Academic literature on the topic 'Synchronisation ventriculaire'

La tomoscintigraphie de perfusion myocardique (TSM) est largement reconnue pour établir le diagnostic de coronaropathie, mais aussi pour en évaluer le pronostic. La TSM reste cependant la technique de référence pour explorer l’ischémie myocardique, en particulier à l’effort, la seule méthode de stress physiologique et dont les résultats peuvent être extrapolés aux conditions de la vie courante. En raison de cette propriété spécifique, la TSM devrait rester une technique majeure dans l’exploration et la surveillance des patients coronariens chroniques. La synchronisation des acquisitions à l’électrocardiogramme (ECG), en permettant une étude couplée de la fonction ventriculaire gauche globale et de la cinétique segmentaire, a amélioré les performances diagnostiques (en augmentant la sensibilité et la spécificité de la scintigraphie de perfusion seule) et a apporté des informations pronostiques complémentaires indépendantes.

AbstractWe report the simultaneous use of cardiac re-synchronisation therapy and total cavopulmonary connection in a patient with dyssynchrony, wide QRS, and cardiac failure. To our knowledge, this simultaneous approach has not been reported previously. On follow-up, we noted that QRS width and brain natriuretic peptide levels improved. In addition, speckle tracking revealed improved synchronisation of ventricular wall motion.

AbstractExtrapolating cardiac resynchronization therapy (CRT) to pediatric patients with heart failure has at times been difficult given the heterogeneity of pediatric cardiomyopathies, varying congenital heart disease (CHD) substrates, and the fact that most pediatric heart failure patients have right bundle branch block (RBBB) as opposed to LBBB. Yet, despite these limitations a number of multi-center retrospective studies in North America and Europe have identified some data to suggest that certain sub-populations tend to respond positively to CRT. In order to address some of the heterogeneity it is helpful to subdivide pediatric and young adult patients with CHD into four potential groups: (1) CRT for chronic RV pacing, (2) dilated cardiomyopathies, (3) pulmonary right ventricles, and (4) systemic right ventricles. The chronic RV paced group, especially long-standing RV apical pacing, with ventricular dyssynchrony has consistently shown to be the group that best responds to a proactive resynchronization course. CRT therapy in pulmonary right ventricles such as post-op tetralogy of Fallot have shown some promise and may be considered especially if there is evidence of concomitant left ventricular dysfunction with an electrical dyssynchrony. Patients with systemic right ventricles such as post-atrial baffle surgery or congenitally corrected transposition reportedly do well with CRT in the presence of both inter-ventricular and intra-ventricular dyssynchrony. There is little doubt that moving forward to best way to identify which pediatric patients with heart failure will respond to CRT, will require a collaborative effort between the electrophysiologist and the echocardiographer to identify appropriate candidates with electrical and mechanical dyssynchrony.

IntroductionRecent studies have shown that the His-Purkinje system pacing (HPSP) can achieve electrocardiomechanical synchronisation, and thus improve cardiac function. For patients with pacing-induced cardiomyopathy (PICM) who should be treated with pacemaker upgrade, the HPSP is a viable alternative to cardiac resynchronisation therapy (CRT). However, no randomised controlled trial has been performed to evaluate the efficacy and safety of HPSP in patients with PICM. The present study compared the efficacy and safety of HPSP with that of traditional CRT in the treatment of patients with PICM.Methods and analysisThis study is a single-centre, randomised controlled non-inferiority trial. This trial was carried out at the cardiac centre of Beijing Anzhen Hospital. A total of 46 patients with PICM who needed pacemaker upgrade treatment between January 2022 and December 2023 will be enrolled in this study. Patients will be randomised into an investigational group (HPSP) and a control group (CRT) at a 1:1 ratio. The primary outcome is the duration of QRS complex (QRS width), and the secondary outcomes are NT-proBNP (N terminal pro B type natriuretic peptide), C reactive protein, the number of antibiotics used, left ventricular ejection fraction, end systolic volume, end diastolic volume, the hospitalisation duration, the incidence of postoperative infection, pacemaker parameters (threshold, sensing and impedance), the 6-minute walking test, and quality of life (36-Item Short Form Survey scale), all-cause mortality, cardiovascular death, heart failure-related rehospitalisation rate, other rehospitalisation rates, major complication rates and procedure costs.Ethics and disseminationThis study has been approved by the Beijing Anzhen Hospital Medical Ethics Committee (No. 2020043X).Trial registration numberChinese Clinical Trial Registry (ChiCTR2000034265).

Introduction: The general objective of this study is to detect silent myocardial ischemia into asymptomatic diabetic patients by myocardial perfusion imaging. Method: 138 asymptomatic diabetic patients were collected over a 16 months period. All patients had a first post stress acquisition after injection of 10mCi 99m Tc-Sestamibi on an Anyscan® dual-head gamma camera equipped with a low-energy, high-resolution collimator (LEHR). The acquisition matrix was 128×128 associated with a zoom of 1,2. A second acquisition, at rest, was performed 3 hours later after injection of 30mCi of 99m Tc-Sestamibi. Synchronization to the electrocardiogram was done both during the stress and rest test. Image processing was done by the iterative MOSEM method. Image analysis was visual and quantitative using the software Emory Cardiac Toolbox. Informed consent was obtained from each patient. The study received approval from the national ethics committee. Results: The mean age of the patients was 52± 9 years with extremes ranging from 29 to 73 years, sex ratio 0.60, and mean duration of diabetes progression was 7 ± 4 years. The most common risk factors in our patients were hypertension, which was the main risk factor (45, 5%), followed by obesity in 31%, dyslipidemia in 13, 6%, physical inactivity and smoking in 6,1% and 3,8% respectively. The exercise stress test was positive in only 14 patients (10.1%) and negative in 124 patients (89,9%). The frequency of myocardial perfusion abnormalities was 60%. Perfusion abnormalities were ischemia in 57 patients (69%), necrosis in 17 (20%) and mixed (necrosis and ischemia) in 9 patients (11%). Left ventricular ejection fraction was abnormal (<50%) in 17.3%. Post-stress telesystolic volume was normal (˂70ml) in 94.2% of cases. Conclusion: myocardial perfusion imaging showed high sensitivity in detecting silent myocardial ischemia in asymptomatic diabetics. However, given its high cost, its place in the diagnostic strategy of diabetic coronary disease in our context remains to be defined. RESUME Objectif : dépister l’ischémie myocardique silencieuse par la tomoscintigraphie myocardique de perfusion chez les patients diabétiques asymptomatiques Patients et méthodes : 138 patients diabétiques asymptomatiques ont été colligés sur une période de 16 mois. Tous ont bénéficié d’une première acquisition d’image post effort après injection de 10mCi de Tc99m-Sestamibi sur une gamma caméra double tête Anyscan® munie d’un collimateur basse énergie et haute résolution (LEHR). La matrice d’acquisition était de 128×128 associée à un zoom de 1,2. Une deuxième acquisition, au repos était réalisée trois heures de temps après si l’examen scintigraphique post stress était anormal. La synchronisation à l’électrocardiogramme (ECG) a été faite à l’effort et au repos. Les images ont été reconstruites par la méthode itérative MOSEM. L’analyse des images a été qualitative visuelle et quantitative grâce au logiciel Emory Cardiac Toolbox. Le consentement éclairé de chaque patient était obtenu. L’étude a reçu l’autorisation du comité national d’éthique. Résultats : L’âge moyen des patients était de 52 ± 9 ans avec des extrêmes allant de 29 à 73 ans, le sex ratio de 0,60. la durée moyenne de l’évolution du diabète était de 7±4ans. Les facteurs de risque associés les plus retrouvés chez nos patients étaient l’HTA qui constituait le principal facteur de risque (45,5%), suivie de l’obésité dans 31% des cas, de la dyslipidémie dans 13,7% des cas, la sédentarité et le tabagisme dans respectivement 6,1% et 3,8% des cas. L’épreuve d’effort était positive chez seulement 14 patients (10,1%) et négative chez 124 patients (89,9%). La fréquence des anomalies de perfusion était de 60%. L’ischémie était majoritaire chez 57 patients (69%), suivie de la nécrose chez 17 patients (20%) et de type mixte (nécrose et ischémie) chez 9 patients (11%). La fraction d’éjection ventriculaire gauche était anormale (<50%) dans 17,3% des cas. Le volume télésystolique post-stress était normal (˂70ml) dans 94,2 % des cas. Conclusion : la tomoscintigraphie myocardique a montré une grande sensibilité dans la détection de l’ischémie myocardique silencieuse chez le diabétique asymptomatique. Cependant compte tenu de son cout élevé, sa place dans la stratégie diagnostique de la maladie coronaire du diabétique dans notre contexte reste à définir.

Abstract Aims Long QT syndrome (LQTS) carries a risk of life-threatening polymorphic ventricular tachycardia (Torsades de Pointes, TdP) and is a major cause of premature sudden cardiac death. TdP is induced by R-on-T premature ventricular complexes (PVCs), thought to be generated by cellular early-afterdepolarisations (EADs). However, EADs in tissue require cellular synchronisation, and their role in TdP induction remains unclear. We aimed to determine the mechanism of TdP induction in rabbit hearts with acquired LQTS (aLQTS). Methods and Results Optical mapping of action potentials (APs) and intracellular Ca2+ was performed in Langendorff-perfused rabbit hearts (n = 17). TdP induced by R-on-T PVCs was observed during aLQTS (50% K+/Mg++ & E4031) conditions in all hearts (p &lt; 0.0001 vs control). Islands of AP prolongation bounded by steep voltage gradients (VGs) were consistently observed before arrhythmia and was more closely related to the PVC upstroke than EADs, both temporally (7 ± 5 ms vs 44 ± 27 ms, p &lt; 0.0001) and spatially (1.0 ± 0.7 vs 3.6 ± 0.9 mm, p &lt; 0.0001). PVCs were initiated at estimated voltages of approx. -40 mV and had upstroke dF/dtmax and Vm-Ca2+ dynamics compatible with ICaL activation. Computational simulations demonstrated that PVCs could arise directly from VGs, through electrotonic triggering of ICaL. In experiments and the model, sub-maximal L-type Ca2+ channel (LTCC) block (200 nM nifedipine and 90% gCaL respectively) abolished both PVCs and TdP in the continued presence of aLQTS. Conclusion These data demonstrate that ICaL activation at sites displaying steep VGs generates the PVCs which induce TdP, providing a mechanism and rationale for LTCC blockers as a novel therapeutic approach in LQTS.

Abstract Funding Acknowledgements This work was supported by the NIHR Leicester Biomedical Research Centre. XL was funded by MRC(MR/S037306/1) and BHF (PG/18/33/33780) Background It remains controversial as to whether rotors detected using phase mapping during persistent atrial fibrillation (persAF) represent main drivers of the underlying mechanism as others found rotors to be located near line of conduction block. Regional electrogram desynchronization (RED) has been suggested as successful targets for persAF ablation, but automatic tools and quantitative measures are lacking. Purpose We aim to use mean phase coherence (MPC) to automatically identify RED regions during persAF. This method was compared with phase singularity density (PSD) maps. Methods Patients undergoing left atrial (LA) persAF ablation were enrolled (n = 10). 2048-channel virtual electrograms (VEGMs) were collected from each patient using non-contact mapping (St Jude Velocity System, Ensite Array) for 10 seconds. To remove far field ventricular activities, QRS onset and T wave end locations were detected from ECG lead I (Figure 1A) and only the VEGM segments from T end to QRS onset were included in the analysis. VEGMs were reconstructed using sinusoidal wavelets fitting and the phase of VEGMs determined using Hilbert transform. Phase singularities (PS) were detected using the topological charge method and repetitive PSD maps were generated. RED was defined as the average of MPC of each node against direct neighbouring nodes on the 3D mesh (Figure 1A-B). Linear regression analysis was used to compare the average MPC vs. PSD and vs. the standard deviation of MPC (MPC_SD). Results A total of 221,184 VEGM segments were analysed with mean duration of 364.2 milliseconds. MPC has shown the ability to quantify the level of synchronisation between VEGMs (Figure 1B). Inverse correlation was found between PSD and average MPC values for all 10 patients (p &lt; 0.0001, Figure 1C). Average MPC and MPC_SD were found to be inversely correlated (p &lt; 0.0001, Figure 1C). Spatially, similar graphic patterns can be found from LA MPC maps and PSD maps for all patients (Figure 1D). Conclusion We have proposed a method to quantify the level of synchronisation between VEGMs. Phase density mapping showed a considerable agreement with RED regions reflecting regional conducting delays, which supports the previous finding where rotors found at conduction block. Inverse correlation between local average MPC and MPC_SD suggests that conduction delays of the identified regions are not heterogenous, posing directional preferences. Rather than solely looking for rotational activities, this method could identify comprehensive RED regions, which may also explain the conflicting results from different studies targeting rotational activities, where incomplete subsets of RED regions could have been targeted. Atrial RED regions can easily be identified with simultaneously collected electrograms from multi-polar catheters and should be targeted in future persAF studies. Abstract Figure 1

La stimulation ventriculaire droite conventionnelle induit une désynchronisation inter et intraventriculaire gauche, majorant le risque d’insuffisance cardiaque au long cours. Les techniques de stimulation permanente du système de conduction, stimulation Hisienne ou stimulation de l’aire de la branche gauche (SABG), visent à préserver une activation ventriculaire physiologique. Nous avons démontré la faisabilité et la sécurité de la stimulation du système de conduction dans des centres débutant leur expérience avec ces techniques. Une enquête menée à l’échelle nationale a permis de confirmer une diminution de l’utilisation de la stimulation Hisienne aux dépens de la SABG. Nous nous sommes intéressés à l’impact électromécanique et avons démontré que la SABG permettait un maintien de la synchronisation inter et intraventriculaire gauche chez les patients ayant des QRS spontanés fins. En cas d’arythmie atriale non contrôlée, la stimulation Hisienne combinée à l’ablation du nœud atrio-ventriculaire (NAV) était faisable et efficace, mais associée à des difficultés techniques. Dans une seconde étude comparant la stimulation Hisienne et la SABG dans cette indication, la SABG était associée à une diminution du taux de reconduction atrio-ventriculaire sans compromettre l’efficacité clinique. La stimulation du système de conduction constitue également une approche intéressante en cas de troubles de la conduction, notamment chez les patients ayant un taux attendu de stimulation ventriculaire élevé : un score a ainsi été développé pour prédire un taux de stimulation ventriculaire ≥ 40% chez les patients implantés d’un stimulateur cardiaque en post-TAVI. Enfin, nous nous sommes intéressés à une indication future potentielle : la régularisation de la cadence ventriculaire chez les patients en fibrillation atriale (FA) permanente atteints d’insuffisance cardiaque à FEVG préservée (IC-FEp). Nous avons développé un paramètre Holter permettant de mesurer l’irrégularité cycle à cycle en FA. Un modèle expérimental de cœur de rat isolé, perfusé et stimulé a été mis en place pour étudier l’impact hémodynamique de l’irrégularité ventriculaire. Enfin, nous avons proposé une étude randomisée visant à comparer traitement médicamenteux versus une stratégie de régularisation ventriculaire par ablation du NAV et stimulation du système de conduction, chez les patients IC-FEp en FA permanente bien contrôlée
Right ventricular pacing induces inter- and intraventricular dyssynchrony, increasing the long-term risk of heart failure. Permanent conduction system pacing (CSP), either His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), aims to preserve physiological ventricular activation. We have demonstrated the feasibility and safety of CSP in centers initiating their experience with these techniques. A nationwide survey confirmed a decrease in the use of HBP in favor of LBBAP. We investigated the electromechanical impact and demonstrated that LBBAP preserved interventricular and left intraventricular mechanical synchrony in patients with spontaneous narrow QRS. We then focused on the use of these techniques combined with atrioventricular node ablation (AVNA) for non-controlled atrial arrhythmia: HBP was feasible and effective, despite significant technical challenges. In another study comparing HBP and LBBAP in the “ablate and pace” strategy, LBBAP was associated with a reduction in symptomatic AV node reconduction rate without compromising clinical efficacy. CSP is also of major interest in cases of AV conduction disease, especially in patients with an expected high ventricular pacing burden: a score was developed to predict a ventricular pacing rate ≥ 40% in post-TAVI patients undergoing pacemaker implantation. Finally, we explored a potential future indication of CSP: ventricular regularization in patients with permanent atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). We developed a new Holter parameter to measure beat-to-beat irregularity during AF. An experimental model of isolated, perfused, and stimulated rat heart was established to study the hemodynamic impact of ventricular irregularity. Finally, we proposed a randomized study to compare medical treatment versus ventricular rate regularization (CSP + AVNA) in patients with well-controlled permanent AF and HFpEF

Background: Synchronised cardioversion (SC) is used to terminate tachycardic arrhythmia by applying electric current to the thorax. SC is synchronised to the R wave of the cardiac cycle and ventricular tachycardia (VT) or ventricular fibrillation (VF) can occur if an electrical shock is provided in a nonsynchronised way. Case Presentation: Here we present a case of a 66-year-old man who had elective cardioversion for atrial fibrillation worsened by severe left ventricular impairment. A manual defibrillator was used for the cardioversion, which, after the first synchronised shock, reverted to defibrillator mode. An unsynchronised shock was administered and induced VT, which was reverted to sinus rhythm with a defibrillation shock. Conclusion: When using manual defibrillator for SC, the machine needs to be set to a synchronised mode. The synchronisation to the R wave needs to be checked before every shock.