Subclinical Atrial Fibrillation Research Articles

The 2024 ESC guidelines for management of atrial fibrillation : AF-CARE as new credo

The new 2024 ESC guidelines on the management of patients with atrial fibrillation (AF) introduces the AF-CARE pathway as the central acronym for AF management. As aresult, the management of Comorbidities and risk factors is moving to the forefront of AF management. However, the new guideline also includes important changes in Avoidance stroke and thromboembolism, such as amodified risk score (CHA2DS2-VA) and astatement on anticoagulation in subclinical atrial fibrillation. There are also changes in the concepts of Rhythm and rate control with an upgrading of rhythm control and catheter ablation. Finally, the guideline recommends regular Evaluation and reassessment of the patient's course for optimal AF management. Here, we summarize key points of the new guidelines and discusses some recommendations on aspects that can also be assessed differently.

In subclinical AF, the benefit of apixaban vs. aspirin on stroke or systemic embolism trended higher with CHA2DS2-VASc >4.

Lopes RD, Granger CB, Wojdyla DM, et al. Apixaban vs aspirin according to CHA2DS2-VASc score in subclinical atrial fibrillation: insights from ARTESiA. J Am Coll Cardiol. 2024;84:354-364. 39019530.

Identifying at-risk patients for atrial high-rate episodes by machine learning

Abstract Background Current evidence suggests that atrial high rate episodes (AHRE)/subclinical atrial fibrillation (AF) are associated with increasing risk of clinical AF, and subsequently, ischaemic stroke and other adverse cardiovascular events. Purpose To construct a high-performance model by machine learning (ML) for the prediction of AHRE detected by a cardiac implantable electronic device (CIED) capable of atrial sensing in a European cohort. Methods We utilized data from a prospective cohort of patients with CIED. AHRE was defined as an episode lasting at least 5 minutes with atrial rate ≥ 175 beats per minute. We divided the cohort into training and internal validation cohorts in 7:3 and used 5-fold cross-validation in the training cohort to assess model performance and prevent model overfitting. Pre-selected features were imported into eight common ML algorithms to predict AHRE, including light gradient boosting machine (LightGBM), random forest (RF), logistic regression, support vector machine, multiple perceptron, eXtreme gradient boosting machine (XGBoost), Gaussian naïve Bayes, and K nearest neighbours. The importance ranking of the features was interpreted by calculating the SHapley Additive exPlanationation (SHAP) value for each feature within the optimal model. Results A total of 500 consecutive patients with CIEDs (mean age 70.2±13.3; 39.2% female) were included. Of these, 164 patients (32.8%) were found to have AHRE. Among all ML models, RF was the best performing model, which obtained the highest AUC (0.738), recall (0.673) and F1-score (0.584) in the internal validation cohort. The results of SHAP showed that antiplatelet, statin, age, white blood cell count, and cardiomyopathy were the first five important features, indicating that the RF model had good interpretability and reliability. Conclusion Our study is the first to demonstrate in a European cohort the effectiveness and feasibility of ML algorithms in predicting AHRE in patients detected by CIEDs. The best RF models require further external validation to assess generalizability to other cohorts.Figure 1Figure 2

Assessing the impact of implantable loop recorder placement on anxiety level

Abstract Background Anxiety is a prolonged state of apprehension or worry that can be an independent predictor of cardiovascular events, associated with a 48% increased risk of cardiac death. About one-third of patients with arrhythmias present with high anxiety levels, and subsequently worse quality of life. In our experience of patient care, many patients feel anxious about the possibility of an arrhythmia that could lead to their demise, especially if their symptoms are undiagnosed. Purpose Our project aims to explore the change in patients’ anxiety levels following implantable loop recorder (ILR) placement. Methods This is a survey-based observational study that was performed in an outpatient clinic and hospital using validated General Anxiety Disorder-7 (GAD-7) questionnaires. Individuals who met indications to undergo ILR implantation including palpitations, syncope, subclinical atrial fibrillation, and cryptogenic stroke underwent baseline assessment of anxiety prior to implantation. Individuals had repeat assessments at 6 weeks and 12 weeks post-implantation to evaluate the effect of ILR placement. Results Our study included 50 individuals. Out of the initial subjects, 10/25 females and 11/25 males were lost to follow-up. The average initial GAD-7 score was 3.3 (Range 0, 15), average 6-week score was 1.6 (Range 0, 14), and average 12-week score was 0.9 (Range 0, 10). Total decrease in GAD-7 score after 6 weeks of having ILR was 50%. Total decrease in GAD-7 score after 12 weeks of ILR was statistically significant at 73% (P=0.03). Females showed greater improvement of GAD-7 scores in comparison to males at 6 weeks (67% vs 36%) and 12 weeks (81% vs 66%). Conclusion Studies have suggested an overall decreased level of anxiety in patients receiving implantable devices that have the potential to treat arrhythmias such as implantable cardiac defibrillators and pacemakers. Our results suggest that the benefit may extend to implantable devices that seek to provide further diagnostic information and aid in the prognostication of disease burden. As seen in our study population, GAD-7 scores showed dramatic improvement with greater percentage in female than male population. After the placement of loop recorders, many patients experience a sense of security with having a device that monitors them. Our study is the first to address the association between ILR and anxiety. Future studies evaluating this association would help increase the power of the study.Figure 1:Bar graph of GAD-7 Scores

Assessment of left atrial function using two-dimensional speckle tracking echocardiography in cryptogenic stroke patients.

Cryptogenic cerebrovascular stroke can be defined as an ischemic stroke that lacks a clear cause, even after a thorough evaluation. It should be distinguished from the embolic stroke of undetermined source (ESUS), a subgroup that includes cardio-embolic sources. This study aims to assess left atrial function through two-dimensional speckle tracking echocardiography (2D-STE) to determine its potential association with cryptogenic stroke andits predictive value for subclinical atrial fibrillation (AF). Our prospective cohort study involved 62 patients with unexplained cerebrovascular stroke or TIA, regardless of gender. Following TEE assessments, 22 patients were excluded due to identified sources of cardio-embolism. The remaining 40 participants were clustered into Group I. Group II, consisted of 40 healthy individuals without significant medical history, served as a control group. Both groups underwent two-dimensional trans-thoracic echocardiography and speckle tracking echocardiography. LA dysfunction parameters exhibited significant differences between Group I and Group II. LV diastolic dysfunction, LAVI, LAEF, and LASr were notably affected in Group I. At the same time, LA diameter in the parasternal long-axis view (PLAX) displayed a significant difference with a p value of 0.001. Within Group I, 14 patients experienced AF episodes (Group Ia, 35%); while, the remaining 26 were categorized as Group Ib (65%). LV diastolic dysfunction displayed a p value < 0.011; while, LAVI, LAEF, and LASr exhibited considerable differences with p values < 0.0001. However, the LA diameter showed no significant variation between the two groups. LASr emerged as the most sensitive and specific parameter for predicting AF, with a cutoff point of ≤ 24.5% and a p value < 0.0001. LAEF showed a cutoff point of ≤ 40.5% and a p value of 0.011. Meanwhile, LAVI demonstrated the lowest sensitivity and specificity, with a mean cutoff point of ≥ 38.5ml/m2 and a p value of 0.003. 2D-STE is crucial for assessing LA dysfunction as a potential cryptogenic stroke cause after TEE and ruling out cardio-embolism sources. LASr serves as a key LA cardiopathy indicator, even preceding AF. LASr independently poses an AF risk. While LAEF and LAVI are significant LA dysfunction parameters and AF predictors, they exhibit lower sensitivity and specificity than LASr.

An international physician survey of current ablation practices in atrial fibrillation: An AIM-AF substudy

BackgroundPractice guidelines recommend ablation (ABL) in atrial fibrillation (AF) for rhythm control. Guidance for antiarrhythmic drugs (AADs) post-ABL is limited. ObjectiveThe purpose of this study was to determine AAD and ABL practices in the United States and Europe. MethodsAn online survey of experienced cardiologists (CDs) (n = 360) and interventional electrophysiologists (EPs) (n = 269) was conducted. AAD- and ABL-related survey questions and responses were analyzed. ResultsABL was preferred more often as first-line AF therapy (Rx) by US CDs/EPs (P ≤.001). ABL was selected to avoid AAD Rx by 46% (50% CDs, 40% EPs); to prevent AF progression by 41% (36% CDs, 47% EPs); and for superior efficacy by 28% (27% CDs, 30% EPs). ABL was used by 9% in asymptomatic AF (9% CDs, 10% EPs), by 14% in subclinical AF (13% CDs, 14% EPs), and by 17% for first AF event (15% CDs, 18% EPs). Primary ABL was preferred in heart failure by 38%. Comorbidities, age, and left atrial size were limitations for ABL by 48%, 40%, and 38%, respectively. AADs were used after ABL for AF/atrial tachycardia (AT) prophylaxis by 34% for 3–6 months and 29% for 1–2 months. AADs were given for a single AF recurrence by 34%, bridging to re-ABL by 32%, and long-term Rx by 34%. AF/AT post-ABL was most often managed with amiodarone (42%–48%). ConclusionABL was frequently preferred over AADs in symptomatic AF but notably also was used for asymptomatic and subclinical AF. Post-ABL AAD Rx for AF prophylaxis or recurrence was frequent, with empiric amiodarone being the most often selected AAD.

Incidence and Clinical Predictors of Atrial Fibrillation in Patients with Dual-Chamber Pacemakers: A Retrospective Analysis

Abstract Atrial fibrillation (AF) is a prevalent cardiac arrhythmia, affecting millions worldwide and increasing in frequency with age. Despite progress in treatment and prevention, AF remains a significant contributor to stroke, heart failure, and overall cardiovascular morbidity. One particularly challenging type of AF, paroxysmal atrial fibrillation (PAF), is often asymptomatic, leading to delayed diagnosis and increasing the risk of severe complications like stroke. The advent of cardiac implantable electronic devices (CIEDs) has significantly improved the ability to detect subclinical AF or atrial high-rate episodes (AHRE), even in patients with no symptoms. These devices, particularly pacemakers, offer long-term, continuous monitoring of atrial rhythms, making them an invaluable tool for diagnosing AF early and assessing its burden in real time. This study focused on a cohort of patients from the Oltenia region who received dual-chamber pacemakers with no prior diagnosis of AF. The research aimed to monitor the incidence of AF in these patients over a follow-up period of 12 to 18 months and to identify potential clinical predictors for developing AF. A total of 91 patients were assessed in this study, all of whom received dual-chamber pacemakers by the pacing guidelines for conditions such as atrioventricular block and sick sinus syndrome. None of the patients had a history of AF at the time of implantation. Follow-up results indicated an incidence of AHRE in 13.19% of patients, with significant predictors including advanced age and the presence of hypertension. These findings align with the broader literature, which consistently associates both factors with an increased risk of AF. The study underscores the importance of continuous monitoring in pacemaker patients, particularly for detecting asymptomatic AF, which may necessitate specific therapeutic interventions. Although the study’s sample size was limited, its findings contribute valuable insights into managing AF in pacemaker patients, particularly regarding early detection and potential risk factors. Future research with larger cohorts is necessary to confirm and expand these results.

Risk of Stroke or Systemic Embolism According to Baseline Frequency and Duration of Subclinical Atrial Fibrillation: Insights From the ARTESiA Trial.

In the ARTESiA trial (Apixaban for the Reduction of Thromboembolism in Patients With Device-Detected Subclinical Atrial Fibrillation), apixaban, compared with aspirin, reduced stroke or systemic embolism in patients with device-detected subclinical atrial fibrillation (SCAF). Clinical guidelines recommend considering SCAF episode duration when deciding whether to prescribe oral anticoagulation for this population. We performed a retrospective cohort study in ARTESiA. Using Cox regression adjusted for CHA2DS2-VASc score and treatment allocation (apixaban or aspirin), we assessed frequency of SCAF episodes and duration of the longest SCAF episode in the 6 months before randomization as predictors of stroke risk and of apixaban treatment effect. Among 3986 patients with complete baseline SCAF data, 703 (17.6%) had no SCAF episode ≥6 minutes in the 6 months before enrollment. Among 3283 patients (82.4%) with ≥1 episode of SCAF ≥6 minutes in the 6 months before enrollment, 2542 (77.4%) had up to 5 episodes, and 741 (22.6%) had ≥6 episodes. The longest episode lasted <1 hour in 1030 patients (31.4%), 1 to <6 hours in 1421 patients (43.3%), and >6 hours in 832 patients (25.3%). Higher baseline SCAF frequency was not associated with increased risk of stroke or systemic embolism: 1.1% for 1 to 5 episodes versus 1.2%/patient-year for ≥6 episodes (adjusted hazard ratio, 0.89 [95% CI, 0.59-1.34]). In an exploratory analysis, patients with previous SCAF but no episode ≥6 minutes in the 6 months before enrollment had a lower risk of stroke or systemic embolism than patients with at least one episode during that period (0.5% versus 1.1%/patient-year; adjusted hazard ratio, 0.48 [95% CI, 0.27-0.85]). The frequency of SCAF did not modify the reduction in stroke or systemic embolism with apixaban (Pinteraction=0.1). The duration of the longest SCAF episode in the 6 months before enrollment was not associated with the risk of stroke or systemic embolism during follow-up (<1 hour: 1.0%/patient-year [reference]; 1-6 hours: 1.2%/patient-year [adjusted hazard ratio, 1.27 (95% CI, 0.85-1.90)]; >6 hours: 1.0%/patient-year [adjusted hazard ratio, 1.02 (95% CI, 0.63-1.66)]). SCAF duration did not modify the reduction in stroke or systemic embolism with apixaban (Ptrend=0.1). In ARTESiA, baseline SCAF frequency and longest episode duration were not associated with risk of stroke or systemic embolism and did not modify the effect of apixaban on reduction of stroke or systemic embolism. URL: https://www.clinicaltrials.gov; Unique identifier: NCT01938248.

The incidence of atrial fibrillation detected by implantable loop recorders: a comparison between patients with and without embolic stroke of undetermined source.

Stroke is the most debilitating outcome of atrial fibrillation (AF). The use of implantable loop recorders increases the detection of AF episodes among patients with embolic stroke of undetermined source. The significance of device-detected AF, or subclinical AF, is unknown. This study aimed to compare the incidence of AF detected by implantable loop recorder in patients with and without embolic stroke of undetermined source. We retrospectively studied all patients without known AF who were referred to our institution for implantable loop recorder implantation following embolic stroke of undetermined source, syncope, or palpitations from March 2009 to November 2019. The primary endpoint was any detection of AF or atrial flutter by implantable loop recorder. Seven hundred and fifty patients were included and followed up for a mean duration of 731 days (SD 443). An implantable loop recorder was implanted following embolic stroke of undetermined source in 323 and for assessment of syncope, palpitations, or another reason in 427 patients. The incidence of AF was significantly (P < 0.001) higher among patients with embolic stroke of undetermined source compared with the non-embolic stroke of undetermined source group; 48.6% vs. 13.8% (for any duration of AF) and 32.2% vs. 12.4% (for AF lasting ≥30 s) both P < 0.001. Kaplan-Meier analysis showed significantly higher incidence of AF for incremental durations of AF up to >5.5 h, but not >24 h. This was driven by longest AF durations of <6 min and between 5.5 h and 24 h, suggesting a bimodal distribution. In a multivariable Cox regression analysis, embolic stroke of undetermined source independently conferred an almost 5-fold increase in the hazard for any duration of AF. The incidence of AF is significantly higher amongst embolic stroke of undetermined source vs. non-embolic stroke of undetermined source patients monitored constantly by an implantable loop recorder. A high number of embolic stroke of undetermined source survivors have short-duration AF episodes. Further work is needed to determine the optimal treatment strategy of these AF episodes in embolic stroke of undetermined source.

Management of Device Detected Subclinical Atrial Fibrillation

Abstract Purpose of Review Whilst the management of clinically apparent atrial fibrillation (AF) is well-described and evidenced, the same is not true for subclinical atrial fibrillation (SCAF) and atrial high rate episodes (AHRE). In this review article we discuss the management of device-detected AHRE/SCAF in light of recent major trials and meta-analyses. Recent Findings Anticoagulation in AHRE/SCAF reduces thromboembolic risk but causes an increase in bleeding events. Of note, ischaemic stroke risk in untreated AHRE/SCAF has been observed to be lesser than that of untreated clinically evident AF. With regard to reduction of AHRE/SCAF prevalence or burden, increased physical activity has been associated with reduced AHRE/SCAF incidence in a dose-dependent manner. There exists mixed evidence for both angiotensin 2 inhibition therapy and statin therapy in the prevention of AHRE/SCAF in studies with smaller populations. Ongoing studies are assessing the impact of sodium-glucose cotransporter-2 inhibition on AHRE/SCAF. Although there is no evidence for atrial overdrive pacing in preventing AHRE/SCAF, limited evidence suggests pacing lead position and reducing ventricular pacing may minimise AHRE/SCAF. Summary The identification of AHRE/SCAF poses unanswered questions regarding treatment. The benefit of anticoagulation in reducing ischaemic stroke is lesser than that seen in clinical AF. As such, anticoagulation decisions in AHRE/SCAF should take into consideration individual bleeding risk, thromboembolic risk, and arrythmia burden. Management of co-morbidities and physical activity show promise in reducing AHRE/SCAF. Further study is required to investigate the impact of various pharmacologic interventions and pacing considerations on the reduction of AHRE/SCAF.

Does apixaban strike out on stroke prevention in subclinical atrial fibrillation?

Does apixaban strike out on stroke prevention in subclinical atrial fibrillation?

Spotlight on hot topics: subclinical atrial fibrillation, risk stratification of channelopathies, and cardioprotection.

Spotlight on hot topics: subclinical atrial fibrillation, risk stratification of channelopathies, and cardioprotection.

Great debate: device-detected subclinical atrial fibrillation should be treated like clinical atrial fibrillation.

Great debate: device-detected subclinical atrial fibrillation should be treated like clinical atrial fibrillation.

Atrial High-Rate Episodes and Subclinical Atrial Fibrillation: State of the Art and Clinical Questions with Complex Solutions.

Atrial high-rate episodes (AHREs) and subclinical atrial fibrillation (AF) are frequently registered in asymptomatic patients with cardiac implantable electronic devices (CIEDs) and insertable cardiac monitors (ICMs). While an increased risk of thromboembolic events (e.g., stroke) and benefits from anticoagulation have been widely assessed in the setting of clinical AF, concerns persist about optimal clinical management of subclinical AF/AHREs. As a matter of fact, an optimal threshold of subclinical episodes' duration to predict stroke risk is still lacking and recently published randomized clinical trials assessing the impact of anticoagulation on thromboembolic events in this specific setting have shown contrasting results. The aim of this review is to summarize current evidence regarding classification and clinical impact of subclinical AF/AHREs and to discuss the latest evidence regarding the potential benefit of anticoagulation in this setting, highlighting which clinical questions are still unanswered.

Heart Failure Events After Long-term Continuous Screening for Atrial Fibrillation: Results From the Randomized LOOP Study.

Mounting evidence indicates that even device-detected subclinical atrial fibrillation is associated with a higher risk of heart failure (HF). However, the potential impact of atrial fibrillation screening on HF remains unknown. The LOOP Study (Atrial Fibrillation detected by Continuous ECG Monitoring using Implantable Loop Recorder to prevent Stroke in High-risk Individuals) evaluated the effects of atrial fibrillation screening on stroke prevention using an implantable loop recorder (ILR) versus usual care in older individuals with additional stroke risk factors. In this secondary analysis, we explored the following HF end points: (1) HF event or cardiovascular death; (2) HF event; (3) event with HF with reduced ejection fraction (HFrEF); and (4) HFrEF event or cardiovascular death. Outcomes were assessed in a Cox model both as time-to-first events and as total (first and recurrent) events analyzed using the Andersen-and-Gill method. Of 6004 participants (mean age 74.7 and 52.7% men), 1501 were randomized to ILR screening and 4503 to the control group. In total, 77 (5.1%) in the ILR group versus 295 (6.6%) in the control group experienced the primary outcome of an HF event or cardiovascular death. Compared with usual care, ILR screening was associated with a nonsignificant reduction in the primary outcome for the time-to-first event analysis (hazard ratio, 0.78 [95% CI, 0.61-1.01]) and the total event analysis (hazard ratio, 0.77 [95% CI, 0.59-1.01]). Similar results were obtained for the HF event. A significant risk reduction in total events was observed in the ILR group for the composite of HFrEF event or cardiovascular death and for HFrEF event (hazard ratio, 0.74 [95% CI, 0.56-0.98] and 0.65 [95% CI, 0.44-0.97], respectively). In an older population with additional stroke risk factors, ILR screening for atrial fibrillation tended to be associated with a lower rate of total HF events and cardiovascular death, particularly those related to HFrEF. These findings should be considered hypothesis-generating and warrant further investigation. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02036450.

Clinical presentation and genetic characterization of early-onset atrial fibrillation in patients affected by long QT syndrome: A single-center experience.

Early-onset atrial fibrillation (AF) has already been observed in approximately 2% of patients with genetically proven long QT syndrome (LQTS). This frequency is higher than population-based estimates of early-onset AF. However, the concomitant expression of AF in LQTS is likely underestimated. The purpose of this study was to examine the clinical presentation, genetic background, and outcomes of a cohort of patients with LQTS and early-onset AF referred to a single tertiary center. Twenty-seven patients diagnosed with congenital LQTS were included in the study based on the documentation of early-onset (age ≤50 years) clinical or subclinical AF episodes in all available medical records, including standard electrocardiograms, wearable monitor or cardiac implantable electronic devices. Seventeen patients experienced clinical AF during the follow-up period. Subclinical AF was detected in 10 patients through insertable or wearable cardiac monitors. In our series, the mean heart rate during AF episodes was found to be relatively low despite the patients' young age and the low or minimal effective doses of beta-blockers used for QTc interval control. All patients exhibiting LQTS and early-onset AF were genotype positive, carrying mutations in the KCNQ1 (66%), KCNH2, KCNE1, and SCN5A genes. Notably, most of these patients carried the same p.(R231C) mutation in the KCNQ1 gene (59%) and were from the same families, suggesting concurrent expression of familial AF and LQTS. LQTS patients are prone to developing clinical and subclinical AF, even at a younger age. The occurrence of early-onset AF in the LQTS population could be more frequent than previously assumed. AF should be considered as a potential dysrhythmia related to LQTS. Our study emphasizes the importance of carefully researching clinical and/or subclinical episodes of AF through strict heart rhythm monitoring in the LQTS population.

Innovative approaches to atrial fibrillation prediction: should polygenic scores and machine learning be implemented in clinical practice?

Atrial fibrillation (AF) prediction and screening are of important clinical interest because of the potential to prevent serious adverse events. Devices capable of detecting short episodes of arrhythmia are now widely available. Although it has recently been suggested that some high-risk patients with AF detected on implantable devices may benefit from anticoagulation, long-term management remains challenging in lower-risk patients and in those with AF detected on monitors or wearable devices as the development of clinically meaningful arrhythmia burden in this group remains unknown. Identification and prediction of clinically relevant AF is therefore of unprecedented importance to the cardiologic community. Family history and underlying genetic markers are important risk factors for AF. Recent studies suggest a good predictive ability of polygenic risk scores, with a possible additive value to clinical AF prediction scores. Artificial intelligence, enabled by the exponentially increasing computing power and digital data sets, has gained traction in the past decade and is of increasing interest in AF prediction using a single or multiple lead sinus rhythm electrocardiogram. Integrating these novel approaches could help predict AF substrate severity, thereby potentially improving the effectiveness of AF screening and personalizing the management of patients presenting with conditions such as embolic stroke of undetermined source or subclinical AF. This review presents current evidence surrounding deep learning and polygenic risk scores in the prediction of incident AF and provides a futuristic outlook on possible ways of implementing these modalities into clinical practice, while considering current limitations and required areas of improvement.

Oral anticoagulation in supraventricular arrhythmia

Atrial fibrillation represents the most frequent persistent cardiac arrhythmia and is associated with an increased morbidity and mortality. An important component of the holistic treatment of atrial fibrillation is oral anticoagulation (OAC) for the prevention of stroke. The CHA2DS2-VASc score as a risk score is recommended for estimation of the individual stroke risk and the concomitant need of OAC in these patients. In the majority of patients the OAC is nowadays carried out with direct oral anticoagulants (DOAC), which have proved to be effective with a moderate side effect profile and have replaced vitamin K antagonists as the standard substance. In the meantime, these principles have become established as the usual practice but some issues regarding OAC in patients with atrial fibrillation are still insufficiently answered. Furthermore, it is unclear whether OACs need to be continued after successful treatment of atrial fibrillation with pulmonary vein ablation or in some cases can even be discontinued. Unanswered questions also remain regarding the treatment of subclinical atrial fibrillation and atrial high-frequency episodes detected by implanted heart rhythm devices. Especially the duration of atrial high-frequency episodes that should trigger the initiation of OAC treatment is still under debate. Therefore, currently the benefits of stroke prevention must be carefully weighed up against the risk of bleeding complications.

Closed loop stimulation reduces the incidence of atrial high-rate episodes compared with conventional rate-adaptive pacing in patients with sinus node dysfunctions.

Subclinical atrial fibrillation (AF) is associated with increased risk of progression to clinical AF, stroke, and cardiovascular death. We hypothesized that in pacemaker patients requiring dual-chamber rate-adaptive (DDDR) pacing, closed loop stimulation (CLS) integrated into the circulatory control system through intra-cardiac impedance monitoring would reduce the occurrence of atrial high-rate episodes (AHREs) compared with conventional DDDR pacing. Patients with sinus node dysfunctions (SNDs) and an implanted pacemaker or defibrillator were randomly allocated to dual-chamber CLS (n = 612) or accelerometer-based DDDR pacing (n = 598) and followed for 3 years. The primary endpoint was time to the composite endpoint of the first AHRE lasting ≥6 min, stroke, or transient ischaemic attack (TIA). All AHREs were independently adjudicated using intra-cardiac electrograms. The incidence of the primary endpoint was lower in the CLS arm (50.6%) than in the DDDR arm (55.7%), primarily due to the reduction in AHREs lasting between 6 h and 7 days. Unadjusted site-stratified hazard ratio (HR) for CLS vs. DDDR was 0.84 [95% confidence interval (CI), 0.72-0.99; P = 0.035]. After adjusting for CHA2DS2-VASc score, the HR remained 0.84 (95% CI, 0.71-0.99; P = 0.033). In subgroup analyses of AHRE incidence, the incremental benefit of CLS was greatest in patients without atrioventricular block (HR, 0.77; P = 0.008) and in patients without AF history (HR, 0.73; P = 0.009). The contribution of stroke/TIA to the primary endpoint (1.3%) was low and not statistically different between study arms. Dual-chamber CLS in patients with SND is associated with a significantly lower AHRE incidence than conventional DDDR pacing.

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.