Daily Atrial Fibrillation Burden Research Articles

Filtering of remote monitoring alerts transmitted by cardiac implantable electronic devices and reclassification of atrial fibrillation events by a new algorithm

Cardiac implantable electronic devices (CIEDs) are an important means of atrial fibrillation (AF) detection. However, the AF burden measurements and notifications transmitted by CIEDs are not directly related to the clinical classification of paroxysmal, persistent, or permanent AF. Moreover, AF alerts are the most frequent form of notification, imposing a time-consuming review on caregivers. The purpose of this study was to compare the incidence of standard AF burden-related notifications in remotely monitored (RM) patients with the incidence of events detected after filtering by a new proprietary algorithm implementing the standard European Society of Cardiology classification of AF. Between 2017 and 2022, all RM patients with daily AF burden measurements available for ≥30 days and ≥1 AF burden-related alerts were enrolled at 68 medical centers. The incidence of CIED-transmitted alerts was compared to that of AF episodes detected by a new proprietary algorithm and classified as "first recorded episode of AF", "paroxysmal AF", "increased paroxysmal AF", "persistent AF", or "end of persistent AF back to paroxysmal AF or back to sinus rhythm." Between January 2017 and September 2022, this retrospective study analyzed data from 4162 recipients of an Abbott, Biotronik, Boston Scientific, or Medtronic CIED, RM over mean follow-up of 605 ± 386 days. The algorithm broke down 67,883 AF burden-related alerts into 9728 (14.3%) clinically relevant AF events. A new AF alert algorithm successfully identified clinically significant AF events in RM CIED recipients and would markedly limit the total number of transmitted alerts that require review by caregivers.

7 EXPLOITABILITY AND DISTRIBUTION OF SLEEP APNEA AND ATRIAL FIBRILLATION BURDEN DURING LONG TERM FOLLOW-UP IN UNSELECTED DUAL-CHAMBER PACEMAKER PATIENTS

Abstract Background Sleep Apnea (SA) and Atrial Fibrillation (AF) are common comorbidities in paced patients (pts). Modern pacemakers (PMs) are capable of storing continuous long-term reliable daily information about: 1) AF burden (AFB); 2) severity of SA, defined by a respiratory disturbances index (RDI) measured by a minute ventilation sensor-based algorithm. Aim of the study This retrospective study aimed to assess exploitability and distributions of daily AFB and RDI over long-term follow-up (FU) in unselected dual-chamber (DC) paced pts implanted with PMs equipped with a dedicated SA monitoring (SAM) algorithm and followed-up in their Institutions. Pts affected by permanent AF were excluded from the study. Methods Data from long-term FU have been collected after implant, together with pts clinical baseline characteristics. Between Aug 2013 and Oct 2018, n=210 pts were implanted with Reply 200/Kora 100 PMs (MicroPort CRM, Saluggia-VC, Italy), equipped with the SAM algorithm. At each FU visit all the daily AFB and RDI data were retrieved from the PM memory. Days of FU have been considered exploitable (Expl-FU) when both the daily AFB and RDI information were available. Results Data from n=864 visits are available for analysis. Pts characteristics: male 56.2%, mean age 76.4±11.1 yrs, BMI 25.6±4.4 Kg/m2; implant indication: sinus node disease 40.5%, AV block 46.2%; 37.1% of pts had a history of paroxysmal AF. The overall FU / Expl-FU durations were 1.94±1.23 / 1.48±1.14 years (23.7% of days were lost due to various technical reasons). The PMs classified RDI as valid in 92.3%±19.5% of nights (85.7% of pts showed >90% of valid nights, Figure 1). Severe or moderate SA was suspected in 43.8% and 59.5% of pts, respectively. An AFB≥25% / 50% was observed in 9.5% / 5.7% of pts (Figure 2). Conclusions In this retrospective study, SA and AF have been shown to highly affect unselected DC paced pts. PM devices proved to be really helpful in consistently and reliably measure both SA (RDI successfully identified in 92.3%±19.5% of nights) and AF (9.5% of pts with AFB≥25%). This is relevant to allow clinicians to implement early preventive actions to improve clinical prognosis.

Association between implantable defibrillator-detected sleep apnea and atrial fibrillation: The DASAP-HF study.

The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe sleep apnea (SA). In the present analysis, we tested the hypothesis that RDI could also predict atrial fibrillation (AF) burden. Patients with ejection fraction ≤35% implanted with an ICD were enrolled and followed up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly mean RDI value was considered, as calculated during the entire follow-up period and over a 1-week period preceding the sleep study. The endpoints were as follows: daily AF burden of ≥5 min, ≥6 h, ≥23 h. Here, 164 patients had usable RDI values during the entire follow-up period. Severe SA (RDI ≥ 30 episodes/h) was diagnosed in 92 (56%) patients at the time of the sleep study. During follow-up, AF burden ≥ 5 min/day was documented in 70 (43%), ≥6 h/day in 48 (29%), and ≥23 h/day in 33 (20%) patients. Device-detected RDI ≥ 30 episodes/h at the time of the polygraphy, as well as the polygraphy-measured apnea hypopnea index ≥ 30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using a time-dependent model, continuously measured weekly mean RDI ≥ 30 episodes/h was independently associated with AF burden ≥ 5 min/day (hazard ratio [HR]: 2.13, 95% confidence interval [CI]: 1.24-3.65, p = .006), ≥6 h/day (HR: 2.75, 95% CI: 1.37-5.49, p = .004), and ≥23 h/day (HR: 2.26, 95% CI: 1.05-4.86, p = .037). In heart failure patients, ICD-diagnosed severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden.

Abstract 6902: Heart Failure Measurements Using Heartlogic Directly Correlates with Increased Burden of Atrial Fibrillation

Introduction: Atrial Fibrillation (AF) is a risk factor for death in patients with heart failure (HF). Device sensor measurements from ICDs/CRT-Ds can provide detailed data on the impact of AF on HF. HeartLogic index, HF sensor monitoring can detect worsening HF with high sensitivity. Hypothesis: We hypothesize HeartLogic sensors would be able to detect worsening HF with increased AF burden. Methods: AF burden was measured as time greater than atrial tachyarrhythmia rate of 170 bpm. Each patient day was grouped into 7 groups based on daily AF burden: No AF/normal sinus rhythm (NSR), >0min, >6min, >1hr, >5.5hr, >12hr, and 24hr. Total 15,533 US patients from ALTITUDE database with HeartLogic devices and a minimum of 365 days of data were analyzed, 754 patients with all 7 levels of AF burden were included. For each group, mean daily heart sounds (S3, S1), respiratory rate (RR), rapid shallow breathing index (RSBI), thoracic impedance (TI), daily and night heart rate (HR, NHR), patient time active, HeartLogic index, and the percent of in-alert days were evaluated. Sensors were compared during each AF burden and during NSR using paired T-test. Results: AF burden groups above 6min were associated to significant worsening in S1, RR, RSBI, NHR, HR and HeartLogic index (figure). Significant reduction in patient activity occurred above 5.5hr of AF burden. In-alert days (%) increased significantly during AF burden above 6min compared with NSR. Conclusions: This data suggests potential use of HeartLogic sensors to identify patients whose HF status is most impacted by development of AF and those who may benefit most from rhythm control. Additional studies using sensor based AF management may improve clinical outcomes.

Implantable defibrillator-computed respiratory disturbance index predicts new-onset atrial fibrillation: the DASAP-HF study

Abstract Introduction Sleep apnea (SA), as measured by polysomnography, is a risk factor for atrial fibrillation (AF). The DASAP-HF study previously demonstrated that the Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe SA, is associated with cardiovascular events, and independently predicts death. Purpose In the present analysis we tested the hypothesis that device-detected RDI could also predict AF burden. Methods Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly average RDI value was considered, as calculated by the algorithm during the entire follow-up period and over a 1 week period preceding the sleep study, and patients were stratified according to an RDI value ≥ or <30 episodes/hour. The endpoints were: daily AF burden of ≥5 minutes, ≥6 hours, ≥23 hours. Results 164 enrolled patients had usable RDI values during the entire follow-up period. Severe SA (RDI≥30 episodes/h) was diagnosed in 92 (56%) patients at the time of the polysomnographic study. During a median follow-up of 25 months, AF burden ≥5 minutes/day was documented in 70 (43%), ≥6 hours/day in 48 (29%), and ≥23 hours/day in 33 (20%) patients. Device-detected RDI≥30 episodes/h at the time of the polysomnographic study, as well as the polysomnography-measured apnea hypopnea index ≥30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using time-dependent Cox model continuously measured weekly average RDI≥30episodes/h was independently associated with AF burden ≥5 minutes/day (HR: 2.13, 95% CI: 1.24–3.65, p=0.006), ≥6 hours/day (HR: 2.75, 95% CI: 1.37–5.49, p=0.004), and ≥23 hours/day (HR: 2.26, 95% CI: 1.05–4.86, p=0.037), after correction for history of AF, left atrial diameter, and gender. Conclusions In heart failure patients implanted with an ICD, device-diagnosed severe SA is associated with a higher risk of AF. In particular, severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Promoted by the Italian Heart Rhythm Society (AIAC).Supported by a research grant from Boston Scientific.

Association Between Changes in Physical Activity and New-Onset Atrial Fibrillation After ICD/CRT-D Implantation.

Background: Changes in physical activity (PA) after implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillators (CRT-D) implantation were unknown. The association of PA changes with new-onset atrial fibrillation (AF), cardiac death and all-cause mortality was unclear in patients at high risk of sudden cardiac death.Methods: Patients receiving ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Changes in PA were considered from baseline status to 1 year after implantation. New-onset AF was defined as the first atrial high-rate episode ≥1% of the daily AF burden detected after implantation.Results: Over a mean follow-up of 50.3 months, 124 new-onset AF events (36.2%), 61 cardiac deaths (17.8%), and 87 all-cause deaths (25.4%) were observed in 343 patients with ICD/CRT-D implantation. PA at 1 year after implantation was increased compared with PA at baseline (11.97 ± 5.83% vs. 10.82 ± 5.43%, P = 0.008), and PA at 1 year was improved in 210 patients (61.2%). Per 1% decrease in PA was associated with 12.4, 18.3, and 14.3% higher risks of new-onset AF, cardiac death and all-cause mortality, regardless of different baseline characteristics. Patients with decreased PA had 2-fold risks of new-onset AF (hazard ratio [HR] = 1.972, 95% confidence interval [CI]: 1.352–2.877, P < 0.001) as high as those with unchanged/increased PA. Decreased PA was an independent risk factor for cardiac death (HR = 3.358, 95% CI: 1.880–5.996, P < 0.001) and all-cause mortality (HR = 2.803, 95% CI:1.732–4.535, P < 0.001).Conclusion: PA decrease after ICD/CRT-D implantation is associated with a higher incidence of new-onset AF, resulting in worsened outcomes in cardiac death and all-cause mortality.

Bucindolol Decreases Atrial Fibrillation Burden in Patients With Heart Failure and the ADRB1 Arg389Arg Genotype.

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Abstract 12993: Oral Anticoagulation Prescription Depends on Both Atrial Fibrillation Duration and CHA 2 DS 2 -VASc Score

Introduction: Current guideline recommendations for oral anticoagulation (OAC) in patients with atrial fibrillation (AF) are based on CHA 2 DS 2 -VASc score alone. In patients with cardiac implantable electronic devices (CIEDs), it is poorly understood how the interaction between AF duration and CHA 2 DS 2 -VASc score influence the decision to prescribe OAC. Methods: Data from the Optum® de-identified Electronic Health Record dataset were linked to the Medtronic CareLink database of CIEDs. An index date was assigned as the later of 6 months after device implant or 1 year after EHR data availability. CHA 2 DS 2 -VASc score was assessed via EHR data prior to the index date. Maximum daily AF burden (No AF, 6 minutes-23.5 hours, and &gt;23.5 hours) was assessed over the 6 months prior to index date. OAC prescription rates were computed prior to the index date as a function of both AF duration and CHA 2 DS 2 -VASc score. Results: A total of 35,779 patients with CHA 2 DS 2 -VASc scores ≥1 were identified, including 8,581 who were prescribed OAC and 27,198 not prescribed OAC during the observation period. The overall OAC prescription rate among the subset of 12,938 patients with device-detected AF &gt;6 minutes was 36.7% and the rate was nearly 60% higher for patients with a maximum daily AF burden &gt;23.5 hours (45.4%) compared to those with 6 minutes-23.5 hours (28.7%). OAC prescription rates increased monotonically with both increasing AF duration and CHA 2 DS 2 -VASc score, reaching a maximum of 67.2% for patients with AF &gt;23.5 hours and a CHA 2 DS 2 -VASc score ≥5 (Table). Conclusion: In contrast with guideline recommendations, real-world prescription of OAC increased with both increasing duration of AF and CHA 2 DS 2 -VASc score. This mirrors recent evidence demonstrating that stroke risk also increases with both of these features and highlights the need for further research into the role of AF duration, stroke risk, and the need for anticoagulation in patients with devices capable of long-term AF monitoring.

Real-world behavior of CRT pacing using the AdaptivCRT algorithm on patient outcomes: Effect on mortality and atrial fibrillation incidence.

BackgroundThe AdaptivCRT (aCRT) algorithm continuously adjusts cardiac resynchronization therapy (CRT) according to intrinsic atrioventricular conduction, providing synchronized left ventricular pacing in patients with normal PR interval and adaptive BiV pacing in patients with prolonged PR interval. Previous analyses demonstrated an association between aCRT and clinical benefit. We evaluated the incidence of patient mortality and atrial fibrillation (AF) with aCRT compared with standard CRT in a real‐world population.Methods and ResultsPatients enrolled in the Medtronic Personalized CRT Registry and implanted with a CRT from 2013‐2018 were divided into aCRT ON or standard CRT groups based upon device‐stored data. A Frailty survival model was used to evaluate the potential survival benefit of aCRT, accounting for patient heterogeneity and center variability. Daily AF burden and first device‐detected AF episodes of various durations were recorded by the device during follow‐up.A total of 1814 CRT patients with no reported long‐standing AF history at implant were included. Mean follow‐up time was 26.1 ± 16.5 months and 1162 patients (64.1%) had aCRT ON. Patient survival probability at 36 months was 88.3% for aCRT ON and 83.7% for standard CRT (covariate‐adjusted hazard ratio [HR] = 0.71, 95% CI: 0.53‐0.96, P = .028). Mean AF burden during follow‐up was consistently lower in aCRT ON patients compared with standard CRT. At 36 months, the probability of AF was lower in patients with aCRT ON, regardless of which AF definition threshold was applied (6 minutes‐30 days, all P < .001).ConclusionUse of the AdaptivCRT algorithm was associated with improved patient survival and lower incidence of AF in a real‐world, prospective, nonrandomized registry.

Abstract 23: Detection of Atrial Fibrillation by Implantable Cardiac Monitoring After Acute Central Retinal Artery Occlusion

Introduction: Central retinal artery occlusion (CRAO) is a form of ischemic stroke and necessitates a comprehensive workup, including for cardioembolic sources such as atrial fibrillation (AF). However, the incidence of new AF diagnosed after CRAO is unknown. We aimed to examine the incidence of new, cardiac device-detected AF after CRAO in a large population-based cohort. Methods: Using patient-level data from the Optum® de-identified EHR dataset (2007-2017) linked with Medtronic implantable cardiac device data, we identified patients that had a diagnosis-code corresponding to CRAO and no known history of AF, and who also had either a device in-situ at the time of CRAO or implanted ≤1 year post-CRAO with continuous AF monitoring data available. AF incidence was defined as ≥2 minutes of device-detected AF in a day. Results: Of 467,167 patients screened, 246/433 (56.8%) with CRAO had no history of AF, of whom 39 had an eligible implantable cardiac device (mean age 66.7±14.8, 41.0% female). Prevalence of vascular risk factors was high (hypertension, 71.8%; hyperlipidemia, 61.5%; coronary artery disease, 46.2%). Within 3 months, 7.7% of these patients (n=3) had device-detected AF. At 36 months, 33.3% of patients (n=13). The maximum daily AF burden post CRAO ranged from 2 minutes to 24 hours with a mean of 390±530 minutes. Of the patients with device-detected AF, 9 were found by an implantable cardiac monitor and 4 by pacemaker or defibrillator. Discussion: The rate of long-term AF detection after CRAO was high in patients with implanted cardiac devices, and appears comparable with rates seen after cryptogenic ischemic stroke and in other high-risk populations. Our findings warrant future prospective studies not limited by selection bias.

Changes in Management Following Detection of Previously Unknown Atrial Fibrillation by an Insertable Cardiac Monitor (from the REVEAL AF Study)

The REVEAL AF study demonstrated a high incidence of previously undetected atrial fibrillation (AF) using insertable cardiac monitors (ICMs) in patients with risk factors for AF and stroke. This analysis evaluated whether ICM monitoring led to changes in clinical management after AF detection. Patients with CHADS2 scores ≥3 (or =2 with ≥1 additional AF risk factor) but no history of AF received an ICM and were followed 18 to 30 months. Physicians recorded changes in clinical management in response to AF detection at scheduled (every 6 months) and unscheduled follow-up visits. Changes in clinical management included oral anticoagulation, rhythm or rate control pharmacotherapy, cardioversion, ablation, and cardiac subspecialist referral. In 387 patients who met inclusion criteria and received an ICM, AF was found in 115. A change in clinical management was taken in 87 patients with AF (76%). In 80 of these 87, a change was taken at the first visit after AF detection. In total, 31 patients (27%) with AF had ≥2 visits at which changes in clinical management were taken. The most common change was initiation of oral anticoagulation (n = 73, 63% of patients with AF). Patients with a change in clinical management at the first visit after AF detection tended to have longer AF episodes and a higher maximal daily AF burden compared with AF patients for whom no change was taken (longest episode: 52 vs 28 minutes; maximal daily AF burden:112 vs 23 minutes). Changes in management more frequently occurred at visits where patients reported AF-compatible symptoms (65% vs 46% of visits, p = 0.01). In conclusion, ICM monitoring to identify AF guides both immediate and long-term patient management in a population at high risk for stroke.

Detection of new atrial fibrillation in patients with cardiac implanted electronic devices and factors associated with transition to higher device-detected atrial fibrillation burden

In patients with cardiac implanted electronic devices, detection of new atrial fibrillation (AF) is associated with an increased risk of stroke. To characterize daily AF burden at first detection and the rate of temporal transition to higher device-detected AF burden. A pooled analysis of data from 3 prospective projects was analyzed, and 6580 patients (mean age 68 ± 12 years, 72% male) with no history of AF and no use of anticoagulants at baseline were identified. Various thresholds of daily AF burden (5 minutes and 1, 6, 12, and 23 hours) were analyzed. Among the study population of 6580 patients, a new AF, with an AF burden of ≥5 minutes, was detected in 2244 patients (34%) during a follow-up period of 2.4 ± 1.7 years. Among these patients, 1091 (49.8%) transitioned to a higher AF-burden threshold during follow-up. A higher duration of daily AF burden manifest at first detection and CHADS2 score ≥2 were associated with faster transition to a subsequent higher burden. Approximately 24% of patients transitioned from a lower threshold to a daily AF burden of ≥23 hours during follow-up. More than one-third of patients with no history of AF developed device-detected AF, with attainment of different thresholds of daily AF burden over time. Continuous long-term monitoring, especially when the initial detection corresponds to a higher daily AF burden and the CHADS2 score is ≥2, could support timely clinical decisions on anticoagulation by capturing transitions to higher AF-burden thresholds.

The increased risk of stroke/transient ischemic attack in women with a cardiac implantable electronic device is not associated with a higher atrial fibrillation burden.

To evaluate if the increased thromboembolic risk in female patients may be related to a higher burden of atrial fibrillation (AF). Data collected in a prospective observational research of patients implanted with a cardiac implantable electrical device (CIED) were analysed. We included 2398 patients: 489 (20.4%) were female and 1909 (79.6%) were male (oral anticoagulants treatment in 23.2%, independent of gender). During the follow-up (mean 42.8, median 37.7 months), 26 thromboembolic events occurred in 22 patients, with an incidence rate ratio of both stroke and stroke/transient ischemic attack (TIA) significantly higher in females compared with males [2.00, 95% confidence interval (CI) 1.53-2.61, P< 0.001 for stroke; 1.77 (95% C1.37-2.31, P< 0.001 for stroke/TIA]. An AF burden ≥5 min was a common finding (44% of patients), with no difference between men and women. The maximum daily AF burden and the time to evolution in permanent AF did not differ according to gender. The results of multivariate Cox regression showed that female gender, as well as history of CABG, were significant independent predictors of stroke and female gender was also an independent predictor of stroke/TIA. Among patients implanted with a CIED, an AF burden of at least 5 min is a common finding, (44% of patients). Female patients have a risk of stroke and TIAs that is around two-fold that of male patients, but this increased risk cannot be ascribed to a higher burden of AF or to differences in the evolution to permanent AF. ClinicalTrials.gov Identifier: NCT01007474.

Patient Activity Decreases and Mortality Increases After the Onset of Persistent Atrial Fibrillation in Patients With Implantable Cardioverter-Defibrillators.

The study sought to determine the effect of persistent atrial fibrillation (AF) on device-measured activity and mortality. Patients with AF often complain of fatigue, which may be reflected in patient activity. Daily activity can be objectively measured by implanted devices. We retrospectively studied patients (n= 266, 88% male, 69 ± 10 years of age) from the deidentified Medtronic CareLink database with persistent AF (≥28 consecutive days with≥23 h of AF/day), dual-chamber implantable cardioverter-defibrillators (ICDs) capable of monitoring daily activity and AF burden, no AF between months 1 and 6 post-implant, and≥1 year of data. The first persistent AF episode occurred 980 ± 534 days after implant and lasted a median of 87 days (interquartile range: 49 to 161 days). Average daily activity over a week just prior (baseline) to the first persistent AF episode was compared to each of the 4 weeks during the AF episode and to each of the weeks following termination ofthe persistent AF episode. Daily activity decreased significantly from the baseline week (135 min/day) compared to each of the 4 consecutive weeks after AF onset (8%, 11%, 14%, and 17% decrease, p< 0.001). Mortality at 4 years was increased in patients with persistent AF compared to a matched group with no persistent AF (20.6% vs. 8.6%, p<0.01). Patients with ICDs have a significant reduction in activity following the onset of persistent AF andasignificant increase in mortality when compared to a matched group without persistent AF. Objective measuresofactivitymay more accurately reflect the impact of persistent AF on patients' functional status.

Anticoagulation after catheter ablation of atrial fibrillation guided by implantable cardiac monitors.

Discontinuation of oral anticoagulation (OAC) after catheter ablation of atrial fibrillation (AF) is not recommended in patients with elevated CHADS2 scores. However, a low incidence of thromboembolic events is reported when OAC is stopped in these patients. We introduce an algorithm for discontinuation of OAC after ablation based on the AF burden documented by implantable cardiac monitors (ICM). Sixty-five patients with CHADS2 scores 1-3 free from AF 3 months after ablation (AF ablation [n = 49] or ablation of possible AF triggers [n = 16]) were included. One day after implantation of the ICM, OAC was stopped. Patients performed a daily interrogation of the ICM which was programmed to alarm the patient if daily AF burden exceeded 1 hour. Study end point was the first recurrence of a daily AF burden ≥1 hour or a thromboembolic event, which both triggered reinitiation of OAC. During a follow-up time of 32 ± 12 months (126 patient-years), 41 of the 65 patients (63%) had an AF burden <1 h/day and were able to stay off OAC. Twenty-one patients (32%) had to reinitiate OAC due to an AF burden ≥1 hour and three patients due to other reasons. No stroke, transitory ischemic attack, or other thromboembolic event was observed during follow-up. Rhythm monitoring by ICM in patients who have stopped OAC after catheter ablation of AF or ablation of possible AF triggers seems to be a safe and promising method to monitor for AF recurrence. Within 1.3 years after ablation, about two-thirds of patients were able to stay off OAC.

Role of atrial fibrillation burden in assessing thromboembolic risk.

Stroke represents the most devastating complication of atrial fibrillation (AF). Our understanding of the pathophysiology of thromboembolism in patients with AF remains incomplete, and as such, our assessment and management of this risk is imperfect. Current guidelines regard the risk of thromboembolism as independent of the frequency or duration of AF.1 Paradoxically, standard practice in the pericardioversion period considers thromboembolic risk to accrue after 48 hours of AF.1 This recommendation, however, is based on limited data, including an observational study of 357 patients which demonstrated that the risk of thromboembolic events was <1% in patients with AF lasting <48 hours who cardioverted without prolonged anticoagulation therapy or a transesophageal echocardiogram.2 No strong randomized control trial data exist to specifically support a 48-hour safety cut-off, and recent data suggest that the duration of AF associated with a significantly increased risk of stroke may in fact be less.3–8 The emergence of technology to allow absolute quantification of the frequency and duration, or burden, of AF offers the opportunity to refine our assessment and management of thromboembolic risk associated with AF. It has been 200 years since William Wood described a ball thrombus in the left atrium of a patient with mitral stenosis9 and 170 years since Virchow identified the critical components required for thrombus formation.10 It took until 1930 for Harvey and Levine to first declare that “auricular fibrillation definitely increases the incidence of auricular thrombosis” in an autopsy series of patients with mural thrombi.11 Uncertainty as to whether nonrheumatic AF resulted in stroke continued for the next 40 plus years until Wolfe and colleagues, in their landmark analysis using the Framingham population data, identified a 5.6-fold increased risk of stroke in patients with chronic nonvalvular AF.12 With time it would become …

The epidemic of inadequate biventricular pacing in patients with persistent or permanent atrial fibrillation and its association with mortality.

We classified patients' atrial fibrillation (AF), assessed its impact on biventricular pacing (BIVP%), and determined whether AF classification or BIVP% independently correlate with mortality in cardiac resynchronization therapy defibrillator patients. Cardiac resynchronization therapy defibrillator patients were classified as permanent (daily mean AF burden ≥23 hours), persistent (≥7 consecutive days of AF ≥23 hours/d), paroxysmal (≥1 day with AF ≥6 hours), or no/little AF (all others) using device-detected AF during the 6 months postimplant. We evaluated subsequent all-cause mortality using a multivariable Cox proportional hazard regression. Among 54 019 patients (age, 70±11 years; 73% male; follow-up, 2.3±1.2 years), 8% of patients each had permanent (N=4449), persistent (N=4237), and paroxysmal AF (N=4219). A high proportion of patients with permanent (69%) and persistent (62%) AF did not achieve high BIVP (>98%). Relative to no/little AF, patients with AF had increased mortality after adjusting for age, sex, BIVP, and shocks (permanent: hazard ratio=1.28 [1.19-1.38]; P<0.001; persistent: hazard ratio=1.51 [1.41-1.61]; P<0.001). Relative to patients with BIVP >98%, patients with reduced BIVP had increased mortality after adjusting for age, sex, AF, and shocks (90%-98%: hazard ratio=1.20 [1.15-1.26]; P<0.001; <90%: hazard ratio=1.32 [1.23-1.41]; P<0.001). High BIVP% was associated with the greatest mortality improvement in permanent AF among the AF classifications. High BIVP% was not achieved in two thirds of 8686 patients with persistent or permanent AF, and these patients had an increased risk of death. A shift toward more aggressive rate control and more pacing may be necessary in patients with AF to maximize the benefits of cardiac resynchronization therapy.

The Prevalence of Sinus Rhythm in Patients with “Permanent” Atrial Fibrillation

The term "permanent" atrial fibrillation (AF) is generally used to describe the rhythm status of patients for whom cardioversion has failed or attempts to restore normal sinus rhythm (NSR) have ceased. However, the rhythm status of such patients is typically assessed by symptoms or intermittent monitoring, and therefore categorization may be imprecise. We evaluated the presence of NSR among patients who were identified by their physicians as having permanent AF and who underwent prior insertion of a cardiac rhythm management device in the OMNI study. Patients with a dual- or triple-chamber device (pacemaker, implantable cardiac defibrillator, or cardiac resynchronization therapy) and ≥30 days of device data were studied. We tabulated the percentage of follow-up days spent entirely in NSR, entirely in AF, or in both NSR and AF. A total of 69 patients met inclusion criteria and were followed for 767 ± 479 days. More than 73% of patients experienced ≥1 entire day in NSR. On average, 38.2% of days were spent entirely in NSR, 11.8% of days were spent in a combination of NSR and AF, and only 50.0% of days were spent entirely in AF. The median daily AF burden during follow-up was 14.6 [1.1-23.7] hours/day. NSR is common in many device patients thought to have permanent AF, suggesting that continuous arrhythmia monitoring could be useful in identifying permanent AF patients who may benefit from renewed rhythm control efforts. Alternatively, some permanent AF patients undergoing atrioventricular nodal ablation may benefit from dual-chamber devices due to likely periods of NSR.

DEVICE DETECTED ATRIAL FIBRILLATION AND RISK FOR STROKE: AN ANALYSIS OF MORE THAN 10,000 PATIENTS FROM THE SOS AF PROJECT (STROKE PREVENTION STRATEGIES BASED ON ATRIAL FIBRILLATION INFORMATION FROM IMPLANTED DEVICES)

Cardiac implanted electronic devices (CIEDs) enhance detection of atrial fibrillation (AF), providing a comprehensive measure of AF burden. To assess the association between maximum daily AF burden and risk of stroke. A pooled analysis of individual patient data from 3 prospective studies was

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