Literatura académica sobre el tema "Technique de resynchronisation"

Conduction system pacing (CSP) is a technique of pacing that involves implantation of permanent pacing leads along different sites of the cardiac conduction system and includes His bundle pacing and left bundle branch pacing. There is an emerging role for CSP to achieve cardiac resynchronisation in patients with heart failure with reduced ejection fraction and inter-ventricular dyssynchrony. In this article, the authors review these strategies for resynchronisation and the available data on the use of CSP in overcoming dyssynchrony.

The authors describe a novel three-dimensional, 252-lead electrocardiography (ECG) and computed tomography (CT)-based non-invasive cardiac imaging and mapping modality. This technique images potentials, electrograms and activation sequences (isochrones) on the epicardial surface of the heart. This tool has been investigated in the normal cardiac electrophysiology and various tachyarrhythmic, conduction and anomalous depo-repolarisation disorders. The clinical application of this system includes a wide range of electrical disorders like atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beat, ventricular tachycardia) and ventricular pre-excitation (Wolff-Parkinson-White syndrome). In addition, the system has been used in exploring abnormalities of the His-Purkinje conduction like the bundle branch block and intraventricular conduction disturbance and thereby useful in electrically treating the associated heart failure (cardiac resynchronisation). It has a potential role in furthering our understanding of abnormalities of ventricular action potential (depolarisation [Brugada syndrome and repolarisation], long QT and early repolarisation syndromes) and in evaluating the impact of drugs on His-Purkinje conduction and cardiac action potential.

Introduction: Cardiac resynchronisation therapy is ineffective in 30–40% of patients with heart failure with reduced ejection fraction. Targeting non-scarred myocardium by selecting the site of latest mechanical activation using echocardiography has been suggested to improve outcomes but at the cost of increased resource utilisation. The interval between the beginning of the QRS complex and the local LV lead electrogram (QLV) might represent an alternative electrical marker. Aims: To determine whether the site of latest myocardial electrical and mechanical activation are concordant. Methods: This was a single-centre, prospective pilot study, enrolling patients between March 2019 and June 2021. Patients underwent speckle-tracking echocardiography (STE) prior to CRT implantation. Intra-procedural QLV measurement and R-wave amplitude were performed in a blinded fashion at all accessible coronary sinus branches. Pearson’s correlation coefficient and Cohen’s Kappa coefficient were utilised for the comparison of electrical and echocardiographic parameters. Results: A total of 20 subjects had complete data sets. In 15, there was a concordance at the optimal site between the electrically targeted region and the mechanically targeted region; in four, the regions were adjacent (within one segment). There was discordance (≥2 segments away) in only one case between the two methods of targeting. There was a statistically significant increase in procedure time and fluoroscopy duration using the intraprocedural QLV strategy. There was no statistical correlation between the quantitative electrical and echocardiographic data. Conclusions: A QLV-guided approach to targeting LV lead placement appears to be a potential alternative to the established echocardiographic-guided technique. However, it is associated with prolonged fluoroscopy and overall procedure time.

ObjectiveComplex cardiac devices including implantable cardioverter defibrillator (ICD) and cardiac resynchronisation therapy (CRT) devices can safely be implanted as a day case procedure as opposed to overnight stay. We assess how common day case complex device therapy is and the cost implications of more widespread adoption across the UK.MethodsA freedom of information request was sent to all centres performing complex cardiac devices across the UK to assess the adoption of this technique. Cost implications were assessed using Department of Health National Schedule of Reference Costs 2016–2017.Results100 UK centres were surveyed, 80% replied. Eighty per cent of UK centres already implant complex cardiac devices as a day case to some extent. 64.06% of centres have a protocol for this. 12.82% of centres do <25% of complex devices as a day case. 15.38% do 25%–50% as day case. 17.95% do 50%–75% as day case and 33.33% do >75% as day case. There was no relationship between centre volume and the proportion of devices done as a day case as opposed to overnight stay. The cost saving of performing a complex device as a day case as opposed to overnight stay was £412 per ICD, £525 per CRT-pacemaker and £2169 per CRT-defibrillator.ConclusionsDay case complex devices are already widespread across the UK, however, there is scope for increase. An increase in proportion of day case devices could translate to £5 583 265 in savings annually for the National Health Service if all centres performed 75% of devices as a day case.

Cardiac resynchronisation therapy is an important intervention to reduce mortality and morbidity, but even in carefully selected patients approximately 30% fail to improve. This has led to alternative pacing approaches to improve patient outcomes. Left ventricular (LV) endocardial pacing allows pacing at site-specific locations that enable the operator to avoid myocardial scar and target areas of latest activation. Left bundle branch area pacing (LBBAP) provides a more physiological activation pattern and may allow effective cardiac resynchronisation. This article discusses LV endocardial pacing in detail, including the indications, techniques and outcomes. It discusses LBBAP, its potential benefits over His bundle pacing and procedural outcomes. Finally, it concludes with the future role of endocardial pacing and LBBAP in heart failure patients.

Cardiac resynchronisation therapy (CRT) is an important therapy for patients with heart failure with a reduced ejection fraction and interventricular conduction delay. Large trials have established the role of CRT in reducing heart failure hospitalisations and improving symptoms, left ventricular (LV) function and mortality. Guidelines from major medical societies are consistent in support of CRT for patients with New York Health Association (NYHA) class II, III and ambulatory class IV heart failure, reduced LV ejection fraction and QRS prolongation, particularly left bundle branch block. The current challenge facing practitioners is to maximise the rate of patients who respond to CRT and the magnitude of that response. Current areas of interest for achieving these goals include tailoring patient selection, individualising LV lead placement and application of new technologies and techniques for CRT delivery.

Cardiac resynchronisation therapy (CRT) is a standard treatment for patients with heart failure; however, the low response rate significantly reduces its cost-effectiveness. A favourable CRT response primarily depends on whether implanters can identify the optimal left ventricular (LV) lead position and accurately place the lead at the recommended site. Myocardial imaging techniques, including echocardiography, cardiac magnetic resonance imaging and nuclear imaging, have been used to assess LV myocardial viability and mechanical dyssynchrony, and deduce the optimal LV lead position. The optimal position, presented as a segment of the myocardial wall, is then overlaid with images of the coronary veins from fluoroscopy to aid navigation of the LV lead to the target venous site. Once validated by large clinical trials, these image-guided techniques for CRT lead placement may have an impact on current clinical practice.

Cardiac resynchronisation therapy (CRT) is a standard treatment for patients with heart failure; however, the low response rate significantly reduces its cost-effectiveness. A favourable CRT response primarily depends on whether implanters can identify the optimal left ventricular (LV) lead position and accurately place the lead at the recommended site. Myocardial imaging techniques, including echocardiography, cardiac magnetic resonance imaging and nuclear imaging, have been used to assess LV myocardial viability and mechanical dyssynchrony, and deduce the optimal LV lead position. The optimal position, presented as a segment of the myocardial wall, is then overlaid with images of the coronary veins from fluoroscopy to aid navigation of the LV lead to the target venous site. Once validated by large clinical trials, these image-guided techniques for CRT lead placement may have an impact on current clinical practice.

L'évolution de la surveillance de l'état des structures (SHM) au cours des dernières années a vu émerger des réseaux de capteurs indépendants à faibles ressources matérielles. Cependant, les signaux enregistrés par ces capteurs pour faire de l'imagerie passive peuvent présenter des désynchronisations qui rendent difficile la localisation des endommagements dans la structure inspectée. Bien que la technique de pic de corrélation (PCT), reposant sur la symétrie des fonctions de corrélation de bruit, puisse être appliquée pour corriger ces décalages, une synchronisation parfaite est difficile à atteindre en présence de bruit électronique et/ou de reconstruction de la fonction de Green. Dans ce manuscrit, une étude du comportement des erreurs résiduelles liées à une resynchronisation imparfaite, en fonction des paramètres statistiques du bruit, est menée. Puis, la dégradation du contraste des images de localisation des défauts est quantifiée en fonction de l'écart type de ces erreurs de resynchronisation. Par la suite, un processus basé sur la pseudo-inversion de Moore-Penrose est développé pour minimiser ces erreurs et améliorer la qualité des images de localisation. Cette étude est ensuite étendue au cas de la localisation de défauts à diffusion anisotrope. Enfin, une étude de faisabilité est effectuée sur un réseau de capteurs communicants sans fil
The evolution of structural health monitoring (SHM) in recent years has witnessed the emergence of independent sensor networks with limited material resources. However, the signals recorded by these sensors for passive imaging can exhibit desynchronizations that make it difficult to locate damage in the inspected structure. Although the peak correlation technique (PCT), based on the symmetry of noise correlation functions, can be applied to correct these offsets, achieving perfect synchronization is challenging in the presence of electronic noise and/or reconstruction of the Green's function. In this manuscript, a study of the behavior of residual errors associated with imperfect resynchronization, as a function of the statistical parameters of noise, is conducted. Then, the degradation of the contrast of defect localization images is quantified as a function of the standard deviation of these resynchronization errors. Subsequently, a process based on the Moore-Penrose pseudo-inversion is developed to minimize these errors and improve the quality of the localization images. This study is then extended to the case of defect localization with anisotropic scattering. Finally, a feasibility study is carried out on a network of wireless communicating sensors

Les techniques de référence à rang réduit sont couramment employées pour résoudre les problèmes d’extraction de source et de resynchronisation de champs physiques, lorsque le nombre de références dépasse celui des sources incohérentes. Dans ce cas, la matrice croisée-spectrale devient mal conditionnée, rendant la solution des moindres carrés invalide. Bien que la décomposition en valeurs singulières tronquée (DVST) soit utilisée pour résoudre ce problème, elle n'est valable que pour un bruit scalaire sur les références. De plus, il est difficile de définir un seuil de troncature lorsque les valeurs singulières diminuent progressivement. Cette thèse propose une solution nommée technique de référence maximale-coherent (RMC), basée sur la recherche d’un ensemble de références virtuelles maximales correlées avec les mesures de champ. Cette technique est optimale, surtout en présence d’un bruit corrélé sur la référence. Cependant, elle nécessite également une troncature des valeurs propres, exigeant la connaissance ou l’estimation préalable du nombre de sources incohérentes, un problème inverse mal posé et peu étudié. La thèse présente trois méthodes d’énumération de sources applicables à toutes les techniques de référence : un test du rapport de vraisemblance contre le modèle saturé, une technique de bootstrap paramétrique et une approche de validation croisée. Une étude comparative basée sur des données numériques et expérimentales montre deux résultats importants. D'abord, le nombre de fenêtres spectrales utilisées affecte grandement la performance des trois méthodes, qui se comportent différemment selon ce nombre. Ensuite, le bootstrap paramétrique s’avère être la meilleure méthode en termes de précision et de robustesse par rapport au nombre de fenêtres utilisées. Enfin, la technique RMC accompagnée de bootstrap a été utilisée pour l’extraction de source et la resynchronisation de données réelles provenant d’expériences en laboratoire et d’un moteur électrique, fournissant de meilleurs résultats que la solution des moindres carrés et la DVST dans les mêmes conditions
Rank-reduced reference/coherence techniques based on the use of references, i.e. fixed sensors, are widely used to solve the two equivalent problems of source extraction and resynchronization encountered during remote sensing of physical fields, when the number of references surpasses the number of incoherent sources. In such case, the cross-spectral matrix (CSM) becomes ill-conditioned, resulting in the invalidity of the least squares LS solution. Although the truncated singular value decomposition (TSVD) was successfully applied in the literature to solve this problem, its validity is limited only to the case of scalar noise on the references. It is also very difficult to define a threshold, for truncation, when the singular values are gradually decreasing. This thesis proposes a solution based on finding a set of virtual references that is maximally correlated with the field measurements, named the maximally-coherent reference (MCR) Technique. This solution is optimal, especially, in the case of correlated noise on the reference, where TSVD fails. However the technique also includes an eigenvalue truncation step, similar to the one required for the TSVD, which necessitates a priori knowledge or the estimation of the number of incoherent sources, i.e. source enumeration, which is an ill-posed inverse problem, insufficiently investigated in the literature within the framework of reference techniques. In this thesis, after providing a unified formalism for all the reference techniques in the literature, three alternative source enumeration methods, applicable to all the reference techniques, were presented namely; a direct likelihood ratio test (LRT) against the saturated model, a parametric bootstrap technique and a cross-validation approach. A comparative study is performed among the three methods, based on simulated numerical data, real sound experimental data, and real electrical motor data. The results showed two important outcomes. The first is that the number of snapshots (spectral windows), used in the spectral analysis, greatly affects the performance of the three methods, and that, they behave differently for the same number of used snapshots. The second is that parametric bootstrapping turned out to be the best method in terms of both estimation accuracy and robustness with regard to the used number of snapshots. Finally, the MCR technique accompanied with bootstrapping was employed for source extraction and resynchronization of real data from laboratory experiments, and an e-motor, and it returned better results than the LS solution and the TSVD when employed for the same purpose

Ce travail de thèse se place dans le contexte clinique de la Thérapie par Resynchronisation Cardiaque (CRT), approche thérapeutique efficace pour les patients souffrant d'insuffisance cardiaque et d'asynchronie ventriculaire. Dans le cadre de la stimulation biventriculaire, la stimulation de la paroi latérale du ventricule gauche via le réseau veineux coronaire, pose en particulier problème. La planification de ce geste interventionnel à partir de données pré-opératoires permettrait d'optimiser la procédure. Afin d'atteindre cet objectif, ce travail a pour finalité l'extraction et la caractérisation 3D du réseau veineux en imagerie scanner multibarrette acquise en phase pré-opératoire. Une approche hybride a été développée spécifiquement pour la détection de vaisseaux présentant des inhomogénéités de contraste. Cette méthode est composée d'un algorithme de suivi de vaisseau 3D basé sur les chemins minimaux, permettant l'extraction d'un vaisseau sur toute sa longueur avec une première estimation de sa ligne centrale. Cette extraction est ensuite complétée par une estimation précise des paramètres locaux du vaisseau à l'aide des moments géométriques. La méthode a été évaluée sur les veines coronaires d'intérêt pour la CRT à partir de bases scanner acquises en phase pré-opératoire. Enfin, une analyse prospective des problèmes liés à la planification de la pose du stimulateur ventriculaire gauche via le réseau veineux a été effectuée.

Les procédures d’électrophysiologie cardiaque ont démontré leur efficacité pour la suppression de symptômes d’arythmie et d’insuffisance cardiaque. Leur taux de succès dépend de la bonne connaissance de l’état du cœur du patient, en termes de conductivité électrique, de qualité tissulaire, et de propriétés mécaniques. Cette intégration d’informations est un enjeu clinique majeur pour ces thérapies. Cette thèse porte sur le développement et l’exploitation de modèles multimodaux spécifiques au patient, pour la planification et l’assistance de l’ablation par radiofréquences (ARF) et de la thérapie de resynchronisation cardiaque (CRT). Des méthodes de segmentation, de recalage et de fusion d’informations multimodales ont dans un premier temps été établies pour la création de ces modèles, permettant de planifier ces procédures. Puis, des approches spécifiques à chacune ont été mises en œuvre pour intégrer ces modèles dans le bloc opératoire, pour assister le geste clinique. Enfin, une analyse postopératoire a permis la synthèse d’un nouveau descripteur multimodal, visant à prédire la réponse de la CRT suivant le site choisi de stimulation du ventricule gauche. Ces études ont été appliquées et validées pour des patients candidats à la CRT et à l’ARF. Elles ont montré la faisabilité et l’intérêt d’intégrer ces modèles multimodaux dans le workflow clinique pour l’assistance à ces gestes interventionnels
Cardiac electrophysiology procedures have been proved to be efficient to suppress arrythmia and heart failure symptoms. Their success rate depends on patient’s heart condition’s knowledge, including electrical and mechanical functions and tissular quality. It is a major clinical concern for these therapies. This work focuses on the development of specific patient multimodal model to plan and assist radio-frequency ablation (RFA) and cardiac resynchronization therapy (CRT). First, segmentation, registration and fusion methods have been developped to create these models, allowing to plan these interventional procedures. For each therapy, specific means of integration within surgical room have been established, for assistance purposes. Finally, a new multimodal descriptor has been synthesized during a post-procedure analysis, aiming to predict the CRT’s response depending on the left ventricular stimulation site. These studies have been applied and validated on patients candidate to CRT and ARF. They showed the feasibility and interest of integrating such multimodal models in the clinical workflow to assist these procedures