Device-detected Atrial High-rate Episodes Research Articles

Outcomes of Device-detected Atrial High-rate Episodes in Patients with No Prior History of Atrial Fibrillation: A Systematic Review and Meta-analysis.

Outcomes of device-detected AF remain unclear in individuals without a prior history of AF. A meta-analysis was conducted to evaluate outcomes in individuals with no prior history of AF who experienced device-detected AF. Outcomes assessed were clinical AF, thromboembolism and all-cause mortality. A fixed-effects model was used to calculate RRs with 95% CI. Compared to individuals who did not experience device-detected AF, those who did had increased risks of clinical AF (RR 3.33, 95% CI [1.99.5.57]; p<0.0001) and thromboembolic events (RR 2.21; 95% CI [1.72.2.85]; p<0.0001). The risk of all-cause mortality was similar between both groups (RR 1.19; 95% CI [0.95.1.49]; p=0.13). Subgroup analysis revealed an increased risk of thromboembolic events among device-detected AF .24 hours (RR 12.34; 95% CI [2.70.56.36]). While there is an increased risk of clinical AF and thromboembolism in individuals with device-detected AF, mortality was insignificant.

Consensus on Stroke Prevention in Atrial Fibrillation and Utilization of NOACs in the Real-World Setting in India

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Prevention of stroke and systemic thromboembolism remainsthe cornerstone of the management of AF. Even today, there are unresolved knowledge gaps in AF pathophysiology, screeningand therapeutic strategies and stroke prevention. The modified DELPHI method was used to develop the best practicerecommendations for the management of AF in a real-world setting with the participation of 500 cardiologists across India.The experts concurred that the decision to initiate antithrombotic treatment in patients with transient AF could be based onthe duration of transient AF, the co-existence of the risk factor for stroke and echocardiographic abnormalities impact thedecision. The decision to initiate anticoagulant therapy in device-detected atrial high-rate episodes (AHRE) can be decidedbased on the duration of AHRE, the burden of AHRE and the individual’s risk of stroke and thromboembolism. The benefitof early anticoagulation should be balanced with the risk of intracerebral hemorrhage (ICH), especially in elderly patientsand in severe strokes. Apixaban is the preferred drug in patients with concomitant ischemic heart disease (IHD), patientswith a history of gastrointestinal (GI) bleeding, patients with underlying malignancy, elderly patients with AF, patients withcomorbid diseases and patients with hepatic disease or renal disease. Apixaban was considered to be an affordable noveloral anticoagulant (NOAC) for Indian patients for primary and secondary stroke prophylaxis in AF patients

Association of Device-Detected Atrial High-Rate Episodes With Long-term Cardiovascular and All-Cause Mortality: A Cohort Study

BackgroundDevice-detected atrial high-rate episodes (AHREs) were associated with an increased thromboembolic risk. Although limited data regarding the long-term prognosis of patients with AHRE were controversial, this study aimed to identify the association of device-detected AHRE with mortality. MethodsThis observational study included patients with implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) placement and no history of atrial fibrillation (AF), atrial flutter (AFL), or atrial tachycardia (AT). During follow-up, patients with at least 1 day of AHRE duration ≥ 15 minutes were identified. The primary endpoint was cardiovascular mortality, and the secondary endpoint was all-cause mortality. ResultsDuring a mean follow-up period of 4.2 years, AHREs were detected in 124 of 343 (36.2%) patients. Of these, 44 deaths (35.5%) occurred in 124 patients with AHREs, which was significantly higher than those without AHREs (43 of 219; 19.6%; P = 0.001). The multivariate analysis revealed that patients with AHRE had a significantly higher risk of cardiovascular (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.23-4.67; P = 0.010), and all-cause mortality (HR, 2.31; 95% CI, 1.49-3.59; P < 0.001). Further analysis indicated that this association remained significant in patients with higher burden (≥ 6 hours) but not in patients with lower burden (≥ 15 minutes to 6 hours). Notably, even after excluding the patients diagnosed with clinical AF during follow-up, the remaining patients with AHREs still exhibited a higher risk of cardiovascular and all-cause mortality compared with patients without AHREs. ConclusionsAHREs were prevalent in ICD or CRT-D recipients with no history of clinical AF, AFL, or AT and were associated with more than twice the risk of cardiovascular and all-cause mortality. Clinical Trial RegistrationNo. ChiCTR-ONRC-13003695.

Are device-detected atrial high-rate episodes a risk marker for stroke?

Are device-detected atrial high-rate episodes a risk marker for stroke?

Anticoagulation with edoxaban in patients with long atrial high-rate episodes ≥24 h.

Patients with long atrial high-rate episodes (AHREs) ≥24 h and stroke risk factors are often treated with anticoagulation for stroke prevention. Anticoagulation has never been compared with no anticoagulation in these patients. This secondary pre-specified analysis of the Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High-rate episodes (NOAH-AFNET 6) trial examined interactions between AHRE duration at baseline and anticoagulation with edoxaban compared with placebo in patients with AHRE and stroke risk factors. The primary efficacy outcome was a composite of stroke, systemic embolism, or cardiovascular death. The safety outcome was a composite of major bleeding and death. Key secondary outcomes were components of these outcomes and electrocardiogram (ECG)-diagnosed atrial fibrillation. Median follow-up of 2389 patients with core lab-verified AHRE was 1.8 years. AHRE ≥24 h were present at baseline in 259/2389 patients (11%, 78 ± 7 years old, 28% women, CHA2DS2-VASc 4). Clinical characteristics were not different from patients with shorter AHRE. The primary outcome occurred in 9/132 patients with AHRE ≥24 h (4.3%/patient-year, 2 strokes) treated with anticoagulation and in 14/127 patients treated with placebo (6.9%/patient-year, 2 strokes). Atrial high-rate episode duration did not interact with the efficacy (P-interaction = .65) or safety (P-interaction = .98) of anticoagulation. Analyses including AHRE as a continuous parameter confirmed this. Patients with AHRE ≥24 h developed more ECG-diagnosed atrial fibrillation (17.0%/patient-year) than patients with shorter AHRE (8.2%/patient-year; P < .001). This hypothesis-generating analysis does not find an interaction between AHRE duration and anticoagulation therapy in patients with device-detected AHRE and stroke risk factors. Further research is needed to identify patients with long AHRE at high stroke risk.

Progression of Device-Detected Atrial High-Rate Episodes and the Risk of All-Cause Mortality

Atrial high-rate episodes (AHREs) are prevalent in approximately 1/3 of patients with cardiac implanted electronic devices and are associated with an increased risk of several adverse outcomes. This study aimed to explore the factors associated with AHRE progression and the risk of all-cause mortality. At least 1day with AHRE burden ≥15minutes was identified in 124 of 343 recipients (36.2%) of an implantable cardioverter defibrillator or cardiac resynchronization therapy device. We included patients whose AHRE burden at the time of first detection was ≥15minutes but <24hours (n=107). Various cut-off values (15minutes, 6hours, and 24hours) of daily AHRE burden were analyzed. During an average follow-up of 4.2years, 60 patients (56.1%) experienced ≥1 progression to greater AHRE burden. Patients with hypertension or greater AHRE burden at first detection were associated with faster progression. In addition, 27 deaths (45%) occurred among 60 patients with AHRE progression, compared with 25.5% (12 of 47) for those without progression. After multivariable adjustment, AHRE progression was independently associated with all-cause mortality (hazard ratio 2.56, 95% confidence interval 1.23 to 5.35, p=0.012). Notably, AHRE progression within 1month after their first detection was associated with an increased risk for all-cause mortality (hazard ratio 4.01, 95% confidence interval 1.76 to 9.16, p=0.001) compared with patients without progression. However, a similar risk was not observed among patients with AHRE progression occurring after 1month after their first detection. In conclusion, >1/2 of the patients with AHRE progressed to a greater burden over time. Continuous monitoring of the AHRE burden may help identify patients at great risk for death.

Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole.

To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min…<1 h, 1 h…<24 h, ≥ 24 h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD. In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs ≥6 min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min…<1 h, 99.6% (253/254) for episodes 1 h…<24 h, 100% (71/71) for episodes ≥24 h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA2DS2-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF. A 99.7% detection accuracy for AHRE ≥1 h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.

Capability of guideline-conform remote atrial high rate episode monitoring with a single-chamber implantable defibrillator with atrial sensing

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): BIOTRONIK, Berlin, Germany Introduction Device-detected atrial high-rate episodes (AHRE) and their burden progression are associated with an increased risk for thromboembolic events in correlation with CHA2DS2-VASc score and AHRE burden. To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend the monitoring of AHRE progression along pre-specified strata (6min…&amp;lt;1h, 1h…&amp;lt;24, ≥24h). We sought to assess the capability of a single-lead implantable cardioverter defibrillator (ICD), that is equipped with an atrial dipole for atrial sensing, to remotely detect and monitor AHRE burden progression in patients with standard indication to single-chamber ICD. Methods From the MATRIX (Management and Detection of Atrial Tachyarrhythmias in Patients Implanted With BIOTRONIK DX Systems) registry, we analyzed remotely transmitted, and electrogram (IEGM) AHREs in a subset of patients with remote transmissions and without history of long-standing AF at baseline. For each patient, we selected the first occurring episode per duration stratum and the first subsequent occurrence when progressing to a stratum of any longer duration. After episode adjudication by an independent electrophysiologist, we assessed the classification performance of the device (positive predictive value [PPV]) and analyzed AHRE onset and progression pathways. Results Of the MATRIX cohort, 1,746 patients matched the inclusions criteria (see table for patient characteristics) and 1,451 had no AF history. Of the 258 patients with AHREs (14.8%), 450 out of 465 evaluated episodes were correctly classified as AHRE. Reasons for misclassification were artifact (13) and R-wave oversensing (2). PPV was 96.8% (95% confidence interval 94.7%-98.2%). Grouped by stratum, PPV was 93.9%, 99.5% and 100% for 6min…&amp;lt;1h, 1h…&amp;lt;24 and ≥24h, respectively. Ninety six of 240 patients (40.0%) with a first episode according to the pre-specified strata were progressing to a stratum of longer duration and 9 patients (3.8%) had further progression (see Figure). In 119 out of 1,451 patients without AF history (8.2%), the device detected AHRE and 81 of them (4.6% of analysis set) had a mid to high risk for stroke and were not on anticoagulation therapy. In 121 out of 295 patients with known history of paroxysmal and persistent AF (41.0%), the arrhythmia was confirmed by the device. Discussion and Conclusion: The single-chamber ICD with atrial sensing capabilities correctly classified ≈97% of all adjudicated AHREs ≥6min. About 7% of patients had device-detected AHRE onset and/or progression and a mid to high stroke risk. These patients would potentially benefit the most from a guideline-conform AF monitoring strategy to timely initiate anticoagulation medication for stroke prevention.

Distinct atrial remodeling in patients with subclinical atrial fibrillation: Lessons from computed tomographic images.

AimsCardiac implanted electronic devices (CIEDs) can detect atrial high‐rate episodes (AHREs) and challenge current management of subclinical atrial fibrillation (AF).MethodsTo characterize the anatomic and functional remodeling of cardiac structures between patients with subclinical AF (SCAF) and clinical AF. The predictors for AHREs ≥6 min were also investigated.ResultsWe compared the atrial volume, dynamic function, and peri‐atrial fat between 104 CIEDs (AHREs = 0, n = 12; SCAF, n = 66; CIEDs with AF, n = 26) and 40 paroxysmal AF patients who were planning for catheter ablation (AF for ablation) using 256‐slice multidetector computed tomography for the duration of the AHREs. The maximal volume of the left atrium (LA) and LA appendage (LAA) were significantly smaller; the total emptying fraction (EF) and active EF of the LA and LAA were significantly better in the patients with SCAF than in those with clinical AF. Less peri‐atrial fat (p < 0.001) and a greater LAA/ascending aorta (AA) Hounsfield unit (HU) ratio (p < 0.05) were noted in the patients with SCAF. Significantly increased volume reduced the total EF of LA and LAA and a reduced LAA/AA HU ratio (0.91 ± 0.18 vs 0.98 ± 0.03 vs 0.97 ± 0.05, p < 0.05) were demonstrated in patients with AHREs ≥6 min compared to those with AHREs <6 min and without AHRE. Multivariate analysis showed the reduced LAA/AA HU ratio is an independent predictor for the development of AHREs ≥6 min.ConclusionAs compared to clinical AF, patients with SCAF show a more favorable LA remodeling process. Among the patients with device‐detected AHREs, worse LA remodeling and a reduced LAA/AA HU ratio were associated with the occurrence of AHREs ≥6 min. These findings may provide an incremental value for understanding SCAF.

The Association between Physical Activity and Cardiovascular Implantable Electronic Device-Detected Atrial High Rate Episodes.

Atrial fibrillation is the most common arrhythmia and it is associated with a higher risk of mortality and morbidity. The goal of this study was to assess the correlation between physical activity (PA) and atrial high rate episodes (AHREs) detected by cardiovascular implantable electronic devices (CIEDs). We prospectively collected data from 81 patients from March 2017 to June 2019. Device-detected PA (hours per day) through an accelerometer and occurrence/burden of AHREs were determined at each outpatient clinic visit. Modest AHREs and long AHREs were defined as at least 1 episode of AHREs lasting ≥ 12 hours and 24 hours, respectively. The percentage of total AHREs in the follow-up period was defined as the burden of AHREs. Generalized estimating equations were used to explore the association between PA and occurrence/burden of AHREs to account for repeated measures within a participant. The patients had 336 follow-up visits (mean 4.1 visits each). The prevalence rates of device-detected modest AHREs and long AHREs were 4.8% and 3.9%, respectively. More PA (hours per day) was associated with a lower risk of modest AHREs [odds ratio (OR) 0.671, 95% confidence interval (CI) 0.452-0.997, p = 0.048] and long AHREs (OR 0.536, 95% CI 0.348-0.824, p = 0.004) after adjusting for age, sex, and basic characteristics. More PA had a trend of association with fewer AHREs (β -0.255, 95% CI -0.512 to 0.001, p = 0.051). More PA was associated with a lower risk of AHREs detected by CIEDs in older patients. PA may reduce the risk of AHREs.

Device-detected atrial high rate episodes and the risk of stroke/thrombo-embolism and atrial fibrillation incidence: a systematic review and meta-analysis

BackgroundAtrial High Rate Episodes (AHRE) are asymptomatic atrial tachy-arrhythmias detected through continuous monitoring with a cardiac implantable electronic device. The risks of stroke/Thromboembolic (TE) events and incident clinical Atrial Fibrillation (AF) associated with AHRE varies markedly. ObjectivesTo assess the relationship between AHRE and TE events, and between AHRE and incident clinical AF. MethodsThis systematic review and meta-analysis was conducted following the PRISMA recommendations. PubMed, Scopus, and Google Scholar were searched from inception to 18/02/2021 for studies reporting TE events and incident clinical AF in patients with AHRE, as compared with patients without. ResultsTen out of 8081 records fulfilled the inclusion criteria, for a total of 37 266 patients. Seven out of ten studies excluded patients with prior history of clinical AF (4961 patients), embracing the most recent definition of AHRE. The risk ratio (RR) for TE events in AHRE patients was 2.13 (95% CI: 1.53–2.95, I2: 0%). The incidence of clinical AF was reported in four studies excluding patients with a history of clinical AF (3574 patients). The RR for incident clinical AF was 3.34 (95%CI: 1.89–5.90, I2: 73%). ConclusionsAHRE are significantly associated with systemic thromboembolism and incident clinical AF. Further studies are needed to improve patients' risk stratification and management.

High-Sensitivity C-Reactive Protein is a Predictor of Subsequent Atrial High-Rate Episodes in Patients with Pacemakers and Preserved Ejection Fraction.

Atrial fibrillation (AF) is associated with morbidity and mortality. Modern pacemakers can detect atrial high-rate episodes (AHREs) as a surrogate for AF. It remains controversial whether inflammation is a cause or a consequence of AF. This study investigated whether the inflammatory biomarker high-sensitivity C-reactive protein (hs-CRP) can predict subsequent AHREs. This study gathered prospective data from patients with pacemakers and a left ventricle EF ≥ 50% between 2015 and 2019. The hs-CRP and other cardiac biomarkers at baseline and device-detected AHREs, defined as atrial rate ≥ 180 bpm and duration ≥ 6 min, were determined. Cox regression analysis was used to estimate the independent predictors for AHREs. A total of 171 consecutive patients were included. During the median follow-up of 614 days, 66 patients (39%) developed subsequent AHREs. In the univariate Cox regression analysis, sick sinus syndrome (p = 0.005), prior AF (p < 0.001), mitral A velocity (p = 0.008), and hs-CRP (p = 0.013) showed significant association with the increased risk of AHREs. In the multivariate Cox regression model, hs-CRP (HR = 1.121, 95% confidence interval = 1.015–1.238, p = 0.024) retained its significance. Our results suggest that elevated hs-CRP could predict subsequent AHREs and that inflammation could play a role in AF pathogenesis in patients with preserved EF.

Left ventricular stiffness assessed by diastolic Wall strain predicts asymptomatic atrial high-rate episodes in patients with pacemaker implantation

BackgroundCardiac implantable electronic device-detected atrial high-rate episodes (AHREs) have been reported to be associated with thromboembolic risks. The present study aimed to investigate the association of echocardiographic and clinical parameters with the occurrence of AHREs in patients with a dual-chamber pacemaker (PMI). MethodsOne hundred forty-seven patients (76 males, 75.2 ± 8.9 years) who did not show atrial tachyarrhythmia before the implantation of the PMI were studied. Diastolic wall strain (DWS) and other measurements were assessed during sinus rhythm using transthoracic echocardiography before the PMI. DWS was calculated from the M-mode echocardiographic measurement of the left ventricular (LV) posterior wall thickness at end-systole (PWs) and end-diastole (PWd), and DWS was defined as (PWs-PWd) / PWs. ResultsAHREs (defined as AHREs duration >6 min and atrial rate >180 bpm) were detected in 50 / 147 patients during follow up (38.3 ± 13.8 months). Patients in the AHREs group had reduced DWS (0.29 ± 0.07 vs. 0.39 ± 0.06, p < 0.0001), larger left atrial volume index, thicker LV posterior diameter, higher rate of patients taking β-blocker / diuretics, and higher prevalence of sinus node dysfunction. On multivariable analysis, only DWS was independently associated with AHREs. Patients with reduced DWS (<0.33) had a higher risk of incidences of AHREs. ConclusionLV stiffness assessed by DWS was associated with AHREs in patients with a PMI.

Left Atrial Function Determined by Cardiac Computed Tomography Predicts Device-Detected Atrial High-Rate Episodes in Patients Treated With Cardiac Resynchronization Therapy.

The objective of this study was to examine whether left atrial (LA) volumes and function were associated with atrial high-rate episodes (AHREs) in patients with cardiac resynchronization therapy (CRT). Ninety-two consecutive patients without prior atrial fibrillation underwent clinical evaluation, echocardiograms, and cardiac computed tomography (CT) before CRT implantation and after 6 months. Left atrial volumes and LA emptying fraction (LAEF) were derived by CT images reconstructed at 5% phase increments of the cardiac cycle. Cox regression was used to assess associations between AHRE and LA anatomical and functional variables. Twenty-two patients (24%) developed AHRE during 1.9 years (SD, 1 year) At baseline, higher LAEF was associated with a lower risk of AHRE (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.91-0.98; P = 0.003), and large LA minimal (LAmin) volume was related to higher risk of AHRE (HR, 1.03; 95% CI, 1.00-1.06; P = 0.04). When combining LAEF and LAmin volume, only LAEF remained associated with occurrence of AHRE. Higher passive LAEF was associated with lower risk of AHRE (HR, 0.95; 95% CI, 0.91-0.98; P = 0.003). In patients with CRT, low preimplant LAEF measured by cardiac CT was independently associated with device-detected AHRE.

When is Device-Detected Atrial Fibrillation Actionable?

Device-detected atrial high-rate episodes (AHREs) are frequently encountered in patients with no history of atrial fibrillation (AF) and represent a challenge for clinicians because patients with device-only documented AF have not been included in clinical trials of anticoagulants and other AF therapies. For patients with known history of AF, wireless continuous rhythm monitoring and rapidly acting oral anticoagulants offer the possibility of tailored anticoagulation in response to AHREs, with studies ongoing to evaluate the safety of this approach. This article provides an overview of current evidence on device-detected AHREs and evolving areas of investigation.

Stroke risk in patients with device-detected atrial high-rate episodes.

Cardiovascular implantable electronic devices (CIEDs) can detect atrial arrhythmias, i. e. atrial high-rate episodes (AHRE). The thrombo-embolic risk in patients showing AHRE appears to be lower than in patients with clinical atrial fibrillation (AF) and it is unclear whether the former will benefit from oral anticoagulants. Based on currently available evidence, it seems reasonable to consider antithrombotic therapy in patients without documented AF showing AHRE >24 hours and a CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes mellitus, prior stroke [doubled], vascular disease, age 65–74 years and female sex) ≥1, awaiting definite answers from ongoing randomised clinical trials. In patients with AHRE <24 hours, current literature does not support starting oral anticoagulation. In these patients, intensifying CIED read-outs can be considered to find progression in AHRE duration sooner, enhancing timely stroke prevention. The notion that AHRE and stroke coincide perseveres but should be abandoned since CIED data show a clear disconnect.

Approach to device-detected subclinical atrial fibrillation

Subclinical atrial fibrillation, a commonly encountered entity in patients with implantable devices, has been associated with a number of adverse outcomes – the most important of which is thromboembolism. Through the detection of atrial high rate episodes, implanted devices offer a method to monitor for atrial fibrillation over extended periods of time. Several studies have demonstrated that patients with device-detected atrial tachyarrhythmias have an increased incidence of stroke, especially in the presence of additional risk factors. Yet, there are many uncertainties with limited evidence from randomised clinical studies and no formal guidelines to inform management in this population. This contributes to marked practice heterogeneity, underrecognition and missed opportunities for stroke prevention. We propose a logical approach to management of patients with device-detected atrial high rate episodes pending additional data from ongoing trials.

Atrial high-rate episodes predict clinical outcome in patients with cardiac resynchronization therapy

Objectives. Up to 50% of patients qualified for cardiac resynchronization therapy (CRT) have documented atrial fibrillation (AF) prior to CRT-implantation. This finding is associated with worse prognosis but few studies have evaluated the importance of post-implant device-detected AF. This study aimed to assess the prognostic impact of device-detected atrial high-rate episodes (AHRE), as a surrogate for AF. Design. Data were retrospectively obtained from consecutive patients receiving CRT. Baseline clinical data and data from CRT device-interrogations, performed at a median of 12.2 months after CRT-implantation, were evaluated with regard to prediction of the composite endpoint of death, heart transplant or appropriate shock therapy. Median follow-up time was 51 months post-implant. Results. The study included 377 patients. Preoperative AF was present in 49% and associated with worse outcome. The cumulative burden of AHRE at 12 months post-implant was an independent predictor of the primary endpoint. During the first 12 months after CRT-implantation, AHRE were detected in 25% of the patients with no preoperative diagnosis of AF. This finding was not associated with worse outcome. Conclusions. In CRT recipients, the cumulative burden of AHRE during the first year of follow-up was associated with worse long-term clinical outcome. Prospective trials are needed to determine if a rhythm control strategy is to be preferred in patients with CRT.

169-05: Atrial high rate episodes are frequently detected in patients with cardiac resynchronization therapy and longer episodes increases the risk of thromboembolic events

Background: Knowledge about the incidence of atrial high rate episodes (AHRE) in patients with cardiac resynchronization therapy (CRT) is limited and conflicting, likewise whether the duration of AHRE have implication for the risk of thromboembolic events (TE). Methods: This observational study included patients who received a CRT device at Aarhus University Hospital between 2000-2010, and with no history of atrial fibrillation. All patients had standard indication for CRT treatment. All device-detected AHRE ≥6 minutes were included, and patients were divided into 3 groups; no AHRE, short AHRE (between 6 minutes and 24 hours) and long AHRE (>24 hours). The annual risk was calculated as events per patient-year with 95% confidence intervals (CI). Results: Of 304 patients, 79 (26%) develop short AHRE and 63 (21%) had long AHRE during a median follow-up of 4.8 years, resulting in an annual risk of short AHRE of 13 (95% CI, 11–15) % and long AHRE of 4 (95% CI, 3–6) %. The mean age was 65 (SD 13) years, mean LVEF was 24 (SD 6) % and median CHA2DS2-VASc score was 3 (IQR 2–5) with no significant difference between the three groups. CRT pacing was lower in patients with long AHRE than those with short or no AHRE (97 (IQR 94–99) vs. 99 (IQR 97–100) vs. 99 (IQR 96–100) %, P < 0.001 and P = 0.44). Anticoagulation therapy was more likely to be initiated in patients with long AHRE than those with short or no AHRE (68 vs. 25 vs. 17%; P < 0.001 and P = 0.12). The annual risk of TE events was similar in patients without AHRE and in patients after the detection of short AHRE, but significantly increased after detection of long AHRE (1.4 (95% CI, 0.9–2.4) % vs. 1.8 (95% CI, 0.8–4.0) % vs. 4.0 (95% CI, 2.0–8.0) %, P = 0.65 and P = 0.03). Conclusion: AHRE ≥6 minutes are detected in nearly half of the patients with no prior atrial fibrillation after CRT implantation, but only AHRE lasting longer than 24 hours are significantly associated with TE events.

Management of device-detected atrial high-rate episodes.

Atrial tachyarrhythmias are common in patients with cardiac implantable electronic devices (CIEDs) with atrial leads. These atrial tachyarrhythmias are detected as atrial high-rate episodes (AHREs) by the CIED. AHREs may be brief, infrequent, and asymptomatic, and may be detected before clinical arrhythmia is apparent. These subclinical device-detected AHREs are associated with an increased stroke risk, similar to, but to a lesser degree than, clinically apparent atrial fibrillation detected by routine methods. Whether a specific duration of AHREs is needed before the risk of stroke increases and whether treatment with anticoagulation for subclinical device-detected AHREs reduces stroke risk is unclear.