Publications by authors named "Christopher A Rinaldi"

132 Publications

Hyperparameter optimisation and validation of registration algorithms for measuring regional ventricular deformation using retrospective gated computed tomography images.

Sci Rep 2021 Mar 11;11(1):5718. Epub 2021 Mar 11.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

Recent dose reduction techniques have made retrospective computed tomography (CT) scans more applicable and extracting myocardial function from cardiac computed tomography (CCT) images feasible. However, hyperparameters of generic image intensity-based registration techniques, which are used for tracking motion, have not been systematically optimised for this modality. There is limited work on their validation for measuring regional strains from retrospective gated CCT images and open-source software for motion analysis is not widely available. We calculated strain using our open-source platform by applying an image registration warping field to a triangulated mesh of the left ventricular endocardium. We optimised hyperparameters of two registration methods to track the wall motion. Both methods required a single semi-automated segmentation of the left ventricle cavity at end-diastolic phase. The motion was characterised by the circumferential and longitudinal strains, as well as local area change throughout the cardiac cycle from a dataset of 24 patients. The derived motion was validated against manually annotated anatomical landmarks and the calculation of strains were verified using idealised problems. Optimising hyperparameters of registration methods allowed tracking of anatomical measurements with a mean error of 6.63% across frames, landmarks, and patients, comparable to an intra-observer error of 7.98%. Both registration methods differentiated between normal and dyssynchronous contraction patterns based on circumferential strain ([Formula: see text], [Formula: see text]). To test whether a typical 10 temporal frames sampling of retrospective gated CCT datasets affects measuring cardiac mechanics, we compared motion tracking results from 10 and 20 frames datasets and found a maximum error of [Formula: see text]. Our findings show that intensity-based registration techniques with optimal hyperparameters are able to accurately measure regional strains from CCT in a very short amount of time. Furthermore, sufficient sensitivity can be achieved to identify heart failure patients and left ventricle mechanics can be quantified with 10 reconstructed temporal frames. Our open-source platform will support increased use of CCT for quantifying cardiac mechanics.
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http://dx.doi.org/10.1038/s41598-021-84935-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7952400PMC
March 2021

Risk stratification of patients undergoing transvenous lead extraction with the ELECTRa Registry Outcome Score (EROS): an ESC EHRA EORP European lead extraction ConTRolled ELECTRa registry analysis.

Europace 2021 Feb 22. Epub 2021 Feb 22.

School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London SE1 7EH, UK.

Aims: Transvenous lead extraction is associated with a significant risk of complications and identifying patients at highest risk pre-procedurally will enable interventions to be planned accordingly. We developed the ELECTRa Registry Outcome Score (EROS) and applied it to the ELECTRa registry to determine if it could appropriately risk-stratify patients.

Methods And Results: EROS was devised to risk-stratify patients into low risk (EROS 1), intermediate risk (EROS 2), and high risk (EROS 3). This was applied to the ESC EORP European Lead Extraction ConTRolled ELECTRa registry; 57.5% EROS 1, 31.8% EROS 2, and 10.7% EROS 3. Patients with EROS 3 or 2 were significantly more likely to require powered sheaths and a femoral approach to complete procedures. Patients with EROS 3 were more likely to suffer procedure-related major complications including deaths (5.1 vs. 1.3%; P < 0.0001), both intra-procedural (3.5 vs. 0.8%; P = 0.0001) and post-procedural (1.6 vs. 0.5%; P = 0.0192). They were more likely to suffer post-procedural deaths (0.8 vs. 0.2%; P 0.0449), cardiac avulsion or tear (3.8 vs. 0.5%; P < 0.0001), and cardiovascular lesions requiring pericardiocentesis, chest tube, or surgical repair (4.6 vs. 1.0%; P < 0.0001). EROS 3 was associated with procedure-related major complications including deaths [odds ratio (OR) 3.333, 95% confidence interval (CI) 1.879-5.914; P < 0.0001] and all-cause in-hospital major complications including deaths (OR 2.339, 95% CI 1.439-3.803; P = 0.0006).

Conclusion: EROS successfully identified patients who were at increased risk of significant procedural complications that require urgent surgical intervention.
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http://dx.doi.org/10.1093/europace/euab037DOI Listing
February 2021

Late-Gadolinium Enhancement Interface Area and Electrophysiological Simulations Predict Arrhythmic Events in Patients With Nonischemic Dilated Cardiomyopathy.

JACC Clin Electrophysiol 2021 02 29;7(2):238-249. Epub 2020 Oct 29.

Department of Biomedical Engineering, School of Biomedical & Imaging Sciences, King's College London, United Kingdom. Electronic address:

Objectives: This study sought to investigate whether shape-based late gadolinium enhancement (LGE) metrics and simulations of re-entrant electrical activity are associated with arrhythmic events in patients with nonischemic dilated cardiomyopathy (NIDCM).

Background: The presence of LGE predicts life-threatening ventricular arrhythmias in NIDCM; however, risk stratification remains imprecise. LGE shape and simulations of electrical activity may be able to provide additional prognostic information.

Methods: Cardiac magnetic resonance (CMR)-LGE shape metrics were computed for a cohort of 156 patients with NIDCM and visible LGE and tested retrospectively for an association with an arrhythmic composite endpoint of sudden cardiac death and ventricular tachycardia. Computational models were created from images and used in conjunction with simulated stimulation protocols to assess the potential for re-entry induction in each patient's scar morphology. A mechanistic analysis of the simulations was carried out to explain the associations.

Results: During a median follow-up of 1,611 (interquartile range: 881 to 2,341) days, 16 patients (10.3%) met the primary endpoint. In an inverse probability weighted Cox regression, the LGE-myocardial interface area (hazard ratio [HR]: 1.75; 95% confidence interval [CI]: 1.24 to 2.47; p = 0.001), number of simulated re-entries (HR: 1.40; 95% CI: 1.23 to 1.59; p < 0.01) and LGE volume (HR: 1.44; 95% CI: 1.07 to 1.94; p = 0.02) were associated with arrhythmic events. Computational modeling revealed repolarization heterogeneity and rate-dependent block of electrical wavefronts at the LGE-myocardial interface as putative arrhythmogenic mechanisms directly related to the LGE interface area.

Conclusions: The area of interface between scar and surviving myocardium, as well as simulated re-entrant activity, are associated with an elevated risk of major arrhythmic events in patients with NIDCM and LGE and represent novel risk predictors.
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http://dx.doi.org/10.1016/j.jacep.2020.08.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900608PMC
February 2021

Modified design of stimulation of the left ventricular endocardium for cardiac resynchronization therapy in nonresponders, previously untreatable and high-risk upgrade patients (SOLVE-CRT) trial.

Am Heart J 2021 Feb 15;235:158-162. Epub 2021 Feb 15.

Namsa, Contract Research Organization, Minneapolis.

The WiSE system is a novel, leadless endocardial system that can provide cardiac resynchronization therapy in patients who cannot be treated with a conventional epicardial left ventricular lead. Safety and efficacy were being evaluated in the pivotal, randomized, double-blind SOLVE-CRT Trial (Stimulation of the Left Ventricular Endocardium for Cardiac Resynchronization Therapy.) The trial was initiated in 2018; however, patient enrollment was significantly impacted by the COVID-19 pandemic necessitating a change in design. This article describes the revised trial and the scientific rationale for the specific changes in the protocol.
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http://dx.doi.org/10.1016/j.ahj.2021.02.008DOI Listing
February 2021

Feasibility of intraprocedural integration of cardiac CT to guide left ventricular lead implantation for CRT upgrades.

J Cardiovasc Electrophysiol 2021 Mar 10;32(3):802-812. Epub 2021 Feb 10.

Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK.

Background: Optimal positioning of the left ventricular (LV) lead is an important determinant of cardiac resynchronization therapy (CRT) response.

Objective: Evaluate the feasibility of intraprocedural integration of cardiac computed tomography (CT) to guide LV lead implantation for CRT upgrades.

Methods: Patients undergoing LV lead upgrade underwent ECG-gated cardiac CT dyssynchrony and LV scar assessment. Target American Heart Association segment selection was determined using latest non-scarred mechanically activating segments overlaid onto real-time fluoroscopy with image co-registration to guide optimal LV lead implantation. Hemodynamic validation was performed using a pressure wire in the LV cavity (dP/dt ).

Results: 18 patients (male 94%, 55.6% ischemic cardiomyopathy) with RV pacing burden 60.0 ± 43.7% and mean QRS duration 154 ± 30 ms underwent cardiac CT. 10/10 ischemic patients had CT evidence of scar and these segments were excluded as targets. Seventeen out of 18 (94%) patients underwent successful LV lead implantation with delivery to the CT target segment in 15 out of 18 (83%) of patients. Acute hemodynamic response (dP/dt  ≥ 10%) was superior with LV stimulation in CT target versus nontarget segments (83.3% vs. 25.0%; p = .012). Reverse remodeling at 6 months (LV end-systolic volume improvement ≥15%) occurred in 60% of subjects (4/8 [50.0%] ischemic cardiomyopathy vs. 5/7 [71.4%] nonischemic cardiomyopathy, p = .608).

Conclusion: Intraprocedural integration of cardiac CT to guide optimal LV lead placement is feasible with superior hemodynamics when pacing in CT target segments and favorable volumetric response rates, despite a high proportion of patients with ischemic cardiomyopathy. Multicentre, randomized controlled studies are needed to evaluate whether intraprocedural integration of cardiac CT is superior to standard care.
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http://dx.doi.org/10.1111/jce.14896DOI Listing
March 2021

In-silico pace-mapping using a detailed whole torso model and implanted electronic device electrograms for more efficient ablation planning.

Comput Biol Med 2020 10 17;125:104005. Epub 2020 Sep 17.

King's College London, London, United Kingdom.

Background: Pace-mapping is a commonly used electrophysiological (EP) procedure which aims to identify exit sites of ventricular tachycardia (VT) by matching ventricular activation patterns (assessed by QRS morphology) at specific pacing locations with activation during VT. However, long procedure durations and the need for VT induction render this technique non-optimal. To demonstrate the potential of in-silico pace-mapping, using stored electrogram (EGM) recordings of clinical VT from implanted devices to guide pre-procedural ablation planning.

Method: Six scar-related VT episodes were simulated in a 3D torso model reconstructed from computed tomography (CT) imaging data, including three different infarct anatomies mapped from infarcted porcine imaging data. In-silico pace-mapping was performed to localise VT exit sites and isthmuses by using 12-lead electrocardiogram (ECG) signals and different combinations of EGM sensing vectors from implanted devices, through the creation of conventional correlation maps and reference-less maps.

Results: Our in-silico platform was successful in identifying VT exit sites for a variety of different VT morphologies from both ECG correlation maps and corresponding EGM maps, with the latter dependent upon the number of sensing vectors used. We also showed the added utility of both ECG and EGM reference-less pace-mapping for the identification of slow-conducting isthmuses, uncovering the optimal algorithm parameters. Finally, EGM-based pace-mapping was shown to be more dependent upon the mapped surface (epicardial/endocardial), relative to the VT origin.

Conclusions: In-silico pace-mapping can be used along with EGMs from implanted devices to localise VT ablation targets in pre-procedural planning.
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http://dx.doi.org/10.1016/j.compbiomed.2020.104005DOI Listing
October 2020

Safety of magnetic resonance imaging scanning in patients with cardiac resynchronization therapy-defibrillators incorporating quadripolar left ventricular leads.

Heart Rhythm 2020 12 7;17(12):2064-2071. Epub 2020 Sep 7.

University of California, San Diego, La Jolla, California for the ENABLE MRI Trial Investigators.

Background: Magnetic resonance imaging (MRI) scanning of magnetic resonance (MR)-conditional cardiac implantable cardioverter-defibrillators (ICDs) can be performed safely following specific protocols. MRI safety with cardiac resynchronization therapy-defibrillators (CRT-Ds) incorporating quadripolar left ventricular (LV) leads is less clear.

Objective: The purpose of this study was to evaluate the safety and effectiveness of ICDs and CRT-D systems with quadripolar LV leads after an MRI scan.

Methods: The ENABLE MRI Study included 230 subjects implanted with a Boston Scientific ImageReady ICD (n = 39) or CRT-D (n = 191) incorporating quadripolar LV leads undergoing nondiagnostic 1.5-T MRI scans (lumbar and thoracic spine imaging) a minimum of 6 weeks postimplant. Pacing capture thresholds (PCTs), sensing amplitudes (SAs), and impedances were measured before and 1 month post-MRI using the same programmed LV pacing vectors. The ability to sense/treat ventricular fibrillation (VF) was assessed in a subset of patients.

Results: A total of 159 patients completed a protocol-required MRI scan (MRI Protection Mode turned on) with no scan-related complications. All right ventricular (RV) and left LV PCT and SA effectiveness endpoints were met: RV PCT 99% (145/146 patients), LV PCT 100% (120/120), RV SA 99% (145/146), and LV SA 98% (116/118). In no instances did MRI result in a change in pacing vector or lead revision. All episodes of VF were appropriately sensed and treated.

Conclusion: This first evaluation of predominantly CRT-D systems with quadripolar LV leads undergoing 1.5-T MRI confirmed that scanning was safe with no significant changes in RV/LV PCT, SA, programmed vectors, and VF treatment, thus suggesting that MRI in patients having a device with quadripolar leads can be performed without negative impact on CRT delivery.
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http://dx.doi.org/10.1016/j.hrthm.2020.08.020DOI Listing
December 2020

Electrocardiographic imaging for cardiac arrhythmias and resynchronization therapy.

Europace 2020 Aug 5. Epub 2020 Aug 5.

Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Rd, London SE1 7EH, UK.

Use of the 12-lead electrocardiogram (ECG) is fundamental for the assessment of heart disease, including arrhythmias, but cannot always reveal the underlying mechanism or the location of the arrhythmia origin. Electrocardiographic imaging (ECGi) is a non-invasive multi-lead ECG-type imaging tool that enhances conventional 12-lead ECG. Although it is an established technology, its continuous development has been shown to assist in arrhythmic activation mapping and provide insights into the mechanism of cardiac resynchronization therapy (CRT). This review addresses the validity, reliability, and overall feasibility of ECGi for use in a diverse range of arrhythmias. A systematic search limited to full-text human studies published in peer-reviewed journals was performed through Medline via PubMed, using various combinations of three key concepts: ECGi, arrhythmia, and CRT. A total of 456 studies were screened through titles and abstracts. Ultimately, 42 studies were included for literature review. Evidence to date suggests that ECGi can be used to provide diagnostic insights regarding the mechanistic basis of arrhythmias and the location of arrhythmia origin. Furthermore, ECGi can yield valuable information to guide therapeutic decision-making, including during CRT. Several studies have used ECGi as a diagnostic tool for atrial and ventricular arrhythmias. More recently, studies have tested the value of this technique in predicting outcomes of CRT. As a non-invasive method for assessing cardiovascular disease, particularly arrhythmias, ECGi represents a significant advancement over standard procedures in contemporary cardiology. Its full potential has yet to be fully explored.
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http://dx.doi.org/10.1093/europace/euaa165DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7544539PMC
August 2020

The effect of centre volume and procedure location on major complications and mortality from transvenous lead extraction: an ESC EHRA EORP European Lead Extraction ConTRolled ELECTRa registry subanalysis.

Europace 2020 11;22(11):1718-1728

Department of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

Aims: Transvenous lead extraction (TLE) should ideally be undertaken by experienced operators in a setting that allows urgent surgical intervention. In this analysis of the ELECTRa registry, we sought to determine whether there was a significant difference in procedure complications and mortality depending on centre volume and extraction location.

Methods And Results: Analysis of the ESC EORP European Lead Extraction ConTRolled ELECTRa registry was conducted. Low-volume (LoV) centres were defined as <30 procedures/year, and high-volume (HiV) centres as ≥30 procedures/year. Three thousand, two hundred, and forty-nine patients underwent TLE by a primary operator cardiologist; 17.1% in LoV centres and 82.9% in HiV centres. Procedures performed by primary operator cardiologists in LoV centres were less likely to be successful (93.5% vs. 97.1%; P < 0.0001) and more likely to be complicated by procedure-related deaths (1.1% vs. 0.4%; P = 0.0417). Transvenous lead extraction undertaken by primary operator cardiologists in LoV centres were associated with increased procedure-related major complications including death (odds ratio 1.858, 95% confidence interval 1.007-3.427; P = 0.0475). Transvenous lead extraction locations varied; 52.0% operating room, 9.5% hybrid theatre and 38.5% catheterization laboratory. Rates of procedure-related major complications, including death occurring in a high-risk environment (combining operating room and hybrid theatre), were similar to those undertaken in the catheterization laboratory (1.7% vs. 1.6%; P = 0.9297).

Conclusion: Primary operator cardiologists in LoV centres are more likely to have extractions complicated by procedure-related deaths. There was no significant difference in procedure complications between different extraction settings. These findings support the need for TLE to be performed in experienced centres with appropriate personnel present.
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http://dx.doi.org/10.1093/europace/euaa131DOI Listing
November 2020

Tracking the motion of intracardiac structures aids the development of future leadless pacing systems.

J Cardiovasc Electrophysiol 2020 09 15;31(9):2431-2439. Epub 2020 Jul 15.

Department of Biomedical Engineering, Cardiac Electromechanics Research Group, School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.

Background: Leadless pacemakers preclude the need for permanent leads to pace endocardium. However, it is yet to be determined whether a leadless pacemaker of a similar design to those manufactured for the right ventricle (RV) fits within the left ventricle (LV), without interfering with intracardiac structures.

Methods: Cardiac computed tomography scans were obtained from 30 patients indicated for cardiac resynchronisation therapy upgrade. The mitral valve annulus, chordae tendineae, papillary muscles and LV endocardial wall were marked in the end-diastolic frame. Intracardiac structures motions were tracked through the cardiac cycle. Two pacemaker designs similar to commercially manufactured leadless systems (Abbott's Nanostim LCP and Medtronic's Micra TPS) as well as theoretical designs with calculated optimal dimensions were evaluated. Pacemakers were virtually placed across the LV endocardial surface and collisions between them and intracardiac structures were detected throughout the cycle.

Results: Probability maps of LV intracardiac structures collisions on a 16-segment AHA model indicated possible placement for the Nanostim LCP, Micra TPS, and theoretical designs. Thresholding these maps at a 20% chance of collision revealed only about 36% of the endocardial surface remained collision-free with the deployment of Micra TPS design. The same threshold left no collision-free surface in the case of the Nanostim LCP. To reach at least half of the LV endocardium, the volume of Micra TPS, which is the smaller design, needed to be decreased by 41%.

Conclusion: Due to the presence of intracardiac structures, placement of leadless pacemakers with dimensions similar to commercially manufactured RV systems would be limited to apical regions.
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http://dx.doi.org/10.1111/jce.14657DOI Listing
September 2020

His-bundle and left bundle pacing with optimized atrioventricular delay achieve superior electrical synchrony over endocardial and epicardial pacing in left bundle branch block patients.

Heart Rhythm 2020 11 27;17(11):1922-1929. Epub 2020 Jun 27.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.

Background: His-bundle pacing (HBP) and left bundle pacing (LBP) are emerging as novel delivery methods for cardiac resynchronization therapy (CRT) in heart failure patients with left bundle branch block (LBBB). HBP and LBP have never been compared to biventricular endocardial (BiV-endo) pacing. Furthermore, there are indications of negative effects of LBP on right ventricular (RV) activation times (ATs), but these effects have not been quantified.

Objective: The purpose of this study was to compare changes in ventricular activation induced by HBP, LBP, left ventricular (LV) septal pacing, BiV-endo, and biventricular epicardial (BiV-epi) pacing using computer simulations.

Methods: We simulated ventricular activation on 24 four-chamber heart meshes inclusive of the His-Purkinje network in the presence of LBBB. We simulated BiV-epi pacing, BiV-endo pacing with left ventricular (LV) lead at the lateral wall, BiV-endo pacing with LV lead at the LV septum, HBP, and LBP.

Results: HBP was superior to BiV-endo and BiV-epi in terms of reduction in LV ATs and interventricular dyssynchrony (P <.05). LBP reduced LV ATs but not interventricular dyssynchrony compared to BiV-epi and BiV-endo pacing. RV latest AT was higher with LBP than with HBP (141.3 ± 10.0 ms vs 111.8 ± 10.4 ms). Optimizing AV delay during LBP reduced RV latest AT (104.7 ± 8.7 ms) and led to comparable response to HBP. In case of complete AV block, BiV-endo septal pacing was equivalent to LBP.

Conclusion: HBP is superior to BiV-epi and BiV-endo. To achieve comparable response to HBP, AV delay optimization during LBP is required in order to reduce RV ATs.
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http://dx.doi.org/10.1016/j.hrthm.2020.06.028DOI Listing
November 2020

A publicly available virtual cohort of four-chamber heart meshes for cardiac electro-mechanics simulations.

PLoS One 2020 26;15(6):e0235145. Epub 2020 Jun 26.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, City of London, United Kingdom.

Computational models of the heart are increasingly being used in the development of devices, patient diagnosis and therapy guidance. While software techniques have been developed for simulating single hearts, there remain significant challenges in simulating cohorts of virtual hearts from multiple patients. To facilitate the development of new simulation and model analysis techniques by groups without direct access to medical data, image analysis techniques and meshing tools, we have created the first publicly available virtual cohort of twenty-four four-chamber hearts. Our cohort was built from heart failure patients, age 67±14 years. We segmented four-chamber heart geometries from end-diastolic (ED) CT images and generated linear tetrahedral meshes with an average edge length of 1.1±0.2mm. Ventricular fibres were added in the ventricles with a rule-based method with an orientation of -60° and 80° at the epicardium and endocardium, respectively. We additionally refined the meshes to an average edge length of 0.39±0.10mm to show that all given meshes can be resampled to achieve an arbitrary desired resolution. We ran simulations for ventricular electrical activation and free mechanical contraction on all 1.1mm-resolution meshes to ensure that our meshes are suitable for electro-mechanical simulations. Simulations for electrical activation resulted in a total activation time of 149±16ms. Free mechanical contractions gave an average left ventricular (LV) and right ventricular (RV) ejection fraction (EF) of 35±1% and 30±2%, respectively, and a LV and RV stroke volume (SV) of 95±28mL and 65±11mL, respectively. By making the cohort publicly available, we hope to facilitate large cohort computational studies and to promote the development of cardiac computational electro-mechanics for clinical applications.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235145PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7319311PMC
September 2020

High mean entropy calculated from cardiac MRI texture analysis is associated with antitachycardia pacing failure.

Pacing Clin Electrophysiol 2020 07 21;43(7):737-745. Epub 2020 Jun 21.

Cardiology Department, Guy's and St Thomas' NHS Foundation Trust, London, UK.

Background: Antitachycardia pacing (ATP), which may avoid unnecessary implantable cardioverter-defibrillator (ICD) shocks, does not always terminate ventricular arrhythmias (VAs). Mean entropy calculated using cardiac magnetic resonance texture analysis (CMR-TA) has been shown to predict appropriate ICD therapy. We examined whether scar heterogeneity, quantified by mean entropy, is associated with ATP failure and explore potential mechanisms using computer modeling.

Methods: A subanalysis of 114 patients undergoing CMR-TA where the primary endpoint was delivery of appropriate ICD therapy (ATP or shock therapy) was performed. Patients receiving appropriate ICD therapy (n = 33) were dichotomized into "successful ATP" versus "shock therapy" groups. In silico computer modeling was used to explore underlying mechanisms.

Results: A total of 16 of 33 (48.5%) patients had successful ATP to terminate VA, and 17 of 33 (51.5%) patients required shock therapy. Mean entropy was significantly higher in the shock versus successful ATP group (6.1 ± 0.5 vs 5.5 ± 0.7, P = .037). Analysis of patients receiving ATP (n = 22) showed significantly higher mean entropy in the six of 22 patients that failed ATP (followed by rescue ICD shock) compared to 16 of 22 that had successful ATP (6.3 ± 0.7 vs 5.5 ± 0.7, P = .048). Computer modeling suggested inability of the paced wavefront in ATP to successfully propagate from the electrode site through patchy fibrosis as a possible mechanism of failed ATP.

Conclusions: Our findings suggest lower scar heterogeneity (mean entropy) is associated with successful ATP, whereas higher scar heterogeneity is associated with more aggressive VAs unresponsive to ATP requiring shock therapy that may be due to inability of the paced wavefront to propagate through scar and terminate the VA circuit.
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http://dx.doi.org/10.1111/pace.13969DOI Listing
July 2020

Completely Leadless Cardiac Resynchronization Defibrillator System.

JACC Clin Electrophysiol 2020 05;6(5):588-589

School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom; Guy's and St. Thomas' Hospital, London, United Kingdom.

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http://dx.doi.org/10.1016/j.jacep.2020.02.012DOI Listing
May 2020

Leadless left ventricular endocardial pacing in nonresponders to conventional cardiac resynchronization therapy.

Pacing Clin Electrophysiol 2020 09 9;43(9):966-973. Epub 2020 May 9.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

Background: Endocardial pacing may be beneficial in patients who fail to improve following conventional epicardial cardiac resynchronization therapy (CRT). The potential to pace anywhere inside the left ventricle thus avoiding myocardial scar and targeting the latest activating segments may be particularly important. The WiSE-CRT system (EBR systems, Sunnyvale, CA) reliably produces wireless, endocardial left ventricular (LV) pacing. The purpose of this analysis was to determine whether this system improved symptoms or led to LV remodeling in patients who were nonresponders to conventional CRT.

Method: An international, multicenter registry of patients who were nonresponders to conventional CRT and underwent implantation with the WiSE-CRT system was collected.

Results: Twenty-two patients were included; 20 patients underwent successful implantation with confirmation of endocardial biventricular pacing and in 2 patients, there was a failure of electrode capture. Eighteen patients proceeded to 6-month follow-up; endocardial pacing resulted in a significant reduction in QRS duration compared with intrinsic QRS duration (26.6 ± 24.4 ms; P = .002) and improvement in left ventricular ejection fraction (LVEF) (4.7 ± 7.9%; P = .021). The mean reduction in left ventricular end-diastolic volume was 8.3 ± 42.3 cm (P = .458) and left ventricular end-systolic volume (LVESV) was 13.1 ± 44.3 cm (P = .271), which were statistically nonsignificant. Overall, 55.6% of patients had improvement in their clinical composite score and 66.7% had a reduction in LVESV ≥15% and/or absolute improvement in LVEF ≥5%.

Conclusion: Nonresponders to conventional CRT have few remaining treatment options. We have shown in this high-risk patient group that the WiSE-CRT system results in improvement in their clinical composite scores and leads to LV remodeling.
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http://dx.doi.org/10.1111/pace.13926DOI Listing
September 2020

3D Electrophysiological Modeling of Interstitial Fibrosis Networks and Their Role in Ventricular Arrhythmias in Non-Ischemic Cardiomyopathy.

IEEE Trans Biomed Eng 2020 11 3;67(11):3125-3133. Epub 2020 Apr 3.

Objective: Interstitial fibrosis is a pathological expansion of the heart's inter-cellular collagen matrix. It is a potential complication of nonischemic cardiomyopathy (NICM), a class of diseases involving electrical and or mechanical dysfunction of cardiac tissue not caused by atherosclerosis. Patients with NICM and interstitial fibrosis often suffer from life threatening arrhythmias, which we aim to simulate in this study.

Methods: Our methodology builds on an efficient discrete finite element (DFE) method which allows for the representation of fibrosis as infinitesimal splits in a mesh. We update the DFE method with a local connectivity analysis which creates a consistent topology in the fibrosis network. This is particularly important in nonischemic disease due to the potential presence of large and contiguous fibrotic regions and therefore potentially complex fibrosis networks.

Results: In experiments with an image-based model, we demonstrate that our methodology is able to simulate reentrant electrical events associated with cardiac arrhythmias. These reentries depended crucially upon sufficient fibrosis density, which was marked by conduction slowing at high pacing rates. We also created a 2D test-case which demonstrated that fibrosis topologies can modulate transient conduction block, and thereby reentrant activations.

Conclusion: Ventricular arrhythmias due to interstitial fibrosis in NICM can be efficiently simulated using our methods in medical image based geometries. Furthermore, fibrosis topology modulates transient conduction block, and should be accounted for in electrophysiological simulations with interstitial fibrosis.

Significance: Our study provides methodology which has the potential to predict arrhythmias and to optimize treatments non-invasively for nonischemic cardiomyopathies.
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http://dx.doi.org/10.1109/TBME.2020.2976924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116885PMC
November 2020

Real-world experience of leadless left ventricular endocardial cardiac resynchronization therapy: A multicenter international registry of the WiSE-CRT pacing system.

Heart Rhythm 2020 08 9;17(8):1291-1297. Epub 2020 Mar 9.

Division of Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom; Cardiology Department, Guys and St Thomas' NHS Foundation Trust, London, United Kingdom.

Background: Biventricular endocardial pacing (BiV ENDO) is a therapy for heart failure patients who cannot receive transvenous epicardial cardiac resynchronization therapy (CRT) or have not responded adequately to CRT. BiV ENDO CRT can be delivered by a new wireless LV ENDO pacing system (WiSE-CRT system; EBR Systems, Sunnyvale, CA), without the requirement for lifelong anticoagulation.

Objective: The purpose of this study was to assess the safety and efficacy of the WiSE-CRT system during real-world clinical use in an international registry.

Methods: Data were prospectively collected from 14 centers implanting the WiSE-CRT system as part of the WiCS-LV Post Market Surveillance Registry. (ClinicalTrials.gov Identifier: NCT02610673).

Results: Ninety patients from 14 European centers underwent implantation with the WiSE-CRT system. Patients were predominantly male, age 68.2 ± 10.5 years, left ventricular ejection fraction 30.6% ± 8.9%, mean QRS duration 180.7 ± 27.0 ms, and 40% with ischemic etiology. Successful implantation and delivery of BiV ENDO pacing was achieved in 94.4% of patients. Acute (<24 hours), 1- to 30-day, and 1- to 6-month complications rates were 4.4%, 18.8%, and 6.7%, respectively. Five deaths (5.6%) occurred within 6 months (3 procedure related). Seventy percent of patients had improvement in heart failure symptoms.

Conclusion: BiV ENDO pacing with the WiSE-CRT system seems to be technically feasible, with a high success rate. Three procedural deaths occurred during the study. Procedural complications mandate adequate operator training and implantation at centers with immediately available cardiothoracic and vascular surgical support.
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http://dx.doi.org/10.1016/j.hrthm.2020.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7397503PMC
August 2020

Complex Interaction Between Low-Frequency APD Oscillations and Beat-to-Beat APD Variability in Humans Is Governed by the Sympathetic Nervous System.

Front Physiol 2019 22;10:1582. Epub 2020 Jan 22.

Institute of Cardiovascular Science, University College London, London, United Kingdom.

Background: Recent clinical, experimental and modeling studies link oscillations of ventricular repolarization in the low frequency (LF) (approx. 0.1 Hz) to arrhythmogenesis. Sympathetic provocation has been shown to enhance both LF oscillations of action potential duration (APD) and beat-to-beat variability (BVR) in humans. We hypothesized that beta-adrenergic blockade would reduce LF oscillations of APD and BVR of APD in humans and that the two processes might be linked.

Methods And Results: Twelve patients with normal ventricles were studied during routine electrophysiological procedures. Activation-recovery intervals (ARI) as a conventional surrogate for APD were recorded from 10 left and 10 right ventricular endocardial sites before and after acute beta-adrenergic adrenergic blockade. Cycle length was maintained constant with right ventricular pacing. Oscillatory behavior of ARI was quantified by spectral analysis and BVR as the short-term variability. Beta-adrenergic blockade reduced LF ARI oscillations (8.6 ± 4.5 ms vs. 5.5 ± 3.5 ms, = 0.027). A significant correlation was present between the initial control values and reduction seen following beta-adrenergic blockade in LF ARI ( = 0.62, = 0.037) such that when initial values are high the effect is greater. A similar relationship was also seen in the beat-to beat variability of ARI ( = 0.74, = 0.008). There was a significant correlation between the beta-adrenergic blockade induced reduction in LF power of ARI and the witnessed reduction of beat-to-beat variability of ARI ( = 0.74, = 0.01). These clinical results accord with recent computational modeling studies which provide mechanistic insight into the interactions of LF oscillations and beat-to-beat variability of APD at the cellular level.

Conclusion: Beta-adrenergic blockade reduces LF oscillatory behavior of APD (ARI) in humans . Our results support the importance of LF oscillations in modulating the response of BVR to beta-adrenergic blockers, suggesting that LF oscillations may play role in modulating beta-adrenergic mechanisms underlying BVR.
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http://dx.doi.org/10.3389/fphys.2019.01582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987475PMC
January 2020

Simulating ventricular systolic motion in a four-chamber heart model with spatially varying robin boundary conditions to model the effect of the pericardium.

J Biomech 2020 03 21;101:109645. Epub 2020 Jan 21.

Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

The pericardium affects cardiac motion by limiting epicardial displacement normal to the surface. In computational studies, it is important for the model to replicate realistic motion, as this affects the physiological fidelity of the model. Previous computational studies showed that accounting for the effect of the pericardium allows for a more realistic motion simulation. In this study, we describe the mechanism through which the pericardium causes improved cardiac motion. We simulated electrical activation and contraction of the ventricles on a four-chamber heart in the presence and absence of the effect of the pericardium. We simulated the mechanical constraints imposed by the pericardium by applying normal Robin boundary conditions on the ventricular epicardium. We defined a regional scaling of normal springs stiffness based on image-derived motion from CT images. The presence of the pericardium reduced the error between simulated and image-derived end-systolic configurations from 12.8±4.1 mm to 5.7±2.5 mm. First, the pericardium prevents the ventricles from spherising during isovolumic contraction, reducing the outward motion of the free walls normal to the surface and the upwards motion of the apex. Second, by restricting the inward motion of the free and apical walls of the ventricles the pericardium increases atrioventricular plane displacement by four folds during ejection. Our results provide a mechanistic explanation of the importance of the pericardium in physiological simulations of electromechanical cardiac function.
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http://dx.doi.org/10.1016/j.jbiomech.2020.109645DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677892PMC
March 2020

Financial and resource costs of transvenous lead extraction in a high-volume lead extraction centre.

Heart 2020 Jun 13;106(12):931-937. Epub 2020 Jan 13.

Cardiology Department, Guy's and Saint Thomas' NHS Foundation Trust, London, UK.

Objectives: Transvenous lead extraction (TLE) poses a significant economic and resource burden on healthcare systems; however, limited data exist on its true cost. We therefore estimate real-world healthcare reimbursement costs of TLE to the UK healthcare system at a single extraction centre.

Methods: Consecutive admissions entailing TLE at a high-volume UK centre between April 2013 and March 2018 were prospectively recorded in a computer registry. In the hospital's National Health Service (NHS) clinical coding/reimbursement database, 447 cases were identified. Mean reimbursement cost (n=445) and length of stay (n=447) were calculated. Ordinary least squares regressions estimated the relationship between cost (bed days) and clinical factors.

Results: Mean reimbursement cost per admission was £17 399.09±£13 966.49. Total reimbursement for all TLE admissions was £7 777 393.51. Mean length of stay was 16.3±15.16 days with a total of 7199 bed days. Implantable cardioverter-defibrillator and cardiac resynchronisation therapy defibrillator devices incurred higher reimbursement costs (70.5% and 68.7% higher, respectively, both p<0.001). Heart failure and prior valve surgery also incurred significantly higher reimbursement costs. Prior valve surgery and heart failure were associated with 8.3 (p=0.017) and 5.5 (p=0.021) additional days in hospital, respectively.

Conclusions: Financial costs to the NHS from TLE are substantial. Consideration should therefore be given to cost/resource-sparing potential of leadless/extravascular cardiac devices that negate the need for TLE particularly in patients with prior valve surgery and/or heart failure. Additionally, use of antibiotic envelopes and other interventions that reduce infection risk in patients receiving transvenous leads should be considered.
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http://dx.doi.org/10.1136/heartjnl-2019-315839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7282498PMC
June 2020

Evidence of reverse electrical remodelling by non-invasive electrocardiographic imaging to assess acute and chronic changes in bulk ventricular activation following cardiac resynchronisation therapy.

J Electrocardiol 2020 Jan - Feb;58:96-102. Epub 2019 Nov 26.

Division of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom; Cardiovascular Department, Guys and St Thomas NHS Foundation Trust, London, United Kingdom.

Introduction: Cardiac resynchronisation therapy (CRT) corrects electrical dyssynchrony. However, the temporal changes in the electrical timing according to substrate are unclear. We used electrocardiographic imaging (ECGi) for serial non-invasive assessment of the underlying electrical substrate and its response to resynchronisation.

Material And Methods: ECGi activation maps were constructed 1 day and 6 months post CRT implant. ECGi maps were analysed offline to determine the total ventricular activation time (TVaT) and the time for the bulk of ventricular activation (10 to 90 percentile activation; VaT Index). Statistical analysis was performed using repeated measures ANOVA with post-hoc pairwise comparisons using paired t-tests. The % relative change within each time point was also calculated and compared between the two time points.

Results: Eleven CRT patients were studied. Both total and bulk ventricular activation significantly decreased with CRT turned ON at day 1. Intrinsic (CRT OFF) TVaT and VaT Index at day 1 were 143 ± 23 and 84 ± 20 ms, respectively, and they significantly decreased post CRT to 115 ± 26 ms (P < 0.001) and 49 ± 17 ms (P < 0.05), respectively. The relative change at day 1 was also statistically significant for TVaT (19 ± 12%, P < 0.001) and VaT Index (39 ± 25%, P < 0.001). After 6 months, the relative decrease in TVaT with CRT ON remained stable (19% vs. 18% at day 1 and 6 months, respectively) whereas reduction the in VaT Index was decreased 39% vs. 26% at day 1 and 6 months, respectively. In non-ischaemic patients both total and bulk activation times reduced following CRT. Volumetric responders exhibited an electrical remodelling for bulk activation not apparent in Non-responders, after 6 months of CRT ON.

Conclusions: Intrinsic bulk myocardium activation becomes more rapid and synchronous with CRT. The bulk activation time is more susceptible to improvement by CRT in ischaemic patients and volumetric responders. These observations are consistent with CRT causing reverse electrophysiological remodelling in the bulk myocardium, but not in late-activating ischaemic or fibrotic regions.
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http://dx.doi.org/10.1016/j.jelectrocard.2019.11.051DOI Listing
November 2019

Evaluation of the reentry vulnerability index to predict ventricular tachycardia circuits using high-density contact mapping.

Heart Rhythm 2020 04 18;17(4):576-583. Epub 2019 Nov 18.

Institute of Cardiovascular Science, University College London, London, United Kingdom; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom. Electronic address:

Background: Identifying arrhythmogenic sites to improve ventricular tachycardia (VT) ablation outcomes remains unresolved. The reentry vulnerability index (RVI) combines activation and repolarization timings to identify sites critical for reentrant arrhythmia initiation without inducing VT.

Objective: The purpose of this study was to provide the first assessment of RVI's capability to identify VT sites of origin using high-density contact mapping and comparison with other activation-repolarization markers of functional substrate.

Methods: Eighteen VT ablation patients (16 male; 72% ischemic) were studied. Unipolar electrograms were recorded during ventricular pacing and analyzed offline. Activation time (AT), activation-recovery interval (ARI), and repolarization time (RT) were measured. Vulnerability to reentry was mapped based on RVI and spatial distribution of AT, ARI, and RT. The distance from sites identified as vulnerable to reentry to the VT site of origin was measured, with distances <10 mm and >20 mm indicating accurate and inaccurate localization, respectively.

Results: The origins of 18 VTs (6 entrainment, 12 pace-mapping) were identified. RVI maps included 1012 (408-2098) (median, 1st-3rd quartiles) points per patient. RVI accurately localized 72.2% VT sites of origin, with median distance of 5.1 (3.2-10.1) mm. Inaccurate localization was significantly less frequent for RVI than AT (5.6% vs 33.3%; odds ratio 0.12; P = .035). Compared to RVI, distance to VT sites of origin was significantly larger for sites showing prolonged RT and ARI and were nonsignificantly larger for sites showing highest AT and ARI gradients.

Conclusion: RVI identifies vulnerable regions closest to VT sites of origin. Activation-repolarization metrics may improve VT substrate delineation and inform novel ablation strategies.
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http://dx.doi.org/10.1016/j.hrthm.2019.11.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105818PMC
April 2020

Transvenous lead extraction procedures in women based on ESC-EHRA EORP European Lead Extraction ConTRolled ELECTRa registry: is female sex a predictor of complications?

Europace 2019 12;21(12):1890-1899

Direttore UO Cardiologia 2 SSN, Azienda Ospedaliero-Universitaria, Pisa, Italy.

Aims: Female sex is considered an independent risk factor of transvenous leads extraction (TLE) procedure. The aim of the study was to evaluate the effectiveness of TLE in women compared with men.

Methods And Results: A post hoc analysis of risk factors and effectiveness of TLE in women and men included in the ESC-EHRA EORP ELECTRa registry was conducted. The rate of major complications was 1.96% in women vs. 0.71% in men; P = 0.0025. The number of leads was higher in men (mean 1.89 vs. 1.71; P < 0.0001) with higher number of abandoned leads in women (46.04% vs. 34.82%; P < 0.0001). Risk factors of TLE differed between the sexes, of which the major were: signs and symptoms of venous occlusion [odds ratio (OR) 3.730, confidence interval (CI) 1.401-9.934; P = 0.0084], cumulative leads dwell time (OR 1.044, CI 1.024-1.065; P < 0.001), number of generator replacements (OR 1.029, CI 1.005-1.054; P = 0.0184) in females and the number of leads (OR 6.053, CI 2.422-15.129; P = 0.0001), use of powered sheaths (OR 2.742, CI 1.404-5.355; P = 0.0031), and white blood cell count (OR 1.138, CI 1.069-1.212; P < 0.001) in males. Individual radiological and clinical success of TLE was 96.29% and 98.14% in women compared with 98.03% and 99.21% in men (P = 0.0046 and 0.0098).

Conclusion: The efficacy of TLE was lower in females than males, with a higher rate of periprocedural major complications. The reasons for this difference are probably related to disparities in risk factors in women, including more pronounced leads adherence to the walls of the veins and myocardium. Lead management may be key to the effectiveness of TLE in females.
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http://dx.doi.org/10.1093/europace/euz277DOI Listing
December 2019

Scar shape analysis and simulated electrical instabilities in a non-ischemic dilated cardiomyopathy patient cohort.

PLoS Comput Biol 2019 10 28;15(10):e1007421. Epub 2019 Oct 28.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.

This paper presents a morphological analysis of fibrotic scarring in non-ischemic dilated cardiomyopathy, and its relationship to electrical instabilities which underlie reentrant arrhythmias. Two dimensional electrophysiological simulation models were constructed from a set of 699 late gadolinium enhanced cardiac magnetic resonance images originating from 157 patients. Areas of late gadolinium enhancement (LGE) in each image were assigned one of 10 possible microstructures, which modelled the details of fibrotic scarring an order of magnitude below the MRI scan resolution. A simulated programmed electrical stimulation protocol tested each model for the possibility of generating either a transmural block or a transmural reentry. The outcomes of the simulations were compared against morphological LGE features extracted from the images. Models which blocked or reentered, grouped by microstructure, were significantly different from one another in myocardial-LGE interface length, number of components and entropy, but not in relative area and transmurality. With an unknown microstructure, transmurality alone was the best predictor of block, whereas a combination of interface length, transmurality and number of components was the best predictor of reentry in linear discriminant analysis.
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http://dx.doi.org/10.1371/journal.pcbi.1007421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6837623PMC
October 2019

Comparison of outcomes in infected cardiovascular implantable electronic devices between complete, partial, and failed lead removal: an ESC-EHRA-EORP ELECTRa (European Lead Extraction ConTrolled) registry.

Europace 2019 12;21(12):1876-1889

Integrated Heart Center, Shaare Zedek Medical Center, Jerusalem, Israel.

Aims: The present study sought to determine predictors for success and outcomes of patients who underwent cardiac implantable electronic devices (CIED) extraction indicated for systemic or local CIED related infection in particular where complete lead removal could not be achieved.

Methods And Results: ESC-EORP ELECTRa (European Lead Extraction ConTRolled Registry) is a European prospective lead extraction registry. Out of the total cohort, 1865/3510 (52.5%) patients underwent removal due to CIED related infection. Predictors and outcomes of failure were analysed. Complete removal was achieved in 1743 (93.5%) patients, partial (<4 cm of lead left) in 88 (4.7%), and failed (>4 cm of lead left) in 32 (1.8%) patients. Removal success was unrelated to type of CIED infection (pocket or systemic). Predictors for failure were older leads and older patients [odds ratio (OR) 1.14 (1.08-1.19), P < 0.0001 and OR 2.68 (1.22-5.91), P = 0.0146, respectively]. In analysis by lead, predictors for failure were: pacemaker vs. defibrillator removal and failure to engage the locking stylet all the way to the tip [OR 0.20 (0.04-0.95), P = 0.03 and OR 0.32 (0.13-0.74), P = 0.008, respectively]. Significantly higher complication rates were noted in the failure group (40.6% vs. 15.9 for partial and 8.7% for success groups, P < 0.0001). Failure to remove a lead was a strong predictor for in hospital mortality [hazard ratio of 2.05 (1.01-4.16), P = 0.046].

Conclusion: A total of 6.5% of infected CIED patients failed attempted extraction. Only were >4 cm of lead remained resulted in higher procedural complications and mortality rates.
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http://dx.doi.org/10.1093/europace/euz269DOI Listing
December 2019

Sex-Dependent QRS Guidelines for Cardiac Resynchronization Therapy Using Computer Model Predictions.

Biophys J 2019 12 28;117(12):2375-2381. Epub 2019 Aug 28.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK. Electronic address:

Cardiac resynchronization therapy (CRT) is an important treatment for heart failure. Low female enrollment in clinical trials means that current CRT guidelines may be biased toward males. However, females have higher response rates at lower QRS duration (QRSd) thresholds. Sex differences in the left ventricle (LV) size could provide an explanation for the improved female response at lower QRSd. We aimed to test if sex differences in CRT response at lower QRSd thresholds are explained by differences in LV size and hence predict sex-specific guidelines for CRT. We investigated the effect that LV size sex difference has on QRSd between male and females in 1093 healthy individuals and 50 CRT patients using electrophysiological computer models of the heart. Simulations on the healthy mean shape models show that LV size sex difference can account for 50-100% of the sex difference in baseline QRSd in healthy individuals. In the CRT patient cohort, model simulations predicted female-specific guidelines for CRT, which were 9-13 ms lower than current guidelines. Sex differences in the LV size are able to account for a significant proportion of the sex difference in QRSd and provide a mechanistic explanation for the sex difference in CRT response. Simulations accounting for the smaller LV size in female CRT patients predict 9-13 ms lower QRSd thresholds for female CRT guidelines.
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http://dx.doi.org/10.1016/j.bpj.2019.08.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6990372PMC
December 2019

Clinical impact of antithrombotic therapy in transvenous lead extraction complications: a sub-analysis from the ESC-EORP EHRA ELECTRa (European Lead Extraction ConTRolled) Registry.

Europace 2019 Jul;21(7):1096-1105

Second Division of Cardiology, Department of Cardiac-Thoracic & Vascular, Azienda Ospedaliera Pisana, Via Paradisa 2, Pisa, Italy.

Aims: A sub-analysis of the ESC-EHRA European Lead Extraction ConTRolled (ELECTRa) Registry to evaluate the clinical impact of antithrombotic (AT) on transvenous lead extraction (TLE) safety and efficacy.

Methods And Results: ELECTRa outcomes were compared between patients without AT therapy (No AT Group) and with different pre-operative AT regimens, including antiplatelets (AP), anticoagulants (AC), or both (AP + AC). Out of 3510 pts, 2398 (68%) were under AT pre-operatively. AT patients were older with more comorbidities (P < 0.0001). AT subgroups, defined as AP, AC, or AP + AC, were 1096 (31.2%), 985 (28%), and 317 (9%), respectively. Regarding AP patients, 1413 (40%) were under AP, 1292 (91%) with a single AP, interrupted in 26% about 3.8 ± 3.7 days before TLE. In total, 1302 (37%) patients were under AC, 881 vitamin K antagonist (68%), 221 (17%) direct oral anticoagulants, 155 (12%) low weight molecular heparin, and 45 (3.5%) unfractionated heparin. AC was 'interrupted without bridging' in 696 (54%) and 'interrupted with bridging' in 504 (39%) about 3.3 ± 2.3 days before TLE, and 'continued' in 87 (7%). TLE success rate was high in all subgroups. Only overall in-hospital death (1.4%), but not the procedure-related one, was higher in the AT subgroups (P = 0.0500). Age >65 years and New York Heart Association Class III/IV, but not AT regimens, were independent predictors of death for any cause. Haematomas were more frequent in AT subgroups, especially in AC 'continued' (P = 0.025), whereas pulmonary embolism in the No-AT (P < 0.01).

Conclusions: AT minimization is safe in patients undergoing TLE. AT does not seem to predict death but identifies a subset of fragile patients with a worse in-hospital TLE outcome.
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http://dx.doi.org/10.1093/europace/euz062DOI Listing
July 2019