Premature Complexes Research Articles

B-PO02-140 EFFECT OF ATRIAL ECTOPY COUPLING INTERVAL ON ATRIAL STRUCTURAL REMODELLING AND ATRIAL FIBRILLATION IN A SWINE MODEL

Frequent premature atrial complexes (PACs) are associated with incident atrial fibrillation (AF), however, the significance of PAC-coupling interval (CI) on atrial structural remodelling as well as development of AF is unknown. To investigate the impact of PAC-CI on atrial structural remodelling and AF inducibility in a swine model. Fifteen swine underwent pacemaker implantation to create a model of paced PACs (50% burden) from the lateral left atrium (LA) via the coronary sinus and were divided into 3 groups: (1) Short CI of 250ms (Short-CI: n=5), (2) Long CI of 400ms (Long-CI: n=5), and (3) controls without PACs (CTRL, n=5). At baseline and after 4 months of PACs, all swine underwent electrophysiologic (atrial ERP and AF induction with 50ms burst pacing) and echocardiographic studies (LA area and peak atrial longitudinal strain). Short-CI group had more LA enlargement compared with Long-CI and CTRL (terminal - baseline; Short-CI 7.0±0.9 vs. Long-CI 4.0±1.1 vs. CTRL 0.5±0.2 cm2; p<0.001). Both Short-CI and Long-CI group had a significant reduction in peak atrial longitudinal strain compared to CTRL (terminal - baseline; -22.8±9.7 vs. -18.3±3.7 vs. 0.1±4.5 %; p<0.001). No change in atrial ERP was observed (terminal - baseline; 3±20 vs -9 ±18 vs -5 ±34 ms; p=0.76). Short-CI group had the longest duration of burst pacing-induced AF (terminal - baseline; 71.2 [IQR 43.1, 102.9] vs. 34.3 [IQR 17.7, 61.0] vs. 5.3 [IQR 4.8, 9.7] secs; p=0.008). In a swine model, frequent PACs led to an atrial myopathy with heightened propensity to AF. Short-coupled PACs had a greater degree of structural remodelling and may contribute to the future development of AF.

Coffee Consumption and Incident Tachyarrhythmias

The notion that caffeine increases the risk of cardiac arrhythmias is common. However, evidence that the consumption of caffeinated products increases the risk of arrhythmias remains poorly substantiated. To assess the association between consumption of common caffeinated products and the risk of arrhythmias. This prospective cohort study analyzed longitudinal data from the UK Biobank between January 1, 2006, and December 31, 2018. After exclusion criteria were applied, 386 258 individuals were available for analyses. Daily coffee intake and genetic polymorphisms that affect caffeine metabolism. Any cardiac arrhythmia, including atrial fibrillation or flutter, supraventricular tachycardia, ventricular tachycardia, premature atrial complexes, and premature ventricular complexes. A total of 386 258 individuals (mean [SD] age, 56 [8] years; 52.3% female) were assessed. During a mean (SD) follow-up of 4.5 (3.1) years, 16 979 participants developed an incident arrhythmia. After adjustment for demographic characteristics, comorbid conditions, and lifestyle habits, each additional cup of habitual coffee consumed was associated with a 3% lower risk of incident arrhythmia (hazard ratio [HR], 0.97; 95% CI, 0.96-0.98; P < .001). In analyses of each arrhythmia alone, statistically significant associations exhibiting a similar magnitude were observed for atrial fibrillation and/or flutter (HR, 0.97; 95% CI, 0.96-0.98; P < .001) and supraventricular tachycardia (HR, 0.96; 95% CI, 0.94-0.99; P = .002). Two distinct interaction analyses, one using a caffeine metabolism-related polygenic score of 7 genetic polymorphisms and another restricted to CYP1A2 rs762551 alone, did not reveal any evidence of effect modification. A mendelian randomization study that used these same genetic variants revealed no significant association between underlying propensities to differing caffeine metabolism and the risk of incident arrhythmia. In this prospective cohort study, greater amounts of habitual coffee consumption were associated with a lower risk of arrhythmia, with no evidence that genetically mediated caffeine metabolism affected that association. Mendelian randomization failed to provide evidence that caffeine consumption was associated with arrhythmias.

Premature atrial complexes can predict atrial fibrillation in ischemic stroke patients: A systematic review and meta-analysis.

Several studies have explored premature atrial complexes (PACs) as high-risk factors for atrial fibrillation (AF) in ischemic stroke patients; however, the results were controversial. The aim of this systematic review and meta-analysis was to examine whether PACs can predict AF in ischemic stroke patients. We comprehensively searched the published literature in PubMed, Embase, and Wiley-Cochrane library databases from inception through August 18, 2020. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed by the fixed-effect model or the random-effect model based on heterogeneity. We identified 12 eligible studies including 2340 stroke patients with a mean age of 65.9 years. PACs were highly associated with AF occurrence in stroke (pooled OR: 4.16, 95% CI: 3.06-5.65) and cryptogenic stroke patients (pooled OR: 3.72, 95% CI: 2.66-5.20). Subgroup analysis showed PAC presence and frequent PACs were correlated with stroke in AF patients (pooled OR: 3.72, 95% CI: 1.65-8.36 and pooled OR: 5.12, 95% CI: 3.12-8.41, respectively). Frequent PACs were identified as the risks for asymptomatic AF (OR: 6.18, 95% CI: 3.23-11.83) and future AF occurrence (OR: 3.71, 95% CI: 2.62-5.26) in stroke patients. The definition of frequent PACs was inconsistent, and was >70 beats/24h based on Holter monitoring. PACs confer high risks for asymptomatic AF and future AF occurrence in stroke patients.

Transition of the heart rate and atrial premature complex after cryoballoon vs. radiofrequency ablation for paroxysmal atrial fibrillation.

The temporal changes in ambulatory monitoring findings after cryoballoon (CB) ablation of atrial fibrillation (AF) have not been well elucidated. This study aims to compare the details of ambulatory monitoring after CB and radiofrequency catheter (RFC) ablation for AF. Of 724 consecutive AF patients who underwent initial ablation using a CB or RFC, 508 (254 pairs) were selected using propensity score matching. Ambulatory monitoring was performed at 1, 3, 6, 12, 24 and 36months after the procedure. After 1, 3 and 6 months, the number of total heart beats (THBs) was larger in the CB group than in the RFC group. It gradually decreased and became significantly similar by 12months after ablation. THBs significantly increased 1, 3, 6 and 12months after ablation in both the RFC and CB groups and became statistically similar by 24months after ablation. The atrial premature contraction burden was higher in the RFC group than in the CB group at 3months after ablation. THB and APC burden after AF ablation were significantly different between the RF and CB groups. THBs returned to statistically similarity by 2years after ablation in both groups.

Arrhythmia spectrum and outcome in children with myocarditis.

Introduction :Myocarditis remains an under-diagnosed entity among children. We evaluated the spectrum of electrocardiogram (ECG) changes and arrhythmias in children with myocarditis.Methods :A single-center prospective observational study was conducted over a period of 18 months at a public university hospital, which included all cases with myocarditis from the ages of 1 month to 12 years. Myocarditis was diagnosed according to standard criteria. Arrhythmias were detected by 12-lead ECG or by multiparameter monitors.Results :There were 63 children with myocarditis. Sinus tachycardia remained the most important ECG finding (61, 96.8%) followed by ST-T changes (30, 47.6%), low voltage QRS complexes (23, 36.5%), and premature complexes (11, 17.4%). Sustained arrhythmias were seen in 14/63 (22.2%) of the children (Group A), while the remaining 49 patients were designated as Group B. There were 11 (17.5%) cases with sustained tachyarrhythmias, comprising 5 with supraventricular tachycardia, 4 with ventricular tachycardia, and 2 with atrial flutter/fibrillation. Bradyarrhythmias were seen in 3 patients, including 2 children with atrioventricular block and 1 with severe sinus bradycardia. A longer hospital stay of 18.5 (4.75) days vs. 13 (4) days, P = 0.001), and more ST-T changes [12 (85.7%) vs. 18 (36.73%), P = 0.003] were seen in Group A. Multivariate regression analysis found only the presence of ST-T changes as predictors for arrhythmia.Conclusions :A variety of arrhythmias and other ECG changes were commonly seen in children with myocarditis. Sustained arrhythmias were seen in one-fifth of the patients, being associated with ST-T changes and a longer hospital stay.

A Detector for Premature Atrial and Ventricular Complexes.

The relationship between premature atrial complexes (PACs) and atrial fibrillation (AF), stroke and myocardium degradation is unclear. Current PAC detectors are beat classifiers that attain low sensitivity on PAC detection. The lack of a proper PAC detector hinders the study of the implications of this event and its monitoring. In this work a PAC and ventricular detector is presented. Two PhysioNet open-source databases were used: the long-term ST database (LTSTDB) and the supraventricular arrhythmia database (SVDB). A combination of heart rate variability (HRV) and morphological features were used to classify beats. Morphological features were extracted from the ECG as well as on the 4th scale of the discrete wavelet transform (DWT). After feature selection, a random forest algorithm was trained for a binary classification of PAC (S) vs. others and for a multi-labels classification to discriminate between normal (N), S and ventricular (V) beats. The algorithm was tested in a 10-fold cross-validation following a patient-wise train-test division (i.e., no beats belonging to the same patient were included both in the test and train set). The resultant median sensitivity, specificity and positive predictive value (PPV) were 99.29, 99.54, and 100% for (N), 95.83, 99.39, and 35.68% for (S), 100, 99.90, and 79.63% for (V). The proposed method attains a greater PAC and ventricular beat sensitivity and PPV than the state-of-the-art classifiers.

Higher premature atrial complex burden from the Holter examination predicts poor cardiovascular outcome

Premature atrial complexes (PACs) have been suggested to increase the risk of adverse events. The distribution of PAC burden and its dose–response effects on all-cause mortality and cardiovascular death had not been elucidated clearly. We analyzed 15,893 patients in a medical referral center from July 1st, 2011, to December 31st, 2018. Multivariate regression driven by ln PAC (beats per 24 h plus 1) or quartiles of PAC burden were examined. Older group had higher PAC burden than younger group (p for trend < 0.001), and both genders shared similar PACs distribution. In Cox model, ln PAC remained an independent risk factor for all-cause mortality (hazard ratio (HR) = 1.09 per ln PAC increase, 95% CI = 1.06‒1.12, p < 0.001). PACs were a significant risk factor in cause-specific model (HR = 1.13, 95% CI = 1.05‒1.22, p = 0.001) or sub-distribution model (HR = 1.12, 95% CI = 1.04‒1.21, p = 0.004). In ordinal PAC model, 4th quartile group had significantly higher risk of all-cause mortality than those in 1st quartile group (HR = 1.47, 95% CI = 1.13‒1.94, p = 0.005), but no difference in cardiovascular death were found in competing risk analysis. In subgroup analysis, the risk of high PAC burden was consistently higher than in low-burden group across pre-specified subgroups. In conclusion, PAC burden has a dose response effect on all-cause mortality and cardiovascular death.

Ablation scar in a single pulmonary vein causes proarrhythmic mechanical destabilization in healthy sheep atria

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Catharina Hospital, Eindhoven Medtronic (unrestricted research grant) Background Ablative pulmonary vein isolation (PVI) prevents AF in 60% of AF patients. The absence of an antiarrhythmic effect of PVI is poorly understood. Atrial and PV stretch is proarrhythmic but the mechanical effect of PV ablation scar on AF arrhythmogenesis is unknown. We hypothesize that single ablation scars are potentially proarrhythmic because they create heterogeneous stretch. Purpose To evaluate the mechanical effect of a purposely incomplete PVI ablation scar on left atrial (LA) electrophysiology. Methods Functional cardiac MRIs in vivo in sheep (n = 11) before and 3-months after incomplete PVI by radiofrequency in the right PV (RPV) were analyzed with a feature-tracking algorithm to obtain local strain in the LA. The ablated hearts were explanted and perfused with 1:5 blood:Krebs solution in a dual-chamber working-heart set-up. Diagnostic multi-electrode endocardial catheters were positioned in the RPV and left PV (LPV). Premature stimulation was performed in each PV in low (∼12mmHg) and high (∼25mmHg) LA pressure. Twelve control hearts without ablation scar underwent similar ex vivo investigation. Results The maximum longitudinal strain of the myocardial wall between the RPV and LPV increased from 20.2 ± 6.2% to 33.5 ± 16.0% (before vs. after ablation, respectively; p = 0.032), whereas the maximum radial strain of the LA septum close to the RPV decreased from 45.6 ± 9.7% to 35.8 ± 7.3% (before vs. after ablation, respectively; p = 0.035). Sustained AF (&amp;gt;30s) was more often induced during stimulation in hearts with ablation scar than in control (25.0% and 11.5% of induction attempts (n = 76 and n = 87) in ablated and control hearts, respectively; p = 0.025). In ablated hearts, an increase in LA pressure augmented AF inducibility (12.8% vs. 37.8% of induction attempts (n = 39 vs. n = 37), low vs. high LA pressure, respectively; p = 0.023), whereas this was not the case in control hearts (4.4% vs. 19.0% of induction attempts (n = 45 vs. n = 42), low vs. high LA pressure; p = 0.289). The number of spontaneous premature atrial complexes (PACs) not leading to AF were similar in ablated and control hearts (0 ± 0 vs. 0 ± 2 total PACs within 20ms of refractory period during premature stimulation protocol, respectively; p = 0.411). The diastolic stimulation threshold of RPV was higher in the ablated than in control hearts (90 ± 63 vs. 79 ± 31mA, respectively; p = 0.049). The refractory period was similar in the ablated and control hearts (237 ± 62 vs. 235 ± 55ms, respectively; p = 0.873). Conclusion Local ablation scar caused regionally disparate bio-mechanical changes in proximity to ablative energy delivery and increased inducibility of sustained AF especially during increased LA stretch. This was associated with decreased tissue excitability without changes in refractoriness. A single incomplete PVI ablation scar therefore is proarrhythmic. Development of ablation lesion sets that homogenize atrial mechanics and electrophysiology may improve AF ablation success.

Major impact of left auricular cardiopathy when associated to supraventricular ectopy?

Abstract Funding Acknowledgements Type of funding sources: None. INTRODUCTION Left atrial cardiopathy (LAC) is an independent predictor of atrial fibrillation (FA) and embolic stroke. It is more frequent in patients with embolic stroke of undetermined source (ESUS) than in non-embolic strokes. The current definition doesn’t include supraventricular ectopy. AIM The aim of this work was to describe the importance of LAC in ESUS and to study the impact of adding the number of atrial premature complexes per hour (APC/h) to LAC criteria. METHODS Retrospective analysis of 123 ESUS patients (pts) admitted to Neurology service from 2014 to 2019. LAC was defined according to two criteria (LAC2: severe left atrial enlargement or p-wave terminal force in lead V1 [PTFV1] &amp;gt;5000 µV*ms) or 3 criteria (LAC3: additionally, &amp;gt;30 APC/h). Survival analysis for the occurrence of AF, stroke recurrence and death according to LAC2 and LAC3. Diagnostic test performance analysis for each criterion with ROC curves. RESULTS 43 (35%) of the ESUS pts had LAC2. Pts with LAC2 (35.0%) were older (p = 0.007), more frequently had hypertension (p = 0.004) and lower total cholesterol levels (p = 0.044) than patients without LAC2. The incidence of AF (median follow-up 21 months, IQR = 9-35) was higher both in LAC2 (p = 0.038) and LAC3 (p = 0.001). There were no differences in stroke recurrence or death between patients with or without LAC2 or 3. Among the 3 atrial dysfunction criteria included in LAC3 definition, the number of APC/h was associated with a higher area under the curve for the occurrence of AF (AUC = 0.822). Cox regression revealed that PTFV1 &amp;gt; 5000 µV·ms (HR = 5.12, IC95%=1.28-20.56, p = 0.021) and &amp;gt;30 APC/h (HR = 13.02, IC95%=3.57-47.56) were independent predictors of AF. In addition, the single predictor of the composite endpoint (occurrence of AF, stroke recurrence and death) was &amp;gt;30 APC/h (HR = 5.2, p &amp;lt; 0,001). CONCLUSION In ESUS pts, the subgroup with LAC2 had different clinical characteristics and a higher AF incidence. APC/h were also independently associated with AF incidence and had better diagnostic test performance than the other criteria. In sum, APC/h inclusion as a diagnostic criterion for LAC should be considered and may help in a better therapeutic approach.

A comparative study and analysis of LSTM deep neural networks for heartbeats classification

Heart diseases and their diagnosis has become a predominant topic in Healthcare systems as the heart is one of the pivotal parts of the human body. Electrocardiogram (ECG) signal-based diagnosis and classification have been experimented with various computational techniques which have demonstrated early detection and treatment of heart disease. Deep learning (DL) is the current interest of different Healthcare applications that includes the heartbeat classification based on ECG signals. There are various studies conducted with different DL models, such as Convolutional Neural Network (CNN), Recurrent Neural Network (RNN) and Gated Recurrent Unit (GRU) for the heartbeat classification using MIT-BIH arrhythmia dataset. This paper aims to provide a comprehensive analysis of Long-Short Term Memory (LSTM) based DL models with multiple performance metrics on the MIT-BIH arrhythmia dataset for the heartbeat classification. The different variants of the LSTM DL model are proposed for the purpose of the classification. Among the variants, the bi-directional LSTM DL model shows high accuracy in the classification of Normal beats (97%), Premature ventricular contractions (PVC) beats (98%), Atrial Premature Complex (APC) beats (98%), and Paced Beats (PB) beats (99%). The comparative analysis of the bi-directional LSTM DL model with the existing works shows 95% sensitivity and 98% specificity in the classification of heartbeats. The results evidently show that the LSTM DL models are appropriate for the classification of heartbeats.

Internet of things-assisted architecture for QRS complex detection in real time

This paper presents the development of an Internet of Things-assisted architecture for QRS complex detection in an electrocardiogram regardless of the age and physiological characteristics of the patient. Detection of the QRS complex is affected by the abnormalities and quality in electrocardiogram recordings; the proposed method can detect QRS complex despite these challenges. Electrocardiogram continuous signal acquisition is performed with the BITalino biomedical data acquisition card. Electrocardiogram signals typically suffer from (a) premature atrial complexes, (b) premature ventricular complexes, (c) low signal-to-noise ratio, (d) right bundle branch blocks, (e) left bundle branch blocks, and (f) non-stationary effects. Interestingly, the signal processing is implemented by means of a bandpass filter, followed by a numerical derivative. Next, the Hilbert transform and the adaptive threshold technique are implemented to detect the QRS complex. Tests are performed to evaluate the Internet of Things-assisted architecture using the obtained signal in real time. Results, and the simplicity of the architecture, demonstrate that it is suitable for wearable, portable, and battery-operated electrocardiogram acquisition card.

Abstract P667: Clinical Variables, Electrocardiogram Parameters and Blood Biomarkers Associated With Atrial Fibrillation Detection in the First Year After Ischaemic Stroke - A Systematic Review and Meta-Analysis

Introduction: Cardiac monitoring is performed to detect atrial fibrillation (AF) after stroke. Identifying patients at high or low risk of AF may allow cardiac monitoring approaches to be tailored on a more personalised basis. We performed a systematic review and meta-analysis to identify variables associated with AF detection after ischaemic stroke. Methods: We followed the Cochrane Collaboration Guidelines and retrieved 8503 studies. After screening, 35 studies were selected and 68 variables were assessed. We assessed 41 clinical variables, 20 ECG parameters and 7 blood biomarkers associated with AF detection &gt;30 seconds duration in the first year after stroke. Comprehensive Meta-analysis software was used to generate an odds ratio and Forest plot for each variable. Studies were assessed for quality using the Quality in Prognostic Studies (QUIPS) tool. Results: The 35 studies included 12010 patients and AF was detected in 1551 patients (13%). Of the 68 variables assessed, 20 were associated with increased odds of AF, 5 were associated with reduced odds of AF and 43 were not associated with AF (Figure 1). The variables most strongly associated with AF detection (odds ratio &gt;3.00) were older age, patients who received IV thrombolytic therapy, maximum P-wave duration, premature atrial complexes, P-wave dispersion, P-wave index, QTc interval and brain natriuretic peptide. Risk of bias was low in 3 studies, moderate in 24 studies and high in 8 studies. Conclusions: We have identified clinically applicable variables that can stratify the probability of AF detection after stroke. Our results will help guide more personalised approaches to cardiac monitoring for AF detection after stroke.

The Role of the Left Septal Fascicle in Fascicular Arrhythmias: Clinical Presentation and Laboratory Evaluation.

This study describes a series of cases best explained by invoking the left septal fascicle (LSF) as a critical component of the arrhythmia circuit. Numerous anatomic studies have shown evidence of the LSF, but its precise role in the onset of arrhythmia is unclear. This paper presents 5 cases that implicated the LSF as a critical component of arrhythmogenesis. The first case had ventricular fibrillation repeatedly documented after a single premature atrial complex, produced left-sided conduction delay and simultaneous earliest activation of the left anterior fascicle (LAF) and left posterior fascicle (LPF). The LSF was ablated, resulting in an arrhythmia cure. The second case showed narrow QRS morphology during fascicular re-entrant tachycardia. The earliest mid-septal diastolic potentials had distal-to-proximal activation suggesting an LSF as a retrograde common pathway. The third case, with multiple ectopic Purkinje-related premature complexes exhibited earliest Purkinje potentials in the mid-septum, with subsequent anterograde activation of the LAF and LPF. Ablation of the LSF eliminated the premature ventricular complexes (PVCs). The fourth case demonstrated LPF and LAF PVCs. The His-left bundle activation showed earliest potentials at the proximal insertion of the left bundle during LPF PVCs, as well as a distal-to-proximal activation pattern duringLAF PVC, suggestive of LSF involvement. The fifth case had focal non-re-entrant fascicular beats successfully ablated over the LSF. Involvement of the LSF is suspected with presentation of multiform fascicular and narrow QRScomplex ventricular episodes of arrhythmia. Diagnoses and ablation require detailed mapping of the entire leftsided conduction system.

Premature complexes, anxiety and quality of life

Premature complexes can be indicative of an increased cardiac risk or can contribute to the initiation or deterioration of heart failure in particular in the presence of organic heart disease. Most premature complexes are benign. The postextrasystolic pause or the augmented postextrasystolic premature beat may cause the following symptoms: feeling of askipped beat or the sensation of apounding heart beat causing the feeling "that something is seriously wrong". It is mentioned that premature beats cause an unconscious reaction of the autonomic nervous system. Symptoms related to premature complexes may cause uneasiness or franc anxiety which may itself intensify the symptoms. This may cause apanic reaction which may be associated with shortness of breath or angina of the chest mimicking dyspnea of heart failure of an acute coronary syndrome. Along the "vicious cycle of anxiety" it is demonstrated how patients may be comforted. In addition, the panic disorder itself should be treated by cognitive behavioral or psychodynamic therapy.

Mapping strategies and ablation of premature atrial complexes.

Premature atrial complexes (PACs) are acommon finding in patients with structural heart disease, as well as in healthy subjects. In addition to the clinical spectrum ranging from asymptomatic patients to irritating palpitations, PACs are suggested to be associated with an increased risk of atrial fibrillation and stroke. Medical treatment leads to asignificant reduction in PACs with clear symptom relief in alarge proportion of patients, but is limited in cases of PACs that are refractory to antiarrhythmic drug (AAD) treatment. Furthermore, proarrhythmic effects of AAD or the patient's refusal of AAD treatment due to side effects need to be considered. Ablation of PACs is agood alternative to medical therapy with acomparable safety profile and at least comparable efficacy. In recent years, ultra-high-density (UHD) mapping with multiple improvements for successful ablation has been evolving. Before the introduction of UHD mapping, ablation strategies included activation mapping with single-tip catheters or conventional mapping aiming for the earliest activation of the PAC locally, with the earliest activation suspected to be the origin of the PAC and targeted by radiofrequency (RF) ablation. Using UHD mapping, athree-dimensional local activation map of the atrium can be acquired, identifying the point of earliest activation within the high-resolution map. PAC ablation has therefore developed into atrue alternative for the treatment of symptomatic PACs.

The relationship between premature atrial complexes and recurrence of atrial fibrillation: a meta-analysis

Objective: To explore the relationship between premature atrial complexes (PACs) and recurrence of atrial fibrillation (AF). Methods: Published literature was searched in PubMed, Embase, Web of Science, Cochrane, Weipu, China national knowledge infrastructure, Wanfang and China Biology Medicine disc up to 25 March 2020. RevMan5.3 software was used to analyzed the data and publication bias was performed by Stata 15.1. Results: A total of 8 studies were identified, including 1 252 AF patients with a mean age of 61.67 years, and male patients accounted for 70.6%. During follow-up, AF recurred in 425 cases. Meta-analysis showed that frequent PACs was an independent risk factor for recurrence of AF (HR=2.64, 95%CI:1.40-4.97). Subgroup analyses showed that PACs not only increasedthe risk of recurrence of AF after electrical cardioversion (HR=2.38, 95%CI:1.25-4.51), but also significantly increased the risk of recurrence of AF after catheter ablation cardioversion (HR=2.90, 95%CI:1.11-7.60). Conclusions: PACs is significantly associated with AF recurrence.

A wearable real-time telemonitoring electrocardiogram device compared with traditional Holter monitoring.

Arrhythmias are very common in the healthy populations as well as patients with cardiovascular diseases. Among them, atrial fibrillation (AF) and malignant ventricular arrhythmias are usually associated with some clinical events. Early diagnosis of arrhythmias, particularly AF and ventricular arrhythmias, is very important for the treatment and prognosis of patients. Holter is a gold standard commonly recommended for noninvasive detection of paroxysmal arrhythmia. However, it has some shortcomings such as fixed detection timings, delayed report and inability of remote real-time detection. To deal with such problems, we designed and applied a new wearable 72-hour triple-lead H3-electrocardiogram (ECG) device with a remote cloud-based ECG platform and an expert-supporting system. In this study, 31 patients were recruited and 24-hour synchronous ECG data by H3-ECG and Holter were recorded. In the H3-ECG group, ECG signals were transmitted using remote real-time modes, and confirmed reports were made by doctors in the remote expert-supporting system, while the traditional modes and detection systems were used in the Holter group. The results showed no significant differences between the two groups in 24-hour total heart rate (HR), averaged HR, maximum HR, minimum HR, premature atrial complexes (PACs) and premature ventricular complexes (PVCs) (P>0.05). The sensitivity and specificity of capture and remote automatic cardiac events detection of PACs, PVCs, and AF by H3-ECG were 93% and 99%, 98% and 99%, 94% and 98%, respectively. Therefore, the long-term limb triple-lead H3-ECG device can be utilized for domiciliary ECG self-monitoring and remote management of patients with common arrhythmia under medical supervision.

An Adaptive Kalman Filter Bank for ECG Denoising.

Model-based Bayesian frameworks proved their effectiveness in the field of ECG processing. However, their performances rely heavily on the pre-defined models extracted from ECG signals. Furthermore, their performances decrease substantially when ECG signals do not comply with their models- a situation generally occurs in the case of arrhythmia-. In this paper, we propose a novel Bayesian framework based on Kalman filter, which does not need a predefined model and can adapt itself to different ECG morphologies. Compared with the previous Bayesian techniques, the proposed method requires much less preprocessing and it only needs to know the location of R-peaks to start ECG processing. Our method uses a filter bank comprised of two adaptive Kalman filters, one for denoising QRS complex (high frequency section) and another one for denoising P and T waves (low frequency section). The parameters of these filters are estimated and iteratively updated using expectation maximization (EM) algorithm. In order to deal with nonstationary noises such as muscle artifact (MA) noise, we used Bryson and Henrikson's technique for the prediction and update steps inside the Kalman filter bank. We evaluated the performance of the proposed method on different ECG databases containing signals having morphological changes and abnormalities such as atrial premature complex (APC), premature ventricular contractions (PVC), Ventricular Tachyarrhythmia (VT) and sudden cardiac death (SCD). The proposed algorithm was compared with several popular ECG denoising methods such as wavelet transform (WD) and empirical mode decomposition (EMD). The comparison results showed that the proposed method performs well in the presence of various ECG morphologies in both stationary and non-stationary environments especially at low input SNRs.

AHA statement addresses growing list of drugs that induce arrhythmias

AHA statement addresses growing list of drugs that induce arrhythmias

Mechanism and interpretation of two-for-one response to premature atrial complexes during atrioventricular node re-entry tachycardia.

The response to premature atrial complexes (PACs) during tachycardia has been shown to differentiate atrioventricular nodal re-entrant tachycardia (AVNRT) from focal junctional tachycardia (JT). His refractory PAC (HrPACs) perturbing the next His (resetting with fusion) is diagnostic of AVNRT and such a late PAC fusing with the native beat cannot reset the focal source of JT. Early PAC advancing the immediate His with continuation of tachycardia suggests JT but can also occur in AVNRT due to simultaneous conduction through the AV nodal fast and slow pathways [two-for-one response (TFOR)]. The objective of this study was to evaluate the incidence and mechanism of TFOR after early premature atrial complexes (ePACs) during AVNRT and to differentiate it from the known response to ePACs during JT. Typical AVNRT cases were diagnosed using standard criteria. We evaluated the responses to scanning PACs delivered during tachycardia in 100 patients undergoing AV node slow pathway modification for AVNRT. The responses to HrPACs and ePACs delivered from coronary sinus os or high right atrium were retrospectively reviewed. In 10 patients, ePACs advanced the immediate His with continuation of tachycardia. In all 10 cases, HrPACs advanced the next His, confirming AVNRT as the mechanism, and indicating a TFOR. A TFOR can occur in a small number of patients during AVNRT and is therefore not diagnostic of JT. However, HrPACs always perturbed the next His in these cases, confirming the diagnosis of AVNRT and allowing for differentiation from JT.