bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of left bundle branch block morphology in predicting response to left bundle branch area pacing for cardiac resynchronization therapy
Authors: Latorre M , Bressi E , Grieco D , Crescenzi C , Golia P , Bruni G , Fagagnini A , Politano A , Panuccio M , De Luca L , Rebecchi M , Calo L , De Ruvo E
Published: May 2024

Background

Left bundle branch area pacing (LBBAP) is a novel pacing technique with an emerging role in resynchronization therapy [1-4]. QRS morphology has shown to significantly influence cardiac resynchronization therapy (CRT) response [5-6].

Purpose

The aim of this study was to assess whether different left bundle branch block (LBBB) definitions are associated with response to LBBAP resynchronization therapy.

Methods

40 consecutive CRT candidates with previously unsuccessful biventricular (BiV) pacing or in which effective CRT could not be achieved with BiV pacing based on anatomical or functional criteria were selected for this study. Both ischemic and non-ischemic heart failure (HF) patients were included. Patients were divided into two groups according to LBBB morphology. Group 1 included 20 patients (45% ischemic HF) with strict LBBB definition according to Strauss criteria [7], while 20 patients in Group 2 (55% ischemic HF) had conventional LBBB morphology. Response to CRT was defined for (1) reduction in QRS duration; (2) increase in left ventricular ejection fraction (LVEF) ≥ 5% and (3) decrease in left ventricular end systolic volume (LVESV) ≥ 15%.

Results

LBBAP was successfully achieved in all patients (mean age: 72.0 years; male: 29). The mean baseline QRS duration before implantation was 178.6±13.8 in the Group 1 and 170.8±29.4 in the Group 2, without a statistically significant difference. Over a mean follow-up of 5.6 months, LBBAP resulted in QRS narrowing in both groups, with a greater reduction in Group 1 (-40.6 ms) compared to Group 2 (-15.1 ms), (p 0.002). Pre-implantation ventricular systolic function did not show significant differences between the two groups, with a mean of 30.1±3.5% in the Strauss LBBB group and 31.0±6.0% in the conventional LBBB group. After implantation LVEF was 42.1±8.5 % in the true LBBB patients and 33.2±7.5 in the conventional LBBB group. Echocardiographic response was observed in 65% of patients with a statistically significant difference between Group 1 (90% of responders) and Group 2 (40% of responders), (p 0,001). HF etiology did not impact the response to LBBAP CRT.

Conclusions

Strict LBBB definition is associated to a greater electrocardiographic and echocardiographic response in patients receiving LBBAP CRT compared to conventional LBBB criteria.\
His bundle pacing implantation in octogenarian patients: a substudy of the PACE-CONDUCT trial
Authors: Stangl D , Buia V , Walascheck J , Bastian D , Rittger H , Vitali-Serdoz L
Published: May 2024

Background

His bundle pacing (HBP) is gaining recognition as a valuable alternative for the management of various cardiac conduction disorders. This substudy, conducted within the framework of the PACE-CONDUCT trial, investigates the outcomes of HBP implantation in patients aged 80 years and older, comparing them with a younger cohort.

Methods

We examined a total of 61 consecutive patients who underwent HBP implantation, utilizing DDD pacemakers, CRT-P, or CRT-D devices, during the years 2021 to 2023. Patients were categorized into two subgroups: those aged younger than 80 years and those aged 80 years or older. The mean age of the entire cohort was 73 years, spanning from 51 to 86 years, with 15 patients (comprising 24.6% of the total) falling into the octogenarian category. His bundle threshold was assessed on the day of implantation, one day post-implantation, and four weeks post-implantation. All HBP implantations were deemed successful, incorporating both selective and non-selective His bundle pacing. Complications were classified as major (necessitating lead or pocket revision) or minor (requiring no revision). Threshold values were converted to volts per milliseconds (volts x milliseconds) for statistical analysis, conducted with IBM SPSS Statistics 29.0.

Results

Initial analysis revealed a consistent success rate of HBP implantation across all patients, with no discernible differences between the two age groups. Threshold measurements at the day of implantation and after one day indicated no differences between the younger and the older group. However, at the four-week mark, a statistically significant lower threshold of His bundle pacing was observed in the octogenarian group (one-sided p-value 0.028), suggesting a faster stabilization to the chronic threshold of the active fixation His Bundle lead. The comparison of major and minor complications between the age groups, conducted using chi-square tests, revealed no age-related discrepancies.

Conclusions

This substudy of the PACE-CONDUCT trial underscores the feasibility and safety of His bundle pacing implantation in octogenarian patients, comparable to their younger counterparts. While no initial threshold variations are observed, the octogenarian group demonstrated improved His bundle pacing thresholds approximately four weeks post-implantation. Importantly, the study revealed no heightened complication risk associated with advanced age, affirming that very old patients aged 80 or older can derive the benefits of His bundle pacing without increased complication rates. Given the relatively modest patient cohort in this study, further investigations are warranted to validate and extend these findings.T-tests and Chi square tests
The pursuit of gender equality: a substudy of the PACE-CONDUCT trial on gender differences in His bundle pacing implantation
Authors: Stangl D , Buia V , Walascheck J , Rittger H , Bastian D , Vitali-Serdoz L
Published: May 2024

Background

His bundle pacing (HBP) is an effective alternative to traditional right ventricular pacing, providing physiological pacing. The impact of gender on the success of HBP implantation has not been extensively explored. We conducted a substudy of the PACE-CONDUCT registry to investigate gender differences in HBP implantation success.

Methods

We analyzed successful HBP implantations performed from 2021 to 2023. A total of 61 patients were included, comprising 22 females (36%) and 39 males (64%) . The mean age of the entire cohort was 73 years, with ages ranging from 51 to 86 years. His bundle thresholds were assessed at implantation, the day following implantation, and four weeks post-implantation. All data were analyzed using IBM SPSS Statistics 29.0, and thresholds were converted into volts × milliseconds for statistical analysis.

Results

The minimal HBP threshold across all measurements was 0.10 volts × milliseconds, equivalent to a standard threshold of 0.25 volts by 0.4 milliseconds, while the maximal threshold was 7.13 volts × milliseconds, corresponding to a standard threshold of 4.75 volts by 1.5 milliseconds. Gender differences were examined, dividing the patient cohort into male and female groups, and an independent-samples t-test was conducted. The results did not reveal any statistically significant differences in HBP threshold between the two groups at the time of implantation, one day post-implantation, or one month post-implantation. Chi square tests were conducted to determine if there could be any gender differences analyzing the complication rates, also finding negative results.

Conclusion

This substudy of the PACE-CONDUCT trial found no significant gender-based differences in the success of His bundle pacing implantations, taking the threshold at implantation, one day after and four weeks after implantation as a surrogate of goodness of the HBP implantation itself. Although the cohort size was limited, our findings provide initial insights, suggesting that gender is not a decisive factor in HBP threshold outcomes or in complication rates. Further investigations with larger sample sizes are warranted to explore this topic in greater depth.statistics output
Right ventricular systolic pressure is an independent risk factor of all-cause death and inappropriate therapies in patients with implanted CRT-D
Authors: Machowicz J , Dyrbus M , Pyka Ł , Kurek A , Niedziela J , Adamowicz-Czoch E , Ostrega M , Sokola K , Pres D , Skrzypek M , Tajstra M , Gasior M
Published: May 2024

Introduction

Cardiac resynchronization therapy-defibrillators (CRT-D) are implanted mostly in patients with low left ventricular ejection fraction (LVEF) and wide QRS. In such subjects, there is often a concomitant right ventricular (RV) dysfunction, which has been associated with higher long-term mortality. However, data on the association between RV dysfunction and arrhythmic outcomes in patients with CRT-D are scarce.

Purpose

To define whether there is any association between right ventricular dysfunction and antiarrhythmic therapies or all-cause mortality in patients with HF and CRT-D.

Methods

The clinical and demographic data of patients enrolled in this study were obtained from the single-centre COMMIT-HF registry. The parameters regarding right ventricular function, such as right ventricle dimension (RVD), tricuspid annular systolic plane systolic excursion (TAPSE) and right ventricular systolic pressure (RVSP) were obtained from electronic patients’ records. The data on the long-term hard endpoints were obtained from the national healthcare provider, while the data on the risk of arrhythmic events, CRT-D shocks and antitachycardia pacing (ATP) were obtained from investigator-initiated and -adjudicated single-centre remote monitoring database updated annually. Multivariable stepwise logistic regression was used to determine independent predictors of the study outcomes, being all-cause death, and the occurrence of appropriate and inappropriate CRT-D therapies.

Results

During the period between July, 2009 and November, 2019, 335 patients were enrolled at the RM programme after implantation of CRT-D. Of them, during the median (Q1-Q3) follow-up period of 5.3 (2.8-6.6) years, (113 (33.7%) died, 111 (33.1%) received appropriate and 37 (11%) inappropriate therapies. In the multivariable analysis, the independent predictors of all-cause death were reduction in LVEF and increase in RVSP. Lower age and increased LVEDD were independent predictors of appropriate therapies, while lower age and increased RVSP were independent predictors of inappropriate therapies. No association between TAPSE and RVD and outcomes was found.

Conclusions

Among right ventricular dysfunction parameters, RVSP is an independent predictor of inappropriate therapies and all-cause death, but not of appropriate therapies in patients with HF and CRT-D.
Strauss criteria for left bundle branch block in cardiac resynchronization therapy: improved response with lower ventricular arrhythmic burden
Authors: Saplaouras A , Vlachos K , Mililis P , Batsouli A , Bazoukis G , Xydonas S , Niarchou P , Dragasis S , Kariki O , Patsiotis I , Toulgaridis F , Fragakis N , Efremidis M , Letsas K
Published: May 2024

Objectives

The study sought to evaluate the impact of the stricter Strauss criteria for left bundle branch block (St-LBBB) on cardiac resynchronization therapy (CRT) response, hospitalizations, ventricular arrhythmia (VA) events and mortality.

Background

Although left bundle branch block (LBBB) is a strong predictor of response to CRT, a significant number of patients remain non-responders.

Methods

This is a retrospective analysis of prospectively collected data on heart failure (HF) patients with LBBB admitted for CRT implantation. Patients were divided in two groups according to the fulfillment or not of St-LBBB criteria.

Results

82 patients with ischemic (ICM) and non-ischemic (NICM) HF [46 (56%) with St-LBBB and 36 (44%) with non-St-LBBB] were included. CRT response was more likely to occur in patients with St-LBBB (p<0.01), with the group of NICM exhibiting the greatest benefit (p<0.01). St-LBBB CRT responders displayed significantly lower rates of HF hospitalization (p<0.0001) compared to non-St-LBBB group. This was mostly evident in patients with NICM (p<0.0001) according to Kaplan-Meier time curves. CRT responders displayed significantly fewer VA events (p<0.001) and lower mortality rates (p<0.0001) than non-responders. Kaplan-Meier estimates demonstrated a significantly lower incidence of VAs in NICM patients with St-LBBB (p:0.049) in comparison to ICM patients with St-LBBB (p:0.25). Lower mortality rates were observed in CRT responders than non-responders (p<0.0001) with the group of NICM with St-LBBB criteria exhibiting the greatest benefit (p:0.0238).

Conclusions

Patients with NICM and St-LBBB present the greatest benefit with respect to CRT response, HF hospitalizations, VA events, and mortality. St-LBBB criteria may improve patient selection for CRT.
Deep septal pacing for pacemaker-induced cardiomyopathy
Authors: Merce Klein J , Di Marco A , Rodriguez Garcia M , Faga V , Rodriguez Garcia J , Dallaglio P , San Antonio Darhandas R , Viedma Ustariz J , Payan Jimenez C , Anguera Camos I
Published: May 2024

Background

Conventional right ventricular pacing can impair left ventricular function and cause heart failure, known as pacing induced cardiomyopathy (PICM). Upgrade to cardiac resynchronization therapy (CRT) is the most common treatment for PICM. Recently, left bundle branch area pacing (LBBAP) has emerged as a potential alternative both to conventional RV pacing and to CRT. In Deep septal pacing (DSP), a simplified alternative to LBBAP, the lead is inserted deep in the septum, does not reach the subendocardial area, but is still able to achieve narrower paced QRS than during conventional pacing.

Purpose

The aim of this study was to assess the effect of DSP in a cohort of patients with PICM.

Methods

We included consecutive patients diagnosed with PICM who were referred to our unit between January 2020 and January 2022 for a device upgrade. The aim was to upgrade patients to DSP. In the absence of terminal R wave in V1, the procedure was considered successful if a paced QRS duration ≤140 ms was obtained. Clinical and device follow-up were performed one and 6 months after the procedure, and echocardiography at 6 months. The study was approved by the Clinical Research Ethics Committee and all patients signed informed consent.

Results

Fifteen patients were recruited during the study period. One patient was excluded because a QRS ≤ 140 ms could not be achieved, and 2 other patients because a terminal R wave in paced QRS in V1 was obtained. The characteristics of the 12 included cases are detailed in Table 1. The mean LVEF was 33% (SD 4%) and the mean percentage of RV pacing was 99% (SD 1%). All patients had symptomatic heart failure.

Non stylet-driven electrodes were used in 8 of the 12 patients. Acute threshold was < 1V - 0’4 ms in all, and remained stable during follow-up. No procedure-related complications or lead dislodgements were detected. The mean paced QRS duration with RV pacing was 172 ms (SD 14 ms) whereas after the upgrade it was 130 ms (SD 7 ms). As compared to RV pacing, DSP was associated with a significant reduction in paced QRS duration (mean difference 41 ms, p<0.001).

As shown in Table 1, after DSP all patients except one (11/12, 92%) experienced an increase in LVEF of at least 10%; five patients (42%) achieved an LVEF>50%. The mean LVEF after the upgrade was 46% (SD 9%). The mean improvement in LVEF with DSP was 13% (SD 10%).

Conclusions

In patients with PICM, deep septal pacing achieves narrower QRS as compared to RV pacing and is associated with a significant improvement in LVEF. Deep septal pacing might be an effective and simpler alternative to biventricular or left bundle branch pacing in patients with PICM.Table 1
Real-time assessment of LV synchrony in AV block population undergoing LBB pacing using ECG Imaging
Authors: Martinez-Perez M , Pujol-Lopez M , Regany-Closa M , Pellicer-Sendra B , Molero R , Borras R , R Graterol F , Reventos-Presmanes J , Serrano-Campaner J , Roca-Luque I , Guasch E , Climent A M , Guillem M S , Tolosana J M , Mont L
Published: May 2024

Background

Left bundle branch pacing (LBBP) may prevent right ventricular (RV) pacing-induced dyssynchrony (DYS). Nowadays, real-time assessment of DYS correction is indirectly measured with QRS narrowing. Non-invasive ECG imaging (ECGI) technique may provide an evaluation of electrical resynchronization based on quantitative assessment of ventricular local activation time (LAT) maps.

Purpose

To assess whether real-time ECGI could evaluate LV synchrony achieved through LBBP, in a consecutive AV block (AVB) population.

Methods

A cohort of 12 patients with AVB were included. ECGI was performed during the implant procedure. ECGI signals were computed using an artificial intelligence derived cardiac geometry model. Ventricular LAT maps were obtained when pacing from septal RV and with LBBP (lead placed according to guidelines ECG criteria) for each of the patients.

The following parameters were obtained from ECGI LAT maps to assess intra and interventricular DYS pacing at the RV septal and LBB locations: total activation time (TAT), left ventricular activation time (LVAT), left ventricular dyssynchrony index (LVDI), ventricular electrical uncoupling (VEU = mean LVAT – mean RV activation time) and histogram overlap between LV and RV activation times distribution.

RESULTS: Nine of the 12 patients were men (75%), with a median age of 79[Q1 75-Q3 82]. QRS duration during RV septal pacing was 150 ms [138-172]. Median LVEF was 47% [26-59]. In Figure 1, it can be observed that dyssynchrony variables are corrected across all patients when reaching LBBP. Figure 2 shows activation maps during RV septal pacing and during LBBP, along with the QRS duration, and the RV and LV histogram of activation times.

Conclusion

ECGI is useful for assessing the LV synchrony correction during LBBP in an AV block population.Dyssynchrony variablesActivation maps with QRS and histograms
Optimal timing of of cardiac implantable electronic device reoperation
Authors: Schvartz N , Haidary A , Operhalski F , Hecker F , Zsigmond E J , Miklos M , Saghy L , Szili-Torok T , Erath J W , Vamos M
Published: May 2024

Background

Early re-intervention may increase the risk of infection of cardiac implantable electronic devices (CIED). Some operators therefore delay lead repositioning in case of dislocation by weeks, however there is no evidence to support this practice. The aim of our study was to evaluate the impact of the timing of re-operation on infection risk.

Methods

Data from consecutive patients (n=249) receiving lead/generator repositioning in one Hungarian and one German tertiary centre between January 1995 and August 2022 were retrospectively analysed. Relative risk of CIED infection in the first year was compared among patients undergoing early (≤1 week) vs. delayed (from 1 week to 1 year) re-operation.

Results

Out of 249 patients (mean age 70 ± 13 years, 54% male) requiring CIED re-intervention (30% single-chamber, 48% dual-chamber, and 22% CRT devices), 55 patients underwent right atrial (22%), 145 patients underwent right ventricular (59%), 20 patients underwent coronary sinus (8%), and 28 patients underwent multiple lead (11%) repositioning. Eighty-five patients (34%) went through an early (median 2, interquartile range (IQ): 1-4.5) and 164 (66%) patients had a delayed lead/pocket revision (median 53, IQ 36-209 days).

A total of 9 (3,6%) wound/device infections were identified during the first year of follow-up, 1 (1,2%) vs. 8 (4,9%) in the in the early vs delayed groups. The risk of infection was numerically lower in the early vs. the delayed intervention groups yielding no statistically significant difference (OR=0.232; 95% CI 0.029-1.888; p=0.172). After adjustment for typical risk factors for CIED infection (i.e., number of implanted leads, diabetes, heart failure, fever prior to implant, therapy with corticosteroids, anticoagulation or antiplatelet therapy, temporary pacemaker) this difference remained non-significant (adjusted OR=0.266, 95% CI 0.032-2.246, p=0.224). System explantation/extraction was necessary in 7 cases (2,8 %), all being revised in the delayed group (OR early vs. delayed 0.128, 95% CI 0.01-2.273, p=0.161).

Conclusion

In this bicentric study, delayed re-intervention did not reduce the risk of CIED infection compared to patients undergoing an early (<1 week) re-operation.
The CHOIR study: acute hemodynamic effects of different pacing strategies in hypertrophic obstructive cardiomyopathy
Authors: Ahmed T , Ross S , Helle-Valle T , Gude E , Holm T , Andreassen A K , Broch K , Ravnestad H , Flattum M , Almaas V , Russel K E , Edvardsen T , Kongsgaard E , Stokke M K , Dejgaard L A
Published: May 2024

Background

The majority of patients with hypertrophic cardiomyopathy present with dynamic left ventricular (LV) outflow tract obstruction (LVOTO), referred to as hypertrophic obstructive cardiomyopathy (HOCM). Symptomatic treatment aims at reducing LVOTO with either medical therapy, invasive septal reducing therapies, or pacemaker therapy. There is conflicting evidence regarding the efficacy of pacemaker therapy. The effect of pacing strategies at physical exertion has not been investigated in HOCM.

Purpose

To identify the optimal pacing strategy for reducing LVOTO without compromising cardiac output at rest and exercise in HOCM.

Methods

In this ongoing project, we have so far included eight patients with symptomatic HOCM referred to our hospital for alcohol septal ablation (ASA). The day before ASA, we placed temporary pacing leads in the right atrium, the right ventricular (RV) apex and on the LV lateral wall. We also inserted a pulmonary artery catheter and performed per operative echocardiography. All patients had sinus rhythm. Intrinsic rhythm served as baseline and was followed by atrial sensed RV pacing, LV pacing and biventricular (BiV) pacing at rest and during supine cycling. We assessed LVOTO by echocardiography, and cardiac output by the thermodilution method under intrinsic rhythm and all pacing modalities.

Results

The mean age was 52±15 years, and two of eight patients were female. The mean maximal LV wall thickness was 16±1 mm. The resting LVOTO was 50±23 mmHg. Due to difficulties in placing the LV lead within a reasonable time frame, complete study protocol was not performed in all patients. All eight patients performed RV pace at rest, but only five patients (63 %) were LV and BiV paced at rest. Five patients performed supine cycling but only four patients completed with RV and BiV pacing. The graphs display LVOTO and CO in sinus rhythm and the different pacing maneuvers at rest and during supine cycling. At rest, 6 out of 8 patients (75%) had LVOTO reduction during RV pace, and CO was unchanged. Four of five patients (80%) had LVOTO reduction during BiV and LV pace compared to sinus rhythm, also with unchanged CO. During supine cycling four of five patients (80%) had a reduction of the LVOTO gradient during RV and BiV pacing, without significant CO change. No complications occurred during the interventions.

Conclusion

In this ongoing study on cardiac pacing in HOCM, RV, LV, and BiV pacing reduced LVOTO while CO remained unchanged at rest and during exercise.
Additional factors associated with sudden cardiac death in HCM patients
Authors: Butko O , Tseluyko V
Published: May 2024

Background

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease characterized by an increase in the thickness of the left ventricular (LV) wall, which is not explained only by abnormal loading conditions. Sudden cardiac death (SCD) is the most devastating complication of HCM occurring in asymptomatic or younger patients without warning.

Purpose

To evaluate additional SCD risk factors in Ukrainian population of HCM patients.

Materials and methods

We retrospectively evaluated 350 consecutive HCM patients that were followed from 2006 to 2021 in our Cardiological Department. General clinical examination, standard 12-lead ECG, transthoracic echocardiography and 24 hours Holter ECG monitoring data were estimated. The 5-year SCD risk was calculated according to the HCM Risk-SCD score.

The endpoint of the study was SCD and its surrogates, including adequate performance of the implantable cardioverter-defibrillator and successful resuscitation.

Results

Follow-up time was 5.0 (1.5-9.5) years. During this time, 16 patients (4.6%) reached the end point, which was 0.9%/year. According to the HCM Risk-SCD score, 5 (31.3%) of this group had a high risk of SCD (≥ 6%) and 3 (18.8%) had an intermediate risk (≥ 4% and < 6%).

In multivariable Cox regression analysis adjusted for conventional SCD risk factors it was found that independent predictors of SCD were unexplained syncope (HR 3.81, 95% CI 1.11-13.12, p=0.034), systolic blood pressure (SBP) (HR 0.97 , 95% CI 0.94- 0.99, p=0.026), "infarct-like" ST elevation on ECG (HR 6.81, 95% CI 2.09-22.16, p=0.001) and PQ interval duration (HR 1.03, 95% CI 1.01-1.05, p=0.002), Harrell's C-index 0.84, 95% CI 0.73-0.95, p < 0.0001).

Conclusions

In our study HCM Risk-SCD score predicted SCD or surrogates only in 50% of cases. In order to improve the risk stratification some additional independent predictors of SCD can be proposed. ECG parameters ("infarct-like" ST elevation and PQ interval duration) and level of SBP were found to have SCD predictive value.
Prediction of Atrial Fibrillation with Single-Lead Mobile ECG during Normal Sinus Rhythm using Deep Learning
Authors: Lee K H , Kim Y R , Yoon N S , Park H W
Published: May 2024

Background

Single-lead ECG (electrocardiogram) acquisition from mobile devices provides more convenient way to identify arrhythmia. Prediction of atrial fibrillation (AF) by artificial intelligence facilitates AF screening. However, little is known about the prediction of AF with a single-lead ECG. Therefore, we proposed a method for predicting AF using single-lead mobile ECG during normal sinus rhythm (NSR).

Methods

Three deep learning models RNN, LSTM, and Resnet50 were used. Out of 13,509 ECGs from a total of 6,719 patients, we utilized a total of 10,287 NSR ECGs from 5,170 patients. Single-lead mobile ECGs were adjusted with noise filtering and segmented every 10 seconds. A random under-sampling was applied to reduce bias from data imbalance. Finally, 31,767 ECG segments composed of 15,157 segments labeled as potential AF and 16,610 segments labeled as healthy were entered for final analysis.

Results

The ResNet50 showed recall of 79.3%, precision of 65.8%, F1-score of 71.9%, accuracy of 70.5%, and AUC of 0.79 for the prediction of AF with NSR ECGs. These scores were higher than the other two models followed by RNN at 0.75 and LSTM at 0.74. For the external validation set, ResNet50 showed an F1-score of 64.1%, recall of 68.9%, precision of 60.0%, accuracy of 63.4%, and AUC of 0.68 for the prediction of AF with NSR ECGs.

Conclusion

A deep learning model using a single-lead mobile ECG during NSR predicted AF at risk in future. However, further study is needed to improve the performance of deep learning models for applying in the clinical setting.
Machine learning for outcome prediction of atrial fibrillation recurrence after catheter ablation
Authors: Knecht S , Cyriac J , Badertscher P , Krisai P , Schlageter V , Osswald S , Zellweger M , Kuhne M , Sticherling C
Published: May 2024

Background

Outcome prediction after catheter ablation for atrial fibrillation (AF) based on electronic health records (EHR) using machine learning (ML) is not yet established.

Purpose

The aim of the study was to assess the value of ML methods to predict the risk of AF recurrence after catheter ablation based on easily accessible EHR.

Methods

We analyzed 1362 patients from our prospective registry. Only patients undergoing a first AF ablation were studied. Follow-up was performed at 3, 6 and 12 months after the ablation including 24-hour and 7-day Holter electrocardiogram (ECG). Four different analyses with increasing complexity out of a set of overall 22 features using seven simple and three ensemble method ML algorithms were performed: model 1 (including age, sex, height, weight, and established anamnestic risk factors: AF-type, coronary artery disease, myocardial infarction, stroke, heart failure, hypertension, current smoker, diabetes, renal insufficiency), model 2: model 1 plus additional AF-history features (duration of AF in months, previous typical atrial flutter, number of previous electrical cardioversions, number of failed antiarrhythmic drugs), model 3: model 2 plus simple echocardiographic parameters (left ventricular ejection fraction, LA diameter), model 4: model 3 plus biomarkers (CRP, creatinine, NTproBNP). To evaluate the performance of the prediction, we report C-statistics, accuracy, and recall (sensitivity). The C-statistics of five risk scores for AF recurrence (APPLE, DR-FLASH, BASE-AF2, ATLAS, CHA2DS2-Vasc) and a logistic regression with a forward selection were calculated for comparison.

Results

Of the 1362 patients, 996 (73%) were male, mean age was 62±10 years and 60% presented with paroxysmal AF. Recurrence of AF during 1-year follow-up was observed in 458 patients (34%). The results for the four models using the eleven different ML algorithms are summarized in the Figure. In detail, the C-statistics were modest with a maximal value of 0.602 for the random forest (RF) classifier for the most complex model 4. The performance for the risk scores was maximal for the APPLE score (C-statistics 0.572) and comparable for the forward-selection logistic regression including five features with a C-statistics of 0.607 (95% CI 0.573-0.641).

Conclusion

In conclusion, outcome prediction of AF recurrence after catheter ablation with easily accessible EHR data remains challenging and cannot be improved simply by applying machine learning methods. Whether a more comprehensive feature selection, such as more complex ECG parameters instead of the selection of easily available features from the EHR, a combination with deep neural network-based feature extraction, or unsupervised ML might improve the result in a clinically relevant way needs further investigation.Results of the eleven ML algorithms
Can prediction of acute myocardial infarction using a deep learning-enabled electrocardiogram be used in real-world practice?
Authors: Jung L , Kim D H , Kim S H , Jun H M , Trinh M C
Published: May 2024

Background

Diagnosing acute myocardial infarction (MI) in the emergency department poses challenges. The utilization of a 12-lead electrocardiogram (ECG) is pivotal for detecting ST-segment elevation myocardial infarction (STEMI), yet enhancing ECG interpretation through a systematic algorithm could significantly improve diagnostic accuracy. Nonetheless, delayed diagnosis or misdiagnosis of STEMI is not uncommon in daily practice.

Purpose

This study aims to develop a fully convolutional network (FCN) based on ECG data as a diagnostic support tool and to evaluate its effectiveness in STEMI detection.

Methods

A retrospective cohort study involved 3,298 patients with angiographically confirmed STEMI and 37,393 control ECGs, comprising normal readings, false positives, and ECGs mimicking STEMI. The FCN underwent internal training, external validation, and testing across various data splits (80:10:10, 70:15:15, and 60:20:20). Performance evaluation on validation data included assessing the area under the receiver operating characteristic curve (AUC). Subsequently, the trained model predicted unseen data, and sensitivity, specificity, false positives, and false negatives were calculated to evaluate model performance.

Results

The FCN exhibited exceptional performance in STEMI detection during both internal training and external validation across different data splits. The receiver operating characteristic curves yielded AUC values of 0.995 (80:10:10), 0.994 (70:15:15), and 0.995 (60:20:20). Consistently high values were observed in precision-recall curves, with AUC values of 0.974 (80:10:10), 0.962 (70:15:15), and 0.973 (60:20:20). When utilizing this FCN model in the clinical setting to reanalyze 20 cases of previously misdiagnosed electrocardiograms, it correctly diagnosed 17 cases.

Conclusion

Integrating the FCN into clinical practice can notably improve the timely and accurate diagnosis of acute MI, reducing instances of delayed or erroneous STEMI diagnoses and facilitating prompt reperfusion therapy.
Repolarization dynamics stability in Brugada type-1 pattern subjects with positive and negative genetics
Authors: Sabatini A , Pellegrini N , Varriale A , Piccolo S , Capocci S , Tomasi L , Mugnai G , Tomei R , Franchi E , Ribichini F , Bolzan B
Published: May 2024

Background

Brugada type-1 pattern (Brgd1) risk stratification in asymptomatic subjects and its repolarization dynamics are complex.

Purpose

This study aims to analyze, from alternative standpoints, superficial 12-lead ECG V1 repolarization patterns (repol.). This method diverges from standard ECG pattern characterization. It rather exploits nonlinear dynamics and stability of ECG repol. to assess stability driving cardiac dynamics. This work consists in analyzing 2 subjects with Brgd1: Subject1 with negative genetics and negative EP study. Subect2 with positive genetics.

Target

To deepen knowledge/insight and applications of control-and-stability-theory applied to 12-lead ECG, aiming to eventually diminish the number of invasive EP studies.

Methods

A stability control closed loop system has been designed to model electrophysiology dynamics of cardiac conduction: ECG segments being the input-output of the system. (Figure). A sequence of V1 repol. have been scanned, digitized, and quantitatively processed yielding stability parameters (poles in S-plane). Scanning and signal processing performed by Matlab R_2023b.

Results

Figures.

Conclusions

Based on our data, 12-lead-ECG repol. seem to be associated with increasing stability in Subject1, exhibiting negative genetics. On the other hand, less stability seems to be associated with Subject2, reporting positive genetic tests.

In conclusion, furthering control-and-stability-theory applied to 12-lead ECGs aims to deeper comprehension of physiological and pathological substrates of malignant arrhythmias, and to focus on noninvasive risk stratification strategies for ICD implantation indication in BrS.

Further development of this technique will be largely facilitated by the implementation of AI methodologies in the near future.
Usability of novel beat-by-beat ECG annotation software portal for generating large-scale machine learning training datasets
Authors: Navara R , Mchugh W , Pallod A , Raj K , Sinha A , Deshpande M , Wang Y , De S , Deleon R , Bolaji O , Asfaha D , Okoroanyanwu S , Paudel B , Manohar R , Patel K
Published: May 2024

Introduction

Despite the availability of numerous large publicly available ECG datasets, there is a distinct absence of specialized software to enable the beat-by-beat annotation and labeling, limiting the ability to generate high-quality machine learning training datasets. This study analyzed the usability of such a novel software interface. Through a survey of several cardiologists and clinic staff, several metrics were gauged, including user satisfaction, system and app simplicity, user interface, and effectiveness. The survey results gleaned insight into the users’ experiences, providing an understanding of the software’s user-friendliness and potential in developing a large-scale machine learning annotated ECG training dataset to advance cardiac health research.

Methods

3 cardiology physicians, and 9 cardiac telemetry unit staff were surveyed following use of the SafeBeat Annotation Software Platform to annotate a large publicly available dataset ECGs (n=10,646) beat-by-beat. The validated Post-Study System Usability Questionnaire (PSSUQ) and mobile Health App Usability Questionnaire (MAUQ) were used to assess the overall usability of the software interface. Results are reported as mean ± standard deviation.

Results

Users completed 10,646 ECG beat-by-beat annotations in 62 days, and averaged 164.0 ECGs per day. Physicians rated the software interface highly, with an overall mean PSSUQ of 6.4 ± 0.8 and MAUQ of 6.4 ± 0.7. Staff also rated the software interface highly, with an overall mean PSSUQ of 6.7 ± 0.6 and MAUQ of 6.8 ± 0.5. Overall 92% of the users reported that they strongly agreed they would use the application again and 83% strongly agreed that it was easy to learn how to use the system.

Conclusion

The usability analysis of this novel beat-by-beat ECG annotation software revealed that it was a highly effective tool for both cardiologists and clinic staff. Both the system and app were reported to be simple to learn, comfortable to use, and easily navigable. With most users responding that they could become productive quickly using this system, there is clear potential for it to be used to develop a large-scale machine learning dataset.Figure 1
Quantitative and qualitative assessment of left atrial cardiomyopathy as well as prediction of atrial fibrillation recurrences upon PVI using machine learning
Authors: Bock M , Tanacli R , Alogna A , Fassina L , Dagres N , Hindricks G , Gerds-Li J H , Hohendanner F
Published: May 2024

Introduction

Atrial fibrillation (AF) is one of the most common heart pathologies in daily clinical practice and confers significant mortality and morbidity. However, AF ablation often proves ineffective - even after successful pulmonary vein isolation (PVI). The prediction of PVI failure for the long-term treatment of AF as well as the improved assessment of the underlying substrate appears pivotal. We hypothesize, that ML can be applied to better characterize the substrate and recurrence in AF patients upon PVI.

Methods & Results

We retrospectively evaluated data from 205 patients that underwent AF ablation between 2019 and 2023, including high-density 3D electroanatomic maps (sinus rhythm), LA rotational angiography, invasive LA hemodynamic measurements (after transseptal passage), echocardiography, 12-lead ECG and laboratory testing. A neuronal net was trained on selected features extracted from those datasets using supervised learning and employed to predict measures of atrial cardiomyopathy and AF recurrence.

Patients were 66±1 years old and received first or second pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation with 18% documented recurrences upon a mean follow-up of 23±1months. First, we extensively refined or developed tools for automated P-wave analysis from 12-lead ECGs as well as local LA voltage and volume quantification. Next, LA hemodynamics and volumes were assessed: Mean LA volume as derived from rotational angiography significantly correlated with LA volume index as obtained using echocardiography. Interestingly, LA size showed no correlation with NT-proBNP, LA low voltage or LA hemodynamics. In addition, global (25±2% of total LA area) and local (i.e. anterior, posterior, roof) LA voltage was determined and shown to be an independent predictor of AF recurrence. In our first unselected subset of 136 patients with 2nd PVI for atrial fibrillation, our ML models predicted LA fibrosis (i.e. low voltage regions; Utah stage) from 12-lead ECGs with an accuracy of 90%. Accuracy was 87% for the prediction of AF recurrences from LA pressure and low-voltage regions. In addition, the algorithm predicted AF recurrences from 12-lead SR ECGs obtained before PVI with an accuracy of 91%.

Conclusion

Artificial neural networks allow to quantitatively and qualitatively predict measures of atrial cardiomyopathy and atrial fibrillation recurrence probability upon complete PVI with high accuracy.Figures
Cost-effectiveness of atrial fibrillation detection with insertable cardiac monitors in large-artery or small-vessel disease stroke in the United Kingdom
Authors: Witte K K , Schwamm L H , Bernstein R A , Reynolds M R , Rose D Z , Lip G Y , Ozturk E , Villinger J , Rosemas S C , Ziegler P D , Yaghi S
Published: May 2024

Background

The randomised STROKE-AF trial demonstrated clinical effectiveness of continuous cardiac monitoring to detect atrial fibrillation (AF) with insertable cardiac monitors (ICMs) for patients with ischemic stroke attributed to large-artery or small-vessel disease (LAD/SVD). ICMs were ten-fold more effective at detecting AF compared to the standard of care (SoC). However, cost-effectiveness of this monitoring strategy is unknown.

Purpose

The aim of this economic evaluation was to assess the cost-effectiveness of long-term continuous cardiac monitoring via ICMs, for detection of AF (and, in event of AF diagnosis, subsequent anticoagulation), in patients with ischemic stroke attributed to large-or-small vessel disease compared to the SoC of conventional follow up in the United Kingdom.

Methods

We constructed a Markov model with a cycle length of three months and a lifetime horizon to conduct the cost-effectiveness analysis, from the National Health Service (NHS) perspective. Costs and health-related benefits were discounted at an annual rate of 3.5%. We expressed outcomes in terms of quality-adjusted life-years (QALYs). Patient characteristics in the analysis and detection probabilities were based on the STROKE-AF trial. Detection of AF resulted in a switch in treatment from antiplatelet to direct oral anticoagulant (DOAC). Risk of cerebrovascular events were dependent on a patient’s AF detection status and subsequent treatment. Scenario, deterministic, and probabilistic sensitivity analyses were conducted to test the robustness of the base-case incremental cost-effectiveness ratio (ICER) and account for uncertainties in the model. We stratified patients into risk groups based on CHA2DS2-VASc scores and risk of AF detection.

Results

The base case incremental cost-effectiveness ratio of the implantation of an ICM was £15,485 per QALY, substantially under the NICE willingness-to-pay threshold of £20,000-£30,000 per QALY. ICM implantations resulted in 0.139 QALYs gained per patient at an incremental cost of £2,147. There were 0.054 fewer stroke events per patient in the ICM arm versus SoC. Results were robust under sensitivity analysis.

Conclusion

ICMs were cost-effective compared to SoC for detection of AF in patients with LAD/SVD stroke in the United Kingdom driven largely by more stroke events avoided. Subgroup analysis showed that ICMs were more cost-effective in patients with higher CHA2DS2-VASc scores and those with a higher individual risk of AF.Markov Model SchematicSummary ICER Results and Events avoided
Association between leukocyte telomere length and heart failure hospitalization based on the presence of the atrial fibrillation
Authors: Lee Y , Yang P S , Jang E S , Kim D , Yu H T , Kim T H , Uhm J S , Sung J H , Pak H N , Lee M H , Joung B
Published: May 2024

Leukocyte telomere length (LTL) is a well-established biomarker linked to cardiovascular disease, with shorter LTL associated with increased severity of heart failure (HF) outcomes. It is also well known that atrial fibrillation (AF) and HF are closely related and often coexist. This study explores the relationship between LTL and hospitalization due to HF, considering both AF and non-AF patients within the UK Biobank cohort. Retrospective analysis of the UK Biobank dataset (n=451,552, mean age 57.0±8.1 years, 45.8% male) excluded individuals with pre-existing HF (n=12,162) and extreme/no LTL data (n=36,829). LTL was quantified using multiplex quantitative polymerase chain reaction. Among 445,895 participants without AF at enrollment, 2,851 were hospitalized for HF (mean age 63.1±5.8, 63.3% male), while 313 with AF (mean age 64.3±5.3, 68.4% male) experienced HF hospitalization. Shorter LTL correlated significantly with HF hospitalization in both non-AF (826.8±117.7 vs 797.9±115.5, P < 0.001) and AF groups (804.8±116.1 vs 789.2±115.9, P < 0.001). Categorized into quartiles, shorter LTL consistently associated with higher HF hospitalization rates in both non-AF (P for trend < 0.001) and AF groups (P for trend = 0.022). Adjusting for age, sex, and cardiovascular risk factors, longer LTL correlated with reduced HF risk (HR, 0.87; 95% CI, 0.77-0.98; P = 0.017), independent of AF presence (P for interaction=0.629). This study establishes an association between shorter LTL and increased HF hospitalization rates, regardless of AF presence. These findings underscore the significance of LTL as a potential prognostic biomarker for HF, emphasizing its relevance in both AF and non-AF populations
Senolysis ameliorates increased susceptibility to ventricular arrhythmias in prediabetes
Authors: Angendohr S , Zoehner C , Duplessis A , Amin E , Polzin A , Dannenberg L , Schmitt J , Srivastava T , Bejinariu A , Rana O , Spieker M , Kloecker N , Kelm M , Gerdes N , Lang A
Published: May 2024

Background

Obesity and associated prediabetes are major risk factors for cardiovascular disease that promote cellular senescence and predispose to ventricular arrhythmias (VA). In consequence, targeting cellular senescence may represent a feasible therapeutical approach that can decrease VA susceptibility in aged hearts. The aim of the present study was to characterize the impact of senolysis on glucose control, left ventricular function (LVF) and VA susceptibility in a prediabetic mouse model.

Methods

Ten – 12 week-old C57Bl/6J mice were fed a high-fat diet over a period of 12 weeks to generate diet-induced-obesity (DIO). Afterwards, mice were treated with dasatinib (5 mg/kg) and quercetin (50 mg/kg) (DQ) or vehicle (10 % DMSO) by oral gavage three times in 7 days. Cardiac senescence was assessed by measuring Cdkn1a mRNA expression levels. Glucose control was monitored by glucose tolerance testing. LVF was evaluated by echocardiography and myocardial contractility was assessed by sarcomere length measurements in paced single cardiomyocytes. VA susceptibility testing was performed by programmed ventricle stimulation combined with an epicardial fluorescence imaging of the LV anterior wall in isolated hearts. VA susceptibility was quantified by an established scoring system.

Results

Cardiac senescence, as assessed by expression of Cdkn1a mRNA (encoding p21), was increased in DIO mice (P=0.0004, Figure 1A), whereas DQ reduced cardiac senescence (P<0.0001, Figure 1A). Glucose control was impaired in DIO mice (P<0.0001) and could be partially restored by DQ (P=0.003). LVF was ameliorated by DQ in DIO mice (P=0.018). In agreement, contractility in single cardiomyocytes was improved (Amplitude of sarcomere contraction: P=0.0003, figure 1B; speed of sarcomere contraction: P=0.046). VA susceptibility was increased in DIO mice (number of inducible VAs: P=0.001, figure 1C; VA score: P=0.0002; VT inducibility: P=0.001) whereas DQ limited VA susceptibility (number of induced VAs: P=0.004, Figure 1C; VA score: P=0.004; VT inducibility: P=0.025) in isolated hearts.

Conclusions

Our findings demonstrate that senolysis ameliorates glucose tolerance and LVF while reducing VA susceptibility in obesity and prediabetes. In consequence, senolysis may offer a perspective therapeutical approach for obese patients at risk for VAs. Further experiments will address underlying molecular mechanisms to identify potential therapeutical targets.