bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of dynamic atrioventricular optimization during patient exercise in cardiac resynchronization therapy
Authors: Covino G , Iuliano A , Sollazzo V , Leccisotti S , Calvanese R , Tavoletta V , Canciello M , Caroli G , Di Renzo A , Medico A , Vittoria D , Spiniello G , Simonetti A , Bianchi V
Published: May 2024

Background

Cardiac resynchronization therapy (CRT) is considered the standard treatment for patients with heart failure and prolonged QRS duration. Recent studies suggest that atrioventricular delay (AVD) optimization can play a key role in QRS narrowing, thus improving CRT outcomes. For this purpose, device-based algorithms have been developed. In particular, the SyncAV algorithm continuously monitors the patient’s intrinsic AVD and dynamically adjusts the pacing AVD to allow fusion of the left ventricle pacing with intrinsic right ventricle depolarization. SyncAV optimization is usually performed in a single patient condition, i.e. at rest, and in a single operating scenario of the device, i.e. during atrial sensing.

Purpose

This study aims to compare QRS narrowing after AVD optimization using SyncAV in CRT-treated patients at rest, during moderate exertion, and during an increase in the atrial pacing rate.

Methods

This is a prospective, non-randomized, non-blinded, multicenter study. The study population consisted of patients in sinus rhythm, PR interval < 350 ms, and rest ventricular rate < 100 bpm. Within one month from the implant, patients were assessed for AVD optimization with SyncAV, selecting the offset (i.e. 10 to 40% AVD) that resulted in the shortest QRS duration (QRSd). Subsequently, patients performed moderate physical activity using a bicycle ergo-meter while a surface ECG was collected. QRSd was assessed once patients achieved a heart rate over 20 bpm to baseline heart rate, up to 100 bpm. Finally, QRSd narrowing was evaluated during a programmed increase in atrial pacing (i.e. >20 bpm of baseline atrial rate).

Results

Nine patients were treated with CRT and enrolled (age 67,3 ± 13,2 years; 66% male; LV ejection fraction 33,7±2,9 %; intrinsic QRSd 155,6 ± 12,7 ms) with intact atrioventricular conduction (PR interval 170,6±25,8 ms). The median SyncAV offset that provided the best QRSd reduction was 20 % (10 - 35%). Intrinsic QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 122,0 ± 11,2 ms (-21,2±8,5%) with SyncAV optimization. During exercise the mean heart rate was 88,1 bpm, the QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 124,9 ± 14,9 ms (-19,3±10,8 %) with SyncAV optimization. The mean heart rate during atrial pacing was 90 bpm with paced QRSd of 126,0 ±13,9 ms (-18,9±7,3% from baseline) with SyncAV optimization and paced PR interval of 198,2±22,7ms.

Conclusion

We evaluated the effectiveness of SyncAV for AVD optimization in out-of-clinic. This study demonstrates the possibility of narrowing the QRSd using SyncAV at several activity levels. Nevertheless, a deeper evaluation is needed to confirm our findings, investigating the SyncAV role in a larger population of patients.
Conduction system pacing improved cardiac functions and functional capacity in heart failure with reduced ejection fraction and right bundle branch block
Authors: Nagy L , Toth A , Sandorfi G , Csanadi Z
Published: May 2024

Conduction system pacing (CSP) is increasingly accepted as an alternative to biventricular pacing in heart failure (HF) patients with left bundle branch block (LBBB) and non-LBBB. However, its efficiency in right bundle branch block (RBBB) is ill-defined. Herein, we report on the clinical outcomes of CSP in HFrEF patients with wide QRS complex and RBBB morphology.

His-bundle (HBP) or LBB-area pacing (LBBAP) was attempted as a primary strategy in patients with RBBB, QRS duration ≥130 ms and left ventricular ejection fraction (LV EF) <35% and NYHA class II to IV HF despite optimized medical treatment for at least 6 months. Data on functional status, NT-pro-BNP levels and echocardiographic parameters were collected during follow-up and expressed as mean ± SEM, Statistical significance was calculated with Student’s paired t-test and chi square distribution.

CSP was performed in 12 RBBB-HF patients (age 64.3±2.9 years) with mean QRS duration of 150±4 msec and baseline LV EF of 25.4±2.3%. The aetiology of HF was ischaemic (6 patients) and non-ischaemic cardiomyopathy (6 patients). During the procedure, HBP was achieved in 7 and LBBAP in 5 patients, resulting in a significant reduction in the QRS-duration (115±2.6 msec, P<0.0001) as compared with baseline value. CSP improved LV function (LV EF= 31.8±2.8%, P=0.009) as well as NYHA functional class (25% of the patients with NYHA II and 75% with NYHA III before vs. 33% with NYHA I, 33% with NYHA II and 33% with NYHA III after CSP, P=0.048) as compared to what was obtained prior to the procedure. A numerical decrease was also found in NT-proBNP levels (4735±2606 ng/ml before CSP vs. 3972±1883 ng/ml after CSP) which did not reach the level of statistical significance (P=0.45).

In conclusion, CSP improved both quality of life and LV function in HFrEF patients with RBBB. Our results support the use of CSP in HFrEF patients with QRS width>130msec and RBBB morphology.
Enhancing heart failure management: a comprehensive analysis of continuous remote monitoring vs. standard care in patients with cardiac implantable electronic devices
Authors: Veres B , Kiss B , Fehervari P , Engh M , Hegyi P , Zima E , Schwertner W , Masszi R , Merkel E , Behon A , Kuthi L , Osztheimer I , Kosztin A , Merkely B
Published: May 2024

Background

Utilizing remote monitoring (RM) in patients with heart failure (HF) who have cardiac implantable electronic devices (CIED) proves to be a dependable method for closely adhering to device-specific and heart failure-related parameters. While there is some favorable outcome data, the results remain incomplete.

Aims

We aimed to evaluate the advantages of continuous RM compared to the standard of care (SoC) in reducing all-cause mortality, cardiovascular-related death (CV), sudden cardiac death, and ICD shocks.

Methods

A systematic review and meta-analysis of randomized controlled trials (RCT) testing RM vs. SoC for the management of HF patients were performed. Endpoints were all-cause mortality, CV mortality, sudden cardiac death, ICD shocks. Odds ratios (ORs), Hazard ratios (HRs) and 95% confidence intervals (CI) were calculated. CENTRAL, EMBASE and MEDLINE were searched up, and only randomized controlled studies were included.

Results

Sixteen RCTs that enrolled a total of 11,140 patients were identified to evaluate all-cause mortality, resulting in an HR 0.83 (95% CI 0.72 to 0.96). When CV mortality was assessed, there was a significant difference between the RM group and SoC group, and the HR was 0.81 (95% CI 0.67 to 0.97) Moreover RM did not have an effect on the rate of sudden cardiac death and ICD shocks.

Conclusions

RM proved to be superior in reducing all-cause mortality and CV mortality compared to SoC despite of the heterogeneous study cohorts and unstandardized alert actions. However, the use of RM did not influence the occurrence of sudden cardiac death and ICD shocks.
Evaluation of CHA2DS2VASc scale as a tool of prognosis of death in transvenous lead extraction patients in long term follow-up
Authors: Wojciechowska C , Jachec W , Polewczyk A , Nowosielecka D , Tulecki L , Kutarski A
Published: May 2024

Background

CHA2DS2VASc scale is commonly used to risk stratification of stroke in atrial fibrillation patients. With the exception of female gender, the remaining components of the scale are also risk factors for long-term prognosis.

Aim

Assessment of the usefulness of the CHA2DS2VASc scale for predicting the short and long term risk of death in the population of transvenous lead extraction (TLE) patients.

Methods

Retrospective analysis of data of 3822 consecutive patients underwent TLE followed by to 6239 days: median (Q1-Q3) 1846 (852 – 3146).

Results

The strong corelation between number of CHA2DS2VASc scale points and mortality was detected both in 30-days, 1-year, 3-year and all time of follow-up (Spearman r for all follow-up = 0.983, p<0.001). In all TLE population multivariable Cox regression shown that number of points of CHA2DS2VASc scale is independent predictor of death [HR=1.181; 95%CI (1.104-1.264), p<0.001], alongside Carlson index, atrial fibrillation, infective TLE indications and renal dysfunction. A scale value higher by 1 point is associated with an increase in the risk of death by 18.1%. In female group the risk increased by 37.5% [HR=1.375; 95%CI(1.193-1.584), p<0.001)] and in male group the risk increased by 22.00% [HR=1.220; 95%CI 1.110-1.342), p<0.001)].

Conclusion

The commonly known stroke risk CHA2DS2VASc scale may be a useful tool for predicting the risk of death both in short and long-term observation in the group of patients after transvenous lead extraction.Table 1
Temporal order of atrial fibrillation and acute myocardial infarction and associated prognosis in the Danish Diet, Cancer, and Health cohort
Authors: Frederiksen T C , Christiansen M K , Benjamin E J , Olsen A , Jensen H K , Dahm C C
Published: May 2024

Background

Atrial fibrillation (AF) and acute myocardial infarction (AMI) share risk factors and are bidirectionally associated. Several studies found higher risks of outcomes in individuals with both conditions. Whether the risks of outcomes differ according to temporal order of AF and AMI is unclear.

Purpose

We aimed to assess the risks of heart failure (HF), ischemic stroke (IS) and all-cause mortality in individuals with both AF and AMI compared to only one. In addition, we assessed risks of outcome according to the temporal order of AF and AMI in individuals with both conditions.

Methods

The study was based on the Danish Diet, Cancer and Health cohort in which 57,053 men and women aged 50-64 years, with no diagnosis of cancer, participated. Assessment of AF, AMI and outcomes were based on diagnosis codes from the Danish National Patient Registry. We examined the risks of HF, IS and all-cause mortality during 10 years of follow-up in participants with both AF and AMI compared to only one and according to the temporal order of AF and AMI in participants with both conditions using Cox regression models.

Results

We identified 5,816 participants with newly diagnosed AF only, 3,448 with first AMI only, 348 with AF before AMI and 721 participants with AMI before AF. The multivariable-adjusted risks of HF, IS and all-cause mortality were higher among participants with both AF and AMI compared to participants with only AF or AMI (Figure 1). In participants with both AF and AMI, there was no difference in risk of HF (HR=0.92, 95% CI 0.72-1.17) or IS (HR=1.12, 95% CI 0.76-1.66) between participants with AF before AMI compared to AMI before AF. AMI before AF was associated with lower all-cause mortality compared to AF before AMI (HR=0.70, 95% CI 0.54-0.90) (Figure 2).

Conclusions

Risks of adverse outcomes were higher among participants with both AF and AMI compared to only AF or AMI. All-cause mortality, but not risk of HF or IS, differed according to temporal order with a lower mortality among participants with AMI before AF.Figure 1Figure 2
Cardiovascular mortality in patients with atrial fibrillation and physical activity intensity: delineating the threshold of vigorous activity
Authors: Lin Y , Chen Y Y , Ling L C , Hsieh Y C , Chien K L , Ling C H , Chen S A
Published: May 2024

Background/Introduction

There is a correlation between light-to-moderate physical activity and reduced atrial fibrillation (AF) incidence and cardiovascular risk. Vigorous activities reduced the benefits and increased the risk of AF. The exact threshold at which physical activity increases the risk of cardiovascular death (CVD) in patients with AF remains to be determined.

Purpose

To determine the threshold of vigorous activity in patients with AF.

Methods

In this study, data from 23856 individuals from the Taiwan Biobank (2017) were analyzed. Physical activity levels were quantified in metabolic equivalent task (MET) hours/week and categorized into four groups based on 20 MET-hour increments. The study employed Kaplan-Meier survival analysis and an adjusted generalized additive model (GAM) to assess the impact of physical activity on CVD risk (adjusting for age, sex, diabetes, hypertension, chronic obstructive pulmonary disease, and chronic kidney disease), with follow-up data from 2017 to 2022.

Results

Over a median 5.51-year follow-up, 238 AF cases (cumulative rate of AF: 0.998%) were identified (48.7% female, mean age 61.7 years). The linear model indicated a lower CVD risk in participants engaging in moderate physical activity (20-40 MET-hours/week; adjusted hazard ratio [HR]: 0.38, 95% CI: 0.16-0.95) compared to the reference group (0-20 MET-hours/week). Notably, the GAM model demonstrated a significant increase in CVD risk for activities exceeding 40 MET-hours/week after multivariable adjustment.

Conclusions

Physical activity levels and CVD risk in AF patients are correlated in a J-shaped manner. The CVD risk of AF decreased with mild to moderate physical activity. For AF patients, it establishes a critical threshold of 40 MET-hours/week beyond which there is an increased risk of CVD, thus clarifying safe physical activity limits.Figure 1:KM sruvival curveFigure 2:Smooth model of GAM
Heart failure events prediction algorithm for patients implanted with multi-brand CIED
Authors: Varma N , Boveda S , Ibnouhsein I , Faedda G , Rosier A , Singh J
Published: May 2024

Background

Heart failure (HF) hospitalizations are associated with poor patient outcomes and generate a large burden on healthcare systems. Mitigation is a priority. Among HF patients with CIEDs, existing HF algorithm-based management solutions are manufacturer and device-specific, which imposes limitations. The SignalHF universal algorithm was developed to democratize access to HF management solutions by enabling prediction of HF decompensation based on CIED sensors data agnostic to manufacturer.

Objective

FORESEE-HF study aims to validate the SignalHF machine learning score and alerting system by matching alerts generated by SignalHF from CIED-related stored data in a universal platform (Implicity™) with HF events available in the French national health database containing medico-administrative data on patients’ characteristics, hospitalizations and deaths across 10 years.

Methods

The study cohort consisted of 19,013 patients (pacemaker (PM) 7,711, ICD 6,022, CRT-D 4,367 and CRT-P 913; age 70.0 ± 13.3, male 70.7%). Co-primary endpoints were sensitivity of HF hospitalizations detection with HF as primary diagnosis, the unexplained alert rate per patient-year defined as alert states not followed within 30 days by a hospitalization with HF as primary or secondary diagnosis (UAR PPY), and the lower quartile on alerting time defined as the lower bound on the time-to-event of 75% of true alert states (see Table 1).

Results

SignalHF for ICD/CRT-Ds demonstrated a sensitivity of 60%, a UAR PPY of 0.66 and a lower quartile on alerting time of 35 days. For PM/CRT-Ps, SignalHF demonstrated a sensitivity of 46%, a UAR PPY of 0.47 and a lower quartile on alerting time of 37 days.

Conclusion

FORESEE-HF demonstrates that SignalHF is an improvement over existing HF monitors for ICD/CRT-Ds, while also providing the same capability for PM/CRT-Ps. Being an algorithm that can be easily activated through a universal CIED remote monitoring platform, SignalHF widens the pool of patients that can benefit from HF monitoring solutions.Table 1:Study coprimary endpointsTable 2:Study results per device type
Machine-learning guided differentiation between photoplethysmography waveforms of supraventricular and ventricular origin
Authors: Manninger M , Lercher I , Hermans A N L , Isaksen J L , Prassl A J , Zirlik A , Vernooy K , Chaldoupi S M , Luermans J , Ter Bekke R M A , Kanters J K , Plank G , Scherr D , Pock T , Linz D
Published: May 2024

Aims

To test, whether a neural network-based classifier could aid in distinguishing photoplethysmographic (PPG) pulse waveforms of ventricular from those of supraventricular origin.

Methods

Thirty patients undergoing invasive electrophysiological studies for documented narrow complex tachycardias between May and December 2021 at a university medical centre were included in the trial. PPG waveforms were recorded using a PPG wristband (Empatica E4) in parallel to 12-lead surface electrograms (ECGs) and intracardiac electrograms from diagnostic catheters. Pulse waves were then annotated to either supraventricular (sinus rhythm, atrial pacing) or ventricular origin (ventricular pacing) based on invasive electrogram recordings, ECGs and stimulation protocols. 21147 data sets were split into test, training and validation data sets and used to develop, train and validate a convolutional neural network (CNN) for classifying PPG waveforms according to their origin into sinus rhythm, atrial or ventricular pacing.

Results

Datasets were complete for 27 patients. 74% were female and median age was 53 (range 18, 78) years, median BMI was 27±5, 19% had arterial hypertension, 11% had diabetes and 15% had coronary artery disease. During the electrophysiological study, typical AV-nodal re-entrant tachycardias could be induced in 63% of patients, 15% had inducible atrial tachycardias and the other patients had no inducible tachyarrhythmias. Our CNN-based classifier was able to correctly predict the origins of pulse waves in 95±1% for sinus rhythm, 96±1% for atrial paced rhythms and 95±1% for ventricular rhythms.

Conclusion

A neural network-based classifier trained on ground truth PPG data obtained by using invasive EP measurements for annotation could accurately predict atrial or ventricular origin from PPG waveforms alone.Graphical abstract
Predictive machine learning model for mechanical dilatation in transvenous lead extraction procedures
Authors: De Lucia R , Micheli A , Parlato A , Podda M , Pedrelli L , Aliprandi F , Parollo M , Segreti L , Di Cori A , Canu A , Grifoni G , Barletta V , Viani S , Zucchelli G
Published: May 2024

Background

Transvenous lead extraction (TLE) remains a procedure that requires a high level of expertise, with a doubled risk of death and clinical failure when performed in low-volume centers compared to high-volume ones (1).

Purpose

The aim of this study was to create a machine learning (ML)-based risk stratification system for predicting the need for mechanical dilatation in patients undergoing TLE due to infection.

Methods

We designed a ML-based risk stratification system trained with data from our registry to predict the need for mechanical dilatation in patients undergoing TLE for infection. An extensive evaluation of 5 different ML models (k-nearest neighbors, support vector machine, decision tree, and decision tree ensembles, such as random forest and gradient boosting machine) was conducted to identify a classifier with the highest potential to correctly predict previously unseen patients.

Results

Data to train the model was extracted from our 25-year registry of patients undergoing TLE (June 1998 – March 2023), for a total of 491 patients (77.8% male; age 69.7 ± 12.8 years) and 938 leads (ICD 21.2%; pacing 78.8%; indwelling time 61 ± 60 months) removed with success in 100% of cases. Each patient was represented by a set of 21 attributes (14 clinical, 7 device-related). Manual traction (MT) was used in 27.5% of cases, and mechanical dilatation (MD) was employed in the remaining 72.5% of cases. 5-fold nested cross validation was used to estimate performances: in turn, 393 patients were used for training and model selection, and 98 patients were used for independent testing. According to the evaluation, Gradient Boosting Machine performed best, achieving test accuracy of 89% (+/- 2% std. dev.), test sensitivity of 95% (+/- 3% std. dev.), test specificity of 73% (+/- 8% std. dev.), test AUROC of 92% (+/- 1% std. dev.). A further interpretability analysis on the best performing decision tree was conducted, showing remarkable adherence between the internal decisions taken by the model to make predictions and the current clinical practice for TLE.

Conclusion

ML models have enhanced the prediction of MD requirements in TLE procedures. This data may support the referral of patients to specialized and high-volume centers, thereby improving preoperative risk assessment.Feature importanceROC Curves
Performance of an online chat-based artificial intelligence interface for patient education on atrial fibrillation ablation
Authors: Han J , Baykaner T , Mittal S
Published: May 2024

Background

Chat-based artificial intelligence (AI) web interfaces that aim to mimic human conversation have increasing utilization in healthcare to help with simple tasks such as scheduling appointments, and even more complex tasks such as providing patient educational responses to COVID-19 questions as done by the World Health Organization.1 Chat-based AI has also been shown to provide accurate responses to cardiovascular disease prevention questions.2 Its ability to provide patient education for more complex treatments like atrial fibrillation (AF) ablation has not been explored.

Purpose

To evaluate the quality of a popular chat-based AI program’s answers to patient questions about AF ablation.

Methods

Twenty commonly asked questions ("prompts") regarding AF ablation were entered into ChatGPT (Chat Generative Pre-trained Transformer), a large language model-based AI program (Fig. 1). Prompts were written in plain language; technical terms were avoided except for "radiofrequency", "cryoablation" and "pulsed field ablation" (PFA). SMOG readability calculator was used to assess responses for difficulty and grade-level, as healthcare organizations recommend ≤ 8th-grade level complexity for patient information. Response content was graded by 3 experienced cardiac electrophysiologists as "reasonable", "missing important elements/some inaccuracies" or "misleading/inappropriate". Responses are presented in mean +/- standard deviation and percentages.

Results

Responses averaged 118±67 words (Fig. 1). Of 20 responses, 17 (85%) were deemed reasonable, 3 (15%) missing important elements/some inaccuracies and none inappropriate or misleading; 16 (80%) emphasized discussion of issues with the healthcare team (Fig. 2). Responses missing important elements/some inaccuracies were those about risks/complications of ablation [missing phrenic nerve palsy, atrioesophageal fistula (AEF), potential need for emergent cardiac surgery or pacemaker, death], concerning symptoms post-procedure (missing symptoms of hematoma, AEF, stroke), and that PFA is not yet approved for use in all regions. Average reading grade level of responses was 13.8 (college level or "professional"): 17 (85%) responses were 12th grade level, 11 (55%) were college-level or higher, and 6 (30%) were college-graduate level ("extremely difficult"). None were ≤ 8th grade level (Fig. 2).

Conclusions

A majority of ChatGPT responses to common patient questions about AF ablation had reasonable content quality that frequently emphasized the importance of discussion with the healthcare team. However, responses to more difficult questions regarding risks, symptoms of potential complications, or newer technology missed important details; more than half of responses required college-level reading skills. While use of Chat-AI for patient education on EP topics appears promising, patients should be advised to use caution. Further AI training to improve content and readability should be explored.
Machine learning approach for prediction of outcomes in anticoagulated patients with atrial fibrillation
Authors: Bernardini A , Bindini L , Berteotti M , Antonucci E , Palareti G , Poli D , Frasconi P , Marcucci R
Published: May 2024

Background

Despite the availability of different risk scores, the accuracy of actual prediction tools for outcomes in patients with atrial fibrillation (AF) remains modest [1]. Although Machine Learning (ML) has been used to predict outcomes in the AF population, evidences about outcome prediction in a population entirely on oral anticoagulation is lacking. The aim of this study is to use ML to predict outcomes in anticoagulated patients with atrial fibrillation, processing data from the Italian AF START-2 Register.

Methods and aims

Different ML models were applied to predict all-cause death, cardiovascular (CV) death, major bleeding and stroke in anticoagulated patients with nonvalvular AF. Overall population, Vitamin K Antagonists (VKA) and Direct Oral Anticoagulants (DOACs) populations were considered for the analyses.

Results

11078 AF patients (male n=6029, 54.3%) were enrolled with a median follow-up period of 1.5 years [IQR 1.0-2.6]. Patients on VKA were 5135 (46.4%), while 5943 (53.6%) were on DOACs. During the follow-up, 785 patients died, of which 169 (21.6%) due to CV causes; 240 major bleeding events were recorded, and 50 strokes occurred. Using Multi-Gate Mixture of Experts (MmoE), a cross-validated AUC of 0.779 ± 0.016 and 0.745 ± 0.022 were obtained, respectively, for the prediction of all-cause death and CV death in the overall population. The best ML model outperformed CHA2DSVA2SC and HAS-BLED for all-cause death prediction (p<0.001 for both). When compared to HAS-BLED, Gradient Boosting improved major bleeding prediction in DOACs patients compared to HAS-BLED score (0.711 vs. 0.586, p<0.001). Body mass index, age, glomerular filtration rate, platelet count and hemoglobin levels resulted the most important variables for ML prediction.

Conclusions

In patients with AF, ML models showed good discriminative ability to predict all-cause death, regardless of the type of anticoagulation strategy, and major bleeding on DOAC therapy, outperforming CHA2DS2VASC and the HAS-BLED scores for risk prediction in these populations. Anemia, platelet count, and BMI emerged as new potential risk predictors in anticoagulated AF patients. The applications of ML prediction models in clinical practice could improve the risk assessment and subsequent management of anticoagulated patients with AF.Graphical AbstractFeature importance for Bleeding in DOACs
Comparison of QT interval readings between smartwatch ECG combined with artificial intelligence and 12-lead ECG in subjects hospitalized for antiarrhythmic drug initiation and follow-up
Authors: Lefebvre B , Lehmann H I , Tordjman D , Henry C , Singh J P
Published: May 2024

Background/Introduction

Class III antiarrhythmic drugs (AADs) are effective for the maintenance of sinus rhythm (SR) in subjects with atrial fibrillation (AF). However, several require initial hospitalization for QT interval monitoring using the 12-lead ECG.

Purpose

The purpose of this study was to evaluate the feasibility of using a smartwatch single lead ECG combined with a deep learning algorithm for routine QT interval determination in the context of AAD initiation.

Methods

A deep learning model was developed using smartwatch and Holter ECG recordings to estimate corrected QT intervals. To evaluate the performance of this model, we carried out a prospective study on subjects hospitalized for initiation of sotalol and/or dofetilide. Subjects recorded near simultaneous (maximal 2 minutes apart) smartwatch ECGs (Apple Watch Series 6) and 12-lead ECG (Mac 5500 HD ECG or GE Carescape B450) right before and 2-3 hours after drug administration twice a day for 2-3 days. Blinded double annotation followed by adjudication of disagreement provided a reference heart rhythm (NSR or AF) and QTc interval. The tangent method was used for QTc interval determination. Bland-Altman analysis was performed to assess the agreement between QTc measures.

Results

Fifty subjects (mean age 67.4±10.9 years, 64% male) were enrolled in the study from February 2022 to October 2022. Out of 386 monitoring visits, 321 near simultaneous pairs of ECGs were collected with a mean delay of +15.0±41.1s for the smartwatch ECG compared to the 12-lead ECG. Overall, a mean QTcF reference value of 419.9±34.0 ms was observed (435.2±38.4 ms for QTcB, r=0.83 between annotators[BL2] ). Among the 139 pairs with 12-lead ECG found in NSR, we observed a mean QTcF difference of +19.7 ms and limits of agreements equal to -21.5 ms and 60.8 ms, with AI-facilitated measurement. In comparison, a mean QTcF difference of +22.5 ms and limits of agreements equal to -23.8 ms and 68.8 ms were observed for manual readings of smartwatch ECGs instead.

Conclusion(s): Our findings suggest that a smartwatch ECG deep learning approach can estimate the QT interval with a fair agreement compared to standard 12-lead monitoring during AAD initiation. This measurement method appears to be at least as accurate as manual measurements on smartwatch ECGs. With further validation, the smartwatch-based automatic detection of QT interval prolongation, could be used for a faster, safe, and extended outpatient QT interval monitoring.Bland-Altman plots
Remote magnetic navigation for catheter ablation of complex arrhythmias in congenital heart disease: an initial experience using a transnational telerobotic approach
Authors: Griffiths J , Shi R , Ailoaei S , Wright P , Hunnybun D , O'connor M , Kempny A , Vlachou C , Pickworth T , Keogh B , Wong T
Published: May 2024

Background

The field of congenital electrophysiology (EP) is still in its relative infacncy with a limited number of electrophysiologists capable of performing catheter ablation in patients with congenital heart disease (CHD). As a result, patients or physicians are often required to travel great distances to performed specialised ablation procedures, something made near impossible during the COVID-19 pandemic.

Objective

We aimed to explore the feasibility and safety of a telerobotic approach to catheter ablation where the remote operator was situated approximately 1200km away from the patient and local team.

Methods

A 3D-printed 'phantom' heart was used in a pilot experiment in which no significant difference was seen between the local and remote operators in electroanatomic (EAM) mapping of the phantom heart using remote magnetic navigation (RMN). Catheter ablation was subsequently performed in patients with severe CHD using a transnational telerobotic approach to catheter ablation where the remote operator was able to view the dedicated console with live fluoroscopy, EAM and EP signals, as well as control the mapping and ablation catheters from 1200km away. As a safety precaution, radiofrequency (RF) could only be delivered by the local team.

Results

In total, 10 procedures were performed in 9 patients with severe CHD (mean age 38) between April and December 2021. All patients underwent an atrial ablation and one additional non-CHD patient underwent denervation of the pulmonary arteries. Median procedure duration was 335 (minutes) (IWR 230-349) with 11.5 minutes (QRS 3-15.4) of fluoroscopy exposure and 752 (IQR 674-905) seconds of RF delivery. There were no acute procedural complications. At one-year follow-up, one patient died as a result of heart failure and there were two arrhythmia recurrences.

Conclusions

Telerobotic catheter ablation is feasible and effective and creates the possibility of exciting new approaches to remote ablation and its use in the tele-proctoring of international fellows.
From ECG to broadband ECG, focused on the ventricular activation
Authors: Jurak P , Viscor I , Halamek J , Sokup L , Plesinger F , Smisek R , Vondra V , Panovsky R , Matejkova M , Nguyen U C , Prinzen F W , Curila K , Leinveber P
Published: May 2024

Background

An ultra-high-frequency ECG (UHF-ECG) technique, recently introduced, provides ventricular activation patterns and identifies electrical dyssynchrony. UHF-ECG interpretation assumes that the ECG amplitude decreases rapidly at higher frequencies with increasing distance from the source. Based on this property, nearby sources can be distinguished. Unfortunately, this assumption has never been experimentally proven.

Purpose

The study aims to show whether there is a decrease in ECG amplitude with distance from the source and whether this decrease is frequency-dependent.

Methods

UHF-ECG resting recordings were acquired in 106 subjects. We used a standard electrode setup for a 12-lead ECG. In addition, we recorded UHF-ECG from six extended precordial electrodes. With the help of magnetic resonance images, we measured the distance of all precordial leads to the ventricular geometrical center. For each lead, we determined the amplitude of frequency components by computing the area of the averaged amplitude envelopes in the region of the QRS complex. We analyzed five frequency bands: LF (0.2-20 Hz), MF (20-80 Hz), HF (80-300 Hz), UHF1 (300-500 Hz), and UHF2 (800-1000 Hz).

Results

The left panel in the figure shows the relative amplitude decrease in five frequency bands with relative distance from the depolarization source. The decay coefficient in the LF band is only 0.56 [0.84, 0.29] median [percentile 25,75] and gradually grows up to 1.23 [1.40, 0.98] in the UHF2 band, p<0.005. It indicates that the amplitude of the ECG signal from distant areas of the ventricles in the LF band drops approximately 50 percent of the original value, and the amplitude in the UHF2 band drops to only 20 percent of the original value.

The right panel demonstrates an amplitude decrease with distance and frequency in the background of heart geometry. The circle's area corresponds to the relative signal intensity recorded in a particular body surface electrode V1, V4, and V6 from RV, LV, and septal ventricular segments. The circle marked in red has a size of 1 and is at the smallest distance from the electrode. The right panel includes the LF band (regular ECG) and the UHF2 band of 800-1000 Hz.

Conclusion

The results show significant differences in ECG signal decay between frequency bands and the ability to localize nearby sources using UHF-ECG. Verifying the principle of frequency dependence of ECG properties opens possibilities for a more accurate description of activation patterns. Combining multiple frequency bands (broadband ECG) has the potential to distinguish the activation of near and distant sources.Different decrease in ECG amplitude
Effect of atrial extrasystoles in electrophysiological properties in heart failure patients
Authors: Pereira Ferraz A , Pool L , Van Schie M , Ms De Groot N
Published: May 2024

Background

Patients with heart failure (HF) most likely have an extensive arrhythmogenic substrate which increases vulnerability to atrial fibrillation (AF). Conduction disorders underlying this increased AF vulnerability -hidden during sinus rhythm- may be unmasked by spontaneous atrial extrasystole (AES).

Objective

The aim of this study is to investigate the impact of AES on potential arrhythmogenic electrophysiological properties in patients with HF and AES.

Methods

Intraoperative epicardial mapping of the right and left atrium (RA, LA), Bachmann’s bundle (BB) and pulmonary vein area (PVA) was performed in 132 patients (10 with HF and 122 without HF). Differences in unipolar potential morphologies and conduction disorders during SR and spontaneous AES were determined.

Results

A median of 1 (1–3) AES per patient were included. In patients with HF, AES were associated with lower median potential voltages (1.94mV versus 4.02mV, P<0.001), more low voltage areas (10.98% versus 4.97%, P=0.004) and a higher number of short double potentials (28.5% versus 13.0% of short double potentials, P<0.001) compared to patients without HF. Comparing differences (AES - SR) in parameters between patients with and without HF, there was a larger increase in long double potentials (+5.32% versus +0.31%, P<0.001), fractionated potential (+4.18% versus +0.49%, P=0.001), conduction block (+3.39% versus +0.63%, P=0.002) and continuous conduction delay and block (+6.72% versus +1.74%, P=0.001) in HF patients.

Conclusions

In HF patients, AES cause lower unipolar potentials voltages and more conduction disorders than in patients without HF. Differences in arrhythmogenic properties between sinus rhythm and atrial extrasystoles are more pronounced in HF patients. These results suggest that HF patients have hidden arrhythmogenic substrates that can be uncovered by AES and may explain the increased AF vulnerability.
Increased circulating BMP10 levels are associated with late postoperative atrial fibrillation after cardiac surgery and left atrial endomysial fibrosis
Authors: Winters J , Kawczynski M J , Gilbers M D , Isaacs A , Zeemering S , Maesen B , Verheule S , Schotten U
Published: May 2024

Background

Serum bone morphogenetic protein 10 (BMP10) levels are a marker for history of atrial fibrillation (AF) and for major adverse cardiovascular events in AF-patients, including stroke, recurrence after catheter ablation, and mortality. The predictive value of BMP10 in patients undergoing cardiac surgery and association with morphological properties of atrial tissue are unknown.

Objective

To study the correlation between BMP10 levels and pre-operative clinical traits, occurrence of early and late postoperative atrial fibrillation (POAF), and atrial fibrosis in patients undergoing cardiac surgery.

Methods

Patients with and without preoperative AF history undergoing first cardiac surgery were included (RACE V, n=147). Pre-operative blood biomarkers were analyzed, left (n=114) and right (n=125) atrial appendage biopsies were histologically assessed following WGA-staining, and post-operative rhythm was monitored continuously with implantable loop recorders (n=134, 2.5yrs).

Results

Multiple logistic regression indicated that BMP10 accurately predicts a history of persistent AF (OR=1.24, 95%CI: 1.10-1.40, p=4.32e-4), similar to NT-pro-BNP. BMP10 levels were associated with increased late-POAF90 occurrence after adjusting for age, sex, AF history, and early-POAF occurrence (HR=1.07 [per 0.1ng/ml increase], 95%CI: 1.00-1.14, p=0.04). Left atrial endomysial fibrosis (St.β=0.22, p=0.04), but not overall fibrosis (St. β= , p=), was associated with circulating BMP10, after adjusting for age, sex, AF history, reduced LVF, and valvular surgery indication.

Conclusion

Increased BMP10 levels were associated with persistent AF-history, increased late-POAF incidence, and LAA endomysial fibrosis in a diverse population of patients undergoing cardiac surgery.
Association of leukocyte telomere length with cardiac conduction disease and sick sinus syndrome
Authors: Park J , Yang P S , Kim D , Sung J H , Jang E , Yu H T , Kim T H , Uhm J S , Pak H N , Lee M H , Joung B
Published: May 2024

Background

Cardiac conduction disease (CCD) and sick sinus syndrome (SSS) may be related to a degenerative process. Leukocyte telomere length (LTL) is associated with the aging process and age-related degenerative diseases. We aimed to investigate the association between LTL and the risks of CCD/SS, and to explore whether LTL is related with cardiovascular imaging and electrocardiographic (ECG) changes.

Methods

This is a population-based cross-sectional study of UK Biobank participants without history of CCD/SSS recruited from 2006 to 2010. LTL was measured using a quantitative polymerase chain reaction method. Cardiovascular measurements were derived from cardiovascular magnetic resonance using machine learning. The median (IQR) duration of follow-up was 12.0 (11.3-12.7) years. The associations of LTL with imaging and ECG measurements and incident CCD/SSS were evaluated by multivariable regression models.

Results

Among the 412,452 white participants, 188,891 (45.8%) were male, with a mean age of 57.3 years. Longer LTL was independently associated with positive cardiac remodeling, including higher left ventricular mass, larger atrial volume, and increased atrial stroke volumes. However, no significant associations were observed with ECG findings including PR interval and P-wave duration. 11991 (2.6%) participants developed CCD and 984 (0.2%) developed SSS. Longer LTL was not associated with younger age. However, longer LTL was not associated with a lower risk of incident CCD (LTL fourth quartile vs. first quartile: hazard ratio, 0.98; 95% CI, 0.97-1.0; P = 0.057) or SSS (LTL fourth quartile vs. first quartile: hazard ratio, 0.98; 95% CI, 0.92-1.05; P = 0.554).

Conclusions

In this cross-sectional study, longer LTL was associated with a larger atrial size with better atrial function in middle age, but not with ECG changes. However, longer LTL was not associated with a lower risk of incident CCD and SSS.
Clinical findings and outcomes of Brugada syndrome in women
Authors: Kruska M K , Perez J P , Wuerfel S W , Tueluemen E T , Fastner C F , Kuschyk J K , Borggrefe M B , Duerschmied D D , Akin I A , Liebe V L , Boris Rudic B R
Published: May 2024

Introduction

Brugada syndrome (BrS) is a genetic disorder characterized by typical ECG changes and association with spontaneous ventricular tachyarrhythmia (VTA) and sudden death in young patients. BrS has been widely established to be particularly prevalent in men, however less information exists regarding female patients and their long-term risk.

Objectives

The purpose of this study was to investigate the clinical characteristics and long-term prognosis of women with BrS.

Methods

This study includes a retrospective analysis of a single-center cohort of patients followed and observed for relevant clinical outcomes. The data collected included demographic data, severity of symptoms (e.g. syncope, VTA), cardioverter-defibrillator logs and occurrence of sudden cardiac death.

Results

317 patients were diagnosed with BrS between 1998 and 2023. Among those, 112 (36%) were female. At presentation, 5 patients (4%) were symptomatic with history of survived cardiac arrest and/or documented VTA. 29 (26%) had history of unexplained syncope and 78 (70%) were asymptomatic. The average age at diagnosis was 42.1±15.1 yrs. as opposed to 40.1±14.2 yrs. in men. Females presented less frequently with a type 1 ECG pattern (5% vs 21%; p<0.01), had a trend to a higher rate of family history of sudden cardiac death (31% vs 25%; p=n.s.), and had less sustained VTA during programmed ventricular stimulation (4% vs 19%; p<0.01). Genetic testing was performed in 89 females (79% of the sample) and pathogenic variants were present in 36 (40%) women. An implantable cardioverter defibrillator was inserted in 24 (31%) females for primary prevention. During mean follow-up of 138±72 months, 11 women had cardiovascular events (syncope, VT/VF or death). Syncope was most common and occurred in 8 cases. No VTA were documented in any female patient. In the group of ICD patients, 8 shocks have occurred. None of these were deemed appropriate by medical controls. There were 3 deaths. Two were considered non-arrhythmic due to pulmonary embolism and breast carcinoma. One ICD patient died suddenly during sleep. Unfortunately, no device interrogation data was available.

Conclusion

Women typically present less symptomatic and demonstrate a reduced incidence of life-threatening arrhythmias during follow-up , often experiencing a frequent occurrence of inappropriate implantable defibrillator therapy. The less frequent prevalence of the BrS ECG pattern in women adds complexity to the diagnostic process. Further studies are still needed to elucidate gender differences for risk stratification of BrS.
Association of sex with heart rate variability in atrial fibrillation patients
Authors: Hammerle P , Schier J , Schlageter V , Knecht S , Aeschbacher S , Paladini R E , Coslovsky M , Conen D , Krisai P , Osswald S , Kuhne M , Meyer-Zurn C
Published: May 2024

Background

Sex-specific differences in cardiac autonomic tone have not been thoroughly investigated in patients with atrial fibrillation (AF) but may play a relevant role.

Purpose

We aimed to investigate cardiac autonomic function of female compared to male AF patients by means of short-term heart rate variability (HRV) analysis.

Methods

In this cross-sectional analysis, we enrolled 1150 patients from the Swiss-AF cohort study with 5-minute resting ECG recordings in sinus rhythm. We calculated the following HRV parameters: HRV triangular index (HRVI), standard deviation of NN intervals (SDNN), root mean square of successive differences, mean heart rate, power in the high frequency and low frequency range. We fitted linear regression models to analyze the association between gender and HRV variables adjusted for age, intake of betablockers, hypertension, diabetes and heart failure.

Results

361 patients (29%) were female (mean age 72.9±7.8 years), 789 (68.6%) were male (mean age 69.8±8.5 years). In the multivariable adjusted models, female sex was associated with significantly lower values of HRVI (β = -0.74; 95% CI -1.44- -0 04, p=0.039) and SDNN (β = 8.95; 95% CI 0.162-17.7, p=0.046). This association persisted in all three age tertiles (<68 years, 68-75 years and ≥ 75 years of age).

Conclusions

In an elderly AF cohort, female sex is associated with reduced global autonomic activity. Whether this is associated with an adverse prognosis has to be investigated.
Morphological identification of brugada type 1 pattern using loop recorder: a feasibility study
Authors: Dinatale A , Crocamo A , Bearzot L , Gonzi G , Guidorossi A , Giacopelli D , Bassini M , Grassini D , Niccoli G , Ardissino D , Notarangelo M F
Published: May 2024

Introduction

The presence of spontaneous type 1 Brugada pattern (BP1) is associated with an elevated risk of arrhythmic events. Diagnosis of this condition is often underestimated due to its intermittent nature. While periodic ambulatory ECG monitoring can distinguish patients with pharmacologically induced patterns from those with spontaneous patterns, the diagnostic capabilities of this method are limited. Implantable cardiac monitors (ICM), designed to continuously record heart rhythm, may offer higher sensitivity in detecting patients with intermittent patterns. However, the ICM's ability to morphologically identify the ST segment elevation associated with BP1 remains uncharted.

Purpose

This study aimed to assess the ICM's capacity to morphologically identify the ST segment elevation associated with BP1.

Methods

We enrolled all patients who underwent ajmaline testing (AT) between November 2022 and September 2023 in our centre. For positive patients, the external simulator of a loop recorder was utilized to evaluate four positions (I-II left intercostal space at a 45° tilt, II-III left intercostal space at a 45° tilt, II-III right parasternal intercostal space, and II-III left parasternal intercostal space). These positions were selected to capture the trace with the most significant ST segment elevation at the J point during the peak positivity of the ECG during the ajmaline test. Measurements from the recorded traces were acquired using dedicated software.

Results

Out of 50 patients, 21 (male-to-female ratio 1.62:1, mean age 43.4±13.1 years) had a positive AT result. Seventeen patients exhibited ST segment elevation in the simulator trace during the highest ajmaline dose. Among these patients, the optimal recording position was in the I-II left intercostal space at a 45° tilt in 66.7% of cases. The median ST segment elevation recorded by the simulator was 0.9 mm (interquartile range 0.6-1.1 mm). Notably, there was no observed correlation between the extent of ST segment elevation in the ECG and that recorded by the simulator trace (Pearson linear coefficient = 0.09).

Conclusions

ICM may offer the potential to record BP1, a finding that holds significant diagnostic and prognostic implications for asymptomatic patients with pharmacologically induced BP1. Further research is needed to develop useful programming algorithms for the automatic recording of this pattern.