Atrioventricular Junction Research Articles

Detection of early signs of right ventricular systolic impairment in unoperated Ebstein's anomaly by cardiac magnetic resonance feature tracking.

Cardiovascular magnetic resonance feature-tracking analysis (CMR-FT) provides a quantitative assessment of myocardial contraction with potential for diagnostic and prognostic ability in a wide spectrum of diseases. Ebstein's anomaly (EA) is a rare congenital heart disease characterized by apical displacement of the tricuspid valve. However, it is also considered a disorder of development affecting the global right ventricular myocardium. Aim of our study is to describe the complex contractile mechanics of the functional right ventricle (RV) in patients affected by EA through CMR-FT. Fifty surgery-free EA patients who had undergone a complete CMR protocol at our institution between January 2017 and December 2020 were selected for the retrospective study. A historical control group of twenty-five healthy subjects was also included. CMR-FT analysis was performed at a dedicated workstation by manually tracing RV endo- end epicardial borders on steady-state-free-precession (SSFP) cine images. Strain values were calculated. Apical displacement of the tricuspid valve (TV) was measured on a 4-chamber cine image from the right atrio-ventricular junction to the functional annulus of the TV. EA patients presented significantly impaired RV global radial strain (GRS) and global circumferential strain (GCS) compared to controls (P<0.0001 and P=0.0008, respectively). In a subgroup analysis, GRS was significantly compromised in patients with a severely displaced TV (>16 mm/m2) compared to milder forms (P=0.03) and to controls (P<0.0001). Among EA patients with a preserved ejection fraction, 12 (48%) vs. 6 (24%) controls had reduced both GRS and GCS. The contractile pattern of the functional RV in EA is characterised by prevalent alterations in the short-axis direction as indicated by reduced GRS and GCS. Strain values might be reduced prior to routine used functional parameters like RV ejection fraction (RVEF) and can possibly serve as an early predictor of myocardial dysfunction in EA patients.

Prenatal ultrasound diagnostics of atrioventricular communication in combination with the tetralogy of Fallot in a fetus with Down's syndrome phenotype

This article presents a description of our own case of ultrasound prenatal diagnostics of complex combined heart disease (complete atrioventricular communication in combination with tetralogy of Fallot) at 19–20 weeks of gestation with ultrasound markers of Down's syndrome in fetus. Pregnancy termination was performed at 21 weeks. Prenatal diagnosis was fully confirmed at the fetus autopsy. This publication discusses the frequency, mechanism of occurrence of such a combination of congenital heart defects, prenatal management, methods, timing and efficiency of surgical correction after birth. Complete atrioventricular communication occurs in approximately 1.7–2% patients with tetralogy of Fallot, and tetralogy of Fallot occurs in 5–10% of patients with atrioventricular communication, most often in patients with Down's syndrome. It is believed that tetralogy of Fallot and a complete defect of the atrioventricular septum develop as a result of different mechanisms, but their joint occurrence is recognized as an association. The prevalence of such a combination in Down syndrome indicates the general foundations of its development.Sonographic diagnosis of atrioventricular communication and tetralogy of Fallot is usually not difficult for prenatal screening. Main diagnostic criteria for complete atrioventricular communication at routine ultrasound screening and targeted fetal echocardiography are an abnormal 4-chamber image of the heart in the form of a common atrioventricular junction and a common five-leafed atrioventricular valve. Typical prenatal sonographic signs of the tetralogy of Fallot are a high defect of the interventricular septum, expansion of the aortic root, displacement of the aorta forward and to the right, narrowing of the pulmonary artery at the level of the valve ring from minor to complete atresia, it is also possible reduction the size of the right ventricle and increasing the size of the left ventricle.The combination of atrioventricular communication with the tetralogy of Fallot refers to severe congenital heart defects requiring surgical correction.

Permanent his bundle pacing in suprahisian versus infrahisian atrioventricular block . A single center experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Permanent His bundle pacing is currently considered the most physiological form of cardiac pacing. The main benefit of the procedure, compared to right ventricular pacing, is encountered in atrioventricular block, where a high burden of ventricular pacing is expected. One of the limits of His bundle pacing is a distal conduction abnormality in the His-Purkinje system. Nevertheless, there is published data that shows the possibility of conduction system capture even in these patients. This retrospective study evaluated the feasibility of permanent His bundle pacing in patients with second or third degree AV block, taking into account the level of block : suprahisian vs. infrahisian. Material and methods 45 patients with second or third degree AV block with an attempt at permanent His bundle pacing and an available intraprocedural hisian electrogram for review were included. The procedure went as follows: a lead delivery system including a preformed 3D shaped sheath and a lumenless lead with a fixed exposed helix was placed at the septal atrioventricular junction. Careful mapping was performed until a His bundle signal was recorded. At that site, the pacing response was evaluated at variable pacing outputs. The procedural criteria for success was conduction system capture (selective or non-selective) with an amplitude of less than 2,5V/1ms. If the criteria was met, the lead was fixed, an atrial lead was placed and both connected to a dual-chamber pacemaker. The periprocedural characteristics and those at the three-months follow-up were noted. Results 28 patients (62,2%) were diagnosed with suprahisian block, with a procedural success rate of 89 % and 17 (37,8%) with infrahisian block, with a procedural success rate of 59%. QRS duration was 96,4±21,6 ms in those with suprahisian block vs. 119,4±23,8 ms in those with infrahisian block (p=0,0027). There was no significant statistical difference regarding acute His bundle pacing thresholds (1,13±0,63 V/1ms vs. 1,25±0,76 V/1ms, p= 0,66), ventricular sensing (3,46±1,5 mV vs. 3,21±1,6 mV, p= 0,68) and fluoroscopy time (12,75±8,3 min vs. 10,78±9,5 min, p= 0,57) between suprahisian and infrahisian block. Also, the paced QRS duration was similar between the two groups (86,9±13,4 ms vs. 82±14,7 ms, p= 0,38) and narrower than the baseline complex. The three-months follow-up showed stable pacing and sensing parameters, without other procedural or lead related complications. Conclusions In atrioventricular block, permanent His bundle pacing achieves atrioventricular resynchronization, while maintaining rapid and synchronous biventricular depolarization. As expected, in suprahisian blocks the success rate is superior to infrahisian blocks. Nevertheless, in a significant proportion of the latter cases, His bundle pacing can recrute the intrinsic conduction system.

Third-degree atrioventricular block secondary to infiltrative cardiac hemangiosarcoma in a dog

A nine-year-old male, castrated Pembroke Welsh Corgi presented with a two-month history of lethargy, hyporexia, and occasional vomiting. There was also a two-week history of exercise intolerance; no syncopal episodes were reported. Auscultation revealed bradycardia with an irregular rhythm and otherwise normal heart and lung sounds. Third-degree atrioventricular block was diagnosed. Two-dimensional transthoracic echocardiography revealed a soft tissue structure arising from the atrioventricular junction and interatrial septum. There was scant abdominal effusion. Pacemaker implantation was offered, but the owner elected humane euthanasia due to the unknown prognosis. Necropsy was consistent with cardiac hemangiosarcoma infiltrating the interatrial and interventricular septum.

BS-400-45 LEFT BUNDLE-BRANCH PACING POST-ATRIOVENTRICULAR JUNCTION ABLATION FOR ATRIAL FIBRILLATION: PROPENSITY-SCORE MATCHING WITH HIS BUNDLE PACING

Left bundle branch pacing (LBBP) has emerged as a promising pacing modality to preserve physiological left ventricular activation but has limited prospective data evaluating long-term safety and efficacy in pacing-dependent patients following atrioventricular junction (AVJ) ablation.

PO-628-07 LEFT BUNDLE-BRANCH PACING POST-ATRIOVENTRICULAR JUNCTION ABLATION FOR ATRIAL FIBRILLATION: PROPENSITY-SCORE MATCHING WITH HIS BUNDLE PACING

Left bundle branch pacing (LBBP) has emerged as a promising pacing modality to preserve physiological left ventricular activation but has limited prospective data evaluating long-term safety and efficacy in pacing-dependent patients following atrioventricular junction (AVJ) ablation.

PC-578-02 JUNCTIONAL TACHYCARDIA

Junctional ectopic tachycardia (JET) is a rare tachyarrhythmia in adults. The precise site of origin within the AV junction is unknown. N/A N/A A 71-year-old male presented with dyspnea on exertion and recently diagnosed tachycardia in March 2021. He had a history of diabetes mellitus, obesity, hypertension, obstructive sleep apnea, and COVID-19 in 2020. A 14-day monitor demonstrated 43% supraventricular ectopy SVE burden and short runs of SVT. He presented for an electrophysiology (EP) study. He presented to the EP lab in sinus rhythm with frequent SVE. Multipolar catheters were placed in the His bundle region, right atrium, coronary sinus, and right ventricle. The SVE beats had the same QRS morphology, and an identical HV interval and His-right bundle activation sequence as in sinus rhythm and no retrograde conduction, consistent with premature junctional complexes (PJCs). Occasional short bursts of junctional tachycardia were noted. Isoproterenol was titrated to a maximum dose of 8 mcg/min. No other SVT was inducible with atrial overdrive pacing or programmed stimulation or with isoproterenol infusion. A 6 mm tip cryoablation catheter was advanced to the right atrium to the anatomical location of the slow pathway in the inferior triangle of Koch using an electroanatomic mapping system (EnSite NavX). Signals immediately prior to ablation (Figure 1) were notable for a pre-potential 26 ms prior to the His with PJCs. Cryoablation was performed at this site (Figure 2) with resolution of the PJCs at the onset of the freeze. After thawing, a second freeze was administered. No further PJCs were noted at baseline or with isoproterenol infusion. JET could originate from anywhere within the AV node or proximal His bundle. The application of cryoablation at a typical AV nodal slow pathway location with a preceding pre- potential and immediate obliteration of PJCs suggests that the origin in this case was from this region rather than a true His bundle extrasystole. Identification of pre-potentials to the junctional ectopy can guide safe ablation of this dysrhythmia.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Technical modification and safe explantation of the Melody valve in the mitral position in small children.

Technical modification and safe explantation of the Melody valve in the mitral position in small children.

Local Variation and Age-Related Change in Atrial and Ventricular Myocardial Contiguity at the Atrioventricular Junction in Human Hearts

Background: We explored the histologic patterns of and age-related changes in atrial and ventricular myocardial contiguity at the left and right atrioventricular (AV) junction that could be a target site for catheter ablation.Methods and Results: Twenty-three structurally normal adult hearts obtained at autopsy were studied. The 2 AV annuli were divided into 13 clinically recognized portions in which we measured distance between the atrial and ventricular myocardium at the AV junction. Overall, measured distance was less on the right than left side (mean [±SD] 0.74±0.59 vs. 1.15±0.78 mm, respectively), and distance increased gradually with age. The gap was smallest at the anterolateral portion on the right side and posterolateral portion on the left side. Three specific features were noted, namely extension of the ventricular myocardium (coarse trabeculae) towards the atrium on the right side of the AV junction, extension of the atrial myocardium onto the AV valve leaflets, and a collection of small myocardial cells, perhaps including specialized cells, in the right anterolateral portion. No concealed AV muscular connections were found.Conclusions: Contiguity and separation of the myocardium at the AV junction have specific patterns, and myocardial proximity is influenced by age. These histologic features of the AV junction may prove to be informative for catheter ablation of tachyarrhythmias related to the AV junction.

High-resolution parahisian mapping and ablation using microelectrode embedded ablation catheters.

Accurate mapping of the compact atrioventricular (AV) node is critical during ablation of a range of arrhythmias. The purpose of this multicenter prospective study was to test the hypothesis that microelectrode (ME)-embedded catheters more accurately define the near-field compact AV node compared to conventional catheters. For the mapping phase, detailed AV junction maps were created in 47 patients using an ME-embedded catheter. His electrograms (EGMs) detected by conventional electrodes (Hisc) and by ME (Hisμ) were annotated. For the ablation phase, AV nodal ablation (Qmode 50 W) was performed in 10 patients after pacemaker implantation, with initial Hisc-only ablation in group 1 (n = 6) and initial Hisμ ablation in group 2 (n = 4). For the clinical phase, a prospective registry of parahisian tachycardia using QDOT was obtained. In the mapping phase, 7.0 ± 5.4 Hisc and 8.0 ± 5.6 Hisμ points were acquired per map (n = 47). Hisμ cloud was smaller and more proximally located than Hisc cloud: (99.4 ± 74.7 mm2 vs 197.6 ± 110.6 mm2; P = .0008). Hisμ EGMs had larger amplitudes than Hisc EGMs (0.40 ± 0.38 mV vs 0.16 ± 0.1 mV; P = .0002). In the ablation phase, for group 1: Hisc-only ablation never resulted in AV block, whereas Hisμ ablation resulted in AV block after limited ablation in all patients (after 13.3 ± 9.2 s); and for group 2: Hisμ ablation always resulted in AV block after 1 application (after 14.3 ± 10.3 s). In the clinical phase, a Hisμ-avoidance strategy could avoid AV block in a prospective registry of 11 patients. ME more accurately defines the region of the compact node, and ablation in this region is associated with a high risk for AV block. ME-based mapping has the potential to significantly enhance ablation safety and efficacy.

Management of Atrial Tachyarrhythmias in Heart Failure-an Interventionalist's Point of View.

Atrial fibrillation (AF) and heart failure (HF) are commonly encountered clinical disorders that often co-exist, accelerating disease progression and adverse outcomes. It is known that restoration of sinus rhythm positively impacts this population; however, the complex comorbidity profile associated with HF introduces intricacies not encountered in other patient populations. The current review focuses on the safety and efficacy of an interventional-based management for atrial tachyarrhythmias in HF. While pharmacotherapy has been the standard treatment of cardiac dysrhythmias in the HF population, recent evidence suggests catheter ablation is more effective and causes less harm than antiarrhythmic drugs (AADs) in the HF population. For the maintenance of sinus rhythm, catheter ablation results in improved freedom from recurrent arrhythmia, with secondary benefit on mortality and hospitalization in those with HF and reduced ejection fraction. For those with permanent AF, cardiac resynchronization therapy and atrioventricular junction ablation result in improved quality of life, physical functioning, and cardiac function.

Morphological and Dynamic Analysis of the Right Atrioventricular Junction in Healthy Subjects with 4D Computed Tomography.

To improve knowledge of the tricuspid valve and right atrioventricular junction (RAVJ) coupling, four-dimensional (4D) imaging is mandatory (3D + time). Based on multiphase cardiac-volume computed tomography (CT) and innovative 4D analysis, we proposed to assess dynamical features of tricuspid annulus (TA) in relation to the right ventricle (RV) and right atrial (RA) functions. Cardiac-volume CT data sets through time were obtained in 30 healthy patients (Male 57%, mean age 57 ± 11 years). Using an in-house software, 3D semi-automated delineation of 18 points around TA perimeter were defined through 10 cardiac phases within RR interval and used to calculate TA features such as 3D/2D areas, perimeters, 360°-diameters and vertical deformation. RV and RA inner contours were also delineated. Bi-dimensional parameters were compared with multiplanar reconstruction (MPR) measurements. TA was elliptical in horizontal projection with a maximal eccentricity index (EcImax) of 0.58 ± 0.12; and saddle-shaped in vertical projection with a horn nearby the antero-septal commissure. This feature remained throughout the cardiac cycle, but TA was more planar and less circular in late diastole (TA-height: 4.53 ± 1.06 mm, EcImax = 0.61 ± 0.14) when TA 3D area and perimeter reached a maximum of 7.05 ± 1.23 and 7.48 ± 0.93cm/m2, respectively. Correlations between minimal and maximal TA 3D areas and TA Projected 2D areas were excellent (r = 0.993 and r = 0.995, p < 0.001). TA 2D area measurements by MPR overestimated the projected values by 22 to 24%. Correlation between RV concentric strain and TA maximal diameter shortening was r = 0.452 (p = 0.01). Cardiac-volume CT improves physiological knowledge of the relationships between the RAVJ components in healthy subjects.

Intraventricular pressure gradient: a promising tool to predict the post-infarction chronic congestive heart failure in rats

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction: Congestive heart failure (CHF), the main reason for morbidity and mortality, is considered a serious consequence of myocardial infarction (MI). The use of left ventricular end-diastolic pressure (LVEDP) as a chief indicator of CHF becomes limited because of the possible impairment of cardiac function and induced aortic valve damage during its recording. Echocardiography is the gold standard approach to diagnose structural myocardial dysfunction. However, its ability to predict chronic CHF following MI is still limited. Recently, intraventricular pressure gradient (IVPG) was presented as a non-invasive, highly sensitive preload-independent diastolic function parameter to assess cardiac function, especially during cardiomyopathy. However, there have not been any investigations demonstrating the feasibility of IVPG in the evaluation of post-infarction chronic CHF. Purpose This study aimed to investigate the utility of IVPG to assess the heart function in a rat model with chronic CHF following MI with evaluating its capacity to predict these changes. Methods Fifty male rats were included. MI was induced via ligation of the left anterior descending artery (LAD) at the level of the atrioventricular junction (MI animals, n = 35). Sham animals were subjected to the same left thoracotomy procedure without LAD ligation (Sham animals, n = 15). Transthoracic conventional echocardiography and colour M-mode echocardiography (CMME) for IVPG were performed in all animals 6 months post-surgery. The next day, animals were anesthetized, ventilated, and euthanized after the recording of hemodynamics. The heart weight, and lung and liver wet-to-dry weight ratios were recorded. J-tree cluster-analysis was performed based on ten echocardiographic variables indicative of CHF. Results Based on the cluster analysis, animals were joined into two clusters; CHF+ (n = 22) and named MI/HF+, and CHF- (n = 28) that was joined from sham (n = 15), and MI/HF- (n = 13). MI/HF+ presented the most severe anatomical and echocardiographic changes indicative of CHF with significant reduction of all IVPG indices and impairment of the hemodynamics. The IVPG indices were significantly (P&amp;lt; 0.0001) correlated with the anatomical and echocardiographic findings, LVDP, LVEDP, HR, -dP/dtmin, and Tau. Meanwhile, LVSP was only significantly correlated with apical IVPG (R = 0.677, P = 0.022). dP/dtmax was significantly correlated with total IVPG, basal IVPG, and apical IVPG (R = 0.797, P = 0.017, R = 0.724, P = 0.003, and R = 0.652, P = 0.026 ; respectively). Moreover, total, basal, mid-to-apical, mid-, and apical IVPG were significant (P&amp;lt; 0.0001) predictors of chronic CHF following MI. Conclusion Compared to the structural, and functional indices of conventional echocardiography, IVPG derived from CMME could provide a substantial non-invasive tool to diagnose and predict CHF after long-term MI.

Junctional AV ablation in patients with atrial fibrillation undergoing cardiac resynchronization therapy (JAVA-CRT): results of a multicenter randomized clinical trial pilot program.

IntroductionCardiac resynchronization therapy (CRT) improves outcomes in sinus rhythm, but the data in atrial fibrillation (AF) is limited. Atrio-ventricular junctional ablation (AVJA) has been proposed as a remedy. The objective was to test if AVJA results in LV end-systolic volume (ESV) reduction ≥ 15% from baseline to 6 months.MethodsThe trial was a prospective multicenter randomized trial in 26 patients with permanent AF who were randomized 1:1 to CRT-D with or without AVJA.ResultsLVESV improved similarly by at least 15% in 5/10 (50%) in the CRT-D-only arm and in 6/12 (50%) in the AVJA + CRT-D arm (OR = 1.00 [0.14, 7.21], p = 1.00). In the CRT-D-only arm, the median 6-month improvement in LVEF was 9.2%, not different from the AVJA + CRT-D arm, 8.2%. When both groups were combined, a significant increase in LVEF was observed (25.4% at baseline vs 36.2% at 6 months, p = 0.002). NYHA class from baseline to 6 months for all patients combined improved 1 class in 15 of 24 (62.5%), whereas 9 remained in the same class and 0 degraded to a worse class.ConclusionIn patients with permanent AF, reduced LVEF, and broad QRS who were eligible for CRT, there was insufficient evidence that AVJA improved echocardiographic or clinical outcomes; the results should be interpreted in light of a smaller than planned sample size. CRT, however, seemed to be effective in the combined study cohort overall, suggesting that CRT can be reasonably deployed in patients with AF.Trial registrationClinicalTrials.gov Identifier: NCT02946853.

Miniseries 1-Part I: the Development of the atrioventricular conduction axis.

Despite years of research, many details of the formation of the atrioventricular conduction axis remain uncertain. In this study, we aimed to clarify the situation. We studied three-dimensional reconstructions of serial histological sections and episcopic datasets of human embryos, supplementing these findings with assessment of material housed at the Human Developmental Biological Resource. We also examined serially sectioned human foetal hearts between 10 and 30 weeks of gestation. The conduction axis originates from the primary interventricular ring, which is initially at right angles to the plane of the atrioventricular canal, with which it co-localizes in the lesser curvature of the heart loop. With rightward expansion of the atrioventricular canal, the primary ring bends rightward, encircling the newly forming right atrioventricular junction. Subsequent to remodelling of the outflow tract, part of the primary ring remains localized on the crest of the muscular ventricular septum. By 7 weeks, its atrioventricular part has extended perpendicular to the septal parts. The atrioventricular node is formed at the inferior transition between the ventricular and atrial parts, with the transition itself marking the site of the penetrating atrioventricular bundle. Only subsequent to muscularization of the true second atrial septum does it become possible to recognize the definitive node. The conversion of the developmental arrangement into the definitive situation as seen postnatally requires additional remodelling in the first month of foetal development, concomitant with formation of the inferior pyramidal space and the infero-septal recess of the subaortic outflow tract.

Pacing of Specialized Conduction System

Right ventricular pacing for bradycardia remains the mainstay of pacing therapy. Chronic right ventricular pacing may lead to pacing-induced cardiomyopathy. We focus on the anatomy of the conduction system and the clinical feasibility of pacing the His bundle and/or left bundle conduction system. We review the hemodynamics of conduction system pacing, the techniques to capture the conduction system and the electrocardiogram and pacing definitions of conduction system capture. Clinical studies of conduction system pacing in the setting of atrioventricular block and after AV junction ablation are reviewed and the evolving role of conduction system pacing is compared with biventricular pacing.

C65. Pace and Ablate as an Alternative Approach for Rate Control Strategy in Patient with Atrial Fibrillation

Abstract Background AF patient with refractory to optimal medical therapy for rate or rhythm control, atrioventricular (AV) nodal ablation with permanent pacemaker (PPM) implantation is an effective strategy for symptomatic relief. Maintenance of controlled ventricular rate helps to avoid frequent exacerbations of CHF and tachycardia-mediated cardiomyopathy, and is also associated with improved quality of life. Case Summary Female 66-year-old suffered from Heart Failure exacerbations caused by paroxysmal AF with rapid ventricular response (RVR) with underlying hypertensive cardiovascular disease. Rhythm control strategy with drip Amiodarone induce sinus bradycardia with unstable hemodynamic, when drugs was stopped then AF RVR reappeared, we tried to rate control strategy with Digoxin but, she experienced same condition as before. She underwent a pragmatical technique AV nodal ablation with cardiac pacing for rate control and she had drastic improvement of symptoms within the next 24 h. Complete AV block was achieved after application of 2 radiofrequency energies over the anatomic AV node. A permanent pacemaker (PPM) was programmed to VVIR at the rate of 70 bpm. Discussion Conventional medical therapies, including beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, and anti-arrhythmic drugs, may fail to control the ventricular rate. Atrioventricular junction ablation and pacing (AVJAP) can be applied for patients whom medication is inadequate or associated with side effects (Recommendation IIA). According to our case, AVJAP is possible but an attractive choice for some elderly patients who are not compliant with treatment or associated with dangerous side effect for patients.

C65. Pace and Ablate as an Alternative Approach for Rate Control Strategy in Patient with Atrial Fibrillation

Abstract Background AF patient with refractory to optimal medical therapy for rate or rhythm control, atrioventricular (AV) nodal ablation with permanent pacemaker (PPM) implantation is an effective strategy for symptomatic relief. Maintenance of controlled ventricular rate helps to avoid frequent exacerbations of CHF and tachycardia-mediated cardiomyopathy, and is also associated with improved quality of life. Case Summary Female 66-year-old suffered from Heart Failure exacerbations caused by paroxysmal AF with rapid ventricular response (RVR) with underlying hypertensive cardiovascular disease. Rhythm control strategy with drip Amiodarone induce sinus bradycardia with unstable hemodynamic, when drugs was stopped then AF RVR reappeared, we tried to rate control strategy with Digoxin but, she experienced same condition as before. She underwent a pragmatical technique AV nodal ablation with cardiac pacing for rate control and she had drastic improvement of symptoms within the next 24 h. Complete AV block was achieved after application of 2 radiofrequency energies over the anatomic AV node. A permanent pacemaker (PPM) was programmed to VVIR at the rate of 70 bpm. Discussion Conventional medical therapies, including beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, and anti-arrhythmic drugs, may fail to control the ventricular rate. Atrioventricular junction ablation and pacing (AVJAP) can be applied for patients whom medication is inadequate or associated with side effects (Recommendation IIA). According to our case, AVJAP is possible but an attractive choice for some elderly patients who are not compliant with treatment or associated with dangerous side effect for patients.

Abstract 13251: Left Bundle Branchpacing Post-Atrioventricular Junction Ablation for Atrial Fibrillation: A Propensity Score Matching Analysis

Introduction: Although left bundle branch pacing (LBBP) has emerged as a novel pacing modality which can allow for safe atrioventricular junction (AVJ) ablation and lower pacing threshold compared to His bundle pacing (HBP), its long-term safety and efficacy in patients with atrial fibrillation (AF) is still unknown. Hypothesis: This study aimed to examine the long-term clinical feasibility, safety, and efficacy of LBBP in AF patients post-AVJ ablation and provide a balanced comparison of LBBP versus HBP. Methods: This study prospectively enrolled patients with AF and heart failure (HF) who underwent AVJ ablation and LBBP from July 2017 to December 2019. The control group patients were selected, by propensity score (PS) matching with a 1:1 ratio, among those HBP implantations performed in the years 2012-2019. Results: A total of 99 patients were enrolled in this study, with successful permanent LBBP post-AVJ ablation in 100% of patients (primary LBBP: 76; secondary LBBP: 23). Significantly improvements were observed in LVEF, tricuspid regurgitation, and mitral regurgitation at 1-year follow-up (p&lt;0.05). The proportion of patients whose acute threshold &lt;1 V@0.5ms was 97.9% and only one patient had an increase in threshold ≥1 V@0.5ms at 1-year follow-up. Further, patients with LBBP as an active-group was compared to patients with HBP (control-group) through PS matching with 170 successfully matched (PS-HBP, N=85; PS-LBBP, N=85). In the control-group, the success rate of permanent HBP was 81.9% (176/215), which was lower than that with LBBP (p&lt;0.001). No significant differences in clinical outcomes were observed between groups (p&gt;0.05), while lower thresholds, greater sensed R-wave amplitudes, and less complication were observed in PS-LBBP group (p&lt;0.05). Conclusions: LBBP is feasible, safe, and effective in AF and HF patients post-AVJ ablation, which has comparable clinical benefit, higher success rate, better pacing parameters, and less complication than HBP.

Response and long-term outcomes with resynchronization therapy in atrial fibrillation

Abstract Background Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected patients (pts) with heart failure (HF). Pts with atrial fibrillation (AF) were excluded from major CRT trials. Studies suggested that pts with AF derive less benefit from CRT. Purpose To compare response and clinical outcomes after CRT in pts in AF or in sinus rhythm (SR). Methods Single-center retrospective study of consecutive pts submitted to CRT implantation (2007–2018). Major adverse cardiac events (MACE) included HF hospitalization or all-cause mortality. Clinical response was defined as NYHA class improvement without MACE in the 1st year of follow-up (FU). Left ventricle end-systolic volume reduction of &amp;gt;15% during the 1st year of FU designated echocardiographic (echo) response. Survival analysis with Kaplan-Meier method and Log-rank test was performed. Results 295 CRT pts (70.5% male, median age 68±16 years, 54.6% implanted with CRT-D) were included. 95 (32.6%) presented in AF. Pts with AF were older (72 vs 67, p=0.007), with higher prevalence of coronary disease (40.2% vs 24.2%, p=0.008), moderate to severe tricuspid regurgitation (21.7% vs 8.8%, p=0.011) and chronic kidney disease (33.0% vs 16.5%, p=0.003). AF pts had larger left atrial diameters (50.5 vs 44.6 mm, p&amp;lt;0.001) and higher baseline N-terminal pro B-type natriuretic peptide values (6738.6 vs 3179.4 pg/ml, p=0.044). There were no differences in terms of HF etiology (p=0.242) or type of device (p=0.127). Pts with AF presented more often with secondary prevention indications for CRT-D (45.0% vs 15.7%, p&amp;lt;0.001). Atrioventricular junction ablation (AVJA) was performed in 14.0% of AF pts. Median percentage of biventricular pacing (BiVp) was significantly lower in AF pts (97% vs 99%, p&amp;lt;0.001). NYHA class improvement (79.3% vs 78.9%, p=0.930) and echo response (65.4% vs 75.2%, p=0.269) were similar between pts in AF and in SR. The rate of clinical response was lower in AF pts (52.7% vs 66.5%, p=0.036). During a median FU of 3±5 years, occurrence of MACE (Log-rank test, p&amp;lt;0.001) and all-cause mortality (Log-rank test, p=0.011) were higher in AF pts – graph 1. When comparing AF pts submitted to AVJA with pts in SR, clinical (62.5% vs 66.5%, p=0.816) and echo (57.1% vs 75.2%, p=0.540) response were similar. Among pts achieving BiVp ≥98% (67.8%), no differences emerged in terms of clinical response (68.4% vs 70.5%, p=0.968) between patients in AF or in SR. Also, mortality was similar between groups (Log-rank test, p=0.214) – graph 2. MACE remained more frequent in the AF group (Log-rank test, p=0.029). Conclusions In this cohort, AF pts, despite having a higher comorbidity burden, showed similar NYHA class improvement and echo response to SR pts. Among pts with BiVp ≥98%, clinical response and all-cause mortality were also similar between groups. Further studies are warranted to select AF pts that benefit most from CRT. Funding Acknowledgement Type of funding sources: None. Graph 1Graph 2