min between cycles; 4,000 stimuli/min, stimulus duration 6 ms, voltage 3 V above the diastolic threshold). A similar procedure was applied to the Sham group, but without performing the actual electrical stimulation. The number and duration of spontaneous AF episodes were evaluated based on continuous ECG monitoring prior to, during, and for one week after transesophageal atrial pacing. The inducibility of AF and the occurrence and duration of spontaneous AF episodes were evaluated and compared between the two groups. Results Atrial fibrillation was induced in 85.7% of the rats subjected to atrial electrical pacing (Figure, A), with an average global inducibility of 44.0% ± 16.9% and a mean AF duration of 123.2 ± 96.3 s. No induced or spontaneous AF episodes were recorded in any of the Sham animals. In the AF group, none of the animals presented spontaneous AF before transesophageal atrial pacing. However, in the AF rats, after atrial electrical stimulation initiation, the number of atrial premature beats significantly increased (21.3 ± 6.8 / 24-h post-stimulation vs. 7.3 ± 6.5 / 24-h at baseline; p&amp;lt; 0.01; Figure, B), and all rats presented spontaneous AF episodes (Figure, C). At the end of the study, AF rats presented a total number of 23.9 ± 2.3 AF episodes / 24-h (Figure, D), with a mean AF burden of 337.7 ± 25.06 s / 24-h. Conclusions Our data demonstrate that, despite the small size of the atria, the "AF begets AF" concept is applicable in small rodents. The study presents a novel rat model of AF, in which spontaneous AF occurs following long-term atrial electrical stimulation. Given that the model is relatively rapid and easy to implement, it provides a setup for further investigation of AF pathophysiology, and for identifying and testing novel therapeutic strategies for AF.Figure 1

Higher Frequency of Premature Atrial Contractions Correlates With Atrial Fibrillation Detection after Cryptogenic Stroke.

Covert atrial fibrillation (AF) is a major cause of cryptogenic stroke. This study investigated whether a dose-dependent relationship exists between the frequency of premature atrial contractions (PACs) and AF detection in patients with cryptogenic stroke using an insertable cardiac monitor (ICM). We enrolled consecutive patients with cryptogenic stroke who underwent ICM implantation between October 2016 and September 2020 at 8 stroke centers in Japan. Patients were divided into 3 groups according to the PAC count on 24-hour Holter ECG: ≤200 (group L), >200 to ≤500 (group M), and >500 (group H). We defined a high AF burden as above the median of the cumulative duration of AF episodes during the entire monitoring period. We evaluated the association of the frequency of PACs with AF detection using log-rank trend test and Cox proportional hazard model and with high AF burden using logistic regression model, adjusting for age, sex, CHADS2 score. Of 417 patients, we analyzed 381 patients with Holter ECG and ICM data. The median age was 70 (interquartile range, 59.5-76.5), 246 patients (65%) were males, and the median duration of ICM recording was 605 days (interquartile range, 397-827 days). The rate of new AF detected by ICM was higher in groups with more frequent PAC (15.5%/y in group L [n=277] versus 44.0%/y in group M [n=42] versus 71.4%/y in group H [n=62]; log-rank trend P<0.01). Compared with group L, the adjusted hazard ratios for AF detection in groups M and H were 2.11 (95% CI, 1.24-3.58) and 3.23 (95% CI, 2.07-5.04), respectively, and the adjusted odds ratio for high AF burden in groups M and H were 2.57 (95% CI, 1.14-5.74) and 4.25 (2.14-8.47), respectively. The frequency of PACs was dose-dependently associated with AF detection in patients with cryptogenic stroke.

Incidence and patterns of atrial fibrillation after catheter ablation of typical atrial flutter-the FLUTFIB study.

In patients with atrial flutter (AFL), ablation of the cavotricuspid isthmus (CTI) is a highly effective procedure to prevent AFL recurrence, but atrial fibrillation (AF) may occur during follow-up. The presented FLUTFIB study was designed to identify the exact incidence, duration, timely occurrence, and associated symptoms of AF after CTI ablation using continuous cardiac monitoring via implantable loop recorders. One hundred patients with AFL without prior AF diagnosis were included after CTI ablation (mean age 69.7 ± 9.7 years, 18% female) and received an implantable loop recorder for AF detection. After a median follow-up of 24 months 77 patients (77%) were diagnosed with AF episodes. Median time to first AF occurrence was 180 (43-298) days. Episodes lasted longer than 1 h in most patients (45/77, 58%). Forty patients (52%) had AF-associated symptoms.Patients with and without AF development showed similar baseline characteristics and neither HATCH- nor CHA2DS2-VASc scores were predictive of future AF episodes. Oral anticoagulation (OAC) was stopped during FU in 32 patients (32%) and was re-initiated after AF detection in 15 patients (15%). No strokes or transient ischaemic attack episodes were observed during follow-up. This study represents the largest investigation using implantable loop recorders (ILRs) to detect AF after AFL ablation and shows a high incidence of AF episodes, most of them being asymptomatic and lasting longer than 1 h. In anticipation of trials determining the duration of AF episodes that should trigger OAC initiation, these results will help to guide anticoagulation management after CTI ablation.

Novel laparoscopic renal denervation immediately reduces atrial fibrillation inducibility: a swine model study

Catheter-based approaches may have inherent limitations in achieving effective renal denervation (RDN) and treatment of atrial fibrillation (AF). This study aimed to investigate the acute effects of novel laparoscopic RDN on modulating AF inducibility using a swine model. Four and five swine were randomly allocated to the sham and RDN groups, respectively. Each swine underwent measurement of the atrial effective refractory period (AERP) and AF induction tests using burst atrial pacing before and immediately after sham or RDN procedures with and without vagal nerve stimulation (VNS). A laparoscopic RDN procedure circumferentially ablated the renal nerves round the renal arteries using radiofrequency energy. There was no significant difference in the baseline AERP between the two groups (p > 0.05). Under VNS, AERP was significantly increased by 20 ms after laparoscopic RDN (95% CI = 0–30, p = 0.004). Compared to the sham group, the RDN group showed significantly reduced AF inducibility [OR (95% CI) = 0.32 (0.13–0.76) and 0.24 (0.11–0.57) with and without VNS, respectively]. After laparoscopic RDN, the duration of inducible AF episodes was significantly shortened from 28 (10–77) s to 7 (3–11) s (p < 0.001). The novel laparoscopic RDN can immediately reduce AF inducibility in a swine model.

Episode-level characteristics of atrial fibrillation are associated with symptomatic events

Abstract Background Symptoms related to Atrial Fibrillation (AF) can be debilitating are the main driver to seek hospital attention. However, many patients do not experience any symptoms and intra-subject variation is also seen. The reasons for this variability are unclear and a better understanding of the features associated with symptomatic AF episodes may improve stratification and personalisation of care. Purpose To evaluate the features associated with symptomatic versus asymptomatic AF episodes recorded using an insertable cardiac monitor (ICM). Methods We linked a deidentified database of aggregated electronic health records from 2007-2021 to a manufacturer’s device data warehouse with continuous diagnostic monitoring data. ICM-detected AF episodes of a minimum of one hour duration were retrospectively analysed. Symptomatic AF was defined as episodes temporally correlated with patient activation of a handheld symptom activator device. Episode- level comparison of mean heart rate at detection and during the entire AF episode, AF episode duration, activity index and AF evidence score (a linear scale based on episode irregularity) between symptomatic and asymptomatic patients was performed. Data was reported as mean ± standard deviation or median (inter-quartile range) if non-normally distributed. Wilcoxon Signed-Rank test was used for per-subject paired analysis. Multi-variate logistic regression model with binomial distribution and exchangeable correlation structure was used to identify factors associated with symptomatic episodes. A Generalized Estimating Equations model was used to account for multiple AF episodes within a subject. Results 417,432 unique episodes were recorded in 11,436 patients. 6,190 (1.48%) episodes from 1776 patients were marked as symptomatic. These were longer (5.5 (12.1) hours vs 3.7 (9.3) hours), had a higher mean HR at onset (105.7±29.3bpm vs 89.1+-24.6bpm) and a greater AF evidence score (97.6+-26.9 vs 82.1+-24.4). On multi- variate logistic regression, AF evidence score, and mean HR was independently associated with symptomatic AF (table 1). Per subject analysis of 1589 patients with both symptomatic and asymptomatic episodes also suggested significantly higher AF evidence scores. (-3.64±22.0). Discussion: This is the largest episode-level characterisation of AF episodes in patients with an ICM. The AF evidence score, a marker of ventricular rate variability, may be useful for the remote stratification of AF episodes. Prospective study of stratification based on this parameter would be of value.Regression model of symptomatic AF

Предиктори утримання синусового ритму в пацієнтів із пізньою персистентною фібриляцією передсердь після електричної кардіоверсії під час 6-місячного проспективного спостереження

The aim – to study the predictors of sinus rhythm (SR) maintenance in patients with persistent atrial fibrillation (AF) and duration of AF episode ≥90 days at 6-months follow-up after elective direct current (DC) cardioversion.Materials and methods. The cohort single-center study analyzed clinical and instrumental data from 59 persistent AF patients with duration of its episode ≥90 days (up to 12 months), who underwent an elective DC cardioversion. At 6-months follow-up, patients were subdivided into the groups depending on SR maintenance: 32 (54 %) patients with a maintained SR (G1), and 27 (46 %) patients with a failure to maintain SR (G2).Results. G2, as compared to G1, demonstrated more advanced heart failure (stage C occurred in 74 % and 44 %, respectively [p=0,019]). According to transthoracic echocardiography (TTE) data, G1, as opposed to G2, was characterized by better baseline structure parameters of left heart chambers, particularly the diameter of left atrium (LA), end-diastolic and end-systolic volumes left ventricular (LV) volumes, higher LV systolic function (by LV ejection fraction [EF]), and the majority of the cases without or with mild pulmonary hypertension (PH). Transesophageal echocardiography data suggested the cases of LA spontaneous (echo) contrast and LA appendage flow velocity (LAAFV) ≤ 40 cm/s to be more frequent in G2, in contrast to G1. We revealed the following predictors of SR maintenance after DC cardioversion at 6-months follow-up: higher LV EF (OR 1,07 (95 % CI 1,01–1,13); р=0,021); LAAFV &gt; 40 cm/s (OR 4,33 (95 % CI 1,06–17,78); р=0,042), and less advanced PH (OR 0,24 (95 % CI 0,06–0,93); р=0,038). TTE data from G1 at 6-months follow-up after DC cardioversion suggested the reverse remodeling of both atria (the decrease of LA diameter, LA and right atrium volumes and their indexes). Additionally, G2 demonstrated a worsening in LV systolic function (the rise of LV end-systolic volume and decrease of LV EF), as opposed to G1. Moreover, at 6-months follow-up, G2 patients presented with more advanced severity of PH, as well as mitral and tricuspid regurgitation, in contrast to G1.Conclusions. Better LV systolic function, LAAFV &gt; 40 cm/s and less advanced PH were the predictors of SR maintenance in patients with persistent AF and duration of its episode ≥ 90 days at 6-months follow-up after elective DC cardioversion. The SR maintenance at 6-months follow-up associated with the reverse remodeling of let heart chambers and right atrium. On the contrary, a failure to maintain SR associated with the decrease of LV systolic function, and more advanced PH, mitral and tricuspid regurgitation.

Atrial Fibrillation Ablation in Young Adults: Measuring Quality of Life Using Patient-Reported Outcomes Over 5 Years.

Ablation is used for both rhythm control and improved quality of life (QoL) in atrial fibrillation (AF). It has been suggested that young adults may experience high recurrence rates after ablation and data remain lacking regarding QoL benefits. We aimed to investigate AF ablation outcomes and QoL benefits in young adults undergoing AF ablation using a large prospectively maintained registry and automated patient-reported outcomes (PRO). All patients undergoing AF ablation (2013-2016) at our center were prospectively enrolled. Patients aged 50 years or younger were included. For PROs, QoL measures and symptoms were assessed at baseline, 3 months after ablation, and every 6 months thereafter. The AF severity score served as the main assessment of QoL. A total of 241 young adults (age, 16-50 years) were included (17% female, 40.3% persistent AF). In all, 77.2% of patients remained arrhythmia-free during the first year of follow-up (80% in nonstructural AF and 66% in structural AF). Using PROs, 90% of patients reported improvement in QoL throughout all survey time points up to 5 years postablation (P<0.0001). The baseline median AF severity score was 14 and improved to between 2 and 4 on all follow-up after ablation (P<0.0001). Patients also reported fewer and shorter AF episodes, fewer emergency room visits secondary to AF, and fewer hospitalizations (P<0.0001). Ablation remains an effective rhythm-control strategy in young adults with AF. Young adults also experience significant improvement in QoL with reduction of the frequency and duration of AF episodes and AF-related healthcare utilization.

Detection of Atrial Fibrillation Using Insertable Cardiac Monitors in Patients With Cryptogenic Stroke in Japan (the LOOK Study): Protocol for a Prospective Multicenter Observational Study

Paroxysmal atrial fibrillation (AF) is a probable cause of cryptogenic stroke (CS), and its detection and treatment are important for the secondary prevention of stroke. Insertable cardiac monitors (ICMs) are clinically effective in screening for AF and are superior to conventional short-term cardiac monitoring. Japanese guidelines for determining clinical indications for ICMs in CS are stricter than those in Western countries. Differences between Japanese and Western guidelines may impact the detection rate and prediction of AF via ICMs in patients with CS. Available data on Japanese patients are limited to small retrospective studies. Furthermore, additional information about AF detection, including the number of episodes, cumulative episode duration, anticoagulation initiation (type and dose of regimen and time of initiation), rate of catheter ablation, role of atrial cardiomyopathy, and stroke recurrence (time of recurrence and cause of the recurrent event), was not provided in the vast majority of previously published studies. In this study, we aim to identify the proportion and timing of AF detection and risk stratification criteria in patients with CS in real-world settings in Japan. This is a multicenter, prospective, observational study that aims to use ICMs to evaluate the proportion, timing, and characteristics of AF detection in patients diagnosed with CS. We will investigate the first detection of AF within the initial 6, 12, and 24 months of follow-up after ICM implantation. Patient characteristics, laboratory data, atrial cardiomyopathy markers, serial magnetic resonance imaging findings at baseline, 6, 12, and 24 months after ICM implantation, electrocardiogram readings, transesophageal echocardiography findings, cognitive status, stroke recurrence, and functional outcomes will be compared between patients with AF and patients without AF. Furthermore, we will obtain additional information regarding the number of AF episodes, duration of cumulative AF episodes, and time of anticoagulation initiation. Study recruitment began in February 2020, and thus far, 213 patients have provided written informed consent and are currently in the follow-up phase. The last recruited participant (May 2021) will have completed the 24-month follow-up in May 2023. The main results are expected to be submitted for publication in 2023. The findings of this study will help identify AF markers and generate a risk scoring system with a novel and superior screening algorithm for occult AF detection while identifying candidates for ICM implantation and aiding the development of diagnostic criteria for CS in Japan. UMIN Clinical Trial Registry UMIN000039809; https://tinyurl.com/3jaewe6a. DERR1-10.2196/39307.

Gq-Mediated Arrhythmogenic Signaling Promotes Atrial Fibrillation

Atrial fibrillation (AF) is promoted by various stimuli like angiotensin II, endothelin-1, epinephrine/norepinephrine, vagal activation, or mechanical stress, all of which activate receptors coupled to G-proteins of the Gαq/Gα11-family (Gq). Besides pro-fibrotic and pro-inflammatory effects, Gq-mediated signaling induces inositol trisphosphate receptor (IP3R)-mediated intracellular Ca2+ mobilization related to delayed after-depolarisations and AF. However, direct evidence of arrhythmogenic Gq-mediated signaling is absent. To define the role of Gq in AF, transgenic mice with tamoxifen-inducible, cardiomyocyte-specific Gαq/Gα11-deficiency (Gq-KO) were created and exposed to intracardiac electrophysiological studies. Baseline electrophysiological properties, including heart rate, sinus node recovery time, and atrial as well as AV nodal effective refractory periods, were comparable in Gq-KO and control mice. However, inducibility and mean duration of AF episodes were significantly reduced in Gq-KO mice-both before and after vagal stimulation. To explore underlying mechanisms, left atrial cardiomyocytes were isolated from Gq-KO and control mice and electrically stimulated to study Ca2+-mobilization during excitation-contraction coupling using confocal microscopy. Spontaneous arrhythmogenic Ca2+ waves and sarcoplasmic reticulum content-corrected Ca2+ sparks were less frequent in Gq-KO mice. Interestingly, nuclear but not cytosolic Ca2+ transient amplitudes were significantly decreased in Gq-KO mice. Gq-signaling promotes arrhythmogenic atrial Ca2+-release and AF in mice. Targeting this pathway, ideally using Gq-selective, biased receptor ligands, may be a promising approach for the treatment and prevention of AF. Importantly, the atrial-specific expression of the Gq-effector IP3R confers atrial selectivity mitigating the risk of life-threatening ventricular pro-arrhythmic effects.

Device-detected atrial fibrillation in a large remote-monitored cohort: implications for anticoagulation and need for new pathways of service delivery

BackgroundRemote monitoring (RM) can facilitate early detection of subclinical and symptomatic atrial fibrillation (AF), providing an opportunity to evaluate the need for stroke prevention therapies. We aimed to characterize the burden of RM AF alerts and its impact on anticoagulation of patients with device-detected AF.MethodsConsecutive patients with a cardiac implantable electronic device, at least one AF episode, undergoing RM were included and assigned an estimated minimum CHA2DS2-VASc score based on age and device type. RM was provided via automated software system, providing rapid alert processing by device specialists and systematic, recurrent prompts for anticoagulation.ResultsFrom 7651 individual, 389,188 AF episodes were identified, 3120 (40.8%) permanent pacemakers, 2260 (29.5%) implantable loop recorders (ILRs), 987 (12.9%) implantable cardioverter defibrillators, 968 (12.7%) cardiac resynchronization therapy (CRT) defibrillators, and 316 (4.1%) CRT pacemakers. ILRs transmitted 48.8% of all AF episodes. At twelve-months, 3404 (44.5%) AF < 6 min, 1367 (17.9%) 6 min–6 h, 1206 (15.8%) 6–24 h, and 1674 (21.9%) ≥ 24 h. A minimum CHA2DS2-VASc score of 2 was assigned to 1704 (63.1%) of the patients with an AF episode of ≥ 6 h, 531 (31.2%) who were not anticoagulated at 12-months, and 1031 (61.6%) patients with an AF episode duration of ≥ 24 h, 290 (28.1%) were not anticoagulated.ConclusionsDespite being intensively managed via RM software system incorporating cues for anticoagulation, a substantial proportion of patients with increased stroke risk remained unanticoagulated after a device-detected AF episode of significant duration. These data highlight the need for improved clinical response pathways and an integrated care approach to RM.Trial registrationAustralian New Zealand Clinical Trial Registry: ACTRN12620001232921.Graphical