Atrial Tachyarrhythmia Burden Research Articles

Effects of sodium glucose co-transporter-2 inhibitor on atrial tachyarrhythmia burden in patients with cardiovascular implantable electronic device

Abstract Introduction Previous studies showed that sodium glucose co-transporter-2 inhibitors (SGLT2i) were associated with a lower atrial fibrillation (AF) incidence. Purpose Since mitochondrial dysfunction has been linked with AF, we aimed to examine the effects of SGLT2i on AF burden and mitochondrial function in patients with cardiovascular implantable electronic device (CIED). Methods Patients with CIED were randomly assigned to receive either dapagliflozin 10 mg daily or placebo for 3 months. The AF burden was measured as atrial high-rate episodes (AHRE) via CIED interrogations, and data were collected at baseline and 3-months post-treatment. Oxidative stress and mitochondrial function were determined in peripheral blood mononuclear cells (PBMCs). Results The study enrolled 54 CIED patients. There were 9 (16.7%) patients with diabetes mellitus and 36 (66.7%) patients with history of clinical AF. The changes of AHRE burden after 3-month treatments did not differ between dapagliflozin and placebo groups. However, in those with clinical AF, dapagliflozin significantly decreased the number of AHRE per month as compared to placebo (-2.2 vs. +0.6 episodes per month, p=0.048) (Table 1). Mitochondrial spare respiratory capacity (SRC) percentage was significantly increased after treatment with dapagliflozin (162.1% to 203.2%, p=0.003), whereas this was not found in the placebo group (Figure 1). In the subgroup analysis of patients with clinical AF, dapagliflozin showed significant improvement in both the SRC percentage (165.7 to 201.7%, p=0.016) and a reduction in cellular oxidative stress (26,840.5 to 18,164.0 arbitrary unit, p=0.049). Conclusions Dapagliflozin significantly reduced the number of AHRE per month in patients with history of clinical AF. The improvement in PBMC’s mitochondrial function and reduced cellular oxidative stress among dapagliflozin users could be the mechanisms responsible for its anti-atrial arrhythmic effect.Table 1Figure 1

Impact of Catheter Ablation on Arrhythmia Burden in Patients With Shock-Resistant Persistent Atrial Fibrillation

BackgroundPersistent shock-resistant atrial fibrillation (AF) is a challenging entity, with modest results from catheter ablation according to conventional survival analysis. ObjectivesThe aim of this study was to determine the effect of catheter ablation on atrial tachyarrhythmia (ATA) burden in persistent AF patients undergoing first-time ablation with the use of an implantable cardiac monitor (ICM). MethodsPatients with drug-resistant ongoing persistent AF and at least 1 previous failed cardioversion were implanted with an ICM 2 months before the procedure. All patients underwent pulmonary vein isolation with or without additional substrate ablation depending on the presence of self-terminating AF on ICM and left atrium size. Median AF burden before and after ablation, off antiarrhythmic medication, was determined from ICM recordings after review by 2 independent investigators. ResultsSixty patients were recruited (mean age 66 ± 9 years, 70% male). Mean left atrial diameter was 48 ± 6 mm and median CHA2DS2VASc score was 2. Ten patients (17%) unexpectedly demonstrated self-terminating AF before ablation. The median burden of ATA before ablation was 100% (95% CI: 19.6%-100%), decreasing to 0% (95% CI: 0%-95.8%) after ablation during the post-blanking follow-up period (median reduction 100%; 95% CI: 4%-100%; P < 0.001). Twenty-seven patients (45%) experienced recurrent ATA during 12-month follow-up. In these patients, median burden before ablation was 100% (95% CI: 26.9%-100%), decreasing to 11.4% (95% CI: 0.35%-99.7%) after ablation (P < 0.001). Quality of life improved significantly from baseline, driven by lack of recurrence. ConclusionsPatient-tailored catheter ablation results in a significant reduction in ATA burden (off antiarrhythmic medication) in shock-resistant persistent AF patients using ICMs implanted 2-months pre-procedure. These data suggest that conventional arrhythmia-free survival analysis does not capture the true impact of catheter ablation in this challenging cohort.

Effect of sodium glucose cotransporter 2 inhibitors on atrial tachy-arrhythmia burden in patients with cardiac implantable electronic devices.

Use of sodium glucose cotransporter 2 inhibitors (SGLT2i) was associated with a reduction in atrial fibrillation hospitalizations. Therefore, we aim to evaluate the effects of SGLT2i on atrial tachy-arrhythmias (ATA) in patients with cardiac implantable electronic devices (CIEDs). All 13 888 consecutive patients implanted with a CIED in two tertiary medical centers were enrolled. Treatment with SGLT2i was assessed as a time dependent variable. The primary endpoint was the total number of ATA. Secondary endpoints included total number of ventricular tachy-arrhythmias (VTA), ATA and VTA, and death. All events were independently adjudicated blinded to the treatment. Multivariable propensity score modeling was performed. During a total follow-up of 24 442 patient years there were 62 725 ATA and 10 324 VTA events. Use of SGLT2i (N = 696) was independently associated with a significant 22% reduction in the risk of ATA (hazard ratio [HR] = 0.78 [95% confidence interval {CI} = 0.70-0.87]; p < .001); 22% reduction in the risk of ATA/VTA (HR = 0.78 [95% CI = 0.71-0.85]; p < .001); and with a 35% reduction in the risk of all-cause mortality (HR = 0.65 [95% CI = 0.45-0.92]; p = .015), but was not significantly associated with VTA risk (HR = 0.92 [95% CI = 0.80-1.06]; p = .26). SGLT2i were associated with a lower ATA burden in heart failure (HF) patients but not among diabetes patients (HF: HR = 0.68, 95% CI = 0.58-0.80, p < .001 vs. Diabetes: HR = 0.95, 95% CI = 0.86-1.05, p = .29; p < .001 for interaction between SGLT2i indication and ATA burden). Our real world findings suggest that in CIED HF patients, those with SGLT2i had a pronounced reduction in ATA burden and all-cause mortality when compared with those not on SGLT2i.

Outcomes of adjunct posterior wall isolation in atrial fibrillation patients with cardiac implantable electronic devices.

Although pulmonary vein isolation (PVI) remains the cornerstone of catheter ablation of atrial fibrillation (AF), several studies have illustrated clinical benefits associated with PVI with posterior wall isolation (PWI). This retrospective study investigated the outcomes of PVI alone versus PVI+PWI performed using the cryoballoon in patients with cardiac implantable electronic devices (CIEDs) and paroxysmal AF (PAF) or persistent AF (PersAF). Acute PVI was achieved in all patients using cryoballoon ablation. Compared to PVI alone, PVI+PWI was associated with longer cryoablation, fluoroscopy, and total procedure times. Adjunct radiofrequency was required to complete PWI in 29/77 patients (37.7%). Adverse events were similar with PVI alone versus PVI+PWI. But at 24±7 months of follow-up, not only cryoballoon PVI+PWI was associated with improved freedom from recurrent AF (74.3%vs. 46.0%, P=.007) and all atrial tachyarrhythmias (71.4%vs. 38.1%, P=.001) in patients with PersAF, cryoballoon PVI+PWI also yielded greater freedom from AF (88.1%vs. 63.7%, P=.003) and all atrial tachyarrhythmias (83.3%vs. 60.8%, P=.008) in those with PAF. Additionally, PVI+PWI was associated with higher reductions in atrial tachyarrhythmia burden (97.9%vs. 91.6%, P<.001), need for cardioversion (5.2%vs. 23.6%, P<.001) and repeat catheter ablation (10.4%vs. 26.1%, P=.005), and a longer time-to-arrhythmia recurrence (16±6 months vs. 8±5 months, P<.001) in both PersAF and PAF patients. In CIED patients with PersAF or PAF, cryoballoon PVI+PWI is associated with a greater freedom from recurrent AF and atrial tachyarrhythmias, as compared to PVI alone during long-term follow-up.

Long-term comparisons of atrial fibrillation ablation outcomes with a cryoballoon or laser-balloon: A propensity-matched analysis based on continuous rhythm monitoring

ObjectiveCryoballoon (CB) and laser-balloon (LB) catheter ablation (CA) has been demonstrated to achieve durable and effective pulmonary vein isolation (PVI). Only one head-to-head comparison with an intermittent rhythm monitor strategy is currently available. The aim of this study was to compare acute and long-term outcomes of CB and LB atrial fibrillation ablation procedures, by using a continuous rhythm monitoring strategy. MethodsThis was a prospective two-arm nonrandomized propensity-matched observational trial that compared the outcomes of atrial fibrillation (AF) ablation using LB and CB techniques. To evaluate AF recurrences, an implantable cardiac monitor (ICM) was implanted before hospital discharge to detect atrial tachyarrhythmia (ATA) recurrences. ResultsA total of 110 propensity-matched patients undergoing AF ablation with an LB (n = 55) or with a CB system (n = 55) were enrolled (paroxysmal AF 57.3%). Procedural time (LB: 87 [73–104] vs. CB 90 [70–130] min; p = 0.264) and fluoroscopy time did not differ. No differences in ATA recurrences were observed at 12 months (LB–30.9% vs. CB–29.1% and LB–45.5% vs. CB–38.2%; log-rank 0.539). As for AF burden, the 12-month median was 0 [0-1] vs. 0 [0-3]% (p = 0.127) in the LB and CB groups, respectively. When considering only PeAF patients, the median 12-month ATA burden was 26 [18.5-40.5] vs. 29 [26-35]% (p = 0.919) for the LB and CB patients, respectively. ConclusionIn a propensity-matched cohort undergoing AF ablation, arrhythmia outcomes assessed by continuous rhythm monitoring did not differ between LB and CB, with an overall low ATA burden. The only predictor of recurrences was persistent AF. There was no difference in procedure or fluoroscopy time.

Combining home monitoringtemporal trends from implanted defibrillators and baseline patient risk profile to predict heart failure hospitalizations: results from the SELENE HF study.

AimsWe developed and validated an algorithm for prediction of heart failure (HF) hospitalizations using remote monitoring (RM) data transmitted by implanted defibrillators.Methods and resultsThe SELENE HF study enrolled 918 patients (median age 69 years, 81% men, median ejection fraction 30%) with cardiac resynchronization therapy (44%), dual-chamber (38%), or single-chamber defibrillators with atrial diagnostics (18%). To develop a predictive algorithm, temporal trends of diurnal and nocturnal heart rates, ventricular extrasystoles, atrial tachyarrhythmia burden, heart rate variability, physical activity, and thoracic impedance obtained by daily automatic RM were combined with a baseline risk-stratifier (Seattle HF Model) into one index. The primary endpoint was the first post-implant adjudicated HF hospitalization. After a median follow-up of 22.5 months since enrolment, patients were randomly allocated to the algorithm derivation group (n = 457; 31 endpoints) or algorithm validation group (n = 461; 29 endpoints). In the derivation group, the index showed a C-statistics of 0.89 [95% confidence interval (CI): 0.83–0.95] with 2.73 odds ratio (CI 1.98–3.78) for first HF hospitalization per unitary increase of index value (P < 0.001). In the validation group, sensitivity of predicting primary endpoint was 65.5% (CI 45.7–82.1%), median alerting time 42 days (interquartile range 21–89), and false (or unexplained) alert rate 0.69 (CI 0.64–0.74) [or 0.63 (CI 0.58–0.68)] per patient-year. Without the baseline risk-stratifier, the sensitivity remained 65.5% and the false/unexplained alert rates increased by ≈10% to 0.76/0.71 per patient-year.ConclusionWith the developed algorithm, two-thirds of first post-implant HF hospitalizations could be predicted timely with only 0.7 false alerts per patient-year.

Paroxysmal atrial fibrillation with high vs. low arrhythmia burden: atrial remodelling and ablation outcome.

The relation between atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF), atrial remodelling, and efficacy of catheter ablation (CA) is unknown. We investigated whether high vs. low-burden paroxysmal AF patients have distinct clinical characteristics or electro-mechanical properties of the left atrium (LA) and whether burden impacts outcome of CA. Atrial tachyarrhythmia burden, defined as the percentage of time spent in ATA, was assessed by insertable cardiac monitors in 105 patients before and after CA. Clinical characteristics and electro-mechanical properties of LA were compared between patients with high vs. low ATA burden. Catheter ablation efficacy was assessed by reduction in ATA burden and 1-year freedom from any ATA. Median ATA burden was 2.7% (highest tertile 9.3%). Clinical characteristics and electrical properties of LA (refractoriness, conduction velocity, low voltage) did not differ between high (≥9.3%) vs. low ATA burden (<9.3%) patients. High ATA burden patients had larger LA diameter (46.5 ± 6 vs. 42.5 ± 6mm, P < 0.01), volume (93.8 ± 22 vs. 80.4 ± 21mL, P = 0.01), and lower LA reservoir and contractile strain (19.7 ± 6 vs. 24.7 ± 6%, P < 0.01; 10.3 ± 3 vs. 12.8 ± 4%, P = 0.01). Catheter ablation reduced ATA burden by 100% (100-100) in both groups (P = 1.0). Freedom from ATA after CA was equally high (83% vs. 89%, P = 0.38). Paroxysmal AF patients with high ATA burden have altered LA mechanical properties, reflected by larger size and impaired function. Despite mechanical remodelling of the atria, they are excellent responders to CA. Most likely the lack of fibrosis and/or advanced electrical remodelling explain why pulmonary veins remain the dominant trigger for AF in this patient cohort.

Closed-loop stimulation as a physiological rate-modulated pacing approach based on intracardiac impedance to lower the atrial tachyarrhythmia burden in patients with sinus node dysfunction and atrial fibrillation.

The effectiveness of rate-modulated pacing for the suppression of atrial fibrillation (AF) is controversial. Closed-loop stimulation (CLS) is a heart rate modulation technique based on the contractility of the right ventricle estimated by sensing myocardial impedance, and CLS can still adapt to the heart rate in conditions where there are no significant changes in acceleration or ventilation, such as emotional stress. We elucidated the association between CLS and atrial tachyarrhythmia (AT) burden in patients with sinus node dysfunction and paroxysmal AF history before pacemaker implantation. We retrospectively reviewed all consecutive patients who underwent pacemaker implantation for sinus node dysfunction with an AF history before implantation. Overall, 146 patients were analyzed, with fixed-rate pacing (FP) in 82, CLS in 31, and non-CLS rate modulation in 33 patients. The AF/AT episodes were detected in 98 patients during a 12-month period. The median AF/AT burden was 1.6% (interquartile: 0.0%, 11.0%) in FP; 0% (0.0%, 2.5%) in CLS, and 1.0% (0.1%, 9.3%) in non-CLS. The AF/AT burden was significantly lower for CLS than for FP and non-CLS rate modulation (P < .01 and P = .04, respectively). CLS was associated with lower risks of AF/AT occurrence (hazard ratio [HR], 0.31; P = .02) and AF/AT burden more than 5% (HR, 0.28; P = .05), even after adjusting for potential confounders. This association was independent of the percentage of atrial pacing. CLS was associated with lower AF/AT burden after pacemaker implantation in patients with sinus node dysfunction and AF history.

Long-term impact of catheter ablation on arrhythmia burden in low-risk patients with paroxysmal atrial fibrillation: The CLOSE to CURE study

Few studies evaluated the impact of catheter ablation (CA) on atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF). In the prospective, patient-controlled CLOSE to CURE study, we determined the longer-term impact of optimized CA on ATA burden by using an insertable cardiac monitor (ICM). A total of 105 patients with paroxysmal AF were implanted with an ICM 65 (interquartile range [IQR] 61-78) days before CA. CA consisted of contact force-guided pulmonary vein isolation targeting an intertag distance of ≤6 mm and a region-specific ablation index. The primary end point was reduction in ICM-detected ATA burden; secondary end points were single-procedure freedom from ATA, quality of life, and adverse events. The mean age was 62 ± 8 years; the median CHA2DS2-VASc score was 1 (IQR 1-2); and the median left atrial diameter was 43 (IQR 39-43) mm. After pulmonary vein isolation (1.13 ± 0.39 procedures per patient), median ATA burden decreased from 2.68% (IQR 0.09%-15.02%) at baseline to 0% (IQR 0%-0%) during the first year and to 0% (IQR 0%-0%) during the second year (reduction in ATA burden 100% [IQR 100%-100%]; P < .001). Single-procedure freedom from any ATA was 87% at 1 year and 78% at 2 years. Quality of life improved significantly across all scores. Adverse events occurred in 5 patients (4.8%). CA has become an effective procedure in paroxysmal AF, with a major impact on ICM-detected ATA burden. Whereas conventional survival analysis suggests a progressive decline in efficacy, we observed that burden reduction is maintained at longer follow-up. These data imply that ATA burden is a more optimal end point for assessing ablation efficacy.

Postoperative and short-term atrial tachyarrhythmia burdens after transcatheter vs surgical pulmonary valve replacement among congenital heart disease patients.

We examined the atrial tachyarrhythmia (AT) burden among patients with congenital heart disease (CHD) following transcatheter (TC-) or surgical (S-) pulmonary valve replacement (PVR). This was a retrospective observational study of patients who underwent PVR from 2010 to 2016 at UCLA Medical Center. Patients of all ages who had prior surgical repair for CHD were included. Patients with a history of congenitally corrected transposition of the great arteries, underwent a hybrid PVR procedure, or had permanent atrial fibrillation (AF) without a concomitant ablation were excluded. The primary outcome was a time-to-event analysis of sustained AT. Sustained ATs were defined as focal AT, intra-atrial reentrant tachycardia/atrial flutter, or AF lasting at least 30seconds or terminating with cardioversion or antitachycardia pacing. Two hundred ninety-seven patients (TC-PVR, n=168 and S-PVR, n=129) were included. During a median follow-up of 1.2years, nine events occurred in TC-PVR group (5%) vs 23 events in S-PVR group (18%). In the propensity adjusted models, the following factors were associated with significant risk of AT after PVR: history of AT, age at valve implantation, severe right atrial enlargement, and S-PVR. In the secondary analysis, TC-PVR was associated with lower adjusted risk of AT events in the postoperative epoch (first 30days), adjusted IRR 0.31 (0.14-0.97), P=.03, but similar risk in the short-term epoch, adjusted IRR 0.64 (0.14-2.94), P=.57. There was an increased risk of AT in the first 30days following S-PVR compared to TC-PVR. Additional factors associated with risk of AT events after PVR were a history of AT, age at valve implantation, and severe right atrial enlargement.

Hidden burden of arrhythmias in patients with small atrial septal defects: a nationwide study.

BackgroundIn recent Danish nationwide register-based study, adults with small, unrepaired atrial septal defects (ASD) have increased risk of pneumonia, atrial fibrillation (AF) and stroke. Moreover, they revealed higher mortality than the background population.ObjectiveIn this nationwide study, we evaluate the hidden burden of atrial and ventricular arrhythmias in adult patients with a small, unrepaired ASD without a previous diagnosis of AF.MethodsAll Danish patients, aged 18–65, diagnosed between 1953 and 2011 with an unrepaired ASD and no documented AF were invited for 7 days Holter-recording, echocardiography and 6 min walk test. The first 48 hours Holter-recording was completely analysed, while only AF was screened for throughout all 7 days. Furthermore, the entire patient group were characterised using the unique Danish registries.ResultsA total of 151 patients (mean age 32 years) were included. Approximately 80% of the patients had spontaneous closure of their defect. Despite this, occult arrhythmias were frequent. The most common arrhythmia was supraventricular tachycardia (n=24, 16%) with non-sustained atrial arrhythmias in 21 patients and AF in two patients. A considerable number of patients had non-sustained ventricular tachycardia (n=12, 8%). Patients with ASD and tachyarrhythmias had increased right ventricular to left ventricular diastolic area in echocardiography and higher age when compared with ASD patients without arrhythmias.ConclusionAdult patients with small, unrepaired ASD have a hidden burden of both atrial and ventricular tachyarrhythmias. The mechanism likely relates to the residua of previous right-heart volume overload and incomplete reverse remodelling. Our results support guidelines recommending continued follow-up of patients with small, unrepaired ASD.

Wearable and implantable diagnostic monitors in early assessment of atrial tachyarrhythmia burden.

Atrial fibrillation (AF) is the cause of substantial direct patient morbidity and a frequent cause of emergency room visits. Even when asymptomatic, AF remains a major cause of stroke, particularly among the elderly. As the risk of both AF and stroke increase with age, the importance of AF-related stroke is growing as a result of demographic shifts in many countries. Oral anticoagulation is highly effective at preventing stroke due to AF; however, AF remains undetected in a large number of individuals. The last decade has witnessed the development of many new technologies to detect AF. Screening studies using single-time point or repeated discrete screening methods have uncovered previously undiagnosed AF in 1-3% of asymptomatic individuals. However, continuous monitoring with implanted devices demonstrates short-lasting AF in over one-third of older individuals with cardiovascular risk factors. Debate remains regarding the minimum burden of AF that is associated with an increase in stroke risk, and the threshold for using oral anticoagulation. Over the next 5 years, ongoing studies will help clarify how wearable and implantable technology can be used to improve outcomes in patients with previously unrecognized AF.

Early Detection and Treatment of Atrial Arrhythmias Alleviates the Arrhythmic Burden in Paced Patients: The SETAM Study.

Remote monitoring (RM) can remotely detect atrial tachyarrhythmias (ATAs). The benefit of RM compared to conventional follow-up in the detection and management of ATA was assessed in recipients of dual-chamber pacemakers. The multicenter randomized SETAM study enrolled 595 patients in sinus rhythm with a CHA2 DS2 -VASc score ≥2, without ATA history and untreated with antiarrhythmics and antithrombotics, randomly assigned to RM (RM-ON; n = 291) versus ambulatory follow-up (RM-OFF; n = 304) during 12.8 ± 3.3 months. ATA occurrence, burden, and management were analyzed together with adverse clinical events. Patients were 79 ± 8 years old, 63% men, with a CHA2 DS2 -VASc score of 3.7± 1.2. ATA were detected in 83 patients (28%) in the RM-ON versus 66 (22%) in the RM-OFF group (P = 0.06). The median time between the pacemaker implantation and the first treated ATA was 114 days [44; 241] in the RM-ON versus 224 days [67; 366] in the RM-OFF group (hazard ratio [HR] = 0.56; 95% confidence interval [CI]: 0.37-0.86; P = 0.01). Therapies for ATA were initiated in 92 patients and the time to treatment of ATA was shortened by 44% in the RM-ON group (HR = 0.565; 95% CI: 0.37-0.86; P = 0.01). Over the last 4 months of follow-up, the mean ATA burden was alleviated by 4 hours/day (18%) in the RM-ON group. The rate of adverse clinical events was similar in both groups. Remotely monitored patients were diagnosed and treated earlier for ATA, and subsequently had a lower ATA burden.

Abstract 11317: Outcomes of Atrial Arrhythmia Surgery for Atrial Tachyarrhythmias in Patients With Repaired Tetralogy of Fallot

Background: Atrial tachyarrhythmia is common in adults with tetralogy of Fallot (TOF) due to surgical scarring from repairs and atrial enlargement. The maze procedure refers to surgical ablation within the right atrium to disrupt arrhythmogenic circuits and is sometimes performed concomitantly during reoperation on repaired TOF patients. Our study aims to evaluate the effectiveness of maze in TOF patients. Methods: We performed a retrospective chart review that identified 30 TOF patients who underwent a pulmonary valve replacement (PVR) with maze and 38 TOF patients who underwent a PVR without maze from 1994 to 2011 and had at least 2 years of post-surgical follow-up at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Preoperative and postoperative arrhythmia status and management were compared in maze and non-maze groups. Results: Before the procedure, the most common pre-operative arrhythmias in the maze group were a history of atrial fibrillation (AFib)(n=16), atrial flutter (AFL)(n=10), and other supraventricular tachycardia (SVT)(n=6). Isolated right atrial maze was performed in 26 patients, and combined right and left atrial maze-cox procedure was performed in 4 patients. Of the 16 patients in the maze group with pre-op Afib, 6 had recurrent Afib within the first 2 years of follow-up (62.5% relative reduction, p=0.012). Of the 10 patients with pre-op AFL, only 1 had recurrence (90% relative reduction, p=0.012). Of the 6 patients with pre-op SVT, 4 had recurrence (33.3% relative reduction, p=0.727). There was no significant arrhythmia status change in the non-maze group at 2 years. Comparing patients with and without maze, the average cardiopulmonary bypass times were 155 minutes and 97 minutes, respectively (p=0.064), and aortic cross clamp times were 122 minutes and 64 minutes, respectively (p=0.004). On average, patients with maze spent 3.7 more days in the hospital compared to those without maze (p=0.001). Conclusions: Performing a concomitant maze procedure in patients undergoing TOF repair was associated with a moderate improvement in atrial tachyarrhythmia burden over 2 years. TOF patients who had the concomitant maze procedure required longer cardiopulmonary bypass time, aortic cross clamp time, and total hospital stay.

Annual atrial tachyarrhythmia burden determined by device interrogation in patients with cardiac implanted electronic devices is associated with a risk of ischaemic stroke independent of known risk factors.

This study evaluated the risk of non-fatal ischaemic stroke associated with increased long-term cumulative duration of atrial tachycardia (AT). We retrospectively reviewed the records of 260 patients with cardiovascular implantable electronic devices capable of monitoring AT. Patients were separated into zero, low and high AT burden groups. The cut-off point between low and high AT burden was defined by the median value of AT burden in the non-zero AT burden groups (5% in 1 year, about 18 days annually). The primary outcome was non-fatal ischaemic stroke. The mean patient age was 63.3 ± 13.7 years, the average follow-up was 7.0 years and 10 patients had strokes. Multivariate analysis showed only hypertension and a diagnosis of atrial fibrillation (AF) were associated with stroke. The risk of stroke in patients with hypertension was 12.57-fold higher than in those without hypertension, and was 20.81-fold higher in patients with paroxysmal AF and 162.59-fold higher in patients with chronic AF than in those without AF. Kaplan-Meier analysis showed that stroke-free survival was significantly different in the three AT burden groups (P = 0.002, long-rank test); the rate was greatest in the zero AT burden group, followed by the low AT burden group and was lowest in the high AT burden group. Patients who accumulated an AT duration exceeding 5% (18 days) of the total time in any of the 1-year periods are more likely to have an ischaemic stroke than those who have a low or zero AT burden.

Paradoxical undersensing of atrial electrograms during atrial fibrillation due to repeated activation of the quiet timer blanking interval: Case report and review of the literature

This report describes a case of paradoxical atrial undersensing by a dual-chamber pacemaker during paroxysmal atrial fibrillation. Undersensing of 5.6mV atrial signals at a programmed sensitivity of 0.5mV returned to normal sensing by decreasing atrial sensitivity to 1.0mV. This uncommon phenomenon can be explained by a repeated activation of the quiet timer blanking interval. Knowledge of this phenomenon is important in the current pacemaker management to improve the accuracy of the diagnostic feature for atrial tachyarrhythmia burden and to avoid unnecessary lead revisions.

Effects of long-term omega-3 polyunsaturated fatty acid supplementation on paroxysmal atrial tachyarrhythmia burden in patients with implanted pacemakers: Results from a prospective randomised study

Sino-atrial node disease and aging increase AF risk. We investigated if long-term fish oil supplementation reduces paroxysmal atrial tachycardia/fibrillation (AT/AF) burden in patients aged ≥60 years with sinoatrial node disease and dual chamber pacemakers. Following a run-in period of 6 months (p1) where AT/AF burden was logged,78 patients were randomised to control or fish oil group (total omega-3 6 g/d) and AT/AF burden evaluated after 6 months (p2; 39 controls, 39 fish oil) and 12 months (p3; 39 controls; 18 fish oil). A subset of 21 fish oil patients crossed over to controls in the final 6 months (crossover group). Median AT/AF burden increased significantly in controls (1.5%, 3.2%, 4.3%, P<.001) but not in fish oil patients at 6 months (1.4% to 2%, P=.46) or those continuing for 12 months (1.5%, 0.98%, 1%, P=.16). Time to first episode of AT/AF >1 min was not significantly different between the groups (P=.9). There was a rebound increase in AT/AF burden in p3 in cross over patients (2.2% to 5.8%, P=.01) reaching a level similar to controls (crossover vs. controls, 5.8% vs. 4.3%, P=.63) and higher than those who continued fish oil for 12 months (crossover vs. continued intake 5.8% vs. 1.2%, P=.02). Fish oil patients had shorter duration episodes of AT/AF with no difference in frequency compared to controls. Long-term fish oil supplementation did not suppress AT/AF burden but may have attenuated its temporal progression related to aging and sinus node disease.

Long-term Omega-3 Polyunsaturated Fatty Acid Supplementation Attenuates Increase in Atrial Tachyarrhythmia Burden in Patients with Sinoatrial Node Disease and Implanted Permanent Pacemakers: Results from a Prospective Randomised Study

Long-term Omega-3 Polyunsaturated Fatty Acid Supplementation Attenuates Increase in Atrial Tachyarrhythmia Burden in Patients with Sinoatrial Node Disease and Implanted Permanent Pacemakers: Results from a Prospective Randomised Study

Cardiac resynchronization therapy for patients with atrial fibrillation

Atrial fibrillation and chronic heart failure are two major and even growing cardiovascular conditions that often coexist. Cardiac resynchronization therapy is an important, device-based, non-pharmacological approach in a selected group of chronic heart failure patients that has been shown to improve left ventricular function and to reduce both morbidity and mortality in large randomized trials. The latest European and American guidelines have considered atrial fibrillation patients with heart failure eligible for cardiac resynchronization therapy. This review summarizes current literature concerning the following topics: prognostic relevance of atrial fibrillation in heart failure, effects of cardiac resynchronization therapy in atrial fibrillation, relevance and strategies of rhythm and rate control in this group of patients. Authors explain how atrial fibrillation may interfere with the delivery of adequate cardiac resynchronization therapy, how to reduce the burden of atrial tachyarrhythmias, and finally present a brief overview.

Progression of new onset to established persistent atrial fibrillation: an implantable device-based analysis with implications for clinical classification of persistent atrial fibrillation

The temporal patterns of onset of persistent atrial fibrillation (AF) recurrences leading to established persistent AF is currently unknown. Three hundred thirty patients with a history of paroxysmal AF and bradycardia (mean age, 70 ± 10years; 61% male) with implanted pacemakers that automatically recorded the cumulative daily atrial tachyarrhythmia (AT) burden were included in the analysis. Persistent AF was defined as device data showing ≥7 consecutive days with ≥23h of AT. We analyzed the pattern and duration of persistent AF recurrences and time to each persistent AF episode recurrence. Seventy-eight patients (24%) developed their first persistent AT/AF after 147 ± 149days. Follow up ranged from 14 to 499days. Median AF burden in the week prior to persistent AF was 3.5h/day. Fifty-four patients (16%) had a minimum of 180days follow up after initial detection of persistent AF. Three of 54 patients (6%) immediately developed established AF; 32 of 51 patients (63%) returned to sinus rhythm but then had a second persistent AF event. These 32 patients had a minimum of 90days follow up and 25 of these 32 patients (78 %) had a third persistent AF event. Time to recurrence analysis showed progressive abbreviation in persistent AF onset. The median durations of the first, second, and third persistent AF events were 16, 13, and 17days, respectively. (1) The time to first, second, and third persistent AF recurrences progressively decreases with a high likelihood of established persistent AF within 9months of onset. (2) These data support intermittent but frequent AF monitoring for the detection of persistent AF recurrences to assess the efficacy of rhythm control interventions.