Atrial Complexes Research Articles

Electrocardiogram-based mortality prediction in patients with COVID-19 using machine learning.

Background and purposeThe electrocardiogram (ECG) is frequently obtained in the work-up of COVID-19 patients. So far, no study has evaluated whether ECG-based machine learning models have added value to predict in-hospital mortality specifically in COVID-19 patients.MethodsUsing data from the CAPACITY-COVID registry, we studied 882 patients admitted with COVID-19 across seven hospitals in the Netherlands. Raw format 12-lead ECGs recorded within 72 h of admission were studied. With data from five hospitals (n = 634), three models were developed: (a) a logistic regression baseline model using age and sex, (b) a least absolute shrinkage and selection operator (LASSO) model using age, sex and human annotated ECG features, and (c) a pre-trained deep neural network (DNN) using age, sex and the raw ECG waveforms. Data from two hospitals (n = 248) was used for external validation.ResultsPerformances for models a, b and c were comparable with an area under the receiver operating curve of 0.73 (95% confidence interval [CI] 0.65–0.79), 0.76 (95% CI 0.68–0.82) and 0.77 (95% CI 0.70–0.83) respectively. Predictors of mortality in the LASSO model were age, low QRS voltage, ST depression, premature atrial complexes, sex, increased ventricular rate, and right bundle branch block.ConclusionThis study shows that the ECG-based prediction models could be helpful for the initial risk stratification of patients diagnosed with COVID-19, and that several ECG abnormalities are associated with in-hospital all-cause mortality of COVID-19 patients. Moreover, this proof-of-principle study shows that the use of pre-trained DNNs for ECG analysis does not underperform compared with time-consuming manual annotation of ECG features.Supplementary InformationThe online version of this article (10.1007/s12471-022-01670-2) contains supplementary material, which is available to authorized users.

Differences in Atrial Remodeling in Hypertrophic Cardiomyopathy Compared to Hypertensive Heart Disease and Athletes' Hearts.

Background: Hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD) and athletes’ heart share an increased prevalence of atrial fibrillation. Atrial cardiomyopathy in these patients may have different characteristics and help to distinguish these conditions. Methods: In this single-center study, we prospectively collected and analyzed electrocardiographic (12-lead ECG, signal-averaged ECG (SAECG), 24 h Holter ECG) and echocardiographic data in patients with HCM and HHD and in endurance athletes. Patients with atrial fibrillation were excluded. Results: We compared data of 27 patients with HCM (70% males, mean age 50 ± 14 years), 324 patients with HHD (52% males, mean age 75 ± 5.5 years), and 215 endurance athletes (72% males, mean age 42 ± 7.5 years). HCM patients had significantly longer filtered P-wave duration (153 ± 26 ms) and PR interval (191 ± 48 ms) compared to HHD patients (144 ± 16 ms, p = 0.012 and 178 ± 31, p = 0.034, respectively) and athletes (134 ± 14 ms, p = 0.001 and 165 ± 26 ms, both p < 0.001, respectively). HCM patients had a mean of 4.9 ± 16 premature atrial complexes per hour. Premature atrial complexes per hour were significantly more frequent in HHD patients (27 ± 86, p < 0.001), but not in athletes (2.7 ± 23, p = 0.639). Left atrial volume index (LAVI) was 43 ± 14 mL/m2 in HCM patients and significantly larger than age- and sex-corrected LAVI in HHD patients 30 ± 10 mL/m2; p < 0.001) and athletes (31 ± 9.5 mL/m2; p < 0.001). A borderline interventricular septum thickness ≥13 mm and ≤15 mm was found in 114 (35%) HHD patients, 12 (6%) athletes and 3 (11%) HCM patients. Conclusions: Structural and electrical atrial remodeling is more advanced in HCM patients compared to HHD patients and athletes.

Morphometric topography of the left atrial appendage in human adult heart

Topography of the left atrial appendage is of importance for supraventricular arrhythmias surgery and sealing of the appendage orifice to prevent thromboembolism in cryptogenic strokes. The aim was to explore the common position of the appendage and delineate variants of its adjacent anatomy in human adults by means cadaveric morphometrics. Material and methods . We studied 54 silicone-filled heart specimens of 200–400 g. With the caliper, we measured the distances from the base of the left atrial appendage to the cardiac apex, to the structures of the atrial complex, nearest large blood vessels, as well as to the left coronary artery. Results. The base of the appendage was 87 ± 13.1 mm from the cardiac apex and 49.7 ± 7.0 mm from the right appendage. The distance from the appendage to the superior caval vein (36.4 ± 8.1 mm) was 16 % longer than the distance to the ascending aorta (30.4 ± 6.4 mm), 1.25 times less than the distance to the oval fossa (45.2 ± 6.0 mm), 1.5 times less than the distance to the inferior caval vein (55.5 ± 8.7). The smallest median value (9.6 mm) and the largest variation (1.4–15.2 mm) were found for the distance to the pulmonary trunk. Four pulmonary veins inflowed to the atrium at different distances from the appendage opening. In 59.6 %, we revealed the left upper pulmonary vein to be closest to the auricle. The mouth of that was 43 % higher and 57 % at the same level with the appendage opening ( p = 0.07). The left coronary artery ran 2.63–18.74 mm inferiorly to the appendage. Interrelations of average strength were found for the parameters of atrial complex. The study showed the length of the ventricular complex as being an unpredictable parameter for determining the adjacent anatomy of left atrial appendage. Conclusions. The morphometric parameters and their interrelations are proposed to use as reference values and criteria for determining the normal atrial complex.

The Beneficial Effects of Beta Blockers on the Long-Term Prognosis of Patients With Premature Atrial Complexes.

AimsPremature atrial complexes (PACs) have been reported to increase the risk of adverse cardiovascular outcomes. Beta blockers at low dosages may help to reduce PAC symptoms, but it is unclear whether they can improve long-term outcomes.MethodsPatients enrolled from a Holter cohort in a medical referral center were stratified into high-burden (≥100 beats/24 h) and low-burden (<100 beats/24 h) sub-cohorts, and propensity score matching between treatment groups and non-treatment groups was conducted for each sub-cohort.ResultsIn the high-burden sub-cohort, after propensity score matching, the treatment group and non-treatment group respectively had 208 and 832 patients. The treatment group had significantly lower mortality rates than the non-treatment group [hazard ratio (HR) = 0.521, 95% confidence interval (CI) = 0.294–0.923, p = 0.025], but there was no difference in new stroke (HR = 0.830, 95% CI = 0.341–2.020, p = 0.681), and new atrial fibrillation (HR = 1.410, 95% CI = 0.867–2.292, p = 0.167) events. In the low-burden sub-cohort, after propensity score matching, there were 614 patients in the treatment group and 1,228 patients in the non-treatment group. Compared to the non-treatment group, up to 40% risk reduction in mortality was found in the treatment group (HR = 0.601, 95% CI = 0.396–0.913, p = 0.017), but no differences in new stroke (HR =0.969, 95% CI = 0.562–1.670, p = 0.910) or atrial fibrillation (HR = 1.074, 95% CI = 0.619–1.863, p = 0.800) were found.ConclusionsBeta blockers consistently decreased long-term mortality in high-burden and low-burden patients. Interestingly, this effect was not achieved through reduction of new-onset stroke or AF, and further research is warranted.

Naked mole-rats maintain cardiac function and body composition well into their fourth decade of life

The prevalence of cardiovascular disease increases exponentially with age, highlighting the contribution of aging mechanisms to cardiac diseases. Although model organisms which share human disease pathologies can elucidate mechanisms driving disease, they do not provide us with innate examples how cardiac aging might be slowed or attenuated. The identification of animal models that preserve cardiac function throughout most of life offers an alternative approach to study mechanisms which might slow cardiac aging. One such species may be the naked mole-rat (NMR), a mouse-sized (40 g) rodent with extraordinary longevity (> 37 years), and constant mortality hazard over its four decades of life. We used a cross-sectional study design to measure a range of physiological parameters in NMRs between 2 and 34 years of age and compared these findings with those of mice aged between 3 months and 2.5 years. We observed a rapid decline in body fat content and bone mineral density in old mice, but no changes in NMRs. Similarly, rhythm disorders (premature atrial and ventricular complexes) occurred in aged mice but not in NMRs. Magnetic resonance and ultrasound imaging showed age-dependent increases in cardiac hypertrophy and diastolic dysfunction in mice which were absent in NMRs. Finally, cardiac stress tests showed an age-dependent decline in normalized cardiac output in mice, which was absent in NMRs. Unlike mice, that manifest several aspects of human cardiac aging, NMRs maintain cardiac function and reserve capacity throughout their long lives and may offer insights on how to delay or prevent cardiac aging.

Hybrid-Pattern Recognition Modeling with Arrhythmia Signal Processing for Ubiquitous Health Management.

We established a web-based ubiquitous health management (UHM) system, “ECG4UHM”, for processing ECG signals with AI-enabled models to recognize hybrid arrhythmia patterns, including atrial premature atrial complex (APC), atrial fibrillation (AFib), ventricular premature complex (VPC), and ventricular tachycardia (VT), versus normal sinus rhythm (NSR). The analytical model coupled machine learning methods, such as multiple layer perceptron (MLP), random forest (RF), support vector machine (SVM), and naive Bayes (NB), to process the hybrid patterns of four arrhythmia symptoms for AI computation. The data pre-processing used Hilbert–Huang transform (HHT) with empirical mode decomposition to calculate ECGs’ intrinsic mode functions (IMFs). The area centroids of the IMFs’ marginal Hilbert spectrum were suggested as the HHT-based features. We engaged the MATLABTM compiler and runtime server in the ECG4UHM to build the recognition modules for driving AI computation to identify the arrhythmia symptoms. The modeling extracted the crucial data sets from the MIT-BIH arrhythmia open database. The validated models, including the premature pattern (i.e., APC–VPC) and the fibril-rapid pattern (i.e., AFib–VT) against NSR, could reach the best area under the curve (AUC) of the receiver operating characteristic (ROC) of approximately 0.99. The models for all hybrid patterns, without VPC versus AFib and VT, achieved an average accuracy of approximately 90%. With the prediction test, the respective AUCs of the NSR and APC versus the AFib, VPC, and VT were 0.94 and 0.93 for the RF and SVM on average. The average accuracy and the AUC of the MLP, RF, and SVM models for APC–VT reached the value of 0.98. The self-developed system with AI computation modeling can be the backend of the intelligent social-health system that can recognize hybrid arrhythmia patterns in the UHM and home-isolated cares.

LONG-TERM AMBULATORY ECG MONITORING AN ESSENTIAL DIAGNOSTIC TOOL FOR CURRENT TIMES

Ambulatory ECG (AECG) monitoring with diary correlation of symptoms has been proven to provide significant diagnostic, therapeutic and prognostic benefit with an arrhythmic cause of symptoms. Arrhythmias can range from premature atrial and ventricular complexes (APCs/ PVCs usually benign), to Atrial and Ventricular Fibrillation which causes significant morbidity and mortality. Symptoms such as palpitations, shortness of breath, chest pain and syncope are common during arrhythmias and their frequency determines the choice of investigation needed to diagnose the arrythmia.&#x0D; Arrhythmias can be a manifestation of many cardiac and non-cardiac diseases. These also include congenital diseases and are often missed due to inadequate monitoring. Since most arrhythmias are intermittent they are more likely to be detected during extended ECG monitoring. Other uses of ambulatory ECG devices include ST segment analysis, heart rate variability, signal averaged ECGs, diurnal QT and QTc analysis (including patients with long QT) (1) obstructive sleep apnea and vectorcardiography (2). These factors have been shown to have relation to significant cardiovascular diseases aiding the diagnosis of various arrhythmias.&#x0D; Syncope although mostly benign, could potentially be a consequence of a life-threatening arrhythmia in up to 20% patients(3). Nonetheless syncope poses a significant cause of disturbance in a patients’ life and definitive diagnosis is necessary to ensure patients well-being.&#x0D; ESC Guidelines on Syncope (2018) recommend further testing with AECG via Holter monitoring, wearable patch recorder, external and internal loop recorders etc. depending on the frequency after initial examination is negative for a definite cause.&#x0D; Atrial Fibrillation (AF) increases risk of stroke more than five times. Atrial Fibrillation diagnosed after stroke is an important hallmark of recurrent stroke risk. (7) Many studies have demonstrated post stroke AECG increases the chances of detecting AF (15% vs 5%) when compared to standard monitoring. An increase incidence in atrial arrythmias (atrial high rate episodes AHRE) has been seen in patients with Permanent Pacemakers which should be documented by AECG to be treated accordingly.(4). Uses can be prognostic if rate was to be monitored in AF to assess efficacy of rate control treatment and offer adequate anticoagulation according to the 2020 ESC atrial fibrillation guidelines. (8)&#x0D; Some limitations of twenty-four hours Holter monitoring have recently been overcome by improvements in hardware and software technology including adhesive patches and wireless telemetry. Newer adhesive patches are softer, waterproof and electrode free monitors which offer unprecedented mobility and ease of carrying out daily routine by the patient. They operate as either recorders or wireless streaming devices (5). These devices were safe and effective during the pandemic even when delivered home through mail to critically ill patients.(6)&#x0D; The advent of smart phones has added endless potential for recording through wireless Bluetooth transmission. Smart devices like the OMSHIRTtm have the added advantage of being comfortable to wear. Newer devices for example Cardiostat has been shown to offer equal quality tracings when compared to standard Holter monitoring, often up to the 99% sensitivity and specificity through better designed R wave (QRS) detection algorithms(7) (8)Studies have shown these newer devices to be easily operable and can even be mailed to patients homes for self-attachment with an equal efficacy to hospital applied machine (6).&#x0D; Many studies have shown a preference over intra cardiac monitors (ICM) due to these above mentioned advantages (9). The effectiveness of even longer recordings through Implantable Loop Recorder has also been satisfactory when following patients after Ablation therapy leading to practice updating guideline changes in rhythm management(10).&#x0D; A recent review article summarized that although physicians in the US had knowledge of how and when to offer monitoring devices based on the frequency of symptoms, they were often seen prescribing Holter monitoring due to familiarity. Data also showed that in case the initial investigation was inconclusive, the physician would still repeat the same investigation(3).&#x0D; In a country like Pakistan where there are limited resources, diagnosis and management of arrythmias still has a long way to go. This article sheds light on the need of utilizing the recommended available devices.

Diagnosis and management of arrhythmias in pregnancy.

Arrhythmias are the most common cardiac complications occurring in pregnancy. Although the majority of palpitations in pregnancy may be explained by atrial or ventricular premature complexes, the full spectrum of arrhythmias can occur. In this article, we establish a systematic approach to the evaluation and management of arrhythmias in pregnancy. Haemodynamically unstable arrhythmias warrant urgent cardioversion. For mild cases of benign arrhythmia, treatment is usually not needed. Symptomatic but haemodynamically stable arrhythmic patients should first undergo a thorough evaluation to establish the type of arrhythmia and the presence or absence of structural heart disease. This will ultimately determine the necessity for treatment given the potential risks of anti-arrhythmic pharmacotherapy in pregnancy. We will discuss the main catalogue of anti-arrhythmic medications, which have some established evidence of safety in pregnancy. Based on our appraisal, we provide a treatment algorithm for the tachyarrhythmic pregnant patient.

754 Non-conducted premature atrial complexes: a new predictor for atrial fibrillation in cryptogenic stroke patients

Abstract Aims Atrial fibrillation (AF) is the main cardiac cause of stroke, but it frequently remains undetected. In these patient monitoring for AF is recommended using a Holter electrocardiogram (ECG). The aim of the present study is to study non-conducted atrial complexes (ncPAC) recorded on Holter ECG as a new predictor of AF. Methods and results Patients admitted to the Stroke Unit of our hospital for cryptogenic stroke from December 2018 to January 2020 who underwent 24-h electrocardiographic monitoring were prospectively enrolled in the study and were subsequently submitted to 3-month and 6-month follow-up to investigate the occurrence of AF. The study recruited 112 patients. At follow-up visit, AF was diagnosed in 21.4% of the population. The only statistically significant difference between the group with and without a AF diagnosis was the presence of ncPAC (83.3% vs. 16.7%; P &amp;lt; 0.0001). ROC analysis was performed and showed that ncPAC had the best diagnostic accuracy in the AF diagnosis [AUC: 0.798; confidence interval (CI): 0.675–0.921]. The AUC of ncPAC was significantly better than the AUC of premature atrial complexes (PACs) (P &amp;lt; 0.05), CHA2DS2-VASc, HATCH, HAVOC, and C2HEST scores (P &amp;lt; 0.01). Kaplan–Meier curve survival estimate for AF onset by the presence of ncPAC revealed that there was a significant difference in the AF onset between patients with ncPAC and those without (P &amp;lt; 0.0001) and multivariate Cox-proportional hazard analysis revealed that ncPAC presence was an independent predictors of AF onset [hazards ratio (HR): 9.28; CI 95%: 2,66–32,40; P = 0.0001]. Conclusions The presence of ncPAC represents a new predictor of AF that could further guide the investigation of AF in patients with cryptogenic stroke.

Arrhythmias Utilizing ConcealedNodoventricular or His-Ventricular Pathways: AStructuredApproach to Diagnosis and Management.

This study sought to describe the electrophysiologic characteristics, diagnostic maneuvers, and treatment of a series of arrhythmias using concealed nodoventricular (cNV) or His-ventricular (cHV) pathways. Confirming the presence and participation of cNV or cHV pathways in tachyarrhythmias is challenging. We present 4 cases of tachycardias with a participatory cNV or cHV pathway. The first patient had a narrow complex tachycardia with ventriculoatrial dissociation. Findings of an entrainment pacing from the right ventricle and fused premature ventricular complexes suggested cNV pathway involvement. The second patient had nonsustained narrow complex tachycardia with more ventricular than atrial complexes. The tachycardia exhibited an anterograde His-right bundle (RB) activation sequence and normal His-ventricular (HV) interval and consistently terminated with fused ventricular extra stimuli, suggesting cNV pathway participation. The third patient had a wide complex tachycardia (WCT) with either a right or left bundle branch block pattern. The WCT showed an eccentric His-RB activation sequence and short HV interval and terminated with fused premature ventricular complexes, suggesting a cHV (or concealed fasciculoventricular) pathway involvement. The fourth patient had a WCT with alternating bundle branch block morphologies with a short HV interval. Entrainment from the basal right ventricle demonstrated fusion and a short postpacing interval, suggesting cHV(or fasciculoventricular) pathway involvement. Ablation at the proximal RB rendered the tachycardia noninducible. A structured approach can help diagnose and treat cNV or cHV pathways. We emphasize the importance of evaluating both the His-RB activation pattern and HV interval during sinus rhythm and tachycardia as well as the ventricular pacing study.

Profibrillatory Structural and Functional Properties of the Atrial-Pulmonary Junction in the Absence of Remodeling.

Background: Sole pulmonary vein (PV) isolation by ablation therapy prevents atrial fibrillation (AF) in patients with short episodes of AF and without comorbidities. Since incomplete PV isolation can be curative, we tested the hypothesis that the PV in the absence of remodeling and comorbidities contains structural and functional properties that are proarrhythmic for AF initiation by reentry.Methods: We performed percutaneous transvenous in vivo endocardial electrophysiological studies and quantitative histological analysis of PV from healthy sheep.Results: The proximal PV contained more myocytes than the distal PV and a higher percentage of collagen and fat tissue relative to myocytes than the left atrium. Local fractionated electrograms occurred in both the distal and proximal PVs, but a large local activation (>0.75 mV) was more often present in the proximal PV than in the distal PV (86 vs. 50% of electrograms, respectively, p = 0.017). Atrial arrhythmias (run of premature atrial complexes) occurred more often following the premature stimulation in the proximal PV than in the distal PV (p = 0.004). The diastolic stimulation threshold was higher in the proximal PV than in the distal PV (0.7 [0.3] vs. 0.4 [0.2] mA, (median [interquartile range]), p = 0.004). The refractory period was shorter in the proximal PV than in the distal PV (170 [50] vs. 248 [52] ms, p < 0.001). A linear relation existed between the gradient in refractoriness (distal-proximal) and atrial arrhythmia inducibility in the proximal PV.Conclusion: The structural and functional properties of the native atrial-PV junction differ from those of the distal PV. Atrial arrhythmias in the absence of arrhythmia-induced remodeling are caused by reentry in the atrial-PV junction. Ablative treatment of early paroxysmal AF, rather than complete isolation of focal arrhythmia, may be limited to inhibition of reentry.

Abstract 11482: A Neural Network-Based Model Detects Low Ejection Fraction from Electrocardiograms Without Overt Rhythm or Conduction-System Abnormalities

Introduction: While detection of asymptomatic left ventricular dysfunction (LVD) is important given the effectiveness of preventive medical treatments, the gold standard method using echocardiograms requires trained experts and thus is less suitable for widespread screening. Previous studies have found that convolutional neural network (CNN) models could detect patients with LVD from 12-lead electrocardiogram (ECG). However, they were developed in an unselected population which included an unknown number of patients with overt rhythm and conduction system abnormalities, which frequently coexist with LVD. It is unclear to what extent these models relied on such obvious features to detect LVD from ECGs. Herein, we aimed to assess the ability of a CNN-based model to detect LVD using ECGs having no apparent rhythm or conduction abnormalities. Methods: 56,985 ECGs with an echocardiogram within a 2-week interval were identified from the BWH ECG database. The dataset was split into 28,465, 11,306 and 17,214 ECGs for derivation, validation and test, respectively, with no overlap of patients across groups. A CNN model was trained as a binary classifier to detect LVD, defined as LV ejection fraction &lt; 35 %. The final model was selected as that with the best area under the receiver operating characteristics curve (AUROC) on the validation set and performance assessed on the test set. The model was further tested after excluding ECGs with overt rhythm and conduction system abnormalities defined as the presence of atrial fibrillation, premature atrial complexes, premature ventricular complexes, electronically paced rhythms, left or right bundle branch block. Results: The mean patient age in the test set was 69.8 years, and 57.3% of patients were male. prevalence of low LVEF was 9.7%. The test dataset contained 7,633 ECGs with overt rhythm and conduction system abnormalities. The model yielded good accuracy with an AUROC of 0.91 (95% CI:0.90-0.91) to identify patients with LVD in the test data set. The model performed similarly in the presence or absence of rhythm or conduction-system abnormalities (AUROC 0.90 95% CI:0.89-0.92 and 0.89 95% CI:0.88-0.90 respectively). Conclusion: The model detected low LVEF from ECG without overt rhythm and conduction system abnormalities.

Abstract 12116: Sex Differences in Arrhythmia Prevalence in a Large Patient Cohort Examined With Mobile Cardiac Telemetry

Introduction: The frequency of clinically relevant arrhythmia on long-term ambulatory ECG recordings is not sufficiently well described. We aimed to address this in a large patient cohort monitored with mobile cardiac telemetry. Methods: All patients 18-100 years who were monitored in the USA in 2017 (n=27.203, 58% female) with the PocketECG device (MediLynx), which registers and transmits a full-disclosure ECG for ≤30 days with beat-to-beat analysis, were included. Frequent premature ventricular complexes (PVCs) and frequent premature atrial complexes (PACs) were defined as ≥200 PVCs or ≥500 PACs in any recording day. Supraventricular tachycardia (SVT) episodes were defined as both any SVT &gt;3 beats, and SVT ≥30 seconds. AV-blocks II and III were not differentiated. Results: In the 18-40-year age group the overall prevalence of any arrhythmia was low (Figure 1 a-f). Frequent PACs, atrial fibrillation, AV-blocks and ventricular arrhythmias were more common in men than women (all p&lt;0.0001), and SVTs, both &gt;3 beats and &gt;30 seconds, were more common in women (p&lt;0.001 and p&lt;0.004, respectively). The overall prevalence of any VT event was 22.9% in women and 40.8% in men (p&lt;0.0001) and the mean age at onset of VT was lower in women (71.9 vs 72.6 years, 95%CI for difference (-1.3; -0.3). Conclusions: Most arrhythmias are more prevalent among men of all ages, but SVTs are more prevalent among women. VT events are common in a patient population, and the age at onset of ventricular tachycardia is lower among women.

Atrial cardiopathy predicts detection of atrial fibrillation in embolic stroke of undetermined source: real-life data.

Atrial cardiopathy (AC) is more frequent in patients with embolic stroke of undetermined source (ESUS) than in patients with non-cardioembolic stroke. The aim of this work was to describe AC in patients with ESUS and to study its impact on detection of atrial fibrillation (AF) during follow-up. This is an observational study of 123 consecutive ESUS patients and 55 ESUS patients from a previous cohort. AC was defined according to the presence of one or more of the following criteria: severe left atrial enlargement, p-wave terminal force in lead V1 > 5000 μVxms, and excessive premature atrial complexes. Unadjusted and adjusted survival analyses for the occurrence of AF and stroke or transient ischemic attack (TIA) were performed. Diagnostic performance of AC for the detection of AF was analyzed. Among 178 patients with ESUS, those with AC (42.7%) were older (p < 0.001), and more frequently had hypertension (p = 0.001) and lower total cholesterol levels (p = 0.001) than patients without AC. The detection of AF during follow-up (median 34months, interquartile range = 12.8-64) was higher in patients with AC (hazard ratio = 7.00, 95% confidence interval = 2.01-24.39, p = 0.002). This association persisted after adjusting for age, arterial hypertension, and other vascular risk factors. The c-statistic for detection of AF during follow-up for AC was 0.719. There were no differences in stroke or TIA recurrence between groups with and without AC. ESUS patients with AC have different baseline clinical characteristics than patients without AC and have a higher detection of AF during follow-up.

ВЗАИМОСВЯЗЬ ПАРАМЕТРОВ НАДЖЕЛУДОЧКОВОГО КОМПОНЕНТА ЭКГ И БРОНХИАЛЬНОЙ ГИПЕРРЕАКТИВНОСТИ У ДЕТЕЙ С БРОНХИАЛЬНОЙ АСТМОЙ

Uncontrolled course of bronchial asthma (BA) is associated with the risk of heart rhythm disturbances. Objective of the study: to analyze the electrocardiographic parameters of the atrial complex and atrioventricular conduction and to assess their relationship with changes in spirometric parameters in tests with dosed physical activity (PA), reflecting bronchial hyperreactivity (BHR) in children with BA. Materials and methods of research: assessment of the parameters of the supraventricular component of the ECG in comparison with changes in spirometric parameters in tests with dosed PA was performed in 55 children aged 6–17 years with atopic asthma. To level the effect of age on ECG indices, the «relative PQ» (rPQ) index was introduced, calculated as the ratio of the patient's PQ interval duration to the median PQ values characteristic of a given age and gender. Results: it was found that a decrease in the Tiffno index (TI) in tests with PA is accompanied by a statistically significant increase in the rPQ index, an increase in the PQ segment (sPQ) and an increase in the proportion of the PQ interval in the structure of the R–R interval (PQ/RR); similar patterns were obtained when comparing the variability instantaneous volumetric expiratory flow rate at the level of 25% of the vital capacity of the lungs (MOS25). Analysis of the available data indicates a statistically significant lengthening of the PQ and sPQ intervals, as well as an increase in the rPQ and PQ/R–R indices in children with BA as the afterload changes in the small bronchi, indirectly assessed by MOC25. Conclusion: children with asthma who have spirometric signs of BHR in the test with PA may have electrocardiographic signs of a slowdown in supraventricular conduction.

Thick Heart, Wide QRS, Broad Differential

Routine electrocardiogram in a middle-aged man with left ventricular hypertrophy showed sinus rhythm, a short PR interval, and delta wave, confirming ventricular pre-excitation. Pre-excitation was fixed after a premature atrial complex and in atrial fibrillation, features diagnostic of a fasciculo-ventricular pathway. Genetic testing confirmed a diagnosis of hypertrophic cardiomyopathy. (Level of Difficulty: Intermediate.)

Localized Pulmonary Vein Scar Promotes Atrial Fibrillation in High Left Atrial Pressure.

BackgroundPulmonary vein (PV) ablation is unsuccessful in atrial fibrillation (AF) patients with high left atrial (LA) pressure. Increased atrial stretch by increased pressure is proarrhythmic for AF, and myocardial scar alters wall deformation. We hypothesized that localized PV scar is proarrhythmic for AF in high LA pressure.MethodsRadiofrequency energy was delivered locally in the right PV of healthy sheep. The sheep recovered for 4 months. Explanted hearts (n = 9 PV scar, n = 9 controls) were perfused with 1:4 blood:Tyrode’s solution in a four-chamber working heart setup. Programmed PV stimulation was performed during low (∼12 mmHg) and high (∼25 mmHg) LA pressure. An AF inducibility index was calculated based on the number of induction attempts and the number of attempts causing AF (run of ≥ 20 premature atrial complexes).ResultsIn high LA pressure, the presence of PV scar increased the AF inducibility index compared with control hearts (0.83 ± 0.20 vs. 0.38 ± 0.40 arb. unit, respectively, p = 0.014). The diastolic stimulation threshold in high LA pressure was higher (108 ± 23 vs. 77 ± 16 mA, respectively, p = 0.006), and its heterogeneity was increased in hearts with PV scar compared with controls. In high LA pressure, the refractory period was shorter in PV scar than in control hearts (178 ± 39 vs. 235 ± 48 ms, p = 0.011).ConclusionLocalized PV scar only in combination with increased LA pressure facilitated the inducibility of AF. This was associated with changes in tissue excitability remote from the PV scar. Localized PV ablation is potentially proarrhythmic in patients with increased LA pressure.

Targeting non-pulmonary vein triggers in persistent atrial fibrillation: results from a prospective, multicentre, observational registry.

We evaluated the efficacy of an ablation strategy empirically targeting pulmonary veins (PVs) and posterior wall (PW) and the prevalence and clinical impact of extrapulmonary trigger inducibility and ablation in a large cohort of patients with persistent atrial fibrillation (PerAF). A total of 1803 PerAF patients were prospectively enrolled. All patients underwent pulmonary vein antrum isolation (PVAI) extended to the entire PW. A standardized protocol was performed to confirm persistent PVAI and elicit any triggers originating from non-PV sites. All non-PV triggers initiating sustained atrial tachyarrhythmias were ablated. Ablation of non-PV sites triggering non-sustained runs (<30 s) of atrial tachyarrhythmias or promoting frequent premature atrial complexes (≥10/min) was left to operator's discretion. Overall, 1319 (73.2%) patients had documented triggers from non-PV areas. After 17.4 ± 8.5 months of follow-up, the cumulative freedom from atrial tachyarrhythmias among patients without inducible non-PV triggers (n = 484) was 70.2%. Patients with ablation of induced non-PV triggers had a significantly higher arrhythmia control than those whose triggers were not ablated (67.9% vs. 39.4%, respectively; P < 0.001). After adjusting for clinically relevant variables, patients in whom non-PV triggers were documented but not ablated had an increased risk of arrhythmia relapse (hazard ratio: 2.39; 95% confidence interval: 2.01-2.83; P < 0.001). Pulmonary vein antrum isolation extended to the entire PW might provide acceptable long-term arrhythmia-free survival in PerAF patients without inducible non-PV triggers. In our population of PerAF patients, non-PV triggers could be elicited in ∼70% of PerAF patients and their elimination significantly improved outcomes.

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.