Bundle Branch Research Articles

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.

A strain-based classification is associated with therapy success in cardiac resynchronization therapy-eligible patients

Abstract Introduction Echocardiography-derived septal strain patterns stages are associated with a stepwise increase in survival for each increment in strain stage among patients treated with cardiac resynchronization therapy (CRT). However, it is unknown whether the strain stages could also predict survival in conservatively-treated (i.e. not CRT-implanted) patients. Purpose This study aims to investigate the interplay between septal strain patterns and long-term survival in both CRT- and conservatively-treated patients. Methods In this multicentre study, CRT-eligible patients from six European centres underwent speckle-tracking strain analysis on echocardiography. CRT-treated patients (CRT) were enrolled prospectively and assessed prior to device implantation. Conservatively-treated patients (CON) were assessed retrospectively. Dyssynchrony was graded through analysis of septal strain curves, categorizing patients into five distinct patterns, denoted as strain Stage-0 (no dyssynchrony) through strain Stage-4 (severe dyssynchrony) (Fig. A). The study endpoint was all-cause mortality. Results A total of 267 CRT patients (69% males, 89% left bundle branch block (LBBB) and QRS 166±20 ms) and 167 CON patients (69% males, 87% LBBB, QRS 155±25 ms) were included. Median follow-up time was 49 (40-57) months. CON patients within the highest strain stages had the worst outcome, whereas CRT-treated patients within the highest strain stages had the best survival (Fig. B). A stepwise increase in survival difference was observed between CRT and CON patients for each increment in strain stage (Fig. B-F). Hazard ratios (HR) were: Stage-0: 1.42 (95% CI: 0.59-3.44, p=0.436) / Stage-1: 2.63 (95% CI: 1.19-5.82, p=0.017) / Stage-2: 3.93 (95% CI: 1.20-12.83, p=0.024) / Stage-3: 5.74 (95% CI: 1.72-19.19, p=0.005) and Stage-4: 16.49 (95% CI: 4.84-56.21, p&amp;lt;0.001). Conclusions The strain stages demonstrated a strong survival benefit for CRT-treated compared to conservatively-treated, but CRT-eligible patients. Patients with more severe dyssynchrony (highest strain stages) have most benefit from CRT implantation. These findings underscore the potential value of the strain stages in refining risk stratification and patient selection of CRT.

Prevalence, characteristics and predictors of left bundle branch block induced cardiomyopathy following transcatheter aortic valve implantation

Abstract Background Left bundle branch block is a relatively common conduction disturbance that can occur as a complication of transcatheter aortic valve implantation (TAVI) procedures. LBBB-induced cardiomyopathy (LBBB-CM) develops due to the mechanical dyssynchrony caused by the conduction abnormality. This dyssynchrony can lead to adverse left ventricular remodeling over time, resulting in a decline in cardiac function. Nevertheless, data on iatrogenic LBBB due to TAVI resulting in cardiomyopathy is lacking. Purpose To investigate the prevalence, characteristics and predictors for LBBB-CM following TAVI. Methods This was a retrospective single center study. A total of 1792 patients underwent TAVI between 2013 and 2021. New LBBB was documented in medical records in 353 patients. After exclusions (figure 1), we remained with 88 patients who were discharged from hospital with complete LBBB, had no pacemaker in situ and had at least 1 year of follow-up. The median follow-up in this study was 40 [17-64] months. LBBB-CM was defined as an absolute decline of &amp;gt;10% in ejection fraction (EF) due to clear septal dyssynchrony and in the absence of an alternative explanation. Results A total of 8 out of 88 patients (9%) developed LBBB-CM over the study period. During the first two years of follow-up, the prevalence was low but gradually increased with extended follow-up. The mean age at discharge from hospital in LBBB-CM group was 83 ± 5 years and the mean EF was 59% ± 3. Patients in the LBBB-CM group had a longer PR interval compared to the no LBBB-CM group (255 ±36 vs 191 ± 38ms, p=0.02) and were more likely to have atrial fibrillation at discharge (50% vs 6%, p&amp;lt;0.001). On Cox regression analysis, both PR interval and QRS duration were identified as significant predictors for the development of LBBB-CM. The HR for PR interval was 1.04 (95% CI 1-1.07, p=0.02) and HR for QRS duration was 1.12 (95% CI 1-1.25, p=0.05). Conclusions This is the largest study to date focusing on LBBB-CM following TAVI. LBBB-CM complicates about 9% of patients discharged with a new complete LBBB, occuring within a median follow-up of 40 [17-64] months. Electrocardiographic predictors for the development of LBBB-CM include prolonged QRS duration and PR interval at discharge. Closer follow-up may be required in this group of patients for timely diagnosis and intervention. Figure

Feasibility of non-invasive echocardiographic estimates of intraventricular pressure differences by blood speckle tracking in adults

Abstract Introduction Non-invasive estimation of the intraventricular pressure difference (IVPD) in early diastole using high-frame-rate ultrasound-based blood speckle tracking (BST) has been reported in pediatric cardiology of various pathologies. This novel echocardiographic technology has recently become available in probes suitable for the adult population. Purpose We tested the feasibility by analyzing intra- and interobserver variability and investigating if IVPD in the left ventricular inflow exhibited the expected differences in controls vs a group of heart failure patients to indicate the ability of this new index to assess diastolic function. Methods Apical BST images of LV inflow were acquired using a GE Vivid E95 ultrasound scanner and the M5Sc probe in healthy volunteers (n=9) and patients with heart failure and left bundle branch block (LBBB) (n=15) implanted with cardiac resynchronization therapy (CRT) 6±2 months (mean±SD) earlier. Echocardiography was performed both with CRT turned on and off. IVPD was analyzed from the BST acquisitions using custom software (Figure 1). Blinded intra- and interobserver variability analysis were performed on the measurements from the healthy controls with the same observer and two other observers, respectively. Results All the controls and 11 of the 15 patients had BST acquisitions eligible for IVPD-analysis, giving a total feasibility of 83%. Intraobserver reliability was excellent (intraclass correlation coefficient 0.96 [0.85, 0.99], mean and 95% CI) and interobserver reliability was good (intraclass correlation coefficient 0.88 [0.59, 0.97] and 0.84 [0.48, 0.96]) respectively. IVPD was highest in controls (-1.7±0.5 mmHg), and higher with CRT on (-1.3±0.7 mmHg, p=NS vs controls) than off (-0.9±0.5 mmHg, p&amp;lt;0.05 compared to both on and controls) in the patients. Conclusions Estimating the intracavitary pressure difference that accelerates blood into the LV during early filling seems feasible and reproducible in adult hearts by BST. IVPD is reduced in patients with heart failure and LBBB, and increases in patients with LBBB when treated with CRT. IVPD based on BST is a potential new echocardiographic method to evaluate diastolic function. Future improvements of the technology are warranted for widespread use.

Incidence, predictors and outcomes associated with pacemaker implantation in transthyretin cardiac amyloidosis

Abstract Background Arrhythmias are poorly tolerated by patients with transthyretin cardiac amyloidosis (ATTR). The occurrence rate of pacemaker (PM) implantation among ATTR, along with its predictors and impact on outcomes has not been extensively investigated. Our objective was to analyze the patterns of permanent PM implantation and to identify predictors for future PM placement in ATTR patients. Methods Consecutive patients with wild-type ATTR diagnosed in one single center between 2016-2022 were included. The primary outcome of the study was PM implantation. Patients with pre-existing PM (n = 31) were excluded. The study population included 160 patients, 88% male, median age 82 (76, 85) years. Clinical, laboratory, electrocardiography (ECG) and comprehensive echocardiography data were analysed. Results During a median follow-up of 30.5 months, 37 (23.1%) patients underwent PM implantation. The main indications for PM implantation were complete atrioventricular (AV) block (9 patients, 24.3%) and advanced conduction impairment (9 patients, 24.3%). ECG demonstrated a more prolonged PR interval and increased QRS duration (both p&amp;lt;0.001) with higher rate of first-degree AV block and right bundle branch block (both p=0.003) in patients requiring PM implantation. The echocardiogram showed greater wall thickness, a more dilated left atrium, along with biventricular dysfunction in the PM group. At multivariable analysis, first-degree AV block (HR=2.96, p=0.012), interventricular septum (IVS) thickness (HR=1.27, p=0.001) and biomarker-based staging system (HR= 2.43, p=0.008) were independently associated with PM implantation. PM implantation was associated with increased mortality or HF hospitalization. Conclusions In our cohort of ATTR patients, 23.1% required a pacemaker, primarily due to conduction system disease. Independent predictors for new pacemaker implantation included first-degree AV block, increased IVS thickness, and the biomarker-based staging system.

Elevated left atrial stiffness index is a poor prognostic factor in heart failure with preserved ejection fraction undergoing transcatheter aortic valve replacement

Abstract Background Patients with severe aortic valve stenosis undergoing transcatheter aortic valve replacement (TAVR) present with a high prevalence of heart failure with preserved ejection fraction (HFpEF). An elevated left atrial stiffness index (LASI) has recently been recognized as a potential prognostic factor for worsened outcomes in HFpEF patients. Purpose This study investigates whether the LASI is a prognostic factor for outcomes following TAVR in HFpEF patients. Methods In this single-center retrospective study, patients with severe aortic valve stenosis who underwent TAVR at our center from February 2020 to May 2023 and had left ventricular ejection fraction &amp;gt;40% were included (Figure 1). The LASI was defined as the ratio of E/e’ to the left atrial reservoir strain from transthoracic echocardiography performed before and one week after TAVR. The primary endpoint was a composite outcome of all-cause mortality and cardiovascular events during the follow-up period. Results We analyzed 178 patients with a median age of 84 years, of whom 69% were female. During a median follow-up period of 549 days, 34 cases (19%) experienced the composite outcome. Multivariate Cox proportional hazards analysis using preoperative indices showed that LASI was independently associated with the occurrence of outcomes (HR 1.84 [95% CI; 1.15-2.95, P = 0.011] per 1.0 increase). A sub-analysis excluding cases had left bundle branch block postoperatively revealed a significant association between postoperative LASI and outcomes (HR 3.62 [95% CI; 2.01-6.51, P = &amp;lt;0.001] per 1.0 increase), particularly pronounced in patients with preoperative grade 2 left ventricular diastolic dysfunction (HR 4.38 [95%CI; 2.07-9.26, P=&amp;lt;0.001] per 1.0 increase) (Figure 2). Conclusion There is potential for LASI as a prognostic factor for outcomes following TAVR in HFpEF patients.

Imaging features of non-dilated left ventricular cardiomyopathy: differences and similarities with dilated cardiomyopathy

Abstract Background and Aim The spectrum of dilated cardiomyopathy (DCM) includes both patients with ventricular dilation and those with systolic dysfunction and no dilation. This latter entity has been called hypokinetic non-dilated cardiomyopathy (H-NDLVC). Our aim was to describe the epidemiological, clinical and imaging features of patients with DCM, comparing those cases of H-NDLVC with patients with classic dilated cardiomyopathy. Methods From January 2014 to December 2022, all patients with a new diagnosis of DCM studied at our tertiary hospital were prospectively included in a multipurpose registry. Transthoracic echocardiogram and cardiac magnetic resonance (CMR) imaging were performed as part of the study. During follow-up, hospitalizations for heart failure (HF), arrhythmic events and mortality were recorded. Results The median age of the patients (n = 227) was 63.8 (53-74) years, and 31.7% were women. Median follow-up was 34.3 (20-56) months. 176 patients (77.5%) had DCM, and 51 patients (22.5%) had H-NDLVC. Epidemiological, clinical, and cardiac imaging characteristics of both groups are shown in the Table. The proportion of men was higher in patients with H-NDLVC, and the presence of left bundle branch block was also more frequent in this group (Figure 1). No differences were found in the distribution of cardiovascular risk factors or comorbidities. Patients with DCM had greater left atrial dilation and more significant mitral regurgitation, as well as worse diastolic function. In relation to the CMR findings, the presence of late enhancement and late enhancement with a high-risk pattern was similar between both groups (Figure 2). Both groups experienced significant improvement in LV systolic volumes (77ml/m2 vs 45 mL/m2 in DCM and 38 ml/m2 vs 28 mL/m2 in H-NDLVC; p&amp;lt;001) and LV ejection fraction (29% vs 43% in DCM and 36% vs 51% in H-NDLVC; p&amp;lt;001) during follow-up. Interestingly, in the subset of patients who had genetic information available (n=78), we found a trend towards higher frequency of positive genetic testing in the group of patients with H-NDLVC (31.2 vs 17.7%; p=0.107). There was a non-significant trend towards lower incidence of events (hospitalization for HF, ventricular arrhythmias, mortality) in patients with H-NDLVC. Conclusions H-NDLVC represent one in 5 patients in our DCM cohort. These patients have less reduction in systolic function, less alteration in diastolic function and less frequency of significant mitral regurgitation. However, the percentage of patients with late gadolinium enhancement and a high-risk pattern is similar to those with true ventricular dilation, and genetic testing was positive in one out of three patients tested. Thus, these patients benefit from an integrated approach with using advance imaging and genetics. Clinical characteristics Imaging findings

Optimizing Patient Selection for Cardiac Resynchronization Therapy With or Without Defibrillator in a Multicenter Study of Japanese Patients ― Assessment of the MADIT-ICD Benefit Score ―

Although the MADIT-ICD benefit score (MBS) helps select suitable implantable cardioverter defibrillator (ICD) candidates, optimal indicators for cardiac resynchronization therapy (CRT) remain uncertain. Evaluating the applicability of the MBS in Japanese CRT patients is imperative. This multicenter study assessed the cumulative incidence of ventricular tachycardia/fibrillation (VT/VF) and non-arrhythmic mortality (AM) in CRT patients grouped according to potential benefit (lowest, highest, and intermediate). Among 400 primary prevention patients (mean age 65 years, 76% male), VT/VF occurred in 4 (7%), 68 (24%), and 14 (23%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.027), over a median follow-up of 34 months. Non-arrhythmic death was observed in 15 (25%), 91 (33%), and 9 (15%) patients in the lowest-, intermediate-, and highest-benefit groups, respectively (P=0.025). Multivariate analysis identified VT/VF score ≥7 (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.09-4.19; P=0.027) as a significant VT/VF predictor. The presence of left bundle branch block (HR 0.51; 95% CI 0.29-0.92; P=0.025) was associated with a reduced risk of VT/VF events. Non-AM score ≥3 (HR 1.70; 95% CI 1.01-2.88; P=0.047), systolic blood pressure <100 mmHg (HR 1.84; 95% CI 1.25-2.70; P=0.002), and estimated glomerular filtration rate <30 mL/min/1.73 m2(HR 1.98; 95% CI 1.23-3.20; P=0.005) were significant predictors of non-arrhythmic death. The MBS can identify suitable candidates for CRT-D among Japanese individuals.

Permanent Left Bundle Branch Area DF-4 Defibrillator Lead Implantation-Feasibility, Procedural Caveats, Safety, and Follow-Up.

Permanent implantation of a DF-4 implantable cardiac defibrillator (ICD) lead in the left bundle branch area (LBBA-ICD) is the next paradigm in amalgamating cardiac resynchronization therapy (CRT) and defibrillation. We systematically investigated feasibility/success rate, procedural caveats, and complications associated with a permanent DF-4 LBBA ICD implant and pertinent data at short-term follow-up. We prospectively attempted implantation of 7 Fr Durata (Abbott, Chicago, IL, USA) single coil DF-4 ICD lead at the LBBA using a fixed-curve non-deflectable CPS locator delivery sheath. Standard criteria defined LBBA capture. Relevant sensing/pacing, defibrillation, radiographic, and echocardiographic parameters testing were recorded at implant, discharge and 5-month follow-up. We enrolled 12 consecutive cardiac device-naïve patients (median age 67.5 years, male 91.7%, median LVEF 30%, median septal thickness 9 mm, median QRS duration 140 ms, class I CRT indication 58.3%, primary prevention ICD indication 75%). Minor complications (two transeptal perforations and one micro-dislodgment) were noted in 3/12 (25%) patients. Successful permanent LBBA ICD implant with adequate sensing/pacing was achieved in 9/12 (75%) subjects. Sustained ventricular fibrillation (VF) was inducible in 7/9 patients with successful implants with effective sensing and defibrillation in all. Follow-up device-related and echocardiographic parameters were similar at discharge and 5-month follow-up. Permanent DF-4 LBBA ICD implant is feasible and successful in 75% of patients with an indication for ICD. With dedicated toolkits, higher volumes, and an obligate learning curve, the higher-than-expected frequency (25%) of minor complications may be ameliorated. Short-term data regarding lead and selected RV parameters remained favorable.

Facilitating confirmation of left conduction system capture in left bundle branch area pacing: the multi-spike technique.

Facilitating confirmation of left conduction system capture in left bundle branch area pacing: the multi-spike technique.

First and Second Degree Left Bundle Branch Block and Masquerading Bundle Branch Block: Lessons Learned During Conduction System Pacing.

First and Second Degree Left Bundle Branch Block and Masquerading Bundle Branch Block: Lessons Learned During Conduction System Pacing.

Late gadolinium enhancement in mid infero-septal area after left bundle branch area pacing in the setting of bifascicular block and syncope: a case report

Abstract Background Conduction system pacing (CSP), which includes His bundle pacing (HBP) and left bundle branch area pacing (LBBAP), is becoming increasingly common in clinical practice. HBP, introduced over two decades ago, continues to see growing use, while LBBAP is gaining traction due to its broader target area and shorter procedure times. However, complications such as septal perforation and lead-related issues may still arise. This case report explores the evaluation and management of recurrent syncope in the context of bifascicular block (BFB), highlighting the importance of thorough assessment, continuous ECG monitoring, and the potential need for permanent pacemaker implantation. Case summary A 60-year-old woman with a history of myocardial infarction, type II diabetes, and dyslipidemia presented with recurrent syncope and BFB, for which a LBBAP device was implanted in August 2023. In February 2024, she was admitted again due to recurrent syncope and frequent premature ventricular contractions. Cardiac MRI revealed two localized myocardial scars: one at the basal anterior wall from the 2018 ischemic event, and another in the mid infero-septal wall at the site of the LBBAP lead. During her hospital stay, she experienced multiple episodes of near-fainting due to orthostatic hypotension, indicative of underlying autonomic neuropathy. Discussion This narrative explores the evolving landscape of cardiac pacing techniques, with a focus on LBBAP, highlighting its advantages over traditional methods while also acknowledging potential complications. Additionally, it emphasizes the importance of a comprehensive workup for syncope and the need for tailored interventions that extend beyond pacemaker implantation.

Left bundle branch area pacing in children – case series

Abstract Background Left bundle branch area pacing (LBBAP) is a new concept that provides physiological pacing with a narrow QRS duration. Recently published data suggest that LBBAP may prevent deleterious effects of right ventricular pacing, namely pacemaker-induced cardiomyopathy, especpecially in patients with expected high ventricular pacing burden, which may be of particular importance in children. Case summary Herein, we report successful implantation of Medtronic SelectSecure (Model 3830, Medtronic Inc.) right ventricle electrode in the region of left bundle branch area in three consecutive children (two 16-year-old and one 8-year-old). Indication for pacemaker implantation was third-degree atrioventricular block in all cases. Implantations were performed under general anaesthesia and there were no acute complications. During the median follow-up of six months, there were no adverse events and the electrical parameters of the device remained stable. Discussion Compared with adult patients, implantation of pacemakers in children may still be challenging, not only because of smaller body size but also due to continuing growth and a higher rate of lead and device-related complications. We have demonstrated that implantation of LBBAP in children is feasible and could be worth considering, particularly in patients with expected high ventricular pacing burden. Further studies are needed to assess the efficacy and safety of left bundle branch area pacing in children during long-term observation.

How to correct QT interval after cardiac resynchronisation therapy.

This study evaluates various formulae used to correct the QT interval in patients with wide QRS complexes to calculate corrected QT (QTc) following Cardiac Resynchronisation Therapy (CRT). We included patients with severe heart failure and left bundle branch block, presenting with a QRS duration of at least 120 milliseconds, who underwent successful CRT implantation. Patients were excluded if they had non-lateral left ventricular lead placement, metabolic disorders, atrial fibrillation, atrial tachycardia, or high-degree atrioventricular block prior to implantation. QT intervals were measured pre- and post-implantation and corrected for QRS duration and heart rate using the Boggosian, Wand, Rautaharju, Yankelson, Tang & Rabkin, Bazett, Framingham, Hodges and Fredericia formulae. A total of 51 patients met the study criteria. After CRT, the QRS duration significantly decreased from 189.68±18.06 milliseconds to 165.25±18.78 milliseconds. However, the QT interval corrected using Bazett's formula showed no significant change (522.30±33.37 milliseconds versus 524.06±36.52 milliseconds). Among the various correction methods, the combination of the Bogossian formula (for QRS duration) followed by the Hodges formula (for heart rate), or the Rautaharju formula followed by the Fredericia formula, produced comparable QT intervals. Similarly, correcting heart rate with the Fredericia formula followed by QRS correction with the Rautaharju formula yielded consistent results. Our findings indicate that different formulae for correcting QT intervals for heart rate and QRS duration may yield varying results. Notably, the use of the Bogossian formula followed by the Hodges formula, or the combination of the Rautaharju and Fredericia formulae, produces relatively consistent QT intervals before and after CRT. Further research is needed to validate these findings.

Blood Pressure Control and Incident Left-Ventricular Conduction Disease.

Cardiac conduction disease, a harbinger of pacemaker implantation, heart failure, and death, is commonly regarded as immutable. However, emerging research suggests it may be a target for upstream prevention strategies such as blood pressure management. This review summarizes recent evidence regarding blood pressure control and the development of conduction disease. Recent observational studies link hypertension to both prevalent and incident conduction disease. In randomized trials, intensive blood pressure control among hypertensive individuals reduced the incidence of left-ventricular conduction abnormalities in the form of fascicular- and left bundle branch blocks, while treatment with lisinopril independent of blood pressure control appeared to reduce conduction disease risk. Understanding factors that influence conduction system disease development may help inform novel primary prevention strategies. Recent evidence suggests that treatment of hypertension may play a key role in the prevention of conduction disease.

Conduction Disorders after Rapid Deployment Aortic Valve Replacement Compared to Conventional Aortic Valve Replacement.

We evaluated and compared early postprocedural and midterm incidence and evolution of atrioventricular and intraventricular conduction disorders following rapid deployment aortic valve replacement (RDAVR) and conventional aortic valve replacement (AVR). One hundred and forty-seven patients who underwent isolated rapid deployment AVR between 2017 and 2021 as well as 128 patients after conventional biological AVR in the same period were included in this study. ECGs recorded at baseline, discharge, and 12 months were retrospectively analyzed. Intrinsic rhythm, PQ interval, QRS duration, and atrioventricular and intraventricular conduction were evaluated and compared between both groups. Patients in both groups had comparable Society of Thoracic surgeons risc (STS) scores (2.9 ± 1.6 vs. 3.1 ± 2.2, p = 0.32) and comparable baseline characteristics. The mean age was 73.4 ± 5.7 years in the RDAVR group and 74.2 ± 5.9 years in the AVR group, respectively. At baseline, the mean QRS width was 95.7 ± 25.5 ms in the RDAVR group, and 97.3 ± 23.5 ms in the AVR group, respectively (p = 0.590). At discharge, the mean QRS width in the RDAVR group was significantly increased with 117.4 ± 28.6 ms and a mean ΔQRS width of 21.7 ± 26.3 ms (p < 0.001) compared with baseline. No significant changes in QRS width were found in the AVR group with a mean value of 101.2 ± 24.1 ms and a mean ΔQRS width of 3.9 ± 23.9 ms at discharge (p = 0.193). The left bundle branch block (LBBB) was increased in the RDAVR group after 12 months (19.3% vs. 5.1%, p < 0.001). Permanent pacemaker implantation (PPI) rates were significantly higher in the RDAVR group after 12 months (hazard ratio (HR): 4.68; 95% CI: 2.23-7.43, p < 0.001). Mortality did not differ between both groups after 12 months (HR: 1.09; 95% CI: 0.46-1.83, p = 0.835) CONCLUSION: Patients after RDAVR showed significantly higher rates of LBBB and PPI after 12 months. However, higher mortality was not observed in the RDAVR group.

Automated Beat-to-Beat Measurement ofR-Wave Peak Time for Left Bundle Branch Area Pacing.

Automated Beat-to-Beat Measurement ofR-Wave Peak Time for Left Bundle Branch Area Pacing.

Association of Right Bundle Branch Block with Ischemic Stroke Incidence: A UK Biobank Cohort Study.

Right bundle branch block (RBBB) is often considered benign; however, its association with ischemic stroke (IS) remains unclear. We aimed to investigate the relationship between RBBB and the incidence of IS. We conducted a retrospective cohort study using the UK Biobank database (2004-2021), which included 3,634 participants with new-onset RBBB and 3,643 matched controls. The primary outcome was the incidence of IS, while the secondary outcomes included atrial fibrillation (AF) and all-cause mortality. We applied a propensity score matching with variables such as age, sex, presence of hypertension, diabetes, dyslipidemia, and the Charlson Comorbidity Index. Subsequently, time-dependent Cox regression analyses were performed to assess the association between RBBB and the outcomes. The cumulative incidence of IS was higher in the RBBB group. RBBB was independently associated with an increased risk of IS (adjusted hazard ratio [aHR], 3.57; 95% confidence interval [CI], 2.12-6.03; p < 0.001), as well as AF (aHR, 4.58; 95% CI, 3.86-5.43; p < 0.001) and all-cause mortality (aHR, 2.66; 95% CI, 2.35-3.02; p < 0.001). RBBB was associated with an increased risk of IS, independent of age, sex, and other comorbidities. These findings emphasize the need for careful monitoring and management of patients with RBBB to mitigate the risk of IS and other adverse outcomes. Further research is needed to elucidate the underlying mechanisms and better inform clinical management strategies for patients with RBBB.

Cardiac resynchronization therapy via left bundle branch pacing in heart failure with complete left bundle branch block: is the defibrillator needed?

This retrospective cohort study aimed to investigate the efficacy of dual-chamber left Bundle branch pacing (LBBP) as an alternative therapy for heart failure patients with complete left bundle branch block (CLBBB) and indications for defibrillator with cardiac resynchronization therapy (CRT-D). 34 patients met inclusion criteria were enrolled in the study. These criteria included a left ventricular ejection fraction (LVEF) of lower than 35%, a New York Heart Association functional class of II-IV, CLBBB meeting Strauss's criteria, intraventricular dyssynchrony, and confirmed correction of CLBBB during LBBP. Patients with ischemic cardiomyopathy, left ventricular noncompaction, significant late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR), and indications for an implantable cardioverter-defibrillator (ICD) as secondary prevention were excluded. Post-LBBP, the LVEF improved from 31.1 ± 4.0% to 61.0 ± 6.0% (P < 0.001). All patients exhibited a super-response to LBBP cardiac resynchronization therapy, achieving complete improvement in cardiac function with a LVEF exceeding 50%. Septal-to-posterior wall motion delay (SPWMD) and systolic dyssynchrony index (SDI) were indicators of intraventricular synchrony, SPWMD decreased from 271.4 ± 76.4 ms to 42.2 ± 22.9 ms (P < 0.001), and SDI decreased from 12.5 ± 5.3% to 1.9 ± 1.0% after implantation (P < 0.001). Heart failure patients meeting the following criteria may be considered for dual-chamber pacing as an alternative to CRT-D, potentially avoiding the need for ICD implantation: (1) CLBBB meeting Strauss's criteria, (2) presence of intraventricular dyssynchrony on echocardiogram, (3) exclusion of secondary prevention ICD indications, (4) absence of evident LGE on CMR, and (5) successful correction of CLBBB during LBBP.

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.