bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical characteristics of deep septal vs. left bundle branch (area) pacing
Authors: Heckman L.I.B , Luermans J , Weijs B , Van Stipdonk A.M.W , Mafi-Rad M , Prinzen F , Vernooy K 
Published: November 2020

Abstract

Background/Introduction
Recent studies have described transvenous left bundle branch (LBB) pacing as a new conduction system pacing strategy. However, information on effect of pacing depth within the septum and the additional effect of LBB capture is unknown.

Purpose
To investigate the relation of electrocardographic characteristics with transseptal LV lead implantation depth and LBB capture.

Methods
20 consecutive patients referred for pacemaker implantation were enrolled. The right atrial (RA) lead was positioned according to routine practice. The LV septal pacing lead (Medtronic 3830) was transvenously positioned against the right side of the interventricular septum and advanced in small steps of 1–2mm towards the left side of the septum. At each depth in the septum 12-lead ECG's were recorded during pacing, from which vectorcardiograms (VCG) were calculated. QRS duration and QRS area were measured, the latter being the integral of the QRSarea in X, Y and Z directions. Successful LBB capture was defined as paced right bundle branch block (RBBB) morphology, stable and short stimulus to LV activation time (LVAT; R in V5) and recorded LBB potential.
Differences were compared among pacing conditions using repeated measures ANOVA with Bonferroni multiple comparisons procedure applied to pairwise comparisons. Statistical significance was assumed at p&lt;0.05.

Results
LV septal lead implantation was successful in all patients. Left bundle branch capture was achieved in 10/20 patients (50%). Post-procedural LV pacing threshold, impedance and sensing was 0.7±0.1 V at 0.5 ms pulse width, 658±5 Ω and 13±10 mV, respectively. Compared to intrinsic rhythm, QRS duration was significantly increased by both RV septum (RVS; 124±5 vs. 161±3 ms) and LV septum pacing (LVS; 142±3 ms).
QRS area increased significantly during RVS pacing as compared to intrinsic rhythm but decreased when moving from RVS to LVS to values close to intrinsic rhythm (panel A & B). LVS-pacing derived QRS area was significantly lower in patients with LBB capture (36±6 mV*ms) compared to patients without LBB capture (deep septal pacing; 46±12 mV*ms).
The reduction in QRS area between RVS and LVS pacing coincided with normalization of the QRS vector in the transverse plane (panel C), which is characterized electrocardiographically by predominantly negative-to-positive inversion of the QRS complex in the precordial leads (V1-V3).

Conclusions
Compared to RV septal pacing, LV septal pacing restores ventricular electrical synchrony, as determined by QRS area, and normalizes the activation vector in the transverse plane to a level comparable to intrinsic rhythm. Differences in resynchronization between left bundle branch pacing and deep septal pacing are small.
LBBAP restores ventricular synchrony

Funding Acknowledgement
Type of funding source: None
Device-device communication stability of leadless anti-tachycardia pacemaker and subcutaneous implantable cardioverter defibrillator over 18 months
Authors: Tjong F.V.Y , Knops R.E , Swackhamer B , Koop B , Soltis B , Brisben A , Carter N , Burke M 
Published: November 2020

Abstract

Background
A novel modular cardiac rhythm management (mCRM) therapy approach is evaluated in this study: the performance of an anti-tachycardia pacing enabled leadless pacemaker (LP) commanded by a subcutaneous-ICD (S-ICD) via wireless, intra-body, device-device communication (DDC).

Objectives
To investigate long-term DDC performance of linked S-ICD to LP (mCRM System) and factors that impact DDC performance.

Methods
The mCRM System was implanted in 37 canine subjects: 33 with an S-ICD and an LP; 4 with an S-ICD and 2 LPs. The S-ICD was implanted using a Parsonnet pouch in the first 8 subjects. Communication thresholds were measured in three postures up to 18 months. Percent tissue encapsulation of the LP was measured at necropsy and ranged from 6% to 100% (mean: 62%). S-ICD system migration was evaluated radiographically at implant vs. at necropsy in two planes (anterior-posterior and left lateral) and evaluated 0–3 scale: none, minimal, moderate, significant. Communication thresholds were evaluated at 0 vs. 3 days using a t-test and 3 days through 18 months using a linear regression analysis. A repeated measures generalized linear model (GLM) was used to evaluate if test posture, percent tissue encapsulation of the LP, Parsonnet pouch use, or S-ICD system migration (no/ minimal migration vs. moderate/significant migration) were significant predictors of DDC performance at the subject's termination time point.

Results
DDC was successful for each tested posture and time point for all subjects (n=37), with 355 tests in Left Lateral (LL), 371 tests in Dorsal (D), and 355 tests in Right Lateral (RL). Follow up data are available up to 18 months for 19 subjects at the time of this abstract; additional follow-up data will be added to the analysis for presentation. Communication thresholds decreased between 0 days and 3 days (LL P&lt;0.01, D P&lt;0.01, RL P&lt;0.05) and did not change significantly from 3 days through 18 months (LL P=0.90, D P=0.83, RL P=0.83). The GLM showed that there is no significant difference in communication thresholds for test posture (P=0.24 LL vs. D, P=0.24 RL vs. D), percent tissue encapsulation of the LP (P=0.63), Parsonnet pouch use (P=0.65), or S-ICD system migration (P=0.95).

Conclusion
Longitudinal studies demonstrate low and stable communication thresholds of a novel mCRM system over time for all three tested postures, regardless of factors such as LP encapsulation, Parsonnet pouch use, or S-ICD system migration.
Device Communication Threshold Stability

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Boston Scientific
Thinking about the future – data on adolescent patients with a subcutaneous ICD
Authors: Willy K , Reinke F , Rath B , Boegeholz N , Wolfes J , Frommeyer G , Eckardt L 
Published: November 2020

Abstract

Background
Implantable cardioverter-defibrillator (ICD) systems are established for the prevention of sudden cardiac death. Long-term data on ICD function in children and adolescents is rare and has suggested higher rates of lead failure as well as oversensing, both leading to inappropriate therapy. The present study displays a long-term single-center follow-up of young patients having received an S-ICD.

Methods and results
The present study represents a single-center experience of patients younger than 25 years who received an S-ICD (n=49). Follow-up data included regular in-house follow-up as well as unscheduled hospitalisations in our center. Mean age at implantation was 19.2±4.1 years and 33 patients (67.4%) were male. In 21 patients (42.9%) electrical heart disease or idiopathic ventricular fibrillation represented the underlying condition of ICD implantation. 15 patients suffered from HCM (30.6%). Median follow-up duration was 2 years. No patient died during the observation period. Appropriate shocks occurred in 7 patients (14.3%). Inappropriate shock delivery was recorded in 6 patients (12.3%). T-wave oversensing was the main cause for inappropriate shock delivery (5/6 patients), in the other patient myopotentials were the reason for inappropriate therapy. In one patient, operative refixation of the subcutaneous lead was necessary due to hypermobility leading to oversensing. After modification of the sensing vector as well as activation of the SMART pass filter no further oversensing episodes occurred in any patient.

Conclusion
ICD therapy in children and adolescents is effective for prevention of sudden cardiac death. Every episode was terminated by the first therapy. The rate of appropriate shock as well as inappropriate therapies was quite high compared to typical ICD cohorts. In particular T-wave oversensing seems to be challenging for the S-ICD detection algorithms also in this cohort.

Funding Acknowledgement
Type of funding source: None
RV Pacing Percentage
Authors: Cha Y.M , Metzl M.D , Canby R.C , Fruechte E.M , Duggal M , Exner D.V , Chung E.S , Singh J.P , O'Donnell D , Zimmerman P , Landman S , Lexcen D.R , Laager V , Schaber D , Cheng A 
Published: November 2020

Abstract

Introduction
Chronic right ventricular pacing (RVP) has been associated with dyssynchrony, leading to increased mortality. However, there have been discrepancies in previous reports in the effect of RVP levels.

Objective
To sub-stratify mortality risk by age for different RVP level groups within a large real-world ICD cohort.

Methods
Optum® de-identified electronic health records were linked to the Medtronic Carelink data to identify dual chamber ICD recipients (2007–2017). RVP level was based on median daily pacing during the first 90 days post-implant and categorized either into groups with a cutoff of 40%, or with groups of 0–9%, 10–19%, 20–29%, 30–39%, 40–49%, and 50–100%. The endpoint was death more than 90 days post-implant. Kaplan-Meier survival curves, log-rank tests, and Cox regression were used to analyze the relationship between RVP and risk of death.

Results
Among 14,832 ICD patients (median age 67; 74.0% male), there were 2,602 deaths within 10 years after implant. In unadjusted comparisons, high RVP (&gt;40%) increased the risk of death relative to low RVP (≤40%) (p&lt;0.001). This effect remained significant in older cohort (≥67 years old at implant) (p&lt;0.001), but not in younger cohort (&lt;67 years old) (p=0.955) (Figure). After controlling for age, gender, pacing mode, MI, SCA, HF hospitalization, diabetes, and renal dysfunction, similar or increased risk was associated with higher pacing groups relative to the 0–9% pacing group in the older cohort, but not in the younger cohort.

Conclusions
Our data from a large contemporaneous real-world source suggests that older age or characteristics associated with age make patients more sensitive to chronic RVP effects. These results help reconcile differences observed in prior studies.

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Medtronic, Inc.
Not the pacing site but the underlying structural heart disease is a reason for wider QRS duration during right ventricular pacing
Authors: Ogano M , Tsuboi I , Tanabe J , Iwasaki Y , Shimizu W 
Published: November 2020

Abstract

Background
Right ventricular (RV) pacing causes changes of the electrical and mechanical activation pattern of the heart. QRS duration is reported to be a useful surrogate marker of electrical dyssynchrony, and wider QRS duration during RV pacing indicates poor prognosis. However, the mechanism of widening QRS duration during RV pacing remains to be elucidated.

Methods
A total of 211 patients who underwent catheter ablation for supraventricular tachyarrhythmias and have no bundle-branch-block on ECG were enrolled. During electrophysiological study, 3-dimensional mapping for QRS duration during RV pacing from RV outflow to RV apex was created, and the difference of QRS duration between RV outflow and RV apex was calculated. The relationship between QRS duration during RV pacing and patients' baseline characteristics including echocardiography data was analyzed.

Results
QRS duration at baseline, during RV pacing from RV outflow, and RV apex were 85.0±7.5msec, 156.2±16.1msec, and 163.7±17.1msec, respectively. The difference of QRS duration between RV outflow and RV apex among patients was only 12.5±10.4msec. The logistic multivariable regression analysis showed baseline QRS duration (odds ratio (OR) 1.24, 95% CI 1.15 to 1.34, p&lt;0.01), interventricular septum thickness (OR 1.35, 95% CI 1.05 to 1.73, p=0.018), and E/e' (OR 1.23, 95% CI 1.12 to 1.36, p&lt;0.01) were significant predictors for QRS duration over 160msec during RV apical pacing.

Conclusions
QRS duration during RV pacing depends largely not on the pacing site, but on the underlying structural heart disease.
QRS duration mapping during RV pacing

Funding Acknowledgement
Type of funding source: None
A novel non-invasive electrical synchrony method to improve cardiac resynchronization therapy responders
Authors: Logarzo E , Ortega D , Barja L , Paolucci A , Mangani N , Revollo G , Aboy J 
Published: November 2020

Abstract

Introduction
Cardiac resynchronization therapy (CRT) has emerged as an important treatment for patients with heart failure and reduced ejection fraction (EF) despite optimal pharmacological therapy. Some studies showed non-responders rate near 30%. Nowaday there is no gold standard method for selection, evaluation and follow up on this group of patients. Multiple techniques used and operator dependence made echocardiogram failed. Synchromax 2 is a device designed to evaluate non-invasive electrical synchrony. It is fast, reproducible and non-operator dependent. Synchromax was evaluated and correlated with other techniques in previous studies.

Objective
Evaluate CRT response rate guided by electrical synchrony during the device implantation and follow up.

Material and methods
43 patients were evaluated in an institution in Buenos Aires. A ICD-CRT was implanted in all patients due dilated cardiomyopathy, low EF (less than 35%) and left bundle branch block (LBBB). Non-invasive electrical synchrony evaluation (Synchromax 2) was performed in all patients in baseline condition, during device implantation and the follow up. Synchrony index and curves were analyzed. Curve type 4 and index between 0,4 and 0,7 were considered synchronous. Curve type 6 and 10 and index more than 0.7 were considered disynchronous. Interventricular intervals were modified to achieve the best curve and synchrony index. Super responders were considered when EF increased &gt;50%. Baseline and 6 month after implantation echocardiogram were performed.

Results
Mean age 64 years. 39% females. Non-coronary dilated cardiomyopathy was main aetiology (63,1%). EF baseline average was 27%. A baseline index more than 0,7 was in 73,3% of the patients. Curve 6 was the most frequent (55,2%). Follow up average EF was 39% (increased 12%), the super responders rate was 18,6% (8 patients). Type 4 curve and index between 0,4 and 0,7 were achieved in 28 cases (65,1%). EF increased from 23% (baseline) to 42% (follow up). Average 19%. Type 4 curve was not achieved in 15 patients (34,9%). In this group, EF increased from 29% (baseline) to 34% (follow up). Average 5%.

Conclusion
Electrical synchrony evaluation using Synchromax 2 during ICD-CRT device implantation improves responders rate. When synchronous type 4 curve is achieved EF improves significantly. If type 4 curve is not found results will be unsuccessfully. Synchromax is fast, simple and non-operator dependent.

Funding Acknowledgement
Type of funding source: None
Atrial and atrioventricular resynchronization the benefit of bachmanns bundle and his bundle pacing
Authors: Wolff P , Strozik P , Gajek A , Ciesielski A , Slawuta A , Gajek J 
Published: November 2020

Abstract

The current treatment of patients with heart failure and concomitant atrioventricular conduction delay is difficult. Recommendations indicate the possibility to use the classic resynchronization but in the presence of narrow QRS-complex such approach could be even harmful. Without a sufficient LBBB morphology as indication for classical CRT, those patients would lose their narrow QRS complex with negative consequences for the hearts functional status.
A new therapeutic option for those patients to re-establish the physiological atrioventricular mechanical sequence is the permanent His-bundle pacing (pHBP). Advantages like physiological activation sequence of the ventricular myocardium, less affected by AF compared to classical CRT and reversal of mitral regurgitation should be enumerated to show it's beneficial effect. Additionally the use of Bachmann's-bundle pacing can correct the prolonged interatrial conduction thus further contribute to the echocardiographic and clinical improvement.
The aim of the study is to assess the influence of Bachmann's-bundle pacing and His-bundle pacing on the reversed remodeling of the heart in patients with heart failure and atrioventricular block.
The study group included 21 patients (7 women and 14 men) undergoing cardiac resynchronization using Bachmann's-bundle pacing and permanent His-bundle pacing from LV channel for atrioventricular conduction delay. All the patients had narrow QRS-complex which prevented us to use classic resynchronization. 13 CRT-D and 8 CRT-P devices were implanted according to the ejection fraction and ventricular arrhythmia risk assessment. In all patients the direct His-bundle pacing was successfully achieved, selective in 17 and non-selective in 4 patients. The mean follow-up (FU) period was 8.8 months (1–26 months). The echocardiographic, clinical and ECG results are presented in the table 1.

Conclusions
1. The correction of atrioventricular and interatrial conduction delay resulting in improvement of atrioventricular mechanical coupling can contribute to the reversed remodeling of the heart.
2. This also improves the patient's functional status.
3. In some patients this approach could lead to the normalization of echocardiographic parameters of the left ventricle.

Funding Acknowledgement
Type of funding source: None
Handling of remote monitoring alerts according to the weekday of transmission: results from the OptiLink HF study
Authors: Wintrich J , Pavlicek V.P , Brachmann J.B , Bosch R.B , Butter C.B , Oswald H.O , Rybak K.R , Mahfoud F.M , Boehm M.B , Ukena C.U 
Published: November 2020

Abstract

Background
Remote monitoring of patients suffering from heart failure (HF) did not result in improved clinical outcomes in the OptiLink-HF trial. However, initiation of medical intervention after transmission of telemedicine alerts triggered by fluid index threshold crossings (FTCs) was low. The relation between weekday of transmission of FTC and subsequent patient contact is unknown.

Methods
Patients enrolled in the intervention arm of the OptiLink HF trial (n=505, age 66.1±10.1, male 77.2, EF 26.7±6.1%) were analyzed according to the weekday of transmission of FTC. Transmissions of FTC on Mondays to Thursdays were categorized as TD1, Fridays to Sundays as well as bank holidays as TD2. Primary endpoint was time between transmission and telephone contact; secondary endpoints were subsequent medical intervention and hospitalizations.

Results
During a follow-up of 18 months, 1364 FTC (866 (63.5%) categorized to TD1, 498 (36.5%) to TD2) alerts occurred in 356 patients. In 46.2% of FTC same day telephone contact was performed in group TD1 compared to 18.3% in group TD2 (p&lt;0.001). Accordingly, the median time to contact was significantly longer in TD2 compared to TD1 (2 (1–3) vs. 0 (0–1); p&lt;0.001). Rates of no telephone contact were not different between the groups (12.1% vs. 12.4%; p=0.866). Although, signs of worsening HF were prevalent in 32.4% in TD1 vs. 32.1% in TD2 (p=0.996), initiation of a pharmacological intervention was more likely in TD1 compared to TD2 (27.9% vs. 22.9%; p=0.041). No differences existed concerning hospitalization for HF within 30 days after FTC (3.9% vs. 3.4%; p=0.636).

Conclusion
Transmission of FTC alerts during weekends and on bank holidays were less likely associated with timely patient contacts and initiation of pharmacological intervention than during the week. Telemedical centers providing 24/7 remote monitoring service might help to optimize patient care.

Funding Acknowledgement
Type of funding source: None
Permanent CIED malfunctions after oncologic radiotherapy: a multi-centre, randomized, in vitro evaluation
Authors: Di Girolamo E , Appignani M , Faustino M , Marini M , De Filippo P , Leidi C , Di Girolamo F , Delana A , Barbareschi A , Andreoli S , Genovesi D , Falco M.D 
Published: November 2020

Abstract

Background
Direct photon exposure of pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs) during oncologic radiotherapy may transiently or permanently affect normal device function. To evaluate potential malfunctions by direct exposure to doses up to 10 Gy in 6-MV oncologic radiotherapy, commonly considered unsafe or even not recommended, 145 PMs and 65 ICDs were observed in three different centres.

Methods
All devices had a baseline interrogation and reprogramming to VVI/40 or to DDD/40 mode, depending on type and model. Rate-adaptive function was disabled in all the devices, whereas in ICDs, even antitachycardia therapies were disabled with the ventricular tachycardia/fibrillation (VT/VF) windows left enabled. To build the corresponding treatment plan, a centring computed tomography was performed with different Treatment Plan Systems among the centres. The devices were blinded randomized to receive either 2-, 5- or 10-Gy direct exposure by a 6-MV linear accelerator (different among the three centres) in a water phantom (600 MU/min). The effective dose received was assessed by a random in-vivo dosimetry. All devices had a telemetry interrogation immediately after exposure and once monthly during a six-month follow-up.

Results
Immediately after photon exposure, no changes in device parameters or software errors were observed in 209 devices (99.5%). A non-reprogrammable reset to emergency back-up mode (VVI/65) occurred in a PM (0.5% overall; 0.7% among PMs). Seven PMs reached the Elective Replacement Indicator immediately after exposure (3.3% overall; 4.8% among PMs). Sixteen ICDs (7.6% overall; 24.6% among ICDs) had multiple VT/VF detections stored in the device memory. Two PMs (1% overall; 1.4% among PMs) reported atrial fibrillation detections.
During a six-month follow-up, a non-reprogrammable software reset (back-up to VVI/65 mode) was reported in one PM three months after a single exposure of 2 Gy (0.5% overall; 0.7% among PMs). Abnormal battery drain was observed in thirteen PMs (6.2% overall; 9% among PMs), and in one ICD (0.5% overall; 1.5% among ICDs). All events presented regardless of exposure dose of either 2, 5, or 10 Gy.

Conclusions
Last-generation devices, both PMs and ICDs, withstood direct 6-MV photon exposure up to 10 Gy, commonly considered not recommended or even unsafe by manufacturer statements and clinical guidelines. The most common failures were referred to battery issues. Malfunctions occurred solely in less recent devices, regardless of photon dose.

Funding Acknowledgement
Type of funding source: None