bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-dimensional volume-strain loops may reflect fibrosis in hypertrophic cardiomyopathy
Authors: Pagourelias E , Antoniadis A , Boulmpou A , Tsarouchas A , Mouselimis D , Bakogiannis C , Papadopoulos C.E , Vassilikos V , Voigt J.U
Published: November 2020

Background

Combined plotting of deformation parameters against other indices [e.g. arterial pressure, left ventricular (LV) volume] might offer additional information about different diseases. Especially in hypertrophic cardiomyopathy (HCM) this approach might offer new insights into the various phenotypic and pathophysiologic features of this entity.

Purpose

Aim of this study was i) to apply strain-volume loops in HCM based on simultaneous frame-by-frame strain and volume changes' recordings acquired by means of three-dimensional (3D) speckle tracking imaging and ii) to investigate potential correlations between these loops and phenotypic features of HCM (including thickness, obstruction and fibrosis).

Methods

We included 40 HCM patients (54.1±14.3 years, 82.5% male, maximum wall thickness 19.3±4.8mm) who have consecutively undergone 3D-speckle tracking echocardiography and cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). Values of 3D strain were plotted vs. volume for each frame to build a strain–volume loop. Peak of radial, longitudinal, and circumferential systolic strain (Rsp, Lsp, and Csp, respectively), systolic slopes of the loops (RsSl, LsSl, CsSl), and strain to end-diastolic volume (EDV) ratio (Rs/V, Ls/V, Cs/V) were computed for the analysis (panel A). Additionally, burden of fibrosis (percentage of LV mass) was defined by LGE extent (>5 standard deviations compared to nulled myocardium) in CMR slices.

Results

All HCM patients had preserved EF (60.5±5,7%), while 16 (40%) had LV outflow tract obstruction (LVOTO>30 mm Hg at rest). Mean LV mass index was 78.9±14.5 g (evaluated by 3D echocardiography). LGE was observed in 23 patients (57.5%) occupying 5.2±4.5% of LV mass. Concerning strain-volume loops the following values were recorded for radial (Rsp 30.8±9.8%, RsSl 0.4±0.13 and Rs/V 0.25±0.09), longitudinal (Lsp −9.4±3.7%, LsSl 0.12±0.06 and Ls/V 0.08±0.04) and circumferential deformation (Csp −14.2±3.5%, CsSl 0.18±0.05 and Cs/V 0.11±0.03). Among typical HCM characteristics tested (LV mass, LVOTO and LGE), only LV mass presented significant correlations with LsSl (r=−0.41, p<0.01). Interestingly, HCM patients with smaller LVMI and without LGE presented steeper and narrower (difference between systolic and diastolic strain for the same volume) longitudinal strain-volume loops compared to patients with larger LVMIs and fibrosis (panel B).

Conclusions

Strain-volume loop is an innovative application of 3D deformation imaging in HCM. According to this new non-invasive method, increase of LVMI in HCM is accompanied by less longitudinal contribution to stroke volume, whereas better systolic-diastolic coupling may exclude the presence of underlying fibrosis.

Funding Acknowledgement

Type of funding source: None
Gen-editing to model Short QT syndrome type 5 using human-induced pluripotent stem cell-derived cardiomyocytes
Authors: El-Battrawy I , Maywald L , Cyganek L , Zhong R , Zhang F , Kleinsorge M , Dinkel H , Lan H , Li X , Huang M , Liao Z , Moscu-Gregor A , Borggrefe M , Zhou X , Akin I
Published: November 2020

Aims

Short QT syndrome (SQTS), a disorder associated with characteristic electrocardiogram QT-segment abbreviation, predisposes afflicted patients to sudden cardiac death. Despite some progress in assessing the organ level pathophysiology and genetic changes of the disorder, the understanding of the human cellular phenotype and discovering of an optimal therapy has lagged due to a lack of appropriate human cellular models of the disorder. The aim of this study was to establish a cellular model of SQTS type 5 using human-induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) and gene-edited cell line using CRISPR/CAS9.

Methods and results

This study recruited one patient with short QT syndrome type 5 carrying a mutation in CACNb2 gene as well as one healthy control subject. We generated hiPSCs from their skin fibroblasts, and differentiated hiPSCs into cardiomyocytes (hiPSC-CMs) for physiological. Isogenic control hiPSC-CMs generated by the CRISPR/CAS9 technique were also used for the study.

The hiPSC-CMs from the patient showed a reduced calcium current (ICa-L) density and shortened action potential duration (APD) compared with healthy control hiPSC-CMs and isogenic hiPSC-CMs. Furthermore, they demonstrated abnormal rhythmic activities. Carbachol increased the arrhythmic events in SQTS significantly but not in healthy and isogenic control cells. Gene and protein expression profiling showed a decreased CACNb2 expression in SQTS cells. Quinidine prolonged the APD and abolished arrhythmic activity.

Conclusions

Patient-specific hiPSC-CMs are able to recapitulate single-cell phenotype features of SQTS type 5 and provide novel opportunities to further elucidate the cellular disease mechanism and test drug effects.

Funding Acknowledgement

Type of funding source: None
Inducibility of atrial fibrillation is associated with disturbed activation pattern in bachmanns bundle
Authors: Van Staveren L , Van Der Does W.F.B , Heida A , De Groot N.M.S
Published: November 2020

Background

Electrophysiological differences in Bachmann's bundle (BB) between patients with a history of atrial fibrillation (AF) and patients without prior tachyarrhythmias have been demonstrated, including a higher proportion of conduction block (CB) and longer lines of CB. However, whether conduction abnormalities in BB influence inducibility of AF is yet unknown.

Purpose

To investigate which electrophysiological characteristics of BB during sinus rhythm increase susceptibility to AF in patients undergoing elective cardiac surgery, using intraoperative high density epicardial mapping data.

Methods

Fifty-four patients without a history of AF, admitted for correction of structural cardiac disease (coronary artery disease, heart valve regurgitation or stenosis or congenital heart disease), were examined. Epicardial mapping of Bachmann's bundle during sinus rhythm was performed using a rectangle-shaped electrode array (192 electrodes, interelectrode distance: 2mm). AF was induced using bursts of fixed rate pacing. Patients in whom sustained AF was induced (lasting throughout the mapping procedure, N=34) and patients in whom AF was non-inducible (N=20) were compared with respect to lines of conduction block (CB, defined as interelectrode conduction time >12ms), total activation time of Bachmann's bundle and patterns of activation.

Results

AF inducibility was not related to patient characteristics. Patients in whom AF was induced showed a higher proportion of CB (3.23 (0.0–23.9)% vs 1.82 (0.048- 4.6)%, p<0.05), longer maximum lines of CB (12 (0–78)mm vs 9 (2–24)mm, p<0.05) and a longer total activation time (55.0 (24.0–154.5)ms vs 41.8 (23.0–73.0)ms, p<0.01) compared to patients in the non-inducibility group. In addition, BB was activated by more separate waves entering the mapping area from different directions in the induced AF group; more than 1 wave entered BB in 22 (65%) of the induced AF patients versus 7 (40%) of non-inducibility patients, p<0.05.

Conclusion

Inducibility of AF is associated with an increased proportion of CB, longer maximum continuous lines of CB, a longer total activation time of BB and more than 1 wave entering the mapping area from different directions during sinus rhythm.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Dutch Heart Foundation
QRS dispersion using 252-leads Body Surface Mapping (BSM) – an explorative study of a novel diagnostic tool for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
Authors: Kommata V , Elshafie M.I , Perez M , Augustine R , Blomstrom-Lundquist C
Published: November 2020

Background

The diagnosis of ARVC is complex and challenging requiring multiple investigational tools, most of which include the demonstration of depolarization/conduction abnormalities, described in recent HRS consensus documents 2019. A simple and user friendly diagnostic tool is warranted.

Purpose

The purpose of our study was therefore to explore whether the analysis of QRS dispersion obtained from 252-leads recorded by a Body Surface Mapping (BSM) system can be used to identify ARVC patients as compared to the traditional ECG criteria including QRS dispersion measured by conventional 12 lead surface ECG.

Methods

12 definite ARVC patients (10/12 with known pathogenic mutation) (Group 1) and 8 healthy family members tested negative for the family mutation served as controls (Group 0), were included. All patients underwent 12-lead ECG (50mm/sec), Signal-averaged ECG for late potentials and 252 lead BSM recordings. The QRS duration was measured in each of the 12 ECG leads manually with digital caliper. The QRS duration from the BSM leads were manually analyzed in Matlab by two observers unaware of the diagnosis. For each lead, the mean value of three randomly chosen beats was calculated. The QRS dispersion was calculated as the difference between the minimum and maximum value for both the 12 lead ECG and the BSM recordings.

Results

The mean age was 49,6 and 38,8 years in ARVC patients and controls, respectively. The number of males in the two groups were 8/12 and 5/8, respectively. Epsilon waves and Terminal Activation Duration (TAD) >55msec were detected in 6/12 and 8/12 ARVC patients, respectively, but in no controls. Late potentials were detected in 11/12 ARVC patients and in 2 controls. The QRS duration and QTc duration was not statistically different in the two Groups.

The ECG-QRS dispersion was significantly more pronounced in Group 1 (42 ms ± 15, range 20–70 ms) than in Group 0 (26 ms ± 8, range 16–36 ms) (p=0.013). The BSM-QRS dispersion was significantly longer in Group 1 (68 ms ± 17, range 29–90ms) than in Group 0 (30 ms ± 7, range 22–41ms) (p=0.001). Only one ARVC patient had a BSM-QRS dispersion <50 msec, whereas none of the controls had a QRS dispersion over 50 msec (Fig. 1).

Conclusion

BSM-QRS dispersion, specifically using the cut off <50 ms, can potentially be a more sensitive and specific method than other ECG related techniques for diagnosing ARVC patients versus non-ARVC patients. Larger patient cohorts and further studies are required to confirm our findings.

Figure 1. ECG and BSM-QRS dispersion

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Selanders Stiftelse
A nationwide 16 year analysis of trends and impact of arrythmias in transplant recipients
Authors: Isath A , Perembeti S , Rao S , Sherif A , Correa A , Chahal A , Padmanabhan D , Garg V , Contreras J , Mehta D
Published: November 2020

Background

Orthotopic heart transplantation is the most effective long-term therapy for end-stage heart disease. Denervation of transplanted heart with the loss of autonomic modulation, vasculopathy, utilization of immunosuppressant drugs, and risk of allograft rejection may result in change in the prevalence of arrhythmias in transplanted hearts.

Purpose

To describe the trends, distribution and the clinical impact of arrhythmias in transplanted hearts in a large nationwide population.

Methods

We queried the National Inpatient Sample with administrative codes. Cardiac transplant patients were identified using procedure ICD-9-CM codes 37.5 and 33.6. Common arrhythmias were extracted using appropriate validated ICD-9-CM codes. Statistical Analysis System (SAS) version 9.4 was used for analysis of data.

Results

There was a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States and 16342 (54.4%) of these had arrhythmias. The prevalence of total arrhythmias increased from 53.6% (n=1,158) in 1999 to 67.3% (n=1,575) in 2014. The most common arrhythmia was atrial fibrillation (26.83%) followed by ventricular tachycardia (22.86%) and the prevalence of individual arrhythmias is as shown in Figure 1.

Cardiogenic shock was higher in transplanted hearts with arrhythmias when compared with patients without arrhythmias (25.96% vs 18.18%; p<0.001). Transplant recipients with arrhythmias were also associated with an increased use of mechanical circulatory device (18.22% vs 12.67%, p<0.001). The use of implantable cardiac defibrillators and permanent pacemaker was also higher in the arrhythmia group (2.19% vs 0.63% and 40.43% vs 30.24% respectively, p<0.0001). However, there was no significant difference in inpatient mortality between transplant recipients with arrhythmias and without arrhythmias (7.72% vs 6.90%, p=0.225). Further, there was no significant difference in frequency of strokes between the groups (4.98% vs 5.08%; p=0.857).

The total hospital cost when adjusted for inflation was significantly higher in the arrhythmic patients, with an average cost of about $570,415±9,590 vs $439,707±8362 in patients without arrhythmias (p<0.0001). The mean length of hospitalization was 44.2±0.8 days in patients with arrhythmias compared to 33.9±0.8 days in patients without arrhythmias (p<0.0001).

Conclusion

A significant proportion of patients with heart transplant have cardiac arrhythmias and are associated with worse in-hospital outcomes of cardiogenic shock, increased length of stay, and cost of hospitalization. However, they are not associated with worse inpatient mortality.

Funding Acknowledgement

Type of funding source: None
Frequency of cardiac arrhythmias in older adults: findings from the subclinical atrial fibrillation and risk of ischemic stroke (SAFARIS) study
Authors: Mannina C , Jin Z , Matsumoto K , Ito K , Biviano A , Elkind M , Rundek T , Homma S , Sacco R , Di Tullio M
Published: November 2020

Background

Prolonged monitoring of cardiac rhythm has been used in patients with symptomatic arrhythmias and to assess for atrial fibrillation (AF) after cryptogenic stroke, but not in the general population and especially in older adults.

Purpose

To evaluate the frequency of arrhythmias in a community-based cohort of older adults through 14-days continuous cardiac monitoring using a patch-based device.

Methods

Cardiac rhythm was analyzed in 533 participants free of AF and congestive heart failure (CHF) from the tri-ethnic (white, black, Hispanic) Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study. AF, supraventricular tachycardia (SVT, defined as 4 beats or more), premature atrial (PACs) and ventricular (PVCs) contractions, ventricular tachycardia (VT, defined as 4 beats or more), sinus pauses (SP) and atrio-ventricular blocks (AVB) were analyzed. Gender, age and race-ethnic differences were examined.

Results

Mean age was 77.2±6.8 years (198 men, 335 women). Recording duration was over 10 days in 91%, and over 13 days in 84%. AF was present in 10 participants (1.9%), atrial flutter in 1 (0.2%). Other arrhythmias are reported in the Table. SP (1.9%) and high-degree AVB (Mobitz II: 0.6%; 3rd degree: 0.9%) were rare. No significant race-ethnic differences were observed.

Conclusion

In older adults without history of stroke or CHF, prolonged rhythm monitoring revealed moderate frequency of AF, but higher than expected frequencies of AF-predisposing conditions such as SVT and frequent PACs. VT episodes were relatively frequent, whereas SP and AVB were less frequent than commonly believed. Most arrhythmias were more frequent in the oldest; ventricular arrhythmias were more common in men than in women.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): NINDS R01 NS083874
Provocation testing is irreplaceable to uncover or refute Brugada syndrome – an electrocardiographic validation study during ajmaline provocation
Authors: Van Der Ree M.H , Vendrik J , Kors J.A , Wilde A.A.M , Tan H.L , Postema P.G
Published: November 2020

Background

A Brugada syndrome (BrS) diagnosis is made upon documenting its characteristic type-1 ECG abnormality, being either spontaneously present or provoked by drug challenge, in the absence of co-morbidities resulting in similar ECG characteristics. In patients without type-1 ECG but in whom a suspicion of BrS exists, several ECG characteristics have been proposed that could aid in distinguishing BrS from non-BrS, particularly in individuals with incomplete right bundle branch block.

Purpose

To validate the diagnostic value of ECG characteristics that were previously proposed.

Methods

For this retrospective study, ECGs were evaluated from consecutive patients suspected of BrS who underwent ajmaline testing (n=1392). Baseline ECG and peak-effect ECG were analyzed with the MEANS software. Parameters considered were P, PR, QRS, S, JT, QT and QTc durations (all in ms), J and S amplitudes (both in mV), and QRS and T axes (both in °). ECG evaluations also included b-angles (in °) and duration of the base of a triangle (DBT) at 0.5 mV from the r' (in ms) in right precordial leads (V1, V2, V1ic3, V2ic3).

Results

Diagnostic type-1 ECGs were uncovered in 345 subjects and 1047 subjects had a negative test. Patients with BrS had significantly more atrial and ventricular conduction abnormalities (P, PR, QRS, and S duration) at baseline; these differences, except in PR duration, were aggravated upon ajmaline administration. In particular, the b-angle (e.g., V1: 28° [20; 46.5] versus 18° [12; 24], p<0.01) and DBT (e.g., V1: 130 ms [89; 214] versus 65 ms [42; 92.3], p<0.01) were significantly larger at baseline in patients with BrS, however, only with modest diagnostic value (area-under-the-curve 0.67–0.80). The optimal b-angle cut-off value based on the ROC curves to rule out BrS was determined at an angle of >15°, negative predictive values ranged from 78.6–95.5 and sensitivities ranged from 80–98.1% among different leads.

Conclusions

Patients with BrS show more baseline ECG abnormalities and display more conduction slowing upon ajmaline infusion. The b-angle and DBT do not demonstrate strong enough diagnostic characteristics to serve as a stand-alone diagnostic tool. Drug provocation tests remain necessary for diagnosing BrS in patients without a spontaneous type-1 ECG.

Funding Acknowledgement

Type of funding source: None
Competency differences in ECG interpretations between medical students, interns, and family residents
Authors: Alanazi H , Ahmed A , Alsadi M , Almousa S , Homoud E , Almutairi R , Alkhalifah B
Published: November 2020

Background

The 12-lead electrocardiogram (ECG) is an indispensable screening and diagnostic tool used to identify cardiovascular abnormalities as well as fatal cardiac emergencies. Our aim was to identify whether a competency difference in interpreting ECG strips between medical students, interns, and family residents exists.

Methods

A cross-sectional, single-center study conducted at tertiary health care facility and its academic institution. Participants were given a self-administered questionnaire which consisted of a demographic sheet and 10-ECGs each with 9 multiple choice questions about the basic ECG parameters. Correct answer was given a 1-point score, with the minimum and maximum scores being 0 and 90, respectively.

Results

The total participants were 93; 54 (58.1%) medical students, 27 (29.0%) interns, and 12 (12.9%) family Medicine residents. Medical students had a statistically significant higher mean score 84.7±9.5 when compared to the medical interns 73.4±12.9 (p<0.001) and family medicine residents 58.2±18.0 (p<0.001). There were no differences in the mean scores between male and female medical students and interns. However, female family medicine residents had a higher mean score when compared to their male colleagues (p-value=0.04). Medical students performed better in detection of more than 65% of all ECG parameters when compared to the interns and residents. Fifty-seven (61.3%) reported that ECGs exposure during their medical program was not sufficient. Lectures were reported as the most effective modality of ECG teaching among 38 medical students (70.4%) and 9 residents (75.0%). However, 9 medical interns reported self-teaching (33.3%) as effective as standard lectures (33.3%) in teaching ECG.

Conclusion

Among our study cohort, medical students had higher ECGs-related skills, interpretation skill and more reading competency than medical interns and family residents. Most used method of learning ECG in all levels was lectures. Although Study generalizability is limited, refining ECG reading skills is required.

Funding Acknowledgement

Type of funding source: None
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

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<0.001), gender (SC=+0.208, P<0.001), heart rate (SC=+0.230, P<0.001), J-point elevation in lead V4 (SC=−0.118, P<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<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

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

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

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<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

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

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 <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<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

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 >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<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<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

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

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<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<0.05). Erythromycin (+26ms, p<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<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
ICD implantation and device therapy: Fabry vs hypertrophic cardiomyopathy
Authors: Vijapurapu R , Zegard A , Leyva F , Bradlow W , Jovanovic A , Hughes D , Geberhiwot T , Steeds R.P
Published: November 2020

Background

Cardiac involvement of Fabry disease (FD) includes left ventricular hypertrophy (LVH), inflammation, arrhythmia and sudden death. There are limited data regarding potential risk predictors and no definitive criteria exist to guide implantation of cardiac devices for primary prevention. Despite phenotypic similarities between FD and hypertrophic cardiomyopathy (HCM), FD is specifically excluded from the ESC sudden cardiac death risk prediction tool used for HCM.

Purpose

To evaluate differences in device implantation and arrhythmic burden between advanced Fabry cardiomyopathy and HCM.

Methods

This multi-centre, retrospective study including genetically confirmed FD and age/gender-matched HCM patients all of whom had an implantable cardioverter defibrillator (ICD). Data was collected prior to device implantation on disease characteristics, biomarkers and CMR imaging. Arrhythmia burden and changes in therapy were captured following implantation.

Results

Of the UK FD population under follow-up, 50/880 had an ICD implanted (80% males, 51% non-classical mutation, mean age at device implantation 57±12 years). A comparator group included 64 age- and gender-matched HCM patients (67% males, mean age at implant 46±39 years). Baseline LV mass was greater in FD (291±97g/m2 vs 218±78g/m2, p=0.012). FD patients had higher troponin (95 vs 19ng/l, p<0.001) but similar NT-pro-BNP (1687 vs 888ng/l, p=0.086) levels.

Indications for ICD insertion in FD included: presumed HCM dual pathology 14%, symptomatic NSVT 18%, asymptomatic NSVT 24%, co-existing long QT 2%, CRT-D 14%, no clear indication (primary prevention in the presence of multiple potential arrhythmic risk factors) 28%. All HCM patients were risk stratified and underwent device implantation based on an estimated 5-year SCD risk >4%. All FD patients had a SCD risk >4% using this risk calculator. Arrhythmia were more common in FD over shorter follow-up (37/50, 74% over 4.3±3.0 years vs 28/64 in HCM, 44% over 6.5±2.9 years, p=0.001). Notably, VT requiring anti-tachycardia pacing (ATP) +/− defibrillation therapy from the ICD was more frequent (FD: 14/50, 28% vs HCM: 8/64, 12%, p=0.055), as was immediate shock therapy for sustained VT (p=0.009, figure panel B). FD patients with arrhythmia were often older, had greater LV mass, a larger left atrium and a broader QRS duration. These clinical features tended to occur more frequently in FD than in the HCM group.

Conclusion

This study has shown that delivery of device therapy in Fabry cardiomyopathy is higher than in HCM. Despite similar rates of asymptomatic NSVT, a higher rate of ventricular arrhythmia requiring ATP/defibrillation therapy occurred in FD. Although both FD and HCM had similar risk percentages according to the ESC calculator, active troponitis in FD was double that of HCM.

Funding Acknowledgement

Type of funding source: None
The Wearable Cardioverter/ Defibrillator: retrospective analysis of efficacy, safety and adherence
Authors: Ehmsen J , Keller H , Stoellberger C
Published: November 2020

Background

The use of the Wearable Cardioverter Defibrillator (WCD) is recommended in national, European and American guidelines. However, there are almost exclusively data from the manufacturer's own data network. Independent data on the experience with the WCD are rare.

Objective

The aim of the retrospective study from one cardiologic department was to record efficiency, safety and compliance of the WCD.

Patients and methods

The study included all patients, to whom a WCD was described between 1.11.2010 and 1.5.2018 at one cardiologic department. Clinical data were obtained from the patients' records and the data about the WCD from the information network of the manufacturer.

Results

This study enrolled 66 patients, 51 males (77%) and 15 females (23%). The median age was 55 years (IQR: 45–63). They suffered from ischemic cardiomyopathy (n=33; 49%), dilated cardiomyopathy (n=12; 18%), myocarditis (n=7; 11%), explantation of an implantable cardioverter/defibrillator (ICD; n=5; 8%) and other indications (n=6; 9%).

The median wearing time of the WCD was 73 days (interquartile range-IQR: 39–126), with median daily use of 22.91 h (IQR: 19.58–23.61). Among 38 patients with LVEF ≤35%, LVEF improved to ≥35% in 19 patients (50%) during WCD therapy. Over 1600 times the WCD detected a VT falsely. Four patients (8%) suffered from 212 non-sustained VT. One patient was successfully shocked because of ventricular fibrillation (appropriate shock rate: 1.5%). There were no inappropriate shocks. All patients, who wore the WCD, survived and one patient died when he did not wear the WCD.

At the end of therapy 32 patients (48%) received an ICD. In terms of wearing time and events (shocks, arrhythmias, artifacts) there were no significant differences between patients receiving ICD and those who did not receive an ICD. Patients who received an ICD had a significantly lower LVEF after 3 months than patients who did not receive an ICD.

Conclusion

Our data confirm, that the WCD is safe and that the patients, who wear a WCD, have a high adherence. More than half of the patients with reduced LVEF improved their systolic function during WCD therapy, thus obviating the need for ICD implantation. Questions about the effectiveness of the detection algorithm remained open.

Funding Acknowledgement

Type of funding source: None