His-Purkinje Conduction Research Articles

Review of Atrioventricular Node Ablation Combined with Permanent His-Purkinje Conduction System Pacing in Patients with Atrial Fibrillation with Heart Failure.

With the advancement of pacing technologies, His-Purkinje conduction system pacing (HPCSP) has been increasingly recognized as superior to conventional right ventricular pacing (RVP) and biventricular pacing (BVP). This method is characterized by a series of strategies that either strengthen the native cardiac conduction system or fully preserve physical atrioventricular activation, ensuring optimal clinical outcomes. Treatment with HPCSP is divided into two pacing categories, His bundle pacing (HBP) and left bundle branch pacing (LBBP), and when combined with atrioventricular node ablation (AVNA), can significantly improve left ventricular (LV) function. It effectively prevents tachycardia and regulates ventricular rates, demonstrating its efficacy and safety across different QRS wave complex durations. Therefore, HPCSP combined with AVNA can alleviate symptoms and improve the quality of life in patients with persistent atrial fibrillation (AF) who are unresponsive to multiple radiofrequency ablation, particularly those with concomitant heart failure (HF) who are at risk of further deterioration. As a result, this "pace and ablate" strategy could become a first-line treatment for refractory AF. As a pacing modality, HBP faces challenges in achieving precise localization and tends to increase the pacing threshold. Thus, LBBP has emerged as a novel approach within HPCSP, offering lower thresholds, higher sensing amplitudes, and improved success rates, potentially making it a preferable alternative to HBP. Future large-scale, prospective, and randomized controlled studies are needed to evaluate patient selection and implantation technology, aiming to clarify the differential clinical outcomes between pacing modalities.

Feasibility and safety of physiologic pacing post-TAVR

Abstract Introduction His-Purkinje conduction system pacing (HPCSP) is an increasingly used technique due to its benefits. The transcatheter aortic valve replacement (TAVR) has in turn been growing and surpasses the number of procedures than surgical aortic valve replacement, however, the main disadvantage with respect to the surgical technique is a greater risk of atrioventricular block and the need for permanent pacing. Purpose Assess the feasibility of HPCSP in patients after TAVR, the success rates and the pacing thresholds. Methods We present a series of consecutive patients (undergoing TAVI in a single center with need for subsequent ventricular stimulation (n=58), from March 2019 to July 2023, performing HPCSP as the first stimulation option. Results We achieved HPCSP in 49 of 58 patients (84.5%). Patients had a mean age of 81.5 years, 60.3% men, mean LVEF 53.82 ± 12.4%. His bundle pacing (HBP) was successful as first option in 41.4% of cases, and left bundle branch area (LBBAP) in 43,1 % of cases (73.5% of the remaining 58.6%) , while the other 9 patients (15.5%) were pace conventionally at right ventricle, septal or wireless. HBP thresholds and R-wave amplitudes at implantation were 0.99 ± 0.72 at 0.5 ms, 4.59 ± 3.67 mV), remaining stable at follow-up at 1 month (1.16 ± 0.92 at 0.5 ms, 4.17 ± 3.97 mV),. Average QRS width was40.8 ± 21.3 ms pre and 122.43 ± 15.2 ms post). LBBAP pacing thresholds and R-wave amplitudes were(0.89 ± 0.45 at 0.5 ms, 6.145 ± 5.3 mV)at implant, and were stable at follow-up at 1 month (0.75 ± 0.3 at 0.5 ms, 8.41 ± 5.8 mV), with no improvements on QRS (129.75 ± 21.01 ms pre, 134.13 ± 17.34 ms post). During a mean follow-up of 23 months. There has been no acute elevation of thresholds or need for reintervention. Only 6 patients have died (10.3%), 2 of them (33%) from cardiovascular causes. Conclusions HPCSP is feasible as a routine techniquein patients after TAVR who need a pacemaker implantation, with low pacing thresholds, which remained stable on the follow-up.

Safety and feasibility of left bundle branch pacing for pediatric and congenital heart disease patients

Abstract Background Conduction system pacing (CSP) has evolved and validated in adults. Due to technical challenges, pediatric and congenital heart disease (CHD) patients were excluded from original trials in this field. We report the safety and feasibility results of our initial experience with pediatric and CHD patients undergoing LBBAP (Left bundle branch area pacing). Purpose To analyze the indications, intraoperative outcomes, electrocardiographic and clinical data from the initial follow-up of pediatric and CHD patients who underwent LBBAP. Methods Indications, intraoperative technical issues, electronic parameters of the implant and early complications of consecutive pediatric and CAD patients submitted to stimulation of the conduction system were evaluated. Results This study was performed between February 2022 and November 2023 and recruited 11 consecutive patients with complete AV block (age: 15-43 years; 7 women) who underwent LBBAP. Four patients had congenital heart disease repaired surgically and two patients with congenitally corrected transposition of the great arteries. Upgrading from VVIR to LBBAP underwent in four patients. Right ventricle (RV) leads were extracted in three patients before CSP. DDD pacemakers with Lumneless 3830 pacing leads were implanted in all patients. The pre-implant QRS duration was 146 (104- 200) ms and 120 (110-130) ms after the procedure. The mean left ventricle activation time was 72 (50-90) ms. The R-wave amplitude was 10.00 (6-29) mV, with a stimulation threshold of 0.8 (0.4-1) V x 0.4 ms and impedance of 676 (534-780) ohms. Transition from non-selective to either myocardial or selective capture and fixation beats were respectively demonstrated in five and three patients. The procedure duration was 125 (70-130) min, and the fluoroscopy time was 15.2 (4-23.6) min. LBBAP substantially shortened the QRS duration and improved LV dyssynchrony echocardiographic parameters in four patients with prior epicardial or endocardial pacing. The LBBAP was successful in all patients with no early complications occured. At mean three months follow-up, QRS duration showed no significant changes compared with baseline. Conclusion Our initial experience on cardiac stimulation of the His-Purkinje conduction system through the stimulation of the left bundle branch is a safe and feasible technique in pediatric and CHD patients. The widespread use of this pacing technique is very useful and cost-effective to prevent heart failure in this vulnerable population.

Upper turnaround point in a reentry circuit of the idiopathic left posterior fascicular ventricular tachycardia.

The anatomic extent of the reentry circuit in idiopathic left posterior fascicular ventricular tachycardia (LPF-VT) is yet to be fully elucidated. We hypothesized that entrainment mapping could be used to delineate the reentry circuit of an LPF-VT, especially including the upper turnaround point. Twenty-three consecutive LPF-VT patients (mean age, 29±9 years, 18 males) were included. We performed overdrive pacing with entrainment attempts at the left bundle branch (LBB) and the left His bundle (HB) region. Overdrive pacing from the LBB region showed concealed fusion in all 23 patients (post-pacing interval [PPI], 322.1±64.3ms; tachycardia cycle length [TCL], 319.0±61.6ms; PPI-TCL, 3.1±4.6ms) with a long stimulus-to-QRS interval (287.9±58.0ms, approximately 90% of the TCL). Pacing from the same LBB region at a slightly faster pacing rate showed manifest fusion with antidromic conduction to the LBB and minimal in-and-out time to the LBB potential (PPI-TCL, 21.3±13.7ms). Overdrive pacing from the left HB region showed manifest fusion with a long PPI-TCL (53.9±22.5ms). Our pacing study results suggest that the upper turnaround point in a reentry circuit of the LPF-VT may extend to the proximal His-Purkinje conduction system near the LBB region but below the left HB region. The LPF may constitute the retrograde limb of the reentry circuit.

Animal study on left bundle branch current of injury and anatomic location of leads in His-purkinje conduction system pacing

Objective: Explore the relationship between tip of the left bundle branch pacing lead and anatomic location of left bundle branch as well as the mechanism of left bundle branch current of injury. To clarify the clinical value of left bundle branch current of injury during operation. Methods: The pacing leads were implanted in the hearts of two living swines. Intraoperative electrophysiological study confirmed that the left bundle branch or only the deep left ventricular septum was captured at low output. Immediately after operation, the gross specimen of swine hearts was stained with iodine to observe the gross distribution of His-purkinje conduction system on the left ventricular endocardium and its relationship with the leads. Subsequently, the swine hearts were fixed with formalin solution, and the pacing leads were removed after the positions were marked. The swine hearts were then sectioned and stained with Masson and Goldner trichrome, and the relationship between the anatomic location of the conduction system and the tip of the lead was observed under a light microscope. Results: After iodine staining of the specimen, the His-purkinje conduction system was observed with the naked eye in a net-like distribution, and the lead tip was screwed deeply and fixed in the left bundle branch area of the left ventricular subendocardium in the ventricular septum. Masson and Goldner trichrome staining showed that left bundle branch pacing lead directly passed through the left bundle branch when there was left bundle branch potential with left bundle branch current of injury, while it was not directly contact the left bundle branch when there was left bundle branch potential without left bundle branch current of injury. Conclusion: The left bundle branch current of injury observed on intracardiac electrocardiogram during His-purkinje conduction system pacing suggests that the pacing lead directly contacted the conduction bundle or its branches, therefore, the captured threshold was relatively low. Left bundle branch current of injury can be used as an important anatomic and electrophysiological evidence of left bundle branch capture.

His-Purkinje Conduction System Pacing Optimized Trial of Cardiac Resynchronization Therapy vs Biventricular Pacing: HOT-CRT Clinical Trial

BackgroundHis-Purkinje conduction system pacing (HPCSP) using His bundle pacing (HBP) or left bundle branch pacing (LBBP) has emerged as an alternative to biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy (CRT). ObjectivesThe aim of the study was to compare the feasibility and clinical efficacy of HOT-CRT (His-Purkinje conduction system pacing Optimized Trial of Cardiac Resynchronization Therapy) with BVP in patients with heart failure, reduced ejection fraction, and indication for CRT. MethodsThis was a prospective, randomized, controlled trial of HOT-CRT and BVP in patients with LVEF <50% and indications for CRT. If HPCSP resulted in incomplete electrical resynchronization, a coronary sinus (CS) lead was added. The primary outcome was the change in left ventricular ejection fraction (LVEF) at 6 months. The primary safety endpoint was freedom from major complications. ResultsA total of 100 patients (female 31%, aged 70 ± 12 years, LVEF 31.5% ± 9.0%) were randomized. HOT-CRT was successful in 48 of 50 (96%) and BVP-CRT in 41 of 50 (82%) patients (P = 0.03). QRS duration significantly decreased from 164 ± 26 ms to 137 ± 20 ms with HOT-CRT and 166 ± 28 ms to 141 ± 19 ms with BVP. Fluoroscopy results (18.8 ± 12.4 min vs 23.8 ± 12.4 min, P = 0.05) and procedure duration (119 ± 42 min vs 114 ± 36 min, P = 0.5) were similar. The primary outcome of change in LVEF at 6 months was greater in HOT-CRT than in BVP (12.4% ± 7.3% vs 8.0% ± 10.1%, P = 0.02). The primary safety endpoint was similar (98% vs 94%, P = 0.62). Echocardiographic response of improvement in LVEF >5% occurred in 80% vs 61% (P = 0.06). Complications occurred in 3 (6%) in HOT-CRT vs 10 (20%) in BVP (P = 0.03). ConclusionsHPCSP-guided CRT resulted in greater change in LVEF compared with BVP. Randomized clinical trials with long-term follow-up are necessary. (His-Purkinje Conduction System Pacing Optimized Trial of Cardiac Resynchronization Therapy [HOT-CRT]; NCT04561778)

ECG characteristics of “true” left bundle branch block: Insights from transcatheter aortic valve–related LBBB and His-Purkinje conduction system pacing–correctable LBBB

Left bundle branch block (LBBB) pattern on the electrocardiogram includes patients with both complete conduction block in the His-Purkinje system as well as nonspecific left ventricular conduction delay without discrete block. The purpose of this study was to characterize electrocardiographic morphological features of LBBB patterns in patients with (1) LBBB after transcatheter aortic valve replacement (TAVR) and (2) LBBB correctable by conduction system pacing (CSP). Consecutive patients with post-TAVR (n = 123) or CSP-correctable LBBB (n = 58) from 2 centers were included in this retrospective evaluation. QRS durations as well as detailed morphological features, including notching and slurring, of QRS complexes in leads I, aVL, V1, V2, V5, and V6 and in all 3 inferior leads were recorded. The mean age of the entire cohort was 78.3 ± 10.1 years, with 48% of the cohort being male(87/181). In the CSP-correctable group (n = 58), 14 (24.1%) underwent His-bundle pacing and 44 (75.9%) left bundle branch area pacing. A total of 17 of 181 (9.4%) of the combined cohort failed to completely meet the Strauss criteria. QRS morphology in lead V1/V2 was always either rS or QS, and there were no q/Q waves noted in lead V5/V6. Although dominant R waves were seen in leads I and aVL of 176 of 181 (97.2%), q/Q waves were present in only 21 of 181 (11.6%). Importantly, notched or slurred QRS complexes were identified in at least 1 lead of 4 leads I, aVL, V5, and V6 in 181 of 181 (100%). Strauss criteria and QRS notching are highly prevalent in LBBB after TAVR and in LBBB correctable by CSP.

Cardiac resynchronization therapy for patients with heart failure and nonspecific intraventricular conduction delay.

The efficacy of cardiac resynchronization therapy (CRT) in heart failure patients with left bundle branch block (LBBB) is well established with Class I or IIa recommendation according to 2021 ESC Guidelines on cardiac pacing and CRT, whereas non-LBBB morphology is less recommended. There is insufficient evidence that proves patients with NICD could benefit from CRT. As patients with NICD are characterized by heterogeneity, the effect of CRT on these patients is still controversial. Although the proportion of NICD in the population is lower than that of LBBB patients, it is still worth investigating the effects of CRT on patients with NICD in an era of His-Purkinje conduction system pacing (HPCSP).

The Case Files

The Case Files

The feasibility and safety of his-purkinje conduction system pacing in patients with heart failure with severely reduced ejection fraction.

The purpose of this study was to evaluate the feasibility and outcomes of conduction system pacing (CSP) in patients with heart failure (HF) who had a severely reduced left ventricular ejection fraction (LVEF) of less than 30% (HFsrEF). Between January 2018 and December 2020, all consecutive HF patients with LVEF < 30% who underwent CSP at our center were evaluated. Clinical outcomes and echocardiographic data [LVEF and left ventricular end-systolic volume (LVESV)], and complications were all recorded. In addition, clinical and echocardiographic (≥5% improvement in LVEF or ≥15% decrease in LVESV) responses were assessed. The patients were classified into a complete left bundle branch block (CLBBB) morphology group and a non-CLBBB morphology group according to the baseline QRS configuration. Seventy patients (66 ± 8.84 years; 55.7% male) with a mean LVEF of 23.2 ± 3.23%, LVEDd of 67.33 ± 7.47 mm and LVESV of 212.08 ± 39.74 ml were included. QRS configuration at baseline was CLBBB in 67.1% (47/70) of patients and non-CLBBB in 32.9%. At implantation, the CSP threshold was 0.6 ± 0.3 V @ 0.4 ms and remained stable during a mean follow-up of 23.43 ± 11.44 months. CSP resulted in significant LVEF improvement from 23.2 ± 3.23% to 34.93 ± 10.34% (P < 0.001) and significant QRS narrowing from 154.99 ± 34.42 to 130.81 ± 25.18 ms (P < 0.001). Clinical and echocardiographic responses were observed in 91.4% (64/70) and 77.1% (54/70) of patients. Super-response to CSP (≥15% improvement in LVEF or ≥30% decrease in LVESV) was observed in 52.9% (37/70) of patients. One patient died due to acute HF and following severe metabolic disorders. Baseline BNP (odds ratio: 0.969; 95% confidence interval: 0.939-0.989; P = 0.045) was associated with echocardiographic response. The proportions of clinical and echocardiographic responses in the CLBBB group were higher than those in the non-CLBBB group but without significant statistical differences. CSP is feasible and safe in patients with HFsrEF. CSP is associated with a significant improvement in clinical and echocardiographic outcomes, even for patients with non-CLBBB widened QRS.

Pacing of the specialized His-Purkinje conduction system: 'back to the future'.

The conduction system of the human heart is composed of specialized cardiomyocytes that initiate and propagate the electric impulse with consequent rhythmic and synchronized contraction of the atria and ventricles, resulting in the normal cardiac cycle. Although the His-Purkinje system (HPS) was already described more than a century ago, there has been a recent resurgence of conduction system pacing (CSP), where pacing leads are positioned in the His bundle region and left bundle branch area to provide physiological cardiac activation as alternatives to the unnatural myocardial stimulation obtained with conventional right ventricular and biventricular pacing. In this review, we describe the fundamental anatomical and pathophysiological aspects of the specialized HPS along with the CSP technique's nuts and bolts to highlight its potential benefits in everyday clinical practice.

Effect of scar and His-Purkinje and myocardium conduction on response to conduction system pacing.

Conduction system pacing (CSP), in the form of His bundle pacing (HBP) or left bundle branch pacing (LBBP), is emerging as a valuable cardiac resynchronization therapy (CRT) delivery method. However, patient selection and therapy personalization for CSP delivery remain poorly characterized. We aim to compare pacing-induced electrical synchrony during CRT, HBP, LBBP, HBP with left ventricular (LV) epicardial lead (His-optimizedCRT [HOT-CRT]), and LBBP with LV epicardial lead (LBBP-optimized CRT [LOT-CRT]) in patients with different conduction disease presentations using computational modeling. We simulated ventricular activation on 24four-chamber heart geometries, including His-Purkinje systems with proximal left bundle branch block (LBBB). We simulated septal scar, LV lateral wall scar, and mild and severe myocardium and LV His-Purkinje system conduction disease by decreasing the conduction velocity (CV) down to 70% and 35% of the healthy CV. Electrical synchrony was measured by the shortest interval to activate 90% of the ventricles (90% of biventricular activation time [BIVAT-90]). Severe LV His-Purkinje conduction disease favored CRT (BIVAT-90: HBP 101.5 ± 7.8 ms vs.CRT 93.0 ± 8.9 ms, p < .05), with additional electrical synchrony induced by HOT-CRT (87.6 ± 6.7 ms, p < .05) and LOT-CRT (73.9 ± 7.6 ms, p < .05). Patients with slow myocardium CV benefit more from CSP compared to CRT (BIVAT-90: CRT 134.5 ± 24.1 ms; HBP 97.1 ± 9.9 ms, p < .01; LBBP: 101.5 ± 10.7 ms, p < .01). Septal but not lateral wall scar made CSP ineffective, while CRT was able to resynchronize the ventricles in the presence of septal scar (BIVAT-90: baseline 119.1 ± 10.8 ms vs.CRT 85.1 ± 14.9 ms, p < .01). Severe LV His-Purkinje conduction disease attenuates the benefits of CSP, with additional improvements achieved with HOT-CRT and LOT-CRT. Septal but not lateral wall scars make CSP ineffective.

His-Purkinje conduction system pacing combined with atrioventricular node ablation improves quality of life in older patients with persistent atrial fibrillation refractory to multiple ablation procedures.

Recurrence of atrial fibrillation (AF) is common in patients with persistent AF even after multiple ablation procedures. His-Purkinje conduction system pacing (HPCSP) combined with atrioventricular node ablation (AVNA) is effective in managing patients with AF and heart failure. This study aimed to determine whether HPCSP combined with AVNA can improve quality of life and alleviate symptoms in older patients with symptomatic persistent AF refractory to multiple ablation procedures, as well as evaluate the feasibility and safety of this therapy. Older patients (≥ 65 years) with symptomatic persistent AF refractory to at least two ablation procedures were treated with combined HPCSP and AVNA. The success rates and complications were recorded. Pacing parameters, European Heart Rhythm Association (EHRA) scores, and Atrial Fibrillation Effect on Quality-of-Life (AFEQT) scores obtained perioperatively were compared with those recorded at the 6-month follow-up examination. Thirty-one patients were enrolled; of those, only thirty patients were eventually treated with AVNA because one patient developed a complete atrioventricular block following the withdrawal of the His bundle pacing lead. The success rates were 100% for HPCSP (22 cases with His bundle pacing, and 9 cases with left bundle branch pacing) and 93.3% (28/30) for AVNA, respectively. By the 6-month follow-up examination, EHRA scores improved significantly (3.00 ± 0.73 vs. 2.44 ± 0.63, P = 0.014) and AFEQT scores increased markedly (49.6 ± 20.6 vs. 70.9 ± 14.0, P = 0.001). No severe complications developed. When used in older patients with symptomatic persistent AF refractory to multiple ablation procedures, HPCSP combined with AVNA significantly alleviated symptoms and improved quality of life during short-term follow-up. This therapy was proved to be safe and effective in this patient population.

His-Purkinje conduction system pacing and atrioventricular node ablation in treatment of persistent atrial fibrillation refractory to multiple ablation procedures: A case report

In patients with symptomatic atrial fibrillation refractory to optimal medical therapy, atrioventricular node ablation followed by permanent pacemaker implantation is an effective treatment option. A 66-year-old woman with symptomatic persistent atrial fibrillation refractory to multiple ablation procedures was referred to our institution. After optimal drug therapy, the patient still had obvious symptoms. Sequential His-Purkinje conduction system pacing and atrioventricular node ablation were performed. Left bundle branch pacing was used as a backup pacing method if thresholds of His bundle pacing were too high or loss of His bundle capture occurred in the follow-up. At the 6-month follow-up, the European Heart Rhythm Association classification for AF was improved, the score of the Atrial Fibrillation Effect on Quality of Life was enhanced, and the 6-Minute Walk Test was ameliorated. The present case was subjected to His-Purkinje conduction system pacing in combination with atrioventricular node ablation as treatment for a symptomatic persistent atrial fibrillation refractory to multiple ablation procedures, and this procedure alleviated symptoms and improved the quality of life in a short-term follow-up.

The Primary Alteration of Ventricular Myocardium Conduction: The Significant Determinant of Left Bundle Branch Block Pattern.

Intraventricular conduction disturbances (IVCD) are currently generally accepted as ECG diagnostic categories. They are characterized by defined QRS complex patterns that reflect the abnormalities in the intraventricular sequence of activation that can be caused by pathology in the His-Purkinje conduction system (HP) or ventricular myocardium. However, the current understanding of the IVCD's underlying mechanism is mostly attributed to HP structural or functional alterations. The involvement of the working ventricular myocardium is only marginally mentioned or not considered. This opinion paper is focused on the alterations of the ventricular working myocardium leading to the most frequent IVCD pattern-the left bundle branch block pattern (LBBB). Recognizing the underlying mechanisms of the LBBB patterns and the involvement of the ventricular working myocardium is of utmost clinical importance, considering a patient's prognosis and indication for cardiac resynchronization therapy.

Recruitment of the cardiac conduction system for optimal resynchronization therapy in failing heart.

Heart failure (HF) is a leading health burden around the world. Although pharmacological development has dramatically advanced medication therapy in the field, hemodynamic disorders or mechanical desynchrony deteriorated by intra or interventricular conduction abnormalities remains a critical target beyond the scope of pharmacotherapy. In the past 2 decades, nonpharmacologic treatment for heart failure, such as cardiac resynchronization therapy (CRT) via biventricular pacing (BVP), has been playing an important role in improving the prognosis of heart failure. However, the response rate of BVP-CRT is variable, leaving one-third of patients not benefiting from the therapy as expected. Considering the non-physiological activation pattern of BVP-CRT, more efforts have been made to optimize resynchronization. The most extensively investigated approach is by stimulating the native conduction system, e.g., His-Purkinje conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). These emerging CRT approaches provide an alternative to traditional BVP-CRT, with multiple proof-of-concept studies indicating the safety and efficacy of its utilization in dyssynchronous heart failure. In this review, we summarize the mechanisms of dyssynchronous HF mediated by conduction disturbance, the rationale and acute effect of CSP for CRT, the recent advancement in clinical research, and possible future directions of CSP.

Atrial-His bundle pacing in fulminant myocarditis with ventricular arrhythmia: a case report

BackgroundFulminant myocarditis is a clinical syndrome associated with threatening dysrhythmia which temporary pacemaker can be used for life-saving support. As a method of physiological pacing, His bundle pacing (HBP) maintain better cardiac synchronization than traditional right ventricular (RV) pacing.Case presentationIt’s a severe case of fulminant myocarditis in a 41-year-old patient who presented for recurrent arrhythmias with hemodynamic instability. Temporary His bundle pacing combined with optimal medical therapy and extracorporeal membrane oxygenators (ECMO) supported him through his critical period of hospitalization.ConclusionsDuring 1-year follow up, the cardiac function recovery was obvious without any pacing related complications. Echocardiography showed better atrioventricular and intra-ventricular synchronization during HBP in DDD mode. This is the first reported case of temporary His-purkinje conduction system pacing used for severe fulminant myocarditis.

Abstract 13585: In Patients With Right Bundle Branch Block, ECG Z-Axis QRS-T Voltage-Time-Integral Predicts Right Ventricular Structure and Function

Introduction: Right bundle branch block (RBBB) is the most common His-Purkinje conduction abnormality seen on ECG. It is currently unclear if there are any quantitative ECG differences in RBBB without and with structural right ventricular (RV) disease. Our aim was to evaluate quantitative ECG predictors of echocardiographic RV measurements [tricuspid annular plane systolic excursion (TAPSE), tissue Doppler imaging RV S’, RV basal and mid diameters, RV systolic pressure (RVSP)]. Hypothesis: QRS-T VTI in patients with RBBB is a marker for adverse RV remodeling and dysfunction. Methods: We included adults with ECG demonstrating typical RBBB and echocardiogram performed within 3 months of each other in 2010-2020. Orthogonal X, Y, Z ECG leads were reconstructed using Kors matrix. In addition to overall QRS duration, QRS voltages and QRS/QRS-T VTIs from 12 standard leads, X, Y, Z leads, and 3D (root-mean-square) ECG were evaluated. Age, sex and BSA-adjusted linear regressions were used to assess associations between ECG variables and RV measurements. We separately generated ROC curves for predicting abnormal RV measurements from ECG variables. Results: We included 782 patients (33% women, 71±14 years). Amongst the ECG variables, BSA-indexed Z-axis QRS-T VTI (VTI QRST-Z *√BSA) was the strongest independent predictor of all 5 RV measurements (Table 1a shows a comparison of QRS duration, Z-axis amplitude and VTI). VTI QRST-Z *√BSA cutoff 62 μVsm had a sensitivity 62.7% and specificity 65.7% to distinguish presence of ≥3 abnormal out of the 5 RV measurements (Table 1b). Conclusions: Adverse RV remodeling causes augmentation of the anterior-posteriorly directed QRS-T potential which is seen as a change in Z-axis VTI. VTI QRST-Z *√BSA could be used as a marker for right heart failure in patients with RBBB.

The review of atrioventricular node ablation combined with His-Purkinje conduction system pacing in the treatment of atrial fibrillation and heart failure

心房颤动是成年人中最常见的持续性心律失常，心房颤动伴快速心室率是引起心力衰竭的重要原因之一。房室结消融联合希氏-浦肯野系统起搏是可行、有效的，尤其适用于难以耐受药物治疗或药物治疗无效、导管射频消融治疗失败的心房颤动伴快速心室率合并心力衰竭的患者。本文对房室结消融联合希氏-浦肯野系统起搏治疗心房颤动伴快速心室率合并心力衰竭的研究进展作一综述。.

Research progress on His-Purkinje Conduction System Pacing in patients with heart failure and left bundle branch block

左束支传导阻滞（LBBB）可导致心室电传导延迟、收缩不同步，是加重心力衰竭（心衰）的重要因素，亦是心衰治疗的重要靶点。传统双心室起搏可纠正LBBB、改善心功能，但其受到技术及解剖的限制，仍有部分患者难以从中获益。随着对希氏-浦肯野系统认识的深入、导线置入工具的改进及技术的发展，希氏-浦肯野系统起搏作为一种生理性起搏方式，成为当前研究的热点。希氏-浦肯野系统起搏可纠正LBBB、恢复电机械同步性，有望作为传统双心室起搏的替代疗法用于心衰伴LBBB患者。该文对希氏-浦肯野系统起搏在心衰伴LBBB患者中应用的理论及临床进展进行了综述。.