Burden of Implanted-Device-Detected Atrial High-Rate Episode Is Associated With Future Heart Failure Events - Clinical Significance of Asymptomatic Atrial Fibrillation in Patients With Implantable Cardiac Electronic Devices

Effect of atrial high-rate episodes (AHREs) on functional status and quality of life (QoL) in heart failure-cardiac resynchronization therapy population

BACKGROUND

New type of arrhythmia called atrial high-rate episodes (AHREs) has been discovered thanks to the ability of cardiac electronic implantable devices to track, record, and analyze complex arrhythmias. The aim is to determine factors associated with AHRE in HFrEF/CRT patients and the effect of AHRE on functional capacity and quality of life (QoL).

RESULTS

We interrogated 100 patients' devices to gauge the incidence and burden of AHRE, then assessed their functional capacity using the standard 6-min walk test (6MWT), and evaluated their QoL using the Minnesota Living with HF questionnaire (MLHFQ) score. 34% of patients had AHRE, and 91.2% of them had AF. By multivariate logistic regression analysis, smoking (OR 9.426, 95% CI [1.33, 66.65], P 0.025), higher BMI (OR 1.336, 95% CI [1.09, 1.635], P 0.005), and increased LAVI (OR 1.16, 95% CI [1.063, 1.262], P < 0.001) are independent predictors for AHRE. There was a significant correlation between AHRE and the distance walked during 6MWT when compared to the distance expected for an equivalent healthy individual (82.02 ± 17.22% in the non-AHRE group vs. 75.15 ± 15.78% in the AHRE group, P < 0.001). It was found that AHRE was statistically linked to a higher total MLHFQ score (46.76 ± 9.82 in the AHRE group vs. 36.97 ± 7.76 in the non-AHRE group, P 0.032), with higher physical scores in the AHRE group.

CONCLUSION

AHRE significantly reduces functional status and perceived quality of life in HFrEF patients receiving CRT. Longer than five minutes of AHRE was associated with a higher MLHFQ score and worse performance on the 6MWT. In that patient population, smoking, obesity, and elevated LAVI were independent predictors of AHRE.

Relationship between predictive factors and atrial high-rate episodes in heart failure with reduced ejection fraction patients with cardiac implantable electronic devices

OBJECTIVE

Atrial high-rate episodes (AHRE) are atrial tachyarrhythmia episodes detected by implanted cardiac devices, characterised by an atrial rate exceeding 180-190 beats per minute. Recent studies have linked AHRE to the development of atrial fibrillation (AF) and increased stroke risk, especially when episodes last longer than 5-6 min. This study aimed to evaluate the relationship between predictive factors and the occurrence of AHRE in heart failure with reduced ejection fraction (HFrEF) patients with cardiac implantable electronic devices (CIEDs).

METHODS

This single-centre, retrospective study included a cohort of 155 consecutive HFrEF patients with CIEDs, but without a diagnosis of AF, enrolled between January 2023 and December 2023. Patients were stratified based on the presence of AHRE detected during device interrogation.

RESULTS

The average age of the patients was 54 ± 14 years, and 83.2% of the study population were male. Patients with AHRE had a reduced left ventricular ejection fraction (LVEF) (p = 0.026) and an increased left atrial diameter (p < 0.001) compared to the group without AHRE. Patients with AHRE had elevated levels of creatinine, uric acid, and TSH compared to those without AHRE (p = 0.006, p = 0.021, p = 0.009, respectively). In the univariable logistic regression analysis, LVEF (HR = 0.690, 95% CI = 0.610-0.913, p = 0.013), left atrial diameter (HR = 8.215, 95% CI = 1.557-43.34, p < 0.001), creatinine (HR = 7.369, 95% CI = 1.749-31.05, p = 0.006), uric acid (HR = 1.073, 95% CI = 1.062-1.196, p = 0.020), total cholesterol (HR = 0.989, 95% CI = 0.979-0.999, p = 0.031), and C-reactive protein levels (HR = 1.146, 95% CI = 1.002-1.131, p = 0.047) were identified as independent predictors of AHRE. In multivariable logistic regression analysis, left ventricular ejection fraction (HR = 0.890, 95% CI = 0.795-0.998, p = 0.046), left atrial diameter (HR = 8.215, 95% CI = 1.557-43.34, p < 0.001), and uric acid concentration (HR = 1.650, 95% CI = 1.063-2.561, p = 0.025) were identified as predictors of atrial high-rate events.

CONCLUSION

LVEF, left atrial diameter, and uric acid level were found to be independent predictors of AHRE in patients with HFrEF. Identifying AHRE is crucial for risk stratification and guiding therapeutic decisions to improve patient outcome.

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

Background

Outcomes of device-detected AF remain unclear in individuals without a prior history of AF.

Methods

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.

Results

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]).

Conclusion

While there is an increased risk of clinical AF and thromboembolism in individuals with device-detected AF, mortality was insignificant.

Role of atrial high-rate episodes in stratifying thromboembolic risk: a multiple cut-off diagnostic meta-analysis

Aims

Despite the high prevalence rate of atrial high-rate episodes (AHREs) detected using cardiac implantable electronic devices (CIEDs), clinical guidelines and consensus documents have disagreed on a universal AHRE definition and a temporal cut-off related to subsequent thromboembolic events. This diagnostic test accuracy meta-analysis aims to derive the optimal temporal threshold of clinically significant AHREs from the available literature.

Methods

The PubMed/MEDLINE and EMBASE databases were screened for studies on CIED patients reporting the incidence of thromboembolic events related to at least one AHRE temporal cut-off. A total of 23 studies were included: 19 considering the longest single AHRE and four the AHRE burden, respectively. A random-effect diagnostic test accuracy meta-analysis with multiple cut-offs was performed. Two analyses were performed according to the AHRE temporal cut-off subtype (longest episode vs. cumulative burden).

Results

The analysis on the longest single AHRE indicated 0.07 min as the optimal duration to differentiate AHRE associated or not with thromboembolic events [sensitivity 65.4% (95% CI 48.8%-79.0%), specificity 52.7% (95% CI 46.0%-59.4%), and area under the summary receiver operating characteristic curve (AUC-SROC): 0.62]. The analysis on AHRE burden indicated 1.4 min as the optimal cut-off [sensitivity 58.2% (95% CI 25.6%-85.0%), specificity 57.5% (95% CI 42.0%-71.7%), and AUC-SROC 0.60]. A sensitivity analysis excluding patients with a history of atrial fibrillation and including high-quality studies only yielded similar results.

Conclusion

The presence of AHRE, rather than a specific duration, relates to an increased, albeit low, thromboembolic risk in CIED patients. Any AHRE should constitute an additional element in patient-specific thromboembolic risk assessment.

Oral Anticoagulation in Patients With Atrial High-Rate Episodes: Focus on Clinical Implications

Background Although previous studies showed that atrial high-rate episodes (AHREs) are associated with a higher risk of developing incident atrial fibrillation (AF) and thromboembolic events, their clinical significance is still unclear. The purpose of this study was to define whether there is any clinical impact on the occurrence of ischemic and hemorrhagic events in patients with AHREs and initiation of oral anticoagulation (OAC). Methodology Patients with AHREs who had received cardiac implantable electronic devices (CIEDs, i.e., dual-chamber pacemaker [PM] or implantable cardioverter defibrillator [ICD]) were included in the study. OAC initiation was decided by the assistant doctor. Patients who received OACs comprised the OAC group, while patients who were not referred for OAC initiation were included in the control group. The primary endpoint was the time to the event of the occurrence of thromboembolic events (thromboembolic event-free survival). Results A total of 154 individuals (77 in each group) were enrolled in the study, with a mean age of 72.5 years. The mean follow-up period for the OAC group was 19.1 months and for the control group, 18.9 months (P = 0.9). Thromboembolic events were noticed only in seven patients. Six of them were in the control group, and only one in the OAC group (P = 0.05). Major bleeding events were noticed in five patients, one of whom was in the control group and the rest in the OAC group (P = 0.17). Conclusions OAC therapy in patients with AHREs was not associated with a significant difference in the risk of thromboembolic and bleeding events. Baseline patient characteristics and AHRE duration may be useful to intensify the monitoring and management of patients with AHREs. Bleeding events may be indicators of cancer in patients with AHREs receiving OACs.

Atrial high-rate episodes intensify R2CHA2DS2-VASc score for prognostic stratification in pacemaker patients

Patients with device detected atrial high-rate episodes (AHRE) have an increased risk of MACE. The R₂CHA₂DS₂-VASc, CHADS₂, R₂CHADS₂ and CHA₂DS₂-VASc score have been investigated for predicting major adverse cardiovascular events (MACE) in different groups of patients. We aimed to evaluate the R₂CHA₂DS₂-VASc score in combination with AHRE ≥ 6 min for predicting MACE in patients with dual-chamber PPM but no prior atrial fibrillation (AF). We retrospectively enrolled 376 consecutive patients undergoing dual-chamber PPM implantation and no prior AF. The primary endpoint was subsequent MACE. For all patients in the cohort, CHADS₂, R₂CHADS₂, CHA₂DS₂-VASc, R₂CHA₂DS₂-VASc scores and AHRE ≥ or < 6 min were determined. AHRE was recorded as a heart rate > 175 bpm (Medtronic) or > 200 bpm (Biotronik) lasting ≥ 30 s. Multivariate Cox regression analysis with time-dependent covariates was used to determine the independent predictors of MACE. ROC-AUC analysis was performed for CHADS₂, R₂CHADS₂, CHA₂DS₂-VASc, and R₂CHA₂DS₂-VASc scores and then adding AHRE ≥ 6 min to the four scores. The median age was 77 years, and 107 patients (28.5%) developed AHRE ≥ 6 min. After a median follow-up of 32 months, 46 (12.2%) MACE occurred. Multivariate Cox regression analysis showed that R₂CHA₂DS₂-VASc score (HR, 1.485; 95% CI, 1.212-1.818; p < 0.001) and AHRE ≥ 6 min (HR, 2.125; 95% CI, 1.162-3.887; p = 0.014) were independent predictors for MACE. The optimal R₂CHA₂DS₂-VASc score cutoff value was 4.5 (set at ≥ 5), with the highest Youden index (AUC, 0.770; 95% CI, 0.709-0.831; p < 0.001). ROC-AUC analysis of the four risk scores separately combined with AHRE ≥ 6 min all showed better discriminatory power than the four scores alone (All Z-statistic p < 0.05). In patients with PPM who develop AHRE ≥ 6 min, it is crucial to perform risk assessment with either four scores to further stratify risk for MACE.

Establishment and Verification of a Nomogram for Predicting the Probability of New-Onset Atrial Fibrillation After Dual-Chamber Pacemaker Implantation

BACKGROUND

This study aims to establish and validate a nomogram as a predictive model in patients with new-onset atrial fibrillation (AF) after dual-chamber cardiac implantable electronic device (pacemaker) implantation.

METHODS

A total of 1120 Chinese patients with new-onset AF after pacemaker implantation were included in this retrospective study. Patients had AF of at least 180/minute lasting 5 minutes or longer, detected by atrial lead and recorded at least 3 months after implantation. Patients with previous atrial tachyarrhythmias before device implantation were excluded. A total of 276 patients were ultimately enrolled, with 51 patients in the AF group and 225 patients in the non-AF group. Least absolute shrinkage and selection operator (LASSO) method was used to determine the best predictors. Through multivariate logistic regression analysis, a nomogram was drawn as a predictive model. Concordance index, calibration plot, and decision curve analyses were applied to evaluate model discrimination, calibration, and clinical applicability. Internal verification was performed using a bootstrap method.

RESULTS

The LASSO method regression analysis found that variables including peripheral arterial disease, atrial pacing-ventricular pacing of at least 50%, atrial sense-ventricular sense of at least 50%, increased left atrium diameter, and age were important predictors of developing AF. In multivariate logistic regression, peripheral arterial disease, atrial pacing-ventricular pacing of at least 50%, and age were found to be independent predictors of new-onset AF.

CONCLUSION

This nomogram may help physicians identify patients at high risk of new-onset AF after pacemaker implantation at an early stage in a Chinese population.

Epidemiology of subclinical atrial fibrillation in patients with cardiac implantable electronic devices: A systematic review and meta-regression

BACKGROUND

In recent years, attention to subclinical atrial fibrillation (SCAF), defined as the presence of atrial high-rate episodes (AHREs), in patients with cardiac implantable electronic devices (CIEDs), has gained much interest as a determinant of clinical AF and stroke risk. We aim to perform a systematic review and meta-regression of the available scientific evidence regarding the epidemiology of SCAF in patients receiving CIEDs.

METHODS

PubMed and EMBASE were searched for all studies documenting the prevalence of AHREs in patients (n=100 or more, <50% with history of AF) with CIEDs from inception to 20th August 2021, screened by two independent blind reviewers. This study was registered in PROSPERO: CRD42019106994.

RESULTS

Among the 2614 results initially retrieved, 54 studies were included, with a total of 72,784 patients. Meta-analysis of included studies showed a pooled prevalence of SCAF of 28.1% (95%CI: 24.3-32.1%), with high heterogeneity between studies (I²=98%). A multivariable meta-regression was able to explain significant proportion of heterogeneity (R²=61.9%, p<0.001), with age and follow-up time non-linearly, directly and independently associated with occurrence of SCAF. Older age, higher CHA₂DS₂-VASc score, history of AF, hypertension, CHF, and stroke/TIA were all associated with SCAF occurrence.

CONCLUSIONS

In this systematic review and meta-regression analysis, SCAF was frequent among CIED recipients and was non-linearly associated with age and follow-up time. Older age, higher thromboembolic risk, and several cardiovascular comorbidities were associated with presence of SCAF.

The Differential Prognostic Impact of Long-Duration Atrial High-Rate Episodes Detected by Cardiac Implantable Electronic Devices between Patients with and without a History of Atrial Fibrillation

Long-duration atrial high-rate episodes (AHREs) monitored using cardiac implantable electronic devices (CIEDs) can predict long-term major adverse cardiovascular events (MACEs). This study aimed to compare the impact of long-duration AHRE on MACE development between patients with and without a history of atrial fibrillation (AF). This single-center observational study included 132 CIED-implanted patients with AHREs detected via remote monitoring. The population was dichotomized into groups: with (n = 69) and without (n = 63) AF. In each group, cumulative incidences of MACEs comprising all-cause deaths, heart failure hospitalizations, strokes, and acute coronary syndromes were compared between patients with AHRE durations of ≥24 h and <24 h. Multivariate analysis was performed to identify predictors of MACEs among patients without AF. MACE incidence was significantly higher in patients with AHRE ≥24 h than in those with <24 h in the group without AF (92% vs. 30%, p = 0.005). MACE incidence did not significantly differ between AHRE ≥24 h and <24 h in the group with AF (54% vs. 26%, p = 0.44). After a multivariate adjustment, AHRE duration of ≥24 h emerged as the only independent predictor of MACEs among patients without AF (p = 0.03). In conclusion, a long-duration AHRE was prognostic in patients without a history of AF but not in patients with a history of AHREs.

Combined Effect of Homocysteine and Uric Acid to Identify Patients With High Risk for Subclinical Atrial Fibrillation

Background

Subclinical atrial fibrillation (SCAF) is often asymptomatic nonetheless harmful. In patients with cardiac implantable electronic devices, we evaluated the combined performance of homocysteine and uric acid (UA) biomarkers to discriminate high‐risk patients for SCAF.

Methods and Results

We enrolled 1224 consecutive patients for evaluation of SCAF in patients with cardiac implantable electronic devices in Dalian, China, between January 2013 and December 2019. Clinical data and blood samples were obtained from patients selected according to the absence or presence of atrial high‐rate episodes >6 minutes. Blood samples were obtained, and homocysteine and UA biomarkers were tested in all patients to distinguish their prognostic performance for SCAF. Homocysteine and UA biomarkers were significantly different in SCAF versus no SCAF. On multivariable Cox regression analysis with potential confounders, elevated homocysteine and UA biomarkers were significantly associated with an increased risk of SCAF. A rise of 1 SD in homocysteine (5.7 μmol/L) was associated with an increased risk of SCAF in men and women regardless of their UA levels. Similarly, a 1‐SD increase in UA (91 μmol/L) was associated with an increased risk of SCAF among the patients with high levels of homocysteine in men (hazard ratio, 1.81; 95% CI, 1.43–2.30) and women (hazard ratio, 2.11; 95% CI, 1.69–2.62). The addition of homocysteine and UA to the atrial fibrillation risk factors recommended by the 2020 European Society of Cardiology Guidelines significantly improved risk discrimination for SCAF.

Conclusions

Homocysteine and UA biomarkers were strongly associated with SCAF. The prediction performance of the European Society of Cardiology model for SCAF was increased by the addition of the selected biomarkers.

Registration

URL: https://www.chictr.org.cn; Unique identifier: Chi‐CTR200003837.

Is Progression From Paroxysmal to Sustained Atrial Fibrillation Bad News?

Atrial fibrillation (AF) is the most common sustained arrhythmia and associated with increased morbidity and mortality resulting from thromboembolism and heart failure. AF often presents initially as paroxysmal and may progress to a sustained form over time. Sustained forms of AF may be associated with increased symptoms and cardiovascular morbidity, and AF progression may be associated with increased risk of clinically adverse events and outcomes. The present review discusses the clinical factors of arrhythmia progression and risk stratification available to assess the probability of AF progression. Furthermore, currently available treatment options for preventing AF progression are explored and evaluated.

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

BACKGROUND

Atrial 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.

OBJECTIVES

To assess the relationship between AHRE and TE events, and between AHRE and incident clinical AF.

METHODS

This 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.

RESULTS

Ten 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%).

CONCLUSIONS

AHRE are significantly associated with systemic thromboembolism and incident clinical AF. Further studies are needed to improve patients' risk stratification and management.

Atrial high-rate episodes predict major adverse cardio/cerebrovascular events in patients with cardiac implantable electrical devices

Patients with atrial high-rate episodes (AHRE) have a high risk of neurologic events, although the causal role and optimal cutoff threshold of AHRE for major adverse cardio/cerebrovascular events (MACCE) are unknown. This study aimed to identify independent factors for AHRE and subsequent atrial fibrillation (AF) after documented AHRE. We enrolled 470 consecutive patients undergoing cardiac implantable electrical device (CIED) implantations. The primary endpoint was subsequent MACCE after AHRE ≥ 6 min, 6 h, and 24 h. AHRE was defined as > 175 beats per minute (bpm) (Medtronic®) or > 200 bpm (Biotronik®) lasting ≥ 30 s. Multivariate Cox regression analysis with time-dependent covariates was used to determine variables associated with independent risk of MACCE. The patients’ median age was 76 year, and 126 patients (26.8%) developed AHRE ≥ 6 min, 63 (13.4%) ≥ 6 h, and 39 (8.3%) ≥ 24 h. During follow-up (median: 29 months), 142 MACCE occurred in 123 patients. Optimal AHRE cutoff value was 6 min, with highest Youden index for MACCE. AHRE ≥ 6 min ~ 24 h was independently associated with MACCE and predicted subsequent AF. Male gender, lower body mass index, or BMI, and left atrial diameter were independently associated with AHRE ≥ 6 min ~ 24 h. Patients with CIEDs who develop AHRE ≥ 6 min have an independently increased risk of MACCE. Comprehensive assessment of patients with CIEDs is warranted.

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

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

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

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

Atrial High-Rate Episodes in Patients with Devices Without a History of Atrial Fibrillation: a Systematic Review and Meta-analysis

PURPOSE

Atrial high-rate episodes (AHREs) recorded with cardiac implantable electronic devices (CIEDs) have been associated with the development of clinical atrial fibrillation (AF) and increase in stroke and death risk. We sought to perform a systematic review with a meta-analysis to evaluate the prevalence of AHREs detected by CIEDs, their association with stroke risk, development of clinical AF, and mortality among patients without a documented history of AF.

METHODS

We searched several databases, ClinicalTrials.gov, references of reviews, and meeting abstract books without any language restrictions up to 9 September 2020. We studied patients with CIEDs in whom AHREs were detected. Exclusion criterion was AF history. Our primary outcome was the risk of ischemic stroke in patients with AHREs.

RESULTS

We deemed eligible eight studies for the meta-analysis enrolling a total of 4322 patients with CIED and without a documented AF history. The overall AHRE incidence ratio was estimated to be 17.56 (95% CI, 8.61 to 35.79) cases per 100 person-years. Evidence of moderate certainty suggests that patients with documented AHREs were 4.45 times (95% CI 2.87-6.91) more likely to develop clinical AF. Evidence of low confidence suggests that AHREs were associated with a 1.90-fold increased stroke risk (95% CI 1.19-3.05). AHREs were not associated with a statistically significant increased mortality risk.

CONCLUSION

The present systematic review and meta-analysis demonstrated that among patients without a documented history of AF, the detection of AHREs by CIEDs was associated with significant increased risk of clinical AF and stroke.

REGISTRATION NUMBER (DOI)

Available in https://doi.org/10.17605/OSF.IO/ZRF6M .

Atrial high‑rate episodes and risk of major adverse cardiovascular events in patients with dual chamber permanent pacemakers: a retrospective study

Patients with atrial high-rate episodes (AHRE) are at higher risk of major adverse cardiovascular events (MACE). The cutoff threshold for AHRE duration for MACE, with/without history of atrial fibrillation (AF) or myocardial infarction (MI), is unknown. A total of 481 consecutive patients with/without history of AF or MI receiving dual-chamber pacemaker implantation were included. The primary outcome was a composite endpoint of MACE after AHRE ≥ 5 min, ≥ 6 h, and ≥ 24 h. AHRE was defined as > 175 bpm (MEDTRONIC) or > 200 bpm (BIOTRONIK) lasting ≥ 5 min. Cox regression analysis with time-dependent covariates was conducted. Patients' mean age was 75.3 ± 10.7 years and 188 (39.1%) developed AHRE ≥ 5 min, 115 (23.9%) ≥ 6 h, and 83 (17.3%) ≥ 24 h. During follow-up (median 39.9 ± 29.8 months), 92 MACE occurred (IR 5.749%/year, 95% CI 3.88-5.85). AHRE ≥ 5 min (HR 5.252, 95% CI 2.575-10.715, P < 0.001) and ≥ 6 h (HR 2.548, 95% CI 1.284-5.058, P = 0.007) was independently associated with MACE, but not AHRE ≥ 24 h. Patients with history of MI (IR 17.80%/year) had higher MACE incidence than those without (IR 3.77%/year, p = 0.001). Significant differences were found between MACE patients with/without history of AF in AHRE ≥ 5 min but not AHRE ≥ 6 h or ≥ 24 h. Patients with dual-chamber pacemakers who develop AHRE have increased risk of MACE, particularly after history of AF or MI.

Relationship between device-detected subclinical atrial fibrillation and heart failure in patients with cardiac resynchronization therapy defibrillator

Background

Atrial fibrillation (AF) is a leading preventable cause of heart failure (HF) for which early detection and treatment is critical. Subclinical‐AF is likely to go untreated in the routine care of patients with cardiac resynchronization therapy defibrillator (CRT‐D).

Hypothesis

The hypothesis of our study is that subclinical‐AF is associated with HF hospitalization and increasing an inappropriate therapy.

Methods

We investigated 153 patients with an ejection fraction less than 35%. We divided into three groups, subclinical‐AF (n = 30), clinical‐AF (n = 45) and no‐AF (n = 78). We compared the baseline characteristics, HF hospitalization, and device therapy among three groups. The follow‐up period was 50 months after classification of the groups.

Results

The average age was 66 ± 15 years and the average ejection fraction was 26 ± 8%. Inappropriate therapy and biventricular pacing were significantly different between subclinical‐AF and other groups (inappropriate therapy: subclinical‐AF 13% vs clinical‐AF 8.9% vs no‐AF 7.7%: P = .04, biventricular pacing: subclinical‐AF 81% vs clinical‐AF 85% vs no‐AF 94%, P = .001). Using Kaplan‐Meier method, subclinical‐AF group had a significantly higher HF hospitalization rate as compared with other groups. (subclinical‐AF 70% vs clinical‐AF 49% vs no‐AF 38%, log‐rank: P = .03). In multivariable analysis, subclinical‐AF was a predictor of HF hospitalization.

Conclusions

Subclinical‐AF after CRT‐D implantation was associated with a significantly increased risk of HF hospitalization. The loss of the biventricular pacing and increasing an inappropriate therapy might affect the risk of HF hospitalization.

The risk factors of new-onset atrial fibrillation after pacemaker implantation

OBJECTIVE

The aim of this study was to determine the incidence of newly detected atrial fibrillation (AF) in patients following dual-chamber pacemaker (PPM) implantation and to define the clinical predictors of new-onset AF in a Chinese cohort.

METHODS

A total of 219 patients without documented AF that underwent dual-chamber PPM implantation for sick sinus syndrome (SSS) (n = 88) or atrioventricular block (AVB) (n = 131) were prospectively studied. All patients were invited to follow-up at 1 month, 3 months and 6 months after the pacemaker implantation procedure, and once every 6 months thereafter. An atrial high-rate episode (AHRE) ≥5 min and an atrial rate ≥180 bpm was defined as AF.

RESULTS

During follow-up of 884 ± 180 days, AF was detected in 56 (26%) patients. Using Kaplan-Meier survival curves with Log-rank test, SSS patients with a cumulative percentage of ventricular pacing (Cum % VP) ≥60% had a significantly higher rate of new-onset AF compared to AVB patients (p = 0.026) and SSS patients with Cum % VP <60% (p = 0.018). On multivariate Cox regression analysis, higher Cum % VP independently predicted higher morbidity of newly detected AF (hazard ratio [HR] 1.01; confidence interval [CI] 1.00 ~ 1.02; p = 0.035) among SSS patients. Larger left atrial (LA) dimension was a predictor of newly detected AF (HR 1.06; CI 1.01 ~ 1.14; p = 0.046) in AVB patients.

CONCLUSION

The incidence of AF following dual-chamber PPM implantation was relatively high in this Chinese cohort. High Cum % VP and larger LA dimension could independently predict new-onset AF after dual-chamber PPM implantation in SSS and AVB patients, respectively.