AF Episodes Research Articles

P228 WEARABLE DEFIBRILLATOR IN CLINICAL PRACTICE. MULTIANNUAL MULTI–CENTER EXPERIENCE

Abstract Introduction Heart failure with reduced left ventricular ejection function (LVEF) represents a life–threatening condition for patients (pts). A period of time of 40–90 days, in optimal medical therapy, is indicated to evaluate the recovery of the LVEF and the indication to ICD implantation. In this period, from 1% to 5% of pts can experience sudden death. We evaluated the usefulness of the wearable cardioverter defibrillator (WCD) as a temporary antiarrhythmic therapy in the interval from discharge to the three–month follow–up. Methods From December 2015 to December 2021, 174 consecutive pts (141 M (81%); mean age 62 years ± 11.6 years) were discharged with reduced FE < 35% in OMT, with WCD and were re–evaluated within 3 months to establish indication for ICD implantation. Results 110 pts (63.2%) recovered LVEF at 3 months and left the indication to ICD. 9 pts refused and/or returned the WCD due to poor compliance (5.2%); 52 pts (29.9%) did not recover LVEF and were implanted with ICD. The WCD was worn continuously by the majority of pts with good compliance for 87.4 ± 52.0 days (range 1 ÷ 303 days), for 22.08 hours / day. 23 episodes of AF were correctly recognized; 10 TVNS> 10 sec; 1 episode of VF in 1 patient in which 1 shock was correctly delivered. 1 inappropriate shock was delivered on tachycardic AF. During the WCD wearing period, 3 deaths occurred (1.7%): in 2 pts due to refractory HF (one of these pts had VF correctly recognized and treated by the WCD but degenerated into pulseless activities); 1 death for terminal cancer). The use of WCD has progressively increased over the years (from 4.5 LV / yy in 2015–16 to 45 LV / yy in 2020–21). Conclusions The use of WCD has gradually increased in clinical practice for patients who have not yet developed clear indications for ICD implantation. In the majority of them, ventricular dysfunction is transient. Wearable cardioverter defibrillator represents additional security during this period. Continuous monitoring makes it possible to identify supraventricular and ventricular arrhythmias, improving therapeutic appropriateness and in general the patients have excellent compliance with the device. Further studies are needed to substantiate this strategy.

Left atrial echocardiographic parameters predict the onset of atrial fibrillation: the SMASH2 scoring system.

As AF-associated morbidity and mortality are increasing, there is an acute need for improved surveillance and prevention strategies to reduce the impact of AF and related strokes. Specific echocardiographic parameters that can best predict future onset of AF within 3 months are lacking. Twenty patients with AF, as identified by presence of ICD-9 diagnosis code, were compared with a control group of twenty age- and sex-matched patients selected from the same clinic population but without a diagnosis of AF. Transthoracic echocardiograms (TTE) obtained within 90 days prior to first documented AF episode (study group) or obtained closest to first clinic visit (control) were selected for review. Baseline characteristics, including age, BMI, presence of hypertension, hyperlipidemia, diabetes, and heart failure were comparable. Increased left atrial (LA) size (end systolic major axis in 2-chamber view: AF 4.62±0.03 vs control 3.79±0.21, P =0.03), increased mitral inflow (E/A ratio: AF 1.35±0.15 vs control 1.06±0.07, P =0.04), and reduced LA global longitudinal strain (AF -2.69±0.26 vs control - 3.59±0.31, P =0.04) were most closely associated with AF compared with the control group. Multivariate logistic regression was used to develop predictive models for AF onset. A combination of imaging and traditional clinical risk factors was the best AF prediction model with AUC of 0.94, which greatly exceeds the current best predictors published. From these parameters, we developed the SMASH2 scoring system for 90- day AF risk estimation. Risk factors for AF and early features of atrial cardiomyopathy including male sex, hypertension, LA enlargement, reduced mitral inflow, and reduced LA strain are powerful predictors of AF onset within 90 days, and may be used to prognosticate future AF risk.

Preventive role of angiotensin receptor blockers on the recurrent AF in hypertensive patients

Abstract Funding Acknowledgements Type of funding sources: None. Background The structural remodeling makes important contributions to the AF substrate. The formation of connective tissue in response to injury (cardiac fibrosis) is a hallmark of arrhythmogenic structural remodeling. The atrial fibrosis decrease can be helpful in preventing the onset and recurrence of AF. Inflammatory mechanisms may form a basis for new agents more likely to prevent recurrent episodes of AF. The renin-angiotensin-aldosterone system plays an important role in the pathogenesis of AF in correlation with the inflammatory process. The aim of this study is to access the role of long-term treatment by sartans on the regression of left heart remodeling and the frequency of AF recurrence after successful cardioversion in hypertensive patients. Methods We have follow up 119 hypertensive patients with paroxysmal / persistent AF after successful cardioversion during 10-12 months. All patients divided into two groups: group A (62 patients) treated by Losartan daily dose 50 -100 mg or Valsartan daily dose 160mg for 10-12 months. As a control group B of similar 57 patients received standard antihypertensive therapy, but without taking sartans. Both groups were received supporting antiarrhythmic therapy with Аmiodarone (200-300 mg daily). The patients underwent clinical examination, echocardiography, ECG Holter monitoring and determination of plasma levels of inflammatory and fibrosis markers - high sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6) and profibrotic cytokine - transforming growth factor beta (TGF-β1) by ELIZA. Statistical analysis was performed by SPSS-16. Results The obtained results have shown that it was no significant differences of the antihypertensive effect in both patients groups. But the obtained data of structural remodeling regression in A and B groups were differed significantly. Thus, in the A group decrease in LVTDV, TMZHP and LVEDD and an improvement in left ventricular diastolic function were revealed, on compared to the B group which showed only a tendency to improve these indicators. Moreover, in group A, there was a significant decrease in the concentration of inflammation and fibrosis markers compared with the control group. We obtained a positive correlation between hsCRP and LAD (r=0.58, p<0.001) and LVEDD (r=0.51, p<0.001), between TGF-β1 and LAD (r=0.55, p<0.001), LVEDD (r=0.59, p<0.001) and number of AF episodes (r=0.489, p<0.001.). The negative correlation was found between hsCRP and TGF-β1 (r=-0.36, p<0.01). It was revealed that in a group recurrence of AF was less than in B group (6.8% vs 10%). Conclusion These results confirmed that the use of angiotensin receptor blockers improves some cardiac remodeling parameters, decreases the frequency of AF recurrence in hypertensive patients with successful cardioversion and contributes to prevent AF episodes.

Short-term atrial fibrillation detection using electrocardiograms: A comparison of machine learning approaches

BackgroundAtrial fibrillation (AF) is one of the most prevalent cardiac arrhythmias, which challenges the healthcare systems globally.Timely detection of AF can potentially reduce the mortality and morbidity rates as well as alleviate the economic burden caused by this.Digital solutions are shown to enhance the diagnosis of cardiac abnormalities. ObjectivesBy the latest advancements in the field of medical informatics and tele-health monitoring, huge amount of electro-physiological signals, such as electrocardiograms (ECG), can be easily collected.One of the most common ways for physicians/cardiologists to analyse these signals is through visual inspection.However, it is not always easy and in most cases cumbersome to analyse these big amounts of ECG data.Therefore, it is of great interest to develop models that are capable of analyzing these data and help physicians making better decisions.This paper proposes and compares well-known machine learning (ML) algorithms to diagnose short episodes of AF. This also paves the way for real-time detection of AF in clinical settings. MethodsDifferent ML algorithms such as Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF), Stacking Classifier (SC), Extreme Gradient Boosting (XGBoost), and Adaptive Boosting (AdaBoost) were applied to detect AF. These models were trained using extracted statistical features from ECG signals. ResultsThe proposed ML models were trained on a dataset with 23 ECG records of length approximately 10 h each using leave one group out cross validation (LOGO-CV) technique and achieved the best sensitivity (Se), specificity (Sp), positive predictive value (PPV), false positive rate (FPR), and F1-score of 85.67%, 81.25%, 90.85%, 18.75% and 88.18%, respectively, to classify AF from normal sinus rhythms (NSR) in short ECG segments of 20 heartbeats.Additionally, the models were examined on three unseen datasets, namely the Long Term AF dataset, MIT-BIH Arrhythmia dataset, and MIT-BIH Normal Sinus Rhythm dataset, to assess their robustness and generalization. ConclusionThe obtained results show high performance and flexibility of some of the applied ML models compared to other well-known algorithms. In general, the empirical results confirm that ensemble methods, such as AdaBoost, generalized well and perform better than other approaches.

Effect of postoperative atrial fibrillation on early and mid-term outcomes of coronary artery bypass graft surgery.

The long-term prognostic role of postoperative atrial fibrillation (POAF) in cardiovascular outcomes in patients undergoing cardiac surgery is uncertain. Our goal was to investigate the impact of new-onset POAF on midterm adverse cardiovascular events after coronary artery bypass graft (CABG) surgery. We performed a retrospective cohort study of patients who underwent isolated CABG without a preoperative history of atrial fibrillation/flutter. POAF was defined as episodes of AF lasting ≥30 s during the hospitalization period. The effect of POAF on midterm all-cause mortality and cerebrovascular accidents/transient ischaemic attacks (CVA/TIA) was assessed using a Cox proportional hazard regression model in a competing risk setting. Additional analyses were performed on patients surviving an event-free early postoperative period (i.e. within 30 postoperative days after the index operation). A total of 9,310 patients were followed for a median duration of 48.7 months. New-onset POAF was associated with an increased risk of midterm all-cause mortality (HR = 1.648, 95% confidence interval: 1.402-1.937; P < 0.001) and CVA/TIA (subdistribution-HR = 1.635, 1.233-2.167; P = 0.001). After excluding patients who died during the early postoperative period, POAF remained significantly associated with higher late all-cause mortality (HR = 1.518, 1.273-1.811; P < 0.001). However, the risk of late CVA/TIA in patients who survived the early postoperative period without having a stroke was similar between those with and without POAF (subdistribution-HR = 1.174, 0.797-1.729; P = 0.418). New-onset POAF after CABG is associated with an increased risk of midterm overall mortality and stroke. However, late stroke risk is likely similar between patients with and without POAF who survive an event-free early postoperative period.

PO-620-07 AN ENSEMBLE OF FEATURES BASED DEEP LEARNING NEURAL NETWORK FOR REDUCTION OF INAPPROPRIATE ATRIAL FIBRILLATION DETECTION IN IMPLANTABLE CARDIAC MONITORS

Multiple studies have been reported for electrocardiogram (ECG) classification using deep learning neural networks. Most of these studies use the ECG as input to a convolution neural network (CNN) which then automatically generate features from the raw ECG signal. To develop an application specific deep learning CNNs using custom ensemble of features to reduce inappropriate AF detections in implantable cardiac monitors (ICM). The ensemble of features was developed and combined to form an input signal for deep learning CNN. The ensemble of features were designed based on the electro-physiological characteristics during AF: presence of fibrillation/flutter waves or absence of single p-wave between two R-waves, incoherence of RR intervals, and AF begetting more AF. A small custom CNN model using 6 convolution layers and the publicly available RESNET18 model were used. The deep learning models were trained and validated using more than 60K ICM detected AF episodes that were adjudicated to be true AF or false detections. The trained models were evaluated using an independent test dataset of ICM detected and adjudicated AF episodes from patients who were not included in the training and validation dataset. The training and validation dataset consisted of 31,768 true AF episodes (2516 patients) and 28,527 false episodes (2126 patients). The validation set used 20% of randomly chosen episodes of each type. The independent test set consisted of 4546 true AF episodes (418 patients) and 5384 false episodes (605 patients). In the validation set, the custom CNN had an area under ROC curve (AUC) of 0.996 (0.993 for RESNET18) and a threshold for discrimination was defined such that a relative sensitivity and specificity of 99.2% and 92.8% (99.2% and 87.9% for RESNET18) was obtained. The performance results for the two models in the independent test dataset for the pre-defined threshold is shown in the figure, with relative sensitivity and specificity of around 99% and 90% respectively. An ensemble of features based deep learning CNN was developed that reduced inappropriate AF detection in ICM by over 90% while preserving sensitivity for detection of true AF. For an application specific feature based CNN, a smaller sized custom CNN performed as well as a larger sized established CNN.

Novel cryoballoon to isolate pulmonary veins in patients with paroxysmal atrial fibrillation: long-term outcomes in a multicentre clinical study

BackgroundRecently, a novel cryoballoon ablation catheter has demonstrated acute safety and efficacy in de novo pulmonary vein isolation (PVI) procedures in patients with paroxysmal atrial fibrillation (PAF). However, there are limited studies demonstrating the long-term efficacy. The aim of this study was to evaluate the long-term safety and efficacy of this novel cryoballoon in treating PAF.MethodsThis was a non-randomized, prospective, multicentre study enrolling 58 consecutive patients. Cryoablation was delivered for 180 s if time to isolation was ≤ 60 s. Otherwise a 240-s cryoablation was performed. One centre performed pre- and post-ablation high-density mapping (n = 9) to characterize lesion formation. After a 3-month blanking period, recurrence was defined as having any documented, symptomatic episode(s) of AF or atrial tachycardia. All patients were followed for 1 year.ResultsAcute PVI was achieved in 230 of 231 pulmonary veins (99.6%) with 5.3 ± 1.6 cryoablations per patient (1.3 ± 0.7 cryoablations per vein). Forty-three (77%) patients remained arrhythmia-free at 1-year follow-up. Four patients (6.9%) experienced phrenic nerve injury (3 resolved during the index procedure; 1 resolved at 6 months). One serious adverse device event was reported: femoral arterial embolism event occurring 2 weeks post-index procedure. For patients who underwent high-density mapping, cryoablation was antral with 50% of the posterior wall ablated.ConclusionsInitial multicentre clinical experience with a novel cryoballoon has demonstrated safety and efficacy of PVI in patients with PAF. Ablation with this cryoballoon provides a wide, antral lesion set with significant debulking of the posterior wall of the left atrium.

Safe electrophysiologic profile of dexmedetomidine in different experimental arrhythmia models

Previous studies suggest an impact of dexmedetomidine on cardiac electrophysiology. However, experimental data is sparse. Therefore, purpose of this study was to investigate the influence of dexmedetomidine on different experimental models of proarrhythmia. 50 rabbit hearts were explanted and retrogradely perfused. The first group (n = 12) was treated with dexmedetomidine in ascending concentrations (3, 5 and 10 µM). Dexmedetomidine did not substantially alter action potential duration (APD) but reduced spatial dispersion of repolarization (SDR) and rendered the action potentials rectangular, resulting in no proarrhythmia. In further 12 hearts, erythromycin (300 µM) was administered to simulate long-QT-syndrome-2 (LQT2). Additional treatment with dexmedetomidine reduced SDR, thereby suppressing torsade de pointes. In the third group (n = 14), 0.5 µM veratridine was added to reduce the repolarization reserve. Further administration of dexmedetomidine did not influence APD, SDR or the occurrence of arrhythmias. In the last group (n = 12), a combination of acetylcholine (1 µM) and isoproterenol (1 µM) was used to facilitate atrial fibrillation. Additional treatment with dexmedetomidine prolonged the atrial APD but did not reduce AF episodes. In this study, dexmedetomidine did not significantly alter cardiac repolarization duration and was not proarrhythmic in different models of ventricular and atrial arrhythmias. Of note, dexmedetomidine might be antiarrhythmic in acquired LQT2 by reducing SDR.

Abstract 8925: Current Clinical AF Treatment Targets Do Not Reflect Patient Priorities

Background: AF clinical trials define success as freedom from any AF episode &gt;30 seconds. Clinically AF treatment is geared towards managing patient symptoms, yet little is known about patients’ expectations for successful AF treatment. Objective: Determine patient expectations for successful AF treatment. Methods: Patients with an AF diagnosis from a tertiary electrophysiology clinic were asked to complete the Toronto Atrial Fibrillation Severity Scale (AFSS) from the perspective of current symptoms, worst ever symptoms, and expected symptoms after successful treatment. Survey and patient clinical data were linked through the EMR. Results: Of the survey respondents (n=27), 41% were female, mean age was 69 (SD 9.7 years), and 30% had prior ablation. Overall, 59% of these patients considered AF treatment successful even with AF occurring one per year or more, and 70% would still consider treatment successful with episodes lasting minutes or more. When selecting the most important factor of success, 80% of patients selected decrease in AF frequency, 20% selected decrease in severity of symptoms, and 0 selected decrease in episode duration. A minority of patients (19%) considered treatment successful only if they never had AF again. Conclusion: A small minority of patients with AF would consider their treatment successful if they never experienced an AF episode again, which contradicts our current assessment of AF treatments. If confirmed in larger cohorts, these data support redesigning AF clinical studies to match outcomes prioritized by patients.

Abstract 12236: Population-Level Analyses of Alcohol Consumption as a Predictor of Acute Atrial Fibrillation Episodes

Introduction: We conducted an instrumental variable analysis to test whether acute alcohol consumption leads to increased emergency department (ED) visits for AF at the level of the general population. Methods: We analyzed blood alcohol concentration measurements obtained from individuals using commercially available Bluetooth-enabled breathalyzer devices (BACtrack, San Francisco, CA) collected between January 1, 2014 and December 31, 2016 to identify dates associated with heightened alcohol consumption that corresponded to recurrent, nationally-recognized events. Outcomes included ED visits with AF (main analysis) or supraventricular tachycardia (SVT; as a negative control) in California between January 1, 2005 to December 30, 2015 using Office of Statewide Health Planning and Development data. A secondary analysis examining rates of new-onset AF was conducted. We utilized population denominators for age, sex, and race/ ethnicity in California from the US Census. Multivariable adjusted Poisson regression models were utilized to compare rates of AF during and 6 days following instrumental events compared to all other days of the year. Results: Using 1,269,054 breath alcohol measurements obtained from 36,158 individuals, we identified 8 recurring events associated with heightened alcohol consumption. After multivariable adjustment, excess alcohol consumption inferred from our instrumental variables was associated with 719 additional AF visits per 100,000 person-years (95% CI 189-1249, p = 0.008; Table ). The association between these events and new-onset AF exhibited a stronger effect (1,757 additional visits, 95% CI 945-2,569, p &lt; 0.001). A negative control analysis failed to exhibit significantly heightened rates of SVT during those same dates. Conclusion: These data suggest that acute alcohol consumption is associated with a higher risk for discrete AF episodes, as well as for new-onset (incident) AF, in the general population.

Implantable Loop Recorder Monitoring and the Incidence of Previously Unrecognized Atrial Fibrillation in Patients on Hemodialysis

IntroductionAtrial fibrillation (AF) is common in patients with kidney failure on hemodialysis (KF-HD). We determined both AF incidence and burden in patients with KF-HD using implantable loop recorder (ILR) monitoring.MethodsPatients with KF-HD were enrolled and received an ILR. In 6 monitoring months, the incidence of AF events lasting ≥6 minutes was captured. Demographic, clinical, and dialysis characteristics were collected, and associations with incident AF were estimated using negative binomial regression models and expressed as incidence rate ratios and 95% CIs.ResultsWe enrolled 66 patients with KF-HD (mean age = 56 years, 70% male); 59 (90%) were without previously diagnosed AF. AF lasting ≥6 minutes was detected in 18 of 59 subjects (31%) without previously diagnosed AF and in 5 of 7 subjects (71%) with a previous AF diagnosis. Among the 23 with detected AF, episodes were present on 16% of patient days. Although 14 of 23 patients (61%) had AF on <5% of monitored days, the average duration of AF episodes was <1 hour in 13 of 23 patients (52%). Among patients with AF ≥6 minutes, 19 of 23 (83%) had a CHA2DS2-VASc score ≥2. When investigating individual HD parameters, higher dialysate calcium (>2.5 vs. 2.5 mEq/l: incidence rate ratio = 0.62; 95% CI, 0.48–0.80) was associated with lower AF risk whereas higher dialysate bicarbonate concentrations (>35 vs. 35 mEq/l: incidence rate ratio = 3.18; 95% CI, 1.13–8.94) were associated with higher AF risk.ConclusionNew AF was detected in approximately one-third of patients with KF-HD. AF affects a substantial proportion of patient days and may be an underappreciated cause of stroke in KF-HD.

Genetic polymorphisms of matrix metalloproteinase-9, tissue inhibitor of matrix metalloproteinase-1 and development of postoperative atrial fibrillation in elderly patients

Abstract Purpose The aim of the study was to assess the association of genetic polymorphisms of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) with atrial fibrillation development in elderly patients with coronary artery disease (CAD), undergoing coronary artery bypass graft (CABG) surgery. Methods Studied were 80 patients who underwent CABG. In all the patients routine laboratory and instrumental tests were performed. Patients also underwent genetic polymorphisms of MMP-9 A8202G and TIMP-1 C536T estimation with polymerase chain reaction. According to occurrence of postoperative atrial fibrillation (POAF) all the patients were divided into two groups: group 1 – patients without POAF (56 patients, 81.8% males, mean age 65.9±4.0 years), group 2 – patients with first detected episode of AF after CABG (24 patients, 87.5% males, mean age 67.7±5.4). Results In group 1 the II grade of stable angina was significantly more often than in patients of the 2 group (32.1% vs 12.5%, p=0.009). Patients of the 2 group had more long history of CAD (87.2±72.4 months vs 46.9±31.4 months, p=0.03), more often – NYHA III (45.8% vs 12.5%, p=0.01) and larger LA diameter (43.8±3.5 mm vs 37.5±3.9 mm, p&amp;lt;0.001) than the patients of the 1 group. Genotype AA MMP-9 A8202G was found in 39.3% patients of the 1 group and in 16.7% patients of the 2 group (p=0.04), genotype AG – in 44.6% and 54.1% respectively (p=0.4), genotype GG – in 16.1% and 29.2% respectively (p=0.06). Genotype CC TIMP-1 C536T was found in 98.2% and 100% patients in 1 and 2 group respectively (p=0.72), genotype CT – in 1.8% patients of the 1 group. According to results of multivariate regression analysis odds ratio of POAF development in patients with stable angina grade III was 1.8 (95% CI 0.5–7.5, p=0.4), NYHA III – 0.85 (95% CI 0.2–3.5, p=0.55), history of CAD more than 20 months – 1.8 (95% CI 1.2–8.1, p=0.03), LA diameter more than 39 mm - 4.2 (95% CI 1.6–9.5, p&amp;lt;0.0001), allele G MMP-9 A8202G – 2.6 (95% CI 1.2–7.5, p=0.03). Conclusion In elderly patients undergoing coronary artery bypass graft surgery left atrial diameter more than 39 mm, history of coronary artery disease more than 20 months and the presence of G allele of MMP-9 A820G are significantly associated with postoperative atrial fibrillation development. Funding Acknowledgement Type of funding sources: None.

Effects of chronic exposure to usual and high doses of Bisphenol A on cardiac arrhythmias, electrophysiology, and autonomic modulation

Abstract Background Bisphenol A (BPA) is a synthetic compound found in plastic bottles, sports equipment, or water pipes. The continuous and inevitable human exposure to BPA has been related to increased cardiovascular risk. In experimental studies, acute exposure to high BPA doses was associated with ventricular arrhythmias. However, the effects of chronic exposure to usual BPA doses (i.e., relevant for usual human exposure) on cardiac arrhythmogenicity have not been properly assessed. Purpose We aimed to assess the effects of chronic exposure to high and usual BPA doses on cardiac arrhythmias, electrophysiology, and autonomic modulation in rats. Methods Adult female Wistar rats were randomized into 3 groups: Control, BPA, and BPA-HD (n=7 each). BPA and BPA-HD rats received 50 μg/kg/day and 25 mg/kg/day of BPA, respectively, for 9 weeks. Rats were implanted with radiotelemetry ECG devices and 24-h ECG recordings were performed prior to and after application of transesophageal atrial burst pacing (4,000 stimuli/min for 20 s; 15 cycles). Heart rate variability (HRV) parameters and atrial and ventricular arrhythmias (i.e., atrial premature beats [APB], atrial fibrillation [AF], ventricular premature beats [VPB], ventricular tachycardia/fibrillation [VT/VF]) were assessed based on the 24-h ECG recordings. The left atrium was then collected and atrial depolarization velocity and action potential duration to 90% (APD90) and 50% (APD50) of complete repolarization were measured. Results Mean heart rate (p=0.48), the number of VPB (p=0.90), AF inducibility (p=0.68), and atrial action potential parameters (all p&amp;gt;0.05) were all similar between the 3 groups. None of the animals presented VT/VF. There was no significant difference in the number of atrial or ventricular arrhythmic events nor in the HRV parameters between BPA and Control (all p&amp;gt;0.05). However, BPA-HD presented a significantly higher number of APB both prior to (p=0.02) and after (p=0.04) atrial pacing, and a significantly higher number of post-pacing spontaneous AF episodes (p&amp;lt;0.01) compared to Control. The parasympathetic indexes SDNN, RMSSD, pNN5, and the NHF of the HRV spectrum were all significantly higher (all p&amp;lt;0.05), whereas the LF/HF ratio, an index of sympathetic and parasympathetic interactions, was significantly lower (p=0.01) in the BPA-HD compared with the Control rats. Conclusions In rats, chronic exposure to BPA doses relevant for usual human exposure was not associated in any significant change in cardiac arrhythmogenicity, electrophysiology, or autonomic modulation. However, high-dose BPA exposure, such as that occurring in workers in the plastics industry, led to significant increase in atrial arrhythmogenicity, including AF, that did not seem to be related to atrial electrophysiology changes. Instead, given the strong atrial proarrhythmic effects of vagal hyperactivity, this effect could be linked to the significant increase in vagal modulation induced by high-dose BPA exposure. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS – UEFISCDI

Frontal plane QRS-T angle predicts early recurrence of acute atrial fibrillation after successful pharmacological cardioversion with intravenous amiodarone.

Although restoration of sinus rhythm is the integral part of the atrial fibrillation (Af) management, recurrence frequency of Af is high after cardioversion. However, little is known about the association of electrocardiography (ECG) parameters with Af recurrence after restoration of sinus rhythm. The present study aimed to investigate whether frontal plane QRS-T (fQRST) angle, as a marker of ventricular repolarization heterogeneity, predicts Af recurrence after successful pharmacological cardioversion. One hundred and sixty-five paroxysmal Af patients with an acute Af episode who underwent successful pharmacological cardioversion with intravenous amiodarone infusion were included into the study. Patients were divided into two groups according to presence or absence of in-hospital Af recurrence. The association between fQRST angle and Af recurrence was investigated. Af recurrence was observed in 42 (25.4%) patients. The mean fQRST angle was significantly higher in patients with Af recurrence compared to those without Af recurrence (90±45.8 vs. 51±38.2, p<0.001). Also, Af recurrence was more frequent in patients who had fQRST angle >90˚, compared to patients with fQRST angle ≤90˚ (54.1% vs. 13.7%, p<0.001). Moreover, ROC curve analysis demonstrated that an increased fQRST angle >92.5˚ predicted in-hospital Af recurrence with a sensitivity of 76.2% and a specificity of 81.4% (AUC:0.728, p<0.001). Furthermore, multivariate analysis demonstrated that fQRST angle was an independent predictor of in-hospital Af recurrence after successful pharmacological cardioversion (OR: 1.892, 95% CI: 1.361-2.917, p<0.001). As a parameter that can be easily calculated from automated ECG recordings, fQRST angle may be useful in the prediction of early Af recurrence after successful pharmacological cardioversion with amiodarone.

Potential of remote monitoring to prevent sensing and detection failures in implantable cardioverter defibrillators

Sensing malfunction and misinterpretation of intracardiac electrograms (IEGMs) in patients with implantable cardioverter defibrillators (ICDs) may lead to inadequate device activity such as inappropriate shock delivery or unnecessary mode-switching. Remote monitoring has the potential for early detection of sensing malfunction or misclassification and may thus prevent adverse device activity. Therefore, the authors analyzed the amount, nature, and distribution of misclassification in current ICD and cardiac resynchronization therapy defibrillator technology using the device transmissions of the IN-TIME study population. All transmitted tachyarrhythmic episodes in the 664 IN-TIME patients, comprising 2214 device-classified atrial fibrillation (DC-AF) episodes lasting ≥ 30 s and 1330 device-classified ventricular tachycardia or fibrillation (DC-VT/VF) episodes, were manually analyzed by two experienced cardiologists. After evaluation of all DC-VT/VF episodes, atotal of 300 VT/VF events (23.1%) were false-positive, with supraventricular tachycardia being the most frequent cause (51.7%), followed by atrial fibrillation (21.3%) and T‑wave oversensing (21.0%). Atotal of 15patients with false-positive DC-VT/VF received inappropriate shocks. According to the inclusion criteria, 616 IEGMs with DC-AF were assessed. Atotal of 19.7% were false-positive AF episodes and R‑wave oversensing was the most common reason (55.9%). Remote monitoring offers the opportunity of early detection of signal misclassification and thus early prevention of adverse device reaction, such as inappropriate shock delivery or mode-switching with intermittent loss of atrioventricular synchrony, by correcting the underlying causes.

B-PO03-186 MONITORING ATRIAL FIBRILLATION PATIENTS USING ACTIVE CONTACTLESS VIDEOPLESTHYMOGRAPHY IMPLEMENTED ON A PERSONAL TABLET

Early detection of subclinical AF can help prevent significant complications such as embolic stroke, heart failure, and AF-related hospitalizations. We evaluated the performance of a facial pulsation detection video technology called videoplethysmography (VPG) to detect the presence of AF using a monitoring method that does not require a dedicated sensor and/or cumbersome recording procedures. We enrolled patients with AF undergoing either cardioversion or ablation therapy. Patients were asked to collect two 25-sec video recordings daily using a smart tablet loaded with the VPG technology. Early recurrence of AF during the 15-day follow-up period was based on continuous ECG recording (14-day patch monitor). ECGs were manually annotated for the presence of AF episodes lasting >15-sec in duration. The VPG algorithm measured pulse irregularity and was designed to minimize false positive detections. Development and validation were performed on independent datasets (½ split without a subject in common). We report the specificity, sensitivity, and accuracy of the video-based method to detect early recurrence of AF during the follow-up period. The motion of the patient's face was tracked, but no feedback was provided to the subjects during the measurement. We enrolled 112 patients (age: 65∓9 years, 81 men) over an 18 month period. Five subjects did not collect any quality data while 107 patients collected 7∓5 minutes of data on average at home (min:30sec, max: 25min) over 12∓3 days (min:1.5, max:14.7 days). Thirty subjects (28%) experienced at least one 15-sec AF episode post-procedure. The sensitivity and specificity of the AF detection algorithm based on a total duration of 7 min. of video recordings, over 12 days were 33% and 95% in the validation dataset (accuracy: 74%). Less than one-minute daily monitoring using a contactless VPG method can detect AF in one-third of patients experiencing an early recurrence of AF with a 5% false-positive rate. The sensitivity of the VPG method is expected to increase with a larger number of daily VPG recordings.

B-PO01-052 ATRIAL-SPECIFIC LKB1 KNOCKDOWN REPRESENTS A NOVEL MOUSE MODEL OF ATRIAL CARDIOMYOPATHY WITH SPONTANEOUS ATRIAL FIBRILLATION

AF is one of the most common cardiac arrhythmias, with > 37 MM patients worldwide. To develop more effective therapies for AF, it is essential to comprehend its underlying mechanisms using better models. Large animal models are more similar to humans, but their availability and cost are big drawbacks. Mice can be genetically manipulated and offer affordable phenotyping platforms. Liver kinase b1 (Lkb1) knockout mice develop spontaneous AF by 8 weeks of age. One of the main limitations of this model, however, is that they also develop ventricular dysfunction and heart failure, complicating the understanding of mechanisms because of the confounding effects of ventricular dysfunction on AF. To develop an effective model of spontaneous AF without confounding ventricular effects. We used the atrial-specific AAV9-ANF-Cre to drive atrial-specific Lkb1-knockdown (Lkb1-aKD) following injection into 5-day-old LKB1FL/FL mice. Starting at week 5, 24-hours ECGs were obtained once/week via subcutaneously implanted telemeters. AF was defined by a lack of P-waves and irregularly irregular R-R intervals for more than 1 second. Lkb1-aKD mice exhibited 100% AF incidence at 6 weeks and an age-dependent increase in the duration of spontaneous AF episodes. Atrial Doppler/echocardiography revealed increased atrial size and diminished mitral valve function, indicating increased atrial cardiomyopathy. No change was seen in left ventricular ejection fraction and end-diastolic dimensions in 12 weeks old LKB1-aKD mice. qRT-PCR and western blot analyses revealed significant Lkb1 downregulation in atrial but not in ventricular tissue, consistent with atrial-restricted Lkb1 knockdown. Picrosirius-red staining and qRT-PCR analysis showed increased collagen content in the atria of LKB1-aKD mice, indicating prominent atrial fibrosis. AAV9-mediated knockdown of Lkb1 produces a novel mouse model of AF and cardiomyopathy without genetic or phenotypic alterations in the ventricles. Lkb1-aKD mice represent a practical atrial-specific mouse model of spontaneous AF, ideally suited for mechanistic studies aimed to uncovering the molecular basis of spontaneous AF without confounding influences from ventricular remodeling.

Prevalence and Predictors of Additional Ablation Beyond Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation.

Background: Pulmonary vein isolation (PVI) is an effective strategy in the treatment of paroxysmal atrial fibrillation (PAF). Yet, there are limited data on additional ablation beyond PVI. In this study, we sought to assess the prevalence, predictors, and outcomes of additional ablation in PAF patients.Methods: A total of 537 consecutive patients with PAF were retrospectively evaluated for the index procedure. PVI was successfully conducted in all patients, after which electrophysiological study and drug provocation were performed, and additional ablations were delivered for concomitant arrhythmias, non-PV triggers, and low voltage zone (LVZ). The prevalence, predictors, and outcomes of additional ablation were analyzed.Results: Among 537 consecutive patients, 372 addition ablations were performed in 241 (44.88%) patients, including 252 (67.74%) concomitant arrhythmias in 198 (36.87%) patients, 56 (15.05%) non-PV triggers in 52 (9.68%) patients and 64 (17.20%) LVZ modification in 47 (8.75%) patients. Lower LVEF (OR = 0.937, p = 0.015), AF episode before procedure (OR = 2.990, p = 0.001), AF episode during procedure (OR = 1.998, p = 0.002) and AF episode induced after PVI (OR = 15.958, p < 0.001) were independent predictors of additional ablation. Single-procedure free from atrial arrhythmias at 58.36 ± 7.12 months post-ablation was 70.48%.Conclusions: Additional ablations were common in patients with PAF for index procedure. Lower LVEF and AF episodes before, during the procedure, and induced after PVI predicts additional ablation.

Postabaltive Pericarditis in Patient with a Prior History of Rheumatic Disease: a Case Report

A 60 year-old male with a previous (40 years ago) history of rheumatic carditis without valve involvement and 5 years history of paroxysmal atrial fibrillation underwent ablation (PV isolation with roof and mitral isthmus lines). The following day patient developed AF episode with severe mid-sternal chest pain with widespread concave ST elevation throughout most of the limb leads (I, II, III, aVL, aVF) and precordial leads (V2-6). Serum troponin I was 87.2 ng/ml with a creatinine concentration of 0.88 mg/dl and hemoglobin level of 15 g/dl. 2D transthoracic echocardiogram excluded wall motion abnormalities, or significant pericardial effusions. Recurrence of acute rheumatic fever was excluded based on revised Jones criteria. Careful analysis of ECG allowed us to recognize the ECG criteria of pericarditis and to avoid unnecessary emergent coronary angiography. Ultimately, the patient was diagnosed with pericarditis. After diagnosis, the patients presenting symptoms resolved with treatment including sotalol 160 mg per day, nonsteroidal anti-inflammatory agents.&#x0D; Conclusions: This is the first reported case study of post-cardiac ablation pericarditis in patient with prior history of rheumatic carditis.

Association of kidney function and atrial fibrillation progression to clinical outcomes in patients with cardiac implantable electronic devices

Kidney function may promote progression of AF. We evaluated the association of kidney function to AF progression and resultant clinical outcomes in patients with cardiac implantable electronic devices (CIED). We performed a retrospective cohort study using national clinical data from the Veterans Health Administration linked to CIED data from the Carelink® remote monitoring data warehouse (Medtronic Inc, Mounds View, MN). All devices had atrial leads and at least 75% of remote monitoring transmission coverage. Patients were included at the date of the first AF episode lasting ≥6 minutes, and followed until the occurrence of persistent AF in the first year, defined as ≥7 consecutive days with continuous AF. We used Cox regression analyses with persistent AF as a time-varying covariate to examine the association to stroke, myocardial infarction, heart failure and death. Of, 10,323 eligible patients, 1,771 had a first CIED-detected AF (mean age 69 ± 10 years, 1.2% female). In the first year 355 (20%) developed persistent AF. Kidney function was not associated with persistent AF after multivariable adjustment including CHA2DS2-VASc variables and prior medications. Only higher age increased the risk (HR: 1.37 per 10 years; 95% CI:1.22-1.54). Persistent AF was associated to higher risk of heart failure (HR: 2.27; 95% CI: 1.88-2.74) and death (HR: 1.60; 95% CI: 1.30-1.96), but not stroke (HR: 1.28; 95% CI: 0.62-2.62) or myocardial infarction (HR: 1.43; 95% CI: 0.91-2.25). Kidney function was not associated to AF progression, whereas higher age was. Preventing AF progression could reduce the risk of heart failure and death.