Bundle Branch Research Articles

Painful Left Bundle Branch Block Syndrome: A Systematic Review of Treatment Strategies in Case Reports.

Painful left bundle branch block (PLBBB) syndrome remains a poorly understood cardiac anomaly. This systematic review consolidates case report evidence to elucidate effective management strategies and patient outcomes. Databases including PubMed, Scopus, Web of Science, and Scielo were searched without restrictions on language or publication date. Following PRISMA guidelines, 128 articles were identified, with 31 meeting inclusion criteria. Data were extracted on patient demographics, clinical presentation, treatment regimens, and outcomes using Microsoft Excel and assessed for bias with the Joanna Briggs Institute's tool. The analysis included 45 patients with a mean age of 55.46 ± 12.23. Predominantly, LBBB episodes occurred during exercise (73.3%). Initial treatments comprised beta-blockers/calcium channel blockers (55.56%), pacemaker implantation (13.3%), antianginal medications (13.3%), and other modalities (17.7%). Refractoriness to initial treatment was observed in 66.7% of patients, with subsequent pacemaker implantation resolving symptoms in most cases. An overall satisfactory response was seen in 73.3% of patients post-treatment adjustments. The diverse approaches in treatment highlight the necessity for tailored therapeutic strategies. While pacemakers have demonstrated efficacy in controlling symptoms in several reported cases, it is essential to recognize the complex nature of this intervention. Pacemaker implantation, being a surgical procedure, carries long-lasting implications for patients. Hence, the continuation of pharmacological treatments might still be preferable until more definitive research is available. This review emphasizes the urgent need for further research to establish evidence-based guidelines, particularly concerning the selection of first line of treatment, to optimize outcomes for PLBBB syndrome.

A new thermoelectric ECG model: influence of bundle branch block and variations in body temperature

Abstract This work proposes a thermoelectric model to investigate the behavior of specific pathological situation, such as bundle branch block. Impact of temperature is evaluated and its role in controlling the pathology determined. Our proposed 2D thermoelectric model incorporates the heart, lungs, torso, and blood cavities. The Fitzhugh-Nagumo equations that simulate the electrical activity of cardiac myocytes are coupled with temperature equations while considering the parameters of the bundle branch block to analyze their impact on the electrocardiogram. We establish that the presence of bundle branch block significantly affects electrocardiogram morphology, resulting in changes in wave amplitude and interval durations. Moreover, our findings reveal that variations in body temperature alter this pathological condition leading to further distortions in the electrocardiogram. Our thermoelectric model provides valuable insights into the behavior of bundle branch block under temperature variations. This knowledge may potentially contribute to the development of novel treatment and management strategies utilizing thermal control to enhance outcomes for patients presenting similar symptoms.

Non-linear dynamics in ECG: a novel approach for robust classification of cardiovascular disorders

Detecting cardiac disorders from multi-channel ECG has significant implications for cardiac care. Current methods face challenges due to ECG waveform variations by electrode placement, high signal non-linearity, and low millivolt amplitudes. The present study introduces a non-linear analysis approach leveraging Recurrence plot visualizations as the patterned occurrence of well-defined structures, such as the QRS complex, can be exploited effectively using Recurrence plots. Using the Physikalisch-Technische Bundesanstalt dataset from PhysioNet, we examined four cardiac disorder classes- Myocardial infarction, Bundle branch blocks, Cardiomyopathy, Dysrhythmia, and healthy controls, achieving an impressive classification accuracy of 100%. Wilcoxon rank-sum test is performed at 95% C.I. on Recurrence Quantitative Analysis (RQA) features, identifying five features with statistically significant differences across pairs of study groups. Additionally, t-SNE visualizations of latent space embeddings derived from Recurrence plots and RQA features reveal clear separation among cardiac disorders and healthy subjects, underscoring the efficacy of the proposed approach.

Mid-term comparison of new-onset AHRE between His bundle and left bundle branch area pacing in patients with AV block.

Atrial high-rate episodes (AHRE) detected by cardiac implanted electronic devices are known markers for adverse cardiac events. Previous studies have shown that the incidence of new-onset AHREs in patients with right ventricular pacing reaches 50%. At the same time, His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) were associated with significantly fewer AHRE. This study aimed to compare the incidence of new-onset AHRE between HBP and LBBAP in patients with atrioventricular block and no history of atrial fibrillation. One hundred and forty-two patients, fifty-nine with HBP and eighty-three with LBBAP for advanced atrioventricular block, were prospectively followed for new-onset AHRE. The mean follow-up period was 624 ± 148.6 days for the HBP patients and 663.4 ± 157.4 days for the LBBAP patients. New-onset AHRE was encountered in 8 of 59 patients (13.5%) with HBP and 14 of 83 (16.8%) with LBBAP (hazard ratio-0.91, log rank p = .84). In the multivariate Cox regression model, HBP and LBBAP had similar predictive values, while only age and diabetes mellitus were significantly associated with new-onset AHRE occurrence. HBP and LBBAP were associated with a similar incidence of device-detected new-onset AHRE during a medium-term follow-up period in patients with atrioventricular block and no history of atrial fibrillation.

Performance of an Active Fixation Stylet-Driven Lead in Left Bundle Branch Area Pacing: Results from INSIGHT-LBBA

Performance of an Active Fixation Stylet-Driven Lead in Left Bundle Branch Area Pacing: Results from INSIGHT-LBBA

Comparative analysis of left bundle branch area pacing in patients with and without a history of open-heart surgery.

Left bundle branch area pacing (LBBAP) is widely performed in routine clinical practice. Achieving LBBAP requires deep insertion of the lead into the interventricular septum. LBBAP may be challenging in patients with a history of open-heart surgery (OHS) because of myocardial fibrosis associated with surgical trauma. This study aimed to report the feasibility and safety of performing LBBAP in patients with a history of OHS. This retrospective analysis included patients who underwent successful LBBAP between November 2020 and September 2024, with approval from our institutional review board. LBBAP was performed using a 3830 SelectSecure lead, and pacing parameters were assessed before and after implantation. One hundred patients were analyzed, including 26 in the OHS group and 74 in the non-OHS group. The success rates of LBBAP were 84.6% in the OHS group and 90.5% in the non-OHS group (p = 0.375). Notably, the number of LBBAP lead placements was higher in the OHS group (3.0 ± 2.1 vs. 2.0 ± 1.4, p = 0.017). The left ventricular activation time in lead V6 was comparable between the groups at implantation (73.6 ± 13.3 ms vs. 75.6 ± 12.1 ms, p = 0.522). The QRS duration was significantly wider in the OHS group at implantation (131.3 ± 14.6 vs. 121.1 ± 12.3 ms, p = 0.002), but parameters remained stable at 1 year. LBBAP in patients with a history of OHS may present a slightly higher level of technical difficulty, but it is both feasible and safe.

Evaluation of Right and Left Ventricular Deformation Analysis in İdiopathic Right Bundle Branch Block by Speckle Tracking Echocardiography.

Idiopathic right bundle branch block (RBBB) is often seen as harmless and common. However, many studies show it might be linked to negative health outcomes. So, it is crucial to fully understand how RBBB affects the heart's ventricles. This study aims to examine the right and left ventricular systolic functions in patients with idiopathic RBBB and compare them to those in a healthy control group. Echocardiographic images were obtained from patients with idiopathic RBBB and healthy control participants. Conventional echocardiographic parameters were measured. Two-dimensional (2D) speckle tracking strain analysis was used to assess deformation indices. Thirty-nine patients with idiopathic RBBB and 35 healthy participants were included in the study. There were no significant differences in the chamber dimensions of the left ventricle (LV) and right ventricle (RV) between the groups. LV ejection fraction (EF), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) measurements were similar between the groups. LV global longitudinal strain (GLS) (-25.5±5.7% vs. -22.1±4.2%, p<0.05), RV GLS (-26.9±4.6% vs. -24.0±4.4%, p<0.05), and interventricular septum longitudinal strain (IVS LS) (-24.3±4.9% vs. -19.1±4.2%, p<0.05) were significantly reduced in patients with idiopathic RBBB compared to controls, indicating impaired myocardial shortening. Significant differences were also observed in LV (15 [5-30] vs. 30 [20-60], p<0.05) and RV (18 [7-35] vs. 36 [24-80], p<0.05) mechanical dispersion, with the differences being more pronounced for the RV between the groups. LV torsion (2.1±0.6 vs. 1.6±0.5, p<0.05) was also worse in patients with idiopathic RBBB. Our findings show that idiopathic RBBB significantly affects the longitudinal strain and synchronization of both the LV and RV.

Cardiac resynchronization therapy in heart failure based on Strauss criteria for left bundle branch block.

The left bundle branch block (LBBB) is a strong predictor of response to cardiac resynchronization therapy (CRT). However, a significant number of patients do not respond to the treatment. The study sought to evaluate the impact of the stricter Strauss criteria for left bundle branch block (St-LBBB) on CRT response, hospitalizations, ventricular arrhythmia (VA) events and mortality. This study is a retrospective analysis of prospectively collected data on heart failure (HF) patients with LBBB admitted for CRT implantation. Patients were divided into two groups according to the fulfilment or not of St-LBBB criteria. The study included 82 patients with ischaemic (ICM) and non-ischaemic (NICM) cardiomyopathy [46 (56%) with St-LBBB and 36 (44%) with non-St-LBBB]. Patients with St-LBBB showed higher CRT response rates compared with those with non-St-LBBB (P<0.01), while the group with NICM exhibited the greatest benefit (P<0.01). St-LBBB CRT responders displayed significantly lower rates of HF hospitalization (P<0.0001) compared with the non-St-LBBB group. According to Kaplan-Meier time curves, this was primarily evident in patients with NICM (P<0.0001). CRT responders displayed significantly fewer VA events (P<0.001) and lower mortality rates (P<0.0001) than non-responders. Kaplan-Meier estimates demonstrated a significantly lower incidence of VAs in NICM patients with St-LBBB (P=0.049) compared with ICM patients with St-LBBB (P=0.25). Lower mortality rates were observed in CRT responders than non-responders (P<0.0001), with the group of NICM with St-LBBB criteria exhibiting the greatest benefit (P=0.0238). Patients with NICM and St-LBBB present the greatest benefit concerning CRT response, HF hospitalizations, VA events and mortality. Although St-LBBB criteria seem to improve patient selection for CRT, more data are needed to elucidate the role of St-LBBB criteria in this setting.

Automated classification of cardiac arrhythmia using short-duration ECG signals and machine learning

Accurate detection of cardiac arrhythmias is crucial for preventing premature deaths. The current study employs a dual-stage Discrete Wavelet Transform (DWT) and a median filter to eliminate noise from ECG signals. Subsequently, ECG signals are segmented, and QRS regions are extracted for further preprocessing. The study considers five cardiac arrhythmias: normal beats, Premature Ventricular Contractions (PVC), Premature Atrial Contractions (PAC), Right Bundle Branch Block (R-BBB), and Left Bundle Branch Block (L-BBB) for classification. Nine distinct temporal features are extracted from the segmented QRS complex. These features are then applied to six different classifiers for arrhythmia classification. The classifiers' performance is evaluated using the MIT-BIH Arrhythmia Database (MIT-BIH AD). Support Vector Machine (SVM) and Ensemble Tree classifiers demonstrate superior performance in classifying the five different classes. Particularly, the Support Vector Machine classifier achieves high sensitivity (97.44%), specificity (99.36%), positive predictive value (97.44%), and accuracy (98.97%) with a Gaussian kernel. This comprehensive approach, integrating preprocessing, and feature extraction, holds promise for improving automatic cardiac arrhythmia classification in clinical trials.

High rate of bradycardia-dependent left bundle branch block after transcatheter aortic valve implantation.

High rate of bradycardia-dependent left bundle branch block after transcatheter aortic valve implantation.

Intraventricular septal hematoma as a complication of left bundle branch pacing: A case report of evolution of hematoma after conservative treatment.

Intraventricular septal hematoma as a complication of left bundle branch pacing: A case report of evolution of hematoma after conservative treatment.

Factors associated with heart failure events in patients with new-onset persistent left bundle branch block at discharge after transcatheter aortic valve replacement.

New-onset persistent left bundle branch block (NOP-LBBB) at discharge after transcatheter aortic valve replacement (TAVR) is frequent but its association with death and hospitalization for heart failure (HHF) remains unclear. We aimed to assess the association of LBBB persistence or resolution post-discharge and of permanent pacemaker (PPM) implantation before discharge with these outcomes. We analyzed consecutive patients undergoing TAVR at Nancy University Hospital from 2009 to 2021, with NOP-LBBB at discharge and available 1-year follow-up. We assessed the association of LBBB persistence (LBBB+) or resolution (LBBB-) at 3 months, and in-hospital PPM implantation (PPM+) or absence (PPM-), with the one-year risk of the composite outcome of mortality or HHF. Out of 1646 TAVR patients, 287 (17.4%) developed NOP-LBBB, with complete follow-up data available for 234 patients. Among them, 73 patients (31.2%) required in-hospital PPM implantation, 142 patients (60.7%) experienced LBBB persistence at 3-month follow-up and 45 (19.2%) had both. The one-year mortality or HHF rate was 6.3% (PPM-/LBBB-), 10.7% (PPM+/LBBB-), 20.6% (PPM-/LBBB+) and 22.2% (PPM+/LBBB+). LBBB persistence was significantly associated with the composite outcome irrespectively of PPM implantation (adjusted hazard ratio [aHR] compared to PPM-/LBBB-: aHR for PPM-/LBBB+=4.91 [1.64-14.64], p=0.004; aHR for PPM+/LBBB+=4.58 [1.43-14.68], p=0.010) whereas PPM implantation with LBBB- was not (p=0.29). This association was mainly driven by HHF (aHR for PPM-/LBBB+=8.36 [1.90-36.83], p=0.005; aHR for PPM+/LBBB+=8.36 [1.80-38.89], p=0.007). The persistence of LBBB beyond discharge, rather than in-hospital PPM implantation, was associated with a higher risk of one-year mortality or HHF in patients with NOP-LBBB at discharge post-TAVR. Assessing post-discharge LBBB persistence may improve prognostic accuracy.

Conduction System Pacing for Cardiac Resynchronization Therapy in Heart Failure with Reduced Ejection Fraction

Most patients with heart failure exhibit ventricular dyssynchrony, which is addressed by cardiac resynchronization therapy, traditionally through the use of biventricular pacing (BVP) devices. Despite this, around 30% of patients do not achieve the desired clinical outcome, and echocardiographic findings show that some patients deteriorate even further. Conduction system pacing (CSP) is a more physiologic pacing technique and includes his-bundle pacing (HBP) and left bundle branch area pacing (LBBAP). In this review, we further discuss and compare various CSP techniques for cardiac resynchronization therapy in patients with heart failure with reduced ejection fraction. After analyzing the current state of the literature on this topic until 2023, eight studies were included in this review and consisted of two trials and five observational studies with a total of 2841 patients. Both BVP and CSP resulted in improved outcomes in terms of NYHA class, QRS duration, and left ventricular ejection fraction over time. These effects were more pronounced in patients undergoing CSP, as the technique is more physiological and results in the synchronized activation of the ventricles. LBBAP yielded better outcomes compared to BVP and resulted in fewer heart failure hospitalizations and a lower all-cause mortality rate.

Correlation of left ventricular global longitudinal strain by speckle-tracking echocardiography with invasive LV filling pressure

Abstract Introduction The left ventricular (LV) systolic function can affect diastolic relaxation. The interaction of systolic and diastolic myocardial function resembles the mechanism of "coil compression and relaxation." This concept has gained significant attention in recent years, challenging the notion of "isolated diastolic dysfunction." Speckle tracking echocardiography (STE) is a sensitive and innovative method for evaluating global myocardial function beyond LVEF. This study examined the possible correlation between left ventricular longitudinal strain (GLS) and different LV filling pressures. Method Patients scheduled for diagnostic coronary angiography and left heart catheterization were included. The exclusion criteria were any degree of mitral stenosis, more than moderate mitral regurgitation or aortic stenosis, left bundle branch block, or atrial fibrillation. Measurements of LV end-diastolic pressure (LVEDP), LV min diastolic pressure (LVMDP), and LV pre-A diastolic pressure (LV pre-A) were taken via cardiac catheterization. On the same day, LV global longitudinal strain (LV GLS) was assessed using the EPIQ 7 Philips vendor. Results A total of seventy patients were studied (mean age: 50.24 ± 12.6 years; 60% male). The mean LVEF was 46.8% (SD:10.3), and the mean E/e’= 11.1 (SD:4.1). Pearson’s correlation coefficient showed a moderate negative relationship between LV GLS and LVEDP (R=-0.45, p&amp;lt;0.001), LVMDP (R=-0.44, p&amp;lt;0.001), and LV pre-A (R=-0.43, p&amp;lt;0.001). Conclusion The correlation of multiple invasive LV filling pressure parameters (LVEDP, LVMDP, and LV pre-A pressure) with LV GLS signifies the possible role of systolic parameters in predicting diastolic dysfunction. Integrating LV GLS with conventional algorithms may improve the non-invasive assessment of diastolic dysfunction.

Use of a Stylet Driven Lead With a Flexible Neck for Left Bundle Branch Area Pacing: A Single Center Experience.

The majority of data on left bundle branch area pacing (LBBAP) are on a lumenless lead. Data on the safety and effectiveness of stylet driven leads are comparatively lacking. We retrospectively analyzed 265 patients who underwent attempted LBBAP with an 7842 (Boston Scientific, Marlborough, MA) lead in the Duke University Health System between 1/1/2020 and 9/1/2023. Outcomes of interest included post-operative 7842 helix extension (≥2 helix rotations beyond the lead tip), complications, and lead parameters. A nested analysis of single and dual chamber LBBAP attempts was performed to compare outcomes among similar patients who underwent attempted LBBAP with the lumenless 3830 (Medtronic, Mineappolis, MN) lead. LBBAP success with 7842 was 89.8%. Characteristics were similar among patients with (n = 238) and without (n = 27) successful implants. Helix extension was evaluable for 222 of 238 successful 7842 implants. Of evaluable leads, helix extension was complete for 174 leads (78%), and partial for 48 (21.6%). A trend towards lower dislodgement rates was observed in patients with full versus partial extension (2.9% vs. 8.3%, p = 0.0895) and the rate of full helix extension increased over time (64.1% over 24 months vs. 81.4% over 21 months, p = 0.0162). The success rate of 3830 LBBAP implants (n = 140) was 92.8% (p = 0.069 vs. 7842). At implant, R waves were similar for 7842 and 3830 leads but were greater for 7842 during follow-up (14.4 + /-0.77 vs. 11.3 + /-0.68, p = 0.004). Pacing impedances were higher with 7842 compared with 3830 at baseline (838 + /-10.44 ohms vs. 772 + /-14.58 ohms, p < 0.001) and during follow-up (652 + /-11.0 ohms vs. 513 + /-9.18 ohms, p < 0.001); similarly, 7842 pacing thresholds (@ 0.4 ms) were slightly higher at baseline (0.85 V + /-0.03 vs. 0.68 V + /-0.03, p < 0.001) and 6 months (0.95 V + /-0.03 vs. 0.80 V + /-0.03, p < 0.001) compared with those for the lumenless 3830. LBBAP implant success rates, complications, and pacing parameters using the 7842 lead are stable over time, and appeared overall similar to the 3830 lead. Incomplete 7842 helix extension is a modifiable risk factor for lead dislodgement.

Myocardial work analysis of aortic stenosis parients with right ventricular pacing: interaction of afterload and mechanical dyssynchrony?

Abstract It is well known that left ventricular (LV) performance is substantially influenced by the corresponding loading conditions and LV synchrony. Notably, data are scarce about the interaction of these factors: previous studies suggest that patients with left bundle branch block (LBBB) has increased afterload sensitivity. This phenomenon may have special importance in certain clinical situations, such as aortic stenosis (AS) patients with concomitant right ventricular pacing (RVP). Accordingly, our aim was to investigate the effects of RVP on LV function in patients with severe AS before and after transcatheter aortic valve replacement (TAVR). Patients with a previously implanted pacemaker and significant AS undergoing TAVR in our Institute were screened. Only subjects with intrinsic non-LBBB QRS were enrolled (n=31). Detailed echocardiographic protocol suitable for speckle-tracking and myocardial work analysis was obtained. Myocardial work measures were calculated by estimating LV pressure as the sum of the systolic blood pressure and the mean aortic gradient. The patients underwent two sets of echocardiographic examinations: one with their narrow QRS rhythm and one with RVP. Those patients (n=19), who did not develop LBBB or complete AV-block also underwent a post-TAVI protocol. We measured LV ejection fraction (EF), global longitudinal strain (GLS) and also global work index (GWI) and global wasted work (GWW). Preoperatively, RVP resulted in significantly lower LV EF (55±9 vs. 49±10%, p≤0.001), GLS (-14.2±3.6 vs. -11.9±3.5%, p≤0.001) and GWI (1830±502 vs. 1322±546 mmHg%, p≤0.001) compared to narrow QRS rhythm, while GWW was markedly higher (222±129 vs. 344±146 mmHg%, p≤0.001). After TAVR, LV EF was comparable (55±9 vs. 52±8%, p=0.11), while GLS (-13.8±.3.8 vs. -11.4±3.8%, p≤0.001) and GWI (1360±403 vs. 1018±385 mmHg%, p≤0.01) was lower in RVP. Notably, the relative change in GWI in response to RVP was significantly lower after TAVR (-31±21 vs. -22±20%, p≤0.05). In patients with severe AS, LV dyssynchrony associated with RVP results in markedly lower LV functional measures. TAVR alleviates LV pressure overload, and the detrimental effect of RVP may dampen with the afterload reduction. Significant AS and RVP may have a highly unfavorable interaction raising the need for early interventions in this population.

3D echocardiographic assessment of permanent pacemaker ventricular lead position according to the type of ventricular pacing

Abstract Introduction In recent years, there has been a significant increase in the use of permanent pacemakers (PPM). Endocardial leads can induce or worsen tricuspid regurgitation (TR) when they interfere with tricuspid valve (TV) leaflets motion. Additionally, right ventricular pacing can also worsen TR and mitral regurgitation (MR). Purpose We aimed to assess: 1) the feasibility of utilizing 3D transthoracic echocardiography (TTE) to visualize PPM lead position, 2) the prevalence of different lead positions relative to the TV leaflets, and 3) the short-term echocardiographic outcomes based on the type of ventricular pacing (right ventricular apical pacing, RVAP, and left bundle branch area pacing, LBBAP). Methods We prospectively enrolled 48 consecutive patients who underwent PPM implantation with RVAP and LBBAP. Both 2D and 3D TTE were obtained from all patients at baseline and at a 3-month follow-up. Results 3D TTE was feasible in 94% of patients. The most common lead location was the posteroseptal commissure, regardless of the ventricular pacing types (65% RVAP vs 60% LBBAP, p = 0.761). TV diameters were similar in both groups (TV maximum diameter: RVAP 37±3 mm vs LBBAP 38±4 mm, p=0.248; TV minimum diameter: RVAP: 27±5 mm vs LBBAP 29±5 mm, p=0.143). However, a greater distance between the TV plane and lead tip insertion was found in RVAP compared to LBBAP. No differences were detected in the biventricular size/function and the severity of MR and TR based on the type of ventricular pacing at the 3-month follow-up (Table). High agreement was observed between two operators in identifying the lead localization by 3DTTE (Cohen K = 0.63, p &amp;lt; 0.001). Conclusions 3D TTE enables precise localization of PPM leads at the tricuspid valve level. Therefore, 3D TTE should be routinely employed, in particular to facilitate the detection of TV interference and the progression of TR after PPM implantation. Table. Echocardiographic characteristics

Apical rocking and septal flash revealed by an electrocardiographic parameter in the left bundle branch block

Abstract Background Assessing the relationship between electrical and mechanical dyssynchrony in patients with left bundle branch block (LBBB) remains a significant challenge for clinicians. Visual echocardiographic parameters, apical rocking (ApR), and septal flash (SF) are accurate markers of the contraction-and-stretch pattern in the septal and lateral wall in LBBB patients. Electrical activity of the LV apical septum and the LV lateral wall is ECG recorded by the aVL and aVF leads. An ECG parameter that integrates the electrical activation of these two contralateral LV walls could reveal subtle electrical features related to the uncoordinated contraction pattern in LBBB. To the best of our knowledge, no studies have examined the relationship between electrical and mechanical uncoordinated activation of the apical septum and lateral LV wall. Purpose This study aimed to assess the relationship between visual echocardiographic parameters of mechanical uncoordinated contraction pattern (ApR and SF) and ECG parameters of electrical intraventricular asynchrony in patients with LBBB. Methods We retrospectively included 157 consecutive patients with LBBB, in sinus rhythm, without significant coronary artery disease, and no more than mild organic valvular heart disease. The ApR and SF were echocardiographic visually assessed as a typical sequence of the septal-to-lateral apex motion for the ApR and the short leftward movement of the septum in early systole for the SF. We measured the following ECG parameters: LV activation times (LVAT), RR1 interval (as the longest interval from the first R wave to the last R1 wave) in lateral leads, intrinsicoid deflection (ID) in lateral and aVF leads, and a newly defined marker – the difference (Diff) between aVL and aVF ID’s (Diff_IDaVL_aVF). Based on the presence and absence of both ApR and SF (ApR_SF), the patients were divided into two groups: patients with (68.2%) and without (31.8%) ApR_SF. Results In the group of patients with ApR_SF, the LVAT, ID, and RR1 measured in lateral leads, and the Diff_IDaVL_aVF were significantly longer, but IDaVF was significantly shorter compared to the group of patients without ApR_SF (p&amp;lt;0.05) (Table 1). In multivariable analysis, the Diff_IDaVL_aVF (p &amp;lt; 0.001) was the only parameter independently correlated with the presence of ApR_SF (Table 2). On ROC analysis, the best cut-off of DIFF_IDaVL_IDaVF for predicting the presence of ApR_SF in LBBB patients was 46 ms (AUC of 0.92, sensitivity 86%, and specificity 80%) (Figure 2). Conclusions In LBBB, a simple ECG parameter incorporating the electrical activation of contralateral LV myocardial segments can provide insights into the myocardial contraction pattern in LBBB patients. A Diff_IDaVL_aVF longer than 46 msec identified LBBB patients with specific contraction patterns (ApR_SF). Considering ECG is the screening tool for LBBB diagnosis, these patients might benefit from early treatment to avoid a worse prognosis.

Recurrent cardiac tamponade as a complication of prolonged left bundle branch area pacing

Post-cardiac injury syndrome (PCIS) is one of the complications of cardiac interventional procedures. This condition has been postulated to be due to an immune reaction, especially with pacemaker lead implantation. Patients with PCIS can have uncomplicated pericardial effusion until they develop cardiac tamponade. The management of PCIS, which can be conservative management or require pericardiocentesis or surgery depends on the patient’s clinical symptoms. As the left bundle branch area pacing (LBBAP) implantation technique and technology are still new, it is associated with longer procedural time than conventional pacemaker implantation. Herein, we report a case of PCIS in a patient who had a prolonged LBBAP procedure due to difficult anatomy and presented with recurrent cardiac tamponade.

Left Bundle Branch Pacing Impact on QRS Amplitude in Different Pacing Voltages.

Left bundle branch pacing (LBBP) emerged as a novel physiological pacing modality that improves clinical outcomes. This study aimed to explore the impact of LBBP on QRS wave amplitude (RWA). This prospective observational study included patients with complete left bundle branch block (CLBBB) and cardiac resynchronization therapy (CRT) indication, as well as patients with QRSd < 120 ms and pacemaker indication. During the procedure, when the LBBP lead reached the target site, 12-lead ECGs at baseline and 1, 2, 3, 4, and 5 times the pacing thresholds and 3.5 V (pacemaker default value) pacing were recorded, and RWA values were measured accordingly. The absolute values of I + aVL, II + III+ aVF, and V1 + V2 + V3 + V4 + V5 + V6 RWA were defined as X-, Y-, and Z-axis ΣRWA. A total of 195 consecutive patients (50 CLBBB and 145 narrow QRS) were enrolled (69.7 ± 10.3 years, 52.3% male). Compared with the baseline, LBBP significantly increased X- and Y-axis ΣRWA independent of pacing voltage in CLBBB (ΔX/Y-axis 0.49 ± 0.78 mV, p < 0.0001/0.61 ± 1.24 mV, p = 0.001) and narrow QRS group (ΔX/Y-axis 0.88 ± 0.61 mV, p < 0.0001/0.91 ± 1.05 mV, p < 0.0001); LBBP significantly reduced Z-axis ΣRWA in CLBBB patients (ΔZ-axis -2.64 ± 3.67 mV, p < 0.0001) but not in narrow QRS group (ΔZ-axis -0.14 ± 1.87 mV, p = 0.36). LBBP significantly improved cardiac function at 1 week of follow-up. LBBP significantly increased X/Y-axis ΣRWA independent of pacing voltage in CLBBB and narrow QRS patients. LBBP significantly reduced Z-axis ΣRWA in CLBBB but not in narrow QRS patients. Whether these ΣRWA changes, through enhancing whole myocardial contractility, have a synergistic effect with LBBP synchronization to further improve cardiac function remains to be investigated.