bluuebunny/crossref_metadata_2025_split huggingface dataset:
The association between body temperature and electrocardiographic parameters in normothermic healthy volunteers
Authors: Hassing G.J , Fienieg B , Van Der Wall H.E.C , Van Westen G.J.P , Kemme M.J.B , Adiyaman A , Elvan A , Burggraaf J , Gal P 
Published: November 2020

Abstract

Introduction
Previous studies have observed that hypo- and hyperthermia are associated with several atrial and ventricular electrocardiographical parameters, including the corrected QT interval. Preclinical studies have shown that drugs that exert an effect on body temperature also exert an effect on the corrected QT interval. Therefore, increased characterization in healthy humans of the association between the corrected QT interval and body temperature within the normal body temperature range aids in understanding the mechanism behind drug induced corrected QT interval effects. The objective of this analysis was to evaluate the association between body temperature and electrocardiographical parameters in normothermic healthy volunteers.

Methods
Data from 3023 volunteers collected at our center were analyzed. Only subjects considered healthy after review of collected data by a physician, including a normal tympanic body temperature (35.5–37.5 °C) and in sinus rhythm, were included in the analysis. Subjects were divided into body temperature quartiles for analysis and a linear multivariate model with body temperature as a continuous was performed. Another multivariate analysis was performed with only the QT subintervals as independent variables and body temperature as dependent variable.

Results
Mean age was 33.8±17.5 years and mean body temperature was 36.6±0.4 °C. Body temperature was independently associated with age (standardized coefficient (SC)=−0.252, P&lt;0.001), gender (SC=+0.208, P&lt;0.001), heart rate (SC=+0.230, P&lt;0.001), J-point elevation in lead V4 (SC=−0.118, P&lt;0.001), and Fridericia corrected QT interval (SC=−0.061, P=0.002). Atrial and AV nodal parameters were not independently associated with body temperature. The effects of temperature on the surface ECG are displayed in figure 1. QT subinterval analysis revealed that only QRS duration (SC=−0.121, P&lt;0.001) was independently associated with body temperature.

Conclusion
Body temperature in normothermic healthy volunteers was associated with heart rate, J-point amplitude in lead V4 and ventricular conductivity, primarily through a prolongation of the QRS duration. In contrast, atrial and AV nodal ECG parameters were not independently associated with body temperature.

Funding Acknowledgement
Type of funding source: None
Performance of an implantable loop recorder in the detection of heart rhythm disturbances in patients with syncope and embolic strokes
Authors: Kremer M , Stierle D.S , Naegele H 
Published: November 2020

Abstract

Aims
The primary goal of this study was the evaluation of the arrhythmia detection performance of an implantable loop recorder (ILR) in patients with syncope of unknown etiology and patients with embolic stroke of undetermined source (ESUS). Secondary goals were the evaluation of diagnostic yield, time to diagnosis and established therapeutical consequences.

Methods
The Reveal LINQ ILR was implanted in n=143 patients (n=84 after ESUS, n=59 after syncope). Automatically detected episodes (n=3213) were transmitted via internet and validated by two experienced cardiologists and either classified as correct or incorrect. Positive-predictive value (ppv = true-positive episodes/true-positive episodes + false-positive episodes) was calculated for each available arrhythmia type. Incorrect episodes were classified as undersensing, oversensing, artifacts or supraventricular/ventricular ectopic beats. The diagnostic yield was defined by asystole ≥3 seconds or the detection of atrial fibrillation. Time to diagnosis was calculated as the time from implantation to detection of an asystole or atrial fibrillation.

Results
Every second asystole episode in syncope-patients was false-positive (ppv 52%), mostly due to undersensing. The atrial fibrillation detection performance in ESUS-patients was 70% (ppv-average). The majority of false-positive episodes was due to premature atrial and ventricular complexes (80%), followed by artifacts (14%) and oversensing (4%). Undersensing accounted for 2%. 36% of syncope-patients were diagnosed with an asystole after a mean time to event of 114 days. In 47% of syncope-patients diagnosed with asystole, a pacemaker was implanted. In 31% of ESUS-patients a diagnosis of atrial fibrillation was established, after a mean time to event of 92 days. 85% of ESUS-patients diagnosed with atrial fibrillation were ultimately treated with an oral anticoagulant.

Conclusion and discussion
The Reveal Linq ILR - advertised as an automatic diagnostic tool for syncope- and ESUS-patients - has its caveats. A high number of false-positive detections due to undersensing limited the asystole detection performance. The atrial fibrillation detection performance presented more reliable, despite a substantial number of false-positive detections. A time-consuming manual episode review still represents an indispensable step in the diagnostic process, and enough human resources have to be factored before starting an ILR program.

Funding Acknowledgement
Type of funding source: None
Non-invasive mid-term ECG monitoring for the detection of atrial fibrillation in an outpatient population
Authors: Cai J , Yeo K.K , Wong P , Ching C.K 
Published: November 2020

Abstract

Background
Atrial fibrillation (AF) is a common arrhythmia with significant morbidity due to an increased risk of ischemic stroke. Outpatient electrocardiogram (ECG) monitoring is an integral part of the diagnosis of AF. Conventional 24 hour Holter monitoring can be cumbersome and often fails to diagnose patients with paroxysmal AF. Spyder ECG is a non-invasive ECG monitoring device that allows wireless transmission of ECG information for analysis. It is small and comfortable, allowing for easy application for the screening and detection of AF over a mid-term duration.

Purpose
This study aims to evaluate the incidence of AF in patients with no prior AF and CHADsVASC score of at least 1 with the use of the Spyder ECG mid-term ECG monitoring device.

Methods
Patients aged 21 to 85 years old with no prior history of AF and CHADsVASC score of at least 1 were recruited from outpatient clinics of 3 large tertiary hospitals in Singapore from December 2016 to April 2019. Patients wore the Spyder ECG device for up to 2 weeks, during which continuous ECG information was uploaded onto a central cloud database and analysed.

Results
There were 363 patients recruited. The mean age was 61±10.0 years and 65.1% were male. There were 80.3% Chinese, 11.6% Malay, 7.5% Indian and 20.6% of other races. 68.3% of the patients were non-smokers and 74.0% of them were non-alcohol drinkers. The mean BMI of 25.5±4.7 kg/m2. The patient population had significant co-morbidities. 76.3% of the patients had hypertension, 69.4% of them had hyperlipidemia and 40.5% of them had diabetes mellitus. 10.0% of them had congestive cardiac failure and 56.7% had ischaemic heart disease. 11.3% of patients had a previous stroke and 20.4% had a prior myocardial infarction. 7.8% of the patients had asthma, 5.8% of them had thyroid disease and 9.9% of them had chronic kidney disease. They were monitored for a mean of 5.4±2.9 days each. There were 15 (4.1%) patients in whom AF was detected. The patients with AF wore the device for a mean of 5.7±2.0 SD days. The mean burden of AF was 9.0% of monitored time. 46.7% of the patients with AF had detection of AF on the first day, 26.7% on the second day, 13.3% on the third day and 13.3% on the seventh day. The mean duration of the first episode of AF was 251±325 minutes. 7 out of 15 (46.7%) of patients had first episodes of AF lasting less than 10 minutes.

Conclusion
Continuous mid-term ECG monitoring was able to detect AF in 15 (4.1%) of a population of 363 patients with no prior AF and CHADsVASC score of at least one, monitored for a mean of 5.4 days. Most episodes (53.3%) of AF were detected after the first day of ECG monitoring.

Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): Duke-NUS Medical School Singapore
Implantable cardiac monitor after cryptogenic stroke: atrial fibrillation detection and predictors
Authors: Ebrille E , Amellone C , Lucciola M.T , Orlando F , Suppo M , Antonacci G , Gotta F , Giammaria M 
Published: November 2020

Abstract

Objective
The main objective of our study was to analyze the incidence and predictors of atrial fibrillation (AF) in patients with cryptogenic stroke (CS) who received an implantable cardiac monitor (ICM) at our Institution.

Methods
From November 2013 to October 2017, a total of 133 patients who had suffered a CS were implanted with an ICM after a thorough screening process. The median time between the thromboembolic event and ICM implantation was 64 days [IQ range: 16–111]. All implanted patients were followed with remote monitoring until the first detected episode of AF or up to December 2018. Every remote monitoring transmission and related electrograms were analyzed by the dedicated Electrophysiology Nursing team and confirmed by experienced Electrophysiologists. AF was defined by any episode lasting greater than or equal to 2 minutes.

Results
During a median follow-up of 14.8 months [IQ range: 3.0–31.2], AF was detected in 65 out of 133 patients (48.9%). The median time from ICM implantation and AF detection was 3.5 months [IQ range: 0.9–6.7]. The prevalence of AF was 22.6%, 34.4%, 40.8% and 48.3% at 3, 6, 12 and 24 months respectively. At the multivariate analysis, high premature atrial contractions (PAC) burden and left atrium (LA) dilation were the only independent predictors of AF detection (HR 2.82, 95% CI 1.64–4.83, p&lt;0.001 for PAC; HR 1.75, 95% CI 1.03–2.97, p=0.038 for LA dimension). Patients were dived into categories based on the probability of AF detection (low, intermediate and high risk) and a new risk stratification algorithm was implemented (Figure 1).

Conclusion
After a thorough screening process, AF detection in patients with CS and ILM was quite high. Having a high PAC burden and LA dilation predicted AF episodes at the multivariate analysis. A new risk stratification algorithm was developed.
Figure 1

Funding Acknowledgement
Type of funding source: None
In-vivo validation of non-invasive electrocardiographic imaging based on the equivalent double layer source model using epicardial and endocardial electroanatomical mapping
Authors: Roudijk R.W , Boonstra M.J , Van Dam P.M , Van Der Heijden J.F , Asselbergs F.W , Loh K.P 
Published: November 2020

Abstract

Background
Noninvasive electrocardiographic imaging (ECGi) using the equivalent double layer (EDL) source model enables both epicardial and endocardial reconstruction of electroanatomical activation patterns during sinus rhythm. The EDL source model has been validated in torso-tank models and animal experiments, however validation in humans using invasive electroanatomical mapping is limited.

Purpose
Validation of EDL based ECGi using invasive electroanatomical mapping.

Methods
Ten patients referred for epicardial and endocardial electroanatomical mapping underwent 67 electrode body surface potential mapping (BSPM), cardiac CT imaging and 3D imaging of electrode positions. Anatomical models of the ventricles, lungs and thorax were created and supplemented with electrode positions. Invasive epicardial (4020±1514 contact points), right ventricle endocardial (724±113 contact points) and left ventricle endocardial (459±117 contact points) local activation timing (LAT) maps were compared to ECGi derived LAT maps.

Results
Included patients (mean age 48±21 years, 80% males) were diagnosed with either arrhythmogenic cardiomyopathy (N=4), dilated cardiomyopathy (N=1), symptomatic premature ventricular complexes (N=3) or myocarditis (N=2). Measured BSMP highly correlated with simulated BSPM (97±2%) with a relative difference of 24% ± 6%. Source models consisted of a mean of 2614±214 nodes with a mean distance between nodes of 8.3±1 mm. Overall, invasive LAT maps and ECGi derived LAT maps showed reasonable correlation for epicardial maps (49% ± 18%) and endocardial maps of the right ventricle (48% ± 27%). Endocardial left ventricular LAT maps showed less correlation (23% ± 28). The absolute difference between invasive and ECGi LAT maps was 16.7±14.2 ms for epicardial maps, 17.2±12.9 ms for right ventricle endocardial maps and 34.0±19.8 ms for left ventricle endocardial maps. Visual comparison showed corresponding areas of breakthrough and regions of latest activation in all cases (Figure). Quantitative comparison of these areas showed a mean absolute difference of 33±7mm or 19±10 ms for epicardial maps, 25±10 mm or 17±13 ms for right ventricle endocardial maps and 39±16 mm or 20±6 ms for left ventricular endocardial maps.

Conclusion
Overall agreement was observed between EDL based ECGi LAT maps and electroanatomical LAT maps. Future research will focus on further quantification of this agreement and improvement of ECGi mapping accuracy.

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Netherlands Cardiovascular Research Initiative, an initiative with support of the Dutch Heart Foundation and UCL Hospitals NIHR Biomedical Research Centre.
The nature of fast and slow pathway interaction during premature pacing: evaluation with high density mapping
Authors: Bailin S , Rhodes T , Chapman J , Kaushik N 
Published: November 2020

Abstract

Background
Dual AV Nodal (AVN) inputs are associated with the fast pathway (FPW) superiorly, while the SPW activates inferiorly. In the present study, we evaluate the impact of PES on dual antegrade conduction.

Objective
To Define Antegrade Conduction Properties of the AV Node during PES

Methods
High density mapping (Orion, Rhythmia) was performed and analyzed in SR and S2 PES in 12 pts. The FPW activates the AVN and travels inferiorly, there is a point where the activation pivots toward the SPW and travels superiorly along the TV. The distance from the pivot point was measured to the HIS location in sinus rhythm and for each coupling interval. Both the distance and prematurity of the S2 coupling was normalized to the BCL during sinus rhythm. The coupling interval was then plotted vs the HIS-Collision distance. A regression analysis was used to compare data sets with significance defined a &lt;0.05.

Results
Data was obtained in all 12 patients. In all patients, as pre-maturity of S2 increased, the pivot point moved superiorly until there was block in the FPW and activation to the AV node was entirely from the SPW. There is a functional line of block (LOB) between the FPW and SPW. Comparing normalized data decrement vs change in pivot point: R=0.8 p&lt;0.0001

Conclusion
During PES, the F/SPW interaction changes: increasing prematurity causes pivot point to move superiorly until the FPW blocks and AVN activates via the SPW. Decremental antegrade conduction occurs within FPW and is associated with the superior pivot shift toward the AVN suggesting a functional LOB. This relationship is linear.

Funding Acknowledgement
Type of funding source: None
Right Atrial Collision Time (RACT): a novel marker of propensity for typical atrial flutter
Authors: Crinion D , Al-Turki M , Al Hammad N , Neira V , De Leon A , Abdollah H , Chacko S , Enriquez A , Simpson C , Baranchuk A , Johri A , Redfearn D 
Published: November 2020

Abstract

Background
The risk of typical atrial flutter (AFL) is increased by factors that increase right atrial (RA) size or cause scarring to reduce conduction velocity. These characteristics ensure the macro re-entrant wave front does not meet its refractory tail. The time taken to traverse the circuit would take account of both of these characteristics (being equal to distance divided by velocity), and may provide a superior marker of propensity to develop AFL.

Purpose
To investigate right atrial collision time (RACT) as a marker of typical AFL.

Methods
This single centre, prospective study recruited consecutive typical AFL ablation cases that were in sinus rhythm. Controls were consecutive cases other than atrial fibrillation and &gt;50 years of age. Exclusion criteria for both groups were a prior ablation in the RA and class I and III antiarrhythmics. While pacing the coronary sinus ostium at 600 ms, a local activation time map was created to locate the latest collision point on the anterolateral wall, excluding the RA appendage (Figure 1). This RACT approximates half a revolution.

Results
The AFL group's (n=34) mean RACT was 132.5±15.06 vs 98.7±12.23ms in the controls (n=40) (p&lt;0.01). No significant difference was observed for age (mean 65.6 vs 62.6 (p=0.18)), male (68.8% vs 60% (p=0.59)), body surface area (mean 2.1 vs 2.03 m2 (p=0.24)). The RACT also proved to be a superior marker than the echocardiographic measurement of right atrial area in an apical four chamber view (mean 17.8 vs 16.3 cm2 (p=0.21).A ROC curve indicated an AUC of 0.97 (95% CI: 0.93–1.0, p&lt;0.01). A RACT cut-off of 120 ms had a specificity of 99% and a sensitivity of 75%.

Conclusion
RACT is a novel and promising marker of propensity for typical AFL. The ability to predict AFL would be of significant clinical value given the risk of stroke and frequent need for ablation.

Funding Acknowledgement
Type of funding source: None
Increasing use of ablation in the management of atrial fibrillation in heart failure: insights from a national database on 10 year trends in the United States
Authors: Narasimhan B , Wu L , Shah A , Kantharia B 
Published: November 2020

Abstract

Background
Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice, even more so among patients with heart failure (HF). Results of the recent CABANA and CASTLE-AF trials indicate significant improvements in ejection fraction, HF readmissions as well as overall mortality with the incorporation of rhythm control strategies in HF patients. These findings challenge existing notions of equivalency of rate vs rhythm control strategies. In this study, we analyzed the impact of this evidence on treatment practices and the short term outcomes of ablation in this patient cohort.

Methods
We conducted a retrospective study using the AHRQ-HCUP National Readmission Database for the years 2005–2014. ICD 9 diagnosis codes were used to identify all adult patients (≥18 years) undergoing AF ablation procedures as well as a sub-cohort of patients with existing HF. Trends in the use of ablation procedures, patient characteristics as well as details of short term procedural outcomes were studied. Multivariate regression analysis was utilized to adjust for confounders. Complications were defined as per the Agency for healthcare research and quality guidelines. Independent risk factors for in-hospital mortality were identified using proportional hazards model.

Results
Our results indicate a trend of rising rates of AF ablation procedures overall with a peak in 2011 at 20,046 and gradual downtrend thereafter (10,195 in 2005 to 11735 in 2014). Our data revealed a consistent rise in ablation procedures among heart failure patients during the same period (832 to 2245). A definite reduction in peri-procedural mortality is noted (0.24% in 2005 to 0.17% in 2014, p=0.2) – an improvement that is maximally apparent in the heart failure group (2.49% to 0.4%, p=0.07). Overall complication rates however are significantly increased overall with a proportional rise noted among HF patients.

Conclusions
Our data from a nationally representative registry indicates an increasing utilization of ablation as a therapeutic modality in the management of atrial fibrillation in HF. Future prospective studies are required to assess the positive impact of these changes in clinical practice as offset by their associated complications.
10 year AF ablation trends in HF

Funding Acknowledgement
Type of funding source: None
Dexmedetomidine reduces ventricular arrhythmias in a model of drug-induced QT-prolongation
Authors: Frommeyer G , Brandt J , Ellermann C , Wolfes J , Eckardt L 
Published: November 2020

Abstract

Background
Dexmedetomidine is increasingly employed for conscious sedation during electrophysiological procedures. Recent experimental data have suggested direct effects of dexmedetomidine on cardiac electrophysiology. The aim of the present study was to assess the effects of dexmedetomidin on drug-induced QT-prolongation.

Methods and results
In 12 isolated rabbit hearts the macrolide antibiotic erythromycin (300μM) was infused as a potent Ikr blocker after obtaining baseline data. Eight endo- and epicardial monophasic action potentials and a simultaneously recorded 12-lead ECG showed a significant prolongation of QT-interval (+25ms, p&lt;0.05) accompanied by a moderate increase of action potential duration (APD, +5ms, p=ns) after infusion of erythromycin as compared with baseline. Effective refractory period (ERP) was also elevated (+33ms, p&lt;0.05). Erythromycin (+26ms, p&lt;0.05) also significantly increased spatial dispersion of repolarisation. Additional infusion of dexmedetomidine (3μM) resulted in a rather stable QT-interval (+7ms, p=ns) and APD (+7ms, p=ns) as compared with sole erythromycin treatment. Of note, a significant decrease of spatial dispersion (−24ms, p&lt;0.05) was observed while ERP was moderately increased (+13ms, p=ns).
Lowering of potassium concentration in bradycardic AV-blocked hearts resulted in the occurrence of early afterdepolarizations (EAD) and drug induced proarrhythmia with torsade de pointes in 6 of 12 erythromycin-treated hearts (40 episodes). Additional infusion of dexmedetomidine reduced the occurrence of torsade de pointes (4 of 12 hearts, 9 episodes).

Conclusion
Infusion of dexmedetomidine resulted in a reduction of spatial dispersion of repolarization in the presence of a prolonged repolarization period. This resulted in a reduction of torsade de pointes with dexmedetomidine. Furthermore, an increase of ventricular refractory periods reduced inducibility of ventricular arrhythmias. Thus, in an experimental setting dexmedetomidine shows significant antiarrhythmic effects, which may influence electrophysiologic findings during clinical electrophysiologic studies. This needs to be studied in the clinical setting.

Funding Acknowledgement
Type of funding source: None