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A 75-year-old male with sick sinus syndrome (SSS) underwent left bundle branch (LBB) pacing (LBBP) implantation. Intraoperative recordings showed that the LBB potential-ventricular (LBB-V) interval gradually decreased from 47 to 19 ms (ms). Two-year follow-up indicated stable pacing parameters and consistent electrocardiogram (ECG) results. Despite potential conduction delays caused by lead implantation, a watchful waiting strategy demonstrated recovery potential without impacting long-term prognosis or pacing parameters., (© 2024. The Author(s).)

A larger left bundle branch (LBB) potential or LBB current of injury (COI) indicates a low LBB capture threshold in LBB pacing. During LBB pacing in an 85-year-old woman, achieving a low LBB capture threshold did not initially present with a larger LBB potential or LBB COI, but rather with a new initial negative deflection in a ventricular electrogram. LBB COI gradually developed over 7 min thereafter, which suggested that the lead tip had reached the left ventricular subendocardium. Therefore, this negative deflection may be the first sign to avoid further lead rotation., (© 2024 Wiley Periodicals LLC.)

Background: Variations in the aortomitral positional anatomy, including aortic root rotation appear to be related to variations in the location of the conduction system, including the bundle of His. However, little is known about their clinical significance., Methods and Results: This study included 147 patients with normal ECGs who underwent mitral valve surgery. The aortomitral anatomy was classified using preoperative 3-dimensional transesophageal echocardiography, and postoperative conduction disorders, including atrioventricular block and bundle branch block, were analyzed. Variations classified as aortomitral appearance were designated as having a center appearance (85.7%, n=126/147) or lateral appearance (14.3%, n=21/147) on the basis of whether the aortic root was located at the center or was shifted to the left fibrous trigone side. Subsequently, those with a center appearance, aortic root rotation was classified as having a center rotation (83.3% [n=105/126]), in which the commissure of the left and noncoronary aortic leaflet was located at the center, lateral rotation (14.3% [n=18/126]), rotated to the left trigone side, or medial rotation (2.4% [n=3/126]), rotated to the right. The incidence of 3-month persistent new-onset conduction disorder was higher in the lateral appearance than the center appearance group (21.1% versus 5.0%; P =0.031) and higher in the lateral rotation than in the center or medial rotation groups (29.4% versus 1.0% versus 0.0%, respectively; P <0.001)., Conclusions: Aortomitral variations can be classified using 3-dimensional transesophageal echocardiography. Lateral appearance and lateral rotation are risk factors for conduction disorders in mitral valve surgery.

Transcatheter aortic valve implantation may be complicated by the development of conduction disturbances, including left bundle branch block and high-grade atrioventricular blocks, especially in patients with predisposing risk factors, such as pre-existing right bundle branch block. Permanent pacemaker implantation is a procedure with potential short- and long-term complications, and it should be reserved to patients with appropriate indications. Electrophysiological testing and/or prolonged ambulatory ECG monitoring are valuable tools for stratifying the risk of pacemaker implantation. However, the management of new-onset conduction disorders is not always straightforward, and there are different approaches depending on the center's attitude. Therefore, the purpose of this review is to define clinical management based on current evidence, while awaiting data from randomized trials.

New-generation transcatheter heart valves have significantly improved technical success and procedural safety of transcatheter aortic valve implantation (TAVI) procedures; however, the incidence of permanent pacemaker implantation (PPI) remains a concern. This study aimed to assess the role of anatomic annulus features in determining periprocedural conduction disturbances leading to new PPI after TAVI using the last-generation Edwards SAPIEN balloon-expandable valves. In the context of a prospective single-center registry, we integrated the clinical and procedural predictors of PPI with anatomic data derived from multislice computed tomography. A total of 210 consecutive patients treated with balloon-expandable Edwards transcatheter heart valve were included in the study from 2015 to 2023. Technical success was achieved in 197 procedures (93.8%), and 26 patients (12.4%) required new PPI at the 30-day follow-up (median time to implantation 3 days). At the univariable logistic regression analysis, preprocedural right bundle branch block (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.01 to 4.97, p = 0.047), annulus eccentricity ≥0.25 (OR 5.43, 95% CI 2.21 to 13.36, p <0.001), calcium volume at annulus of the right coronary cusp >48 mm 3 (OR 2.60, 95% CI 1.13 to 5.96, p = 0.024), and prosthesis implantation depth greater than membranous septum length (OR 2.17, 95% CI 1.10 to 4.28, p = 0.026) were associated with new PPI risk. In the multivariable analysis, preprocedural right bundle branch block (OR 2.81, 95% CI 1.01 to 7.85, p = 0.049), annulus eccentricity ≥0.25 (OR 4.14, 95% CI 1.85 to 9.27, p <0.001), and annulus right coronary cusp calcium >48 mm 3 (OR 2.89, 95% CI 1.07 to 7.82, p = 0.037) were confirmed as independent predictors of new PPI. In conclusion, specific anatomic features of the aortic valve annulus might have an additive role in determining the occurrence of conduction disturbances in patients who underwent TAVI with balloon-expandable valves. This suggests the possibility to use multislice computed tomography to improve the prediction of post-TAVI new PPI risk., Competing Interests: Declaration of competing interest Dr. Romagnoli received speaker fees from Abbott Vascular and Terumo. F. Burzotta and C. Trani received speaker fees from Abbott Vascular, Abiomed, Medtronic, and Terumo. Dr. Aurigemma received speaker fees from Abbott Vascular, Abiomed, Medtronic, Terumo, and Daiichi Sankyo. Dr. Bianchini received a research grant from Abbott. The remaining authors have no competing interests to declare., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Left bundle branch block (LBBB) represents a frequently encountered conduction system disorder. Despite its widespread occurrence, a continual dilemma persists regarding its intricate association with underlying cardiomyopathy and its pivotal role in the initiation of dilated cardiomyopathy. The pathologic alterations linked to LBBB-induced cardiomyopathy (LBBB-CM) have remained elusive., Objective: This study sought to investigate the chronologic dynamics of LBBB to left ventricular dysfunction and the pathologic mechanism of LBBB-CM., Methods: LBBB model was established through main left bundle branch trunk ablation in 14 canines. All LBBB dogs underwent transesophageal echocardiography and electrocardiography before ablation and at 1 month, 3 months, 6 months, and 12 months after LBBB induction. Single-photon emission computed tomography imaging was performed at 12 months. We then harvested the heart from all LBBB dogs and 14 healthy adult dogs as normal controls for anatomic observation, Purkinje fiber staining, histologic staining, and connexin43 protein expression quantitation., Results: LBBB induction caused significant fibrotic changes in the endocardium and mid-myocardium. Purkinje fibers exhibited fatty degeneration, vacuolization, and fibrosis along with downregulated connexin43 protein expression. During a 12-month follow-up, left ventricular dysfunction progressively worsened, peaking at the end of the observation period. The association between myocardial dysfunction, hypoperfusion, and fibrosis was observed in the LBBB-afflicted canines., Conclusion: LBBB may lead to profound myocardial injury beyond its conduction impairment effects. The temporal progression of left ventricular dysfunction and the pathologic alterations observed shed light on the complex relationship between LBBB and cardiomyopathy. These findings offer insights into potential mechanisms and clinical implications of LBBB-CM., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. All rights reserved.)

Aims: To characterize the diagnosis, frequency, and procedural implications of septal venous channel perforation during left bundle branch area pacing (LBBAP)., Methods and Results: All consecutive patients undergoing LBBAP over an 8-month period were prospectively studied. During lead placement, obligatory septal contrast injection was performed twice, at initiation (implant entry zone) and at completion (fixation zone). An intuitive fluoroscopic schema using orthogonal views (left anterior oblique/right anterior oblique) and familiar landmarks is described. Using this, we resolved zonal distribution (I-VI) of lead position on the ventricular septum and its angulation (post-fixation angle θ). Subjects with and without septal venous channel perforation were compared. Sixty-one patients {male 57.3%, median age [interquartile range (IQR)] 69.5 [62.5-74.5] years} were enrolled. Septal venous channel perforation was observed in eight (13.1%) patients [male 28.5%, median age (IQR) 64 (50-75) years]. They had higher frequency of (i) right-sided implant (25% vs. 1.9%, P = 0.04), (ii) fixation in zone III at the mid-superior septum (75% vs. 28.3%, P = 0.04), (iii) steeper angle of fixation-median θ (IQR) [19 (10-30)° vs. 5 (4-19)°, P = 0.01], and (iv) longer median penetrated-lead length (IQR) [13 (10-14.8) vs. 10 (8.5-12.5) mm, P = 0.03]. Coronary sinus drainage of contrast was noted in five (62.5%) patients. Abnormal impedance drops during implantation (12.5% vs. 5.7%, P = NS) were not significantly different., Conclusion: When evaluated systematically, septal venous channel perforation may be encountered commonly after LBBAP. The fiducial reference framework described using fluoroscopic imaging identified salient associated findings. This may be addressed with lead repositioning to a more inferior location and is not associated with adverse consequence acutely or in early follow-up., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: A delayed and recurrent complete atrioventricular block (CAVB) is a life-threatening complication of transcatheter aortic valve replacement (TAVR). Post-TAVR evaluation may be important in predicting delayed and recurrent CAVB requiring permanent pacemaker implantation (PPI). The impact of new-onset right bundle-branch block (RBBB) after TAVR on PPI remains unknown., Methods and Results: In total, 407 patients with aortic stenosis who underwent TAVR were included in this analysis. Intraprocedural CAVB was defined as CAVB that occurred during TAVR. A 12-lead ECG was evaluated at baseline, immediately after TAVR, on postoperative days 1 and 5, and according to the need to identify new-onset bundle-branch block (BBB) and CAVB after TAVR. Forty patients (9.8%) required PPI, 17 patients (4.2%) had persistent intraprocedural CAVB, and 23 (5.7%) had delayed or recurrent CAVB after TAVR. The rates of no new-onset BBB, new-onset left BBB, and new-onset RBBB were 65.1%, 26.8%, and 4.7%, respectively. Compared with patients without new-onset BBB and those with new-onset left BBB, the rate of PPI was higher in patients with new-onset RBBB (3.4% versus 5.6% versus 44.4%, P <0.0001). On post-TAVR evaluation in patients without persistent intraprocedural CAVB, the multivariate logistic regression analysis showed that new-onset RBBB was a statistically significant predictor of PPI compared with no new-onset BBB (odds ratio [OR], 18.0 [95% CI, 5.94-54.4]) in addition to the use of a self-expanding valve (OR, 2.97 [95% CI, 1.09-8.10])., Conclusions: Patients with new-onset RBBB after TAVR are at high risk for PPI.

Background: According to the current literature, there is no difference between left bundle brunch area pacing (LBBAP) and right ventricular apical pacing in terms of lead dislodgement and capture threshold elevation. However, there are no large-scale studies reporting the data about long-term lead stability in patients with severe tricuspid regurgitation., Methods and Results: We present a case of lead dislodgement with possible infective endocarditis six months after implantation in a patient with severe tricuspid regurgitation who underwent LBBAP., Conclusions: We concluded that severe preoperative tricuspid regurgitation may cause lead dislodgement, and infective endocarditis may be a facilitator or main reason of lead dislodgement in cases of LBBAP., (© 2023 Wiley Periodicals LLC.)

Introduction: Right ventricular (RV) pacing sometimes causes left ventricular (LV) systolic dysfunction, also known as pacing-induced cardiomyopathy (PICM). However, the association between specifically paced QRS morphology and PICM development has not been elucidated. This study aimed to investigate the association between paced QRS mimicking a complete left bundle branch block (CLBBB) and PICM development., Methods: We retrospectively screened 2009 patients who underwent pacemaker implantation from 2010 to 2020 in seven institutions. Patients who received pacemakers for an advanced atrioventricular block or bradycardia with atrial fibrillation, baseline LV ejection fraction (LVEF) ≥ 50%, and echocardiogram recorded at least 6 months postimplantation were included. The paced QRS recorded immediately after implantation was analyzed. A CLBBB-like paced QRS was defined as meeting the CLBBB criteria of the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society in 2009. PICM was defined as a ≥10% LVEF decrease, resulting in an LVEF of <50%., Results: Among the 270 patients analyzed, PICM was observed in 38. Baseline LVEF was lower in patients with PICM, and CLBBB-like paced QRS was frequently observed in PICM. Multivariate analysis revealed that low baseline LVEF (odds ratio [OR]: 0.93 per 1% increase, 95% confidence interval [CI]: 0.89-0.98, p = 0.006) and CLBBB-like paced QRS (OR: 2.69, 95% CI: 1.25-5.76, p = 0.011) were significantly associated with PICM development., Conclusion: CLBBB-like paced QRS may be a novel risk factor for PICM. RV pacing, which causes CLBBB-like QRS morphology, may need to be avoided, and patients with CLBBB-like paced QRS should be followed-up carefully., (© 2024 Wiley Periodicals LLC.)

BACKGROUND Paroxysmal third-degree atrioventricular block (AVB) can exhibit a vast array of symptoms, but commonly, paroxysmal AVB leads to presyncope, syncope, or possibly sudden cardiac death. We present a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. CASE REPORT A 65-year-old man with frequent episodes of presyncope and syncope for 3 weeks was admitted to our hospital for further diagnosis. A resting 12-lead electrocardiogram showed an incomplete right bundle branch block, and a 24-h Holter recording showed multiple episodes of third-degree AVB. Intracardiac tracing revealed that the block site was distal, at the infra-His-Purkinje system. CONCLUSIONS This case highlights a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. This type of AVB is an abrupt, unexpected, repetitive block of atrial impulses as they propagate to the ventricles. It is relatively rare, and due to its transient nature, it is often under recognized and can lead to sudden cardiac death.

Background: Left bundle branch block (LBBB) and atrial fibrillation (AF) are commonly coexisting conditions. The impact of LBBB on catheter ablation of AF has not been well determined. This study aims to explore the long-term outcomes of patients with AF and LBBB after catheter ablation., Methods: Forty-two patients with LBBB of 11,752 patients who underwent catheter ablation of AF from 2011 to 2020 were enrolled as LBBB group. After propensity score matching in a 1:4 ratio, 168 AF patients without LBBB were enrolled as non-LBBB group. Late recurrence and a composite endpoint of stroke, all-cause mortality, and cardiovascular hospitalization were compared between the two groups., Results: Late recurrence rate was significantly higher in the LBBB group than that in the non-LBBB group (54.8% vs. 31.5%, p = .034). Multivariate analysis showed that LBBB was an independent risk factor for late recurrence after catheter ablation of AF (hazard ratio [HR] 2.19, 95% confidence interval [CI] 1.09-4.40, p = .031). LBBB group was also associated with a significantly higher incidence of the composite endpoint (21.4% vs. 6.5%, HR 3.98, 95% CI 1.64-9.64, p = .002)., Conclusions: LBBB was associated with a higher risk for late recurrence and a higher incidence of composite endpoint in the patients underwent catheter ablation., (© 2024 Wiley Periodicals LLC.)

Aims: Right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs) have been associated with the presence of non-ischaemic left ventricular scar (NLVS) in athletes. The aim of this cross-sectional study was to identify clinical and electrocardiogram (ECG) predictors of the presence of NLVS in athletes with RBBB VAs., Methods and Results: Sixty-four athletes [median age 39 (24-53) years, 79% males] with non-sustained RBBB VAs underwent cardiac magnetic resonance (CMR) with late gadolinium enhancement in order to exclude the presence of a concealed structural heart disease. Thirty-six athletes (56%) showed NLVS at CMR and were assigned to the NLVS positive group, whereas 28 athletes (44%) to the NLVS negative group. Family history of cardiomyopathy and seven different ECG variables were statistically more prevalent in the NLVS positive group. At univariate analysis, seven ECG variables (low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I-aVL, negative T waves in precordial leads V4-V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads) proved to be statistically associated with the finding of NLVS; these were grouped together in a score. A score ≥2 was proved to be the optimal cut-off point, identifying NLVS athletes in 92% of cases and showing the best accuracy (86% sensitivity and 100% specificity, respectively). However, a cut-off ≥1 correctly identified all patients with NLVS (absence of false negatives)., Conclusion: In athletes with RBBB morphology non-sustained VAs, specific ECG abnormalities at 12-lead ECG can help in detecting subjects with NLVS at CMR., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Transcatheter aortic valve replacement (TAVR) often leads to conduction abnormalities, necessitating pacemaker implantation. This review of 38 meta-analyses identified preexisting right bundle branch block (RBBB), LAHB, and new-onset left bundle branch block as key risk factors, with a higher PPM risk in male and older patients. Procedural factors like transfemoral access and self-expandable valves also increase this risk. Prevention focuses on tailoring TAVR to individual electrophysiological and anatomical profiles. However, there's a lack of consensus in managing these conduction disturbances post-TAVR, highlighting the need for further research and standardized treatment strategies., (© 2024 Wiley Periodicals LLC.)

Background and Aims: Right bundle branch block (RBBB) and resulting right ventricular (RV) electromechanical discoordination are thought to play a role in the disease process of subpulmonary RV dysfunction that frequently occur post-repair tetralogy of Fallot (ToF). We sought to describe this disease entity, the role of pulmonary re-valvulation, and the potential added value of RV cardiac resynchronization therapy (RV-CRT)., Methods: Two patients with repaired ToF, complete RBBB, pulmonary regurgitation, and significantly decreased RV function underwent echocardiography, cardiac magnetic resonance, and an invasive study to evaluate the potential for RV-CRT as part of the management strategy. The data were used to personalize the CircAdapt model of the human heart and circulation. Resulting Digital Twins were analysed to quantify the relative effects of RV pressure and volume overload and to predict the effect of RV-CRT., Results: Echocardiography showed components of a classic RV dyssynchrony pattern which could be reversed by RV-CRT during invasive study and resulted in acute improvement in RV systolic function. The Digital Twins confirmed a contribution of electromechanical RV dyssynchrony to RV dysfunction and suggested improvement of RV contraction efficiency after RV-CRT. The one patient who underwent successful permanent RV-CRT as part of the pulmonary re-valvulation procedure carried improvements that were in line with the predictions based on his Digital Twin., Conclusion: An integrative diagnostic approach to RV dysfunction, including the construction of Digital Twins may help to identify candidates for RV-CRT as part of the lifetime management of ToF and similar congenital heart lesions., Competing Interests: Conflict of interest: J.L. has received research grants from the Dutch Heart Foundation (Dr Dekker programme grant 2015T082) and the Netherlands Organisation for Scientific Research (NWO—ZonMw grant 016.176.340). All remaining authors have declared no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The incidence and prognosis of right bundle branch block (RBBB) following transcatheter aortic valve replacement (TAVR) are unknown. Hence, we sought to characterize the incidence of post-TAVR RBBB and determine associated risks of permanent pacemaker (PPM) implantation and mortality., Methods: All patients 18 years and above without preexisting RBBB or PPM who underwent TAVR at US Mayo Clinic sites and Mayo Clinic Health Systems from June 2010 to May 2021 were evaluated. Post-TAVR RBBB was defined as new-onset RBBB in the postimplantation period. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling. The risks of PPM implantation (within 90 days) and mortality following TAVR were compared for patients with and without post-TAVR RBBB using Kaplan-Meier analysis and Cox proportional hazards modeling., Results: Of 1992 patients, 15 (0.75%) experienced new RBBB post-TAVR. There was a higher degree of valve oversizing among patients with new RBBB post-TAVR versus those without (17.9% versus 10.0%; P =0.034). Ten patients (66.7%) with post-TAVR RBBB experienced high-grade atrioventricular block and underwent PPM implantation (median 1 day; Q1, 0.2 and Q3, 4), compared with 268/1977 (13.6%) without RBBB. Following propensity score adjustment for covariates (age, sex, balloon-expandable valve, annulus diameter, and valve oversizing), post-TAVR RBBB was significantly associated with PPM implantation (hazard ratio, 8.36 [95% CI, 4.19-16.7]; P <0.001). No statistically significant increase in mortality was seen with post-TAVR RBBB (hazard ratio, 0.83 [95% CI, 0.33-2.11]; P =0.69), adjusting for age and sex., Conclusions: Although infrequent, post-TAVR RBBB was associated with elevated PPM implantation risk. The mechanisms for its development and its clinical prognosis require further study., Competing Interests: Disclosures None.

Background: New-generation self-expanding valves can improve the success rate of transcatheter aortic valve replacement (TAVR) for severe pure native aortic regurgitation (PNAR). However, predictors of new-onset conduction block post-TAVR using new-generation self-expanding valves in patients with PNAR remain to be established. Therefore, this study aimed to identify predictors of new-onset conduction block post-TAVR using new-generation self-expanding valves (VitaFlow Liberty™) in patients with PNAR., Methods: In this retrospective cohort study, patients were categorized into pacemaker and non-pacemaker groups based on their need for new postoperative permanent pacemaker implantation (PPI). Based on the postoperative presence of either new-onset complete left bundle branch block (cLBBB) or high-grade atrioventricular block (AVB), patients were further classified into conduction disorder and non-conduction disorder groups. Laboratory, echocardiographic, computed tomography, preoperative and postoperative electrocardiography, and procedural and clinical data were collected immediately after TAVR and during hospitalization and compared between the groups. Multivariate logistic regression analysis was performed incorporating the significant variables from the univariate analyses., Results: This study examined 68 consecutive patients with severe PNAR who underwent TAVR. In 20 patients, a permanent pacemaker was fitted postoperatively. Multivariate logistic regression analysis revealed an association between the need for postoperative PPI and preoperative complete right bundle branch block (cRBBB) or first-degree AVB, as well as a non-tubular left ventricular outflow tract (LVOT). In addition, valve implantation depth and angle of aortic root were independent predictors of new-onset cLBBB or high-grade AVB developing post-TAVR. The predictive value of valve implantation depth and angle of aortic root was further supported by receiver operating characteristic curve analysis results., Conclusions: In patients with PNAR undergoing TAVR using self-expanding valves, preoperative cRBBB or first-degree AVB and a non-tubular LVOT were indicators of a higher likelihood of PPI requirement. Moreover, deeper valve implantation depth and greater angle of aortic root may be independent risk factors for new-onset cLBBB or high-grade AVB post-TAVR. Valve implantation depth and angle of aortic root values may be used to predict the possibility of new cLBBB or high-grade AVB post-TAVR., (© 2024. The Author(s).)

Background: The aim of the study was to evaluate whether left ventricular apical-to-basal longitudinal strain differences, representing advanced basal interstitial fibrosis, are associated with conduction disorders after aortic valve replacement (AVR) in patients with severe aortic stenosis., Methods: Patients with aortic stenosis undergoing AVR were included. The apical-to-basal strain ratio was calculated by dividing the average strain of the apical segments by the average strain of the basal segments. Values >1.9 were considered abnormal, as previously described. All patients were followed up for the occurrence of complete left or right bundle branch block or permanent pacemaker implantation within 2 years after AVR. Subgroup analysis was performed in patients undergoing transcatheter AVR., Results: Two hundred seventy-four patients were included (median age of 74 years [interquartile range, 65, 80], 46.4% male). During a median follow-up of 12.2 months (interquartile range, 0.2, 24.3), 74 patients (27%) developed complete bundle branch block or were implanted with a permanent pacemaker. These patients more often had an abnormal apical-to-basal strain ratio. Cumulative event-free survival analysis showed worse outcome in patients with an abnormal apical-to-basal strain ratio (log rank χ 2  = 7.258, P = .007). In multivariable Cox regression analysis, an abnormal apical-to-basal strain ratio was the only independent factor associated with the occurrence of complete bundle branch block or permanent pacemaker implantation after adjusting for other factors previously shown to be associated with conduction disorders after AVR. Subgroup analysis confirmed the independent association of an abnormal apical-to-basal strain ratio with conduction disorders after transcatheter AVR., Conclusion: The apical-to-basal strain ratio is independently associated with conduction disorders after AVR and could guide risk stratification in patients potentially at risk for pacemaker implantation., Competing Interests: Conflicts of Interest The Department of Cardiology of Leiden University Medical Center received research grants from Abbott Vascular, Bayer, Biotronik, Bioventrix, Boston Scientific, Edwards Lifesciences, GE Healthcare, Medtronic, and Novartis. J.J.B.received speaker fees from Abbott Vascular, Edwards Lifesciences, and Omron. N.A.M. received speaker fees from Abbott Vascular and GE Healthcare. The other authors have nothing to disclose., (Copyright © 2023 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Background: There are conflicting data on the effect of cardiac resynchronization therapy with a defibrillator (CRT-D) on the risk of life-threatening ventricular tachyarrhythmia in heart failure patients., Objectives: The authors aimed to assess whether QRS morphology is associated with risk of ventricular arrhythmias in CRT recipients., Methods: The study population comprised 2,862 patients implanted with implantable cardioverter defibrillator (ICD)/CRT-D for primary prevention who were enrolled in 5 landmark primary prevention ICD trials (MADIT-II [Multicenter Automated Defibrillator Implantation Trial], MADIT-CRT [Multicenter Automated Defibrillator Implantation Trial-Cardiac Resynchronization Therapy], MADIT-RIT [Multicenter Automated Defibrillator Implantation Trial-Reduction in Inappropriate Therapy], MADIT-RISK [Multicenter Automated Defibrillator Implantation Trial-RISK], and RAID [Ranolazine in High-Risk Patients With Implanted Cardioverter Defibrillators]). Patients with QRS duration ≥130 ms were divided into 2 groups: those implanted with an ICD only vs CRT-D. The primary endpoint was fast ventricular tachycardia (VT)/ventricular fibrillation (VF) (defined as VT ≥200 beats/min or VF), accounting for the competing risk of death. Secondary endpoints included appropriate shocks, any sustained VT or VF, and the burden of fast VT/VF, assessed in a recurrent event analysis., Results: Among patients with left bundle branch block (n = 1,792), those with CRT-D (n = 1,112) experienced a significant 44% (P < 0.001) reduction in the risk of fast VT/VF compared with ICD-only patients (n = 680), a significantly lower burden of fast VT/VF (HR: 0.55; P = 0.001), with a reduced burden of appropriate shocks (HR: 0.44; P < 0.001). In contrast, among patients with non-left bundle branch block (NLBBB) (N = 1,070), CRT-D was not associated with reduction in fast VT/VF (HR: 1.33; P = 0.195). Furthermore, NLBBB patients with CRT-D experienced a statistically significant increase in the burden of fast VT/VF events compared with ICD-only patients (HR: 1.90; P = 0.013)., Conclusions: Our data suggest a potential proarrhythmic effect of CRT among patients with NLBBB. These data should be considered in patient selection for treatment with CRT., Competing Interests: Funding Support and Author Disclosures The MADIT studies were funded by an unrestricted research grant from Boston Scientific to the University of Rochester Medical Center, Rochester, New York. All authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: 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., Objective: 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)., Methods: 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, V 1 , V 2 , V 5 , and V 6 and in all 3 inferior leads were recorded., Results: 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 V 1 /V 2 was always either rS or QS, and there were no q/Q waves noted in lead V 5 /V 6 . 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, V 5 , and V 6 in 181 of 181 (100%)., Conclusion: Strauss criteria and QRS notching are highly prevalent in LBBB after TAVR and in LBBB correctable by CSP., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: To avoid rhythm disturbance, sutures for ventricular septal defect closure have been traditionally placed 2∼5 mm or more away from the edge of the ventricular septal defect. However, the traditional suturing method appears to induce right bundle branch block and tricuspid valve regurgitation after ventricular septal defect closure more than our alternative technique, shallow suturing just at the edge of the ventricular septal defect (shallower bites at the postero-inferior margin). We aimed to verify our clinical experience of perimembranous ventricular septal defect repair., Methods: The alternative shallow suturing method has been applied since 2003 at our institution. We retrospectively reviewed the clinical data of 556 isolated perimembranous ventricular septal defect patients who underwent surgical closure from 2000 to 2019. We investigated the postoperative occurrence of right bundle branch block or progression of tricuspid regurgitation and analysed risk factors for right bundle branch block and tricuspid regurgitation., Results: Traditional suturing method (Group T) was used in 374 cases (66.8%), and alternative suturing method (Group A) was used in 186 cases (33.2%). The right bundle branch block occurred more frequently in Group T (39.6%) than in Group A (14.9%). In multivariable logistic regression analysis, Group T and patch material were significant risk factors for late right bundle branch block. More patients with progression of tricuspid regurgitation were found in Group T., Conclusions: Shallow suturing just at the edge of the ventricular septal defect may reduce the rate of right bundle branch block occurrence and tricuspid regurgitation progression without other complications.

The existence of a tetrafascicular intraventricular conduction system is widely accepted by researchers. In this review, we have updated the criteria for left septal fascicular block (LSFB) and the differential diagnosis of prominent anterior QRS forces. More and more evidence points to the fact that the main cause of LSFB is critical proximal stenosis of the left anterior descending coronary artery before its first septal perforator branch. The most important characteristic of LSFB that has been incorporated in the corresponding diagnostic electrocardiographic criteria is its transient/intermittent nature mostly observed in clinical scenarios of acute (ie, acute coronary syndrome including vasospastic angina) or chronic (ie, exercise-induced ischemia) ischemic coronary artery disease. In addition, the phenomenon proved to be phase 4 bradycardia rate dependent and induced by early atrial extrastimulus. Finally, we believe that intermittent LSFB has the same clinical significance as "Wellens syndrome" and the "de Winter pattern" in the acute coronary syndrome scenario., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The right bundle branch (RBB), due to its endocardial course, is susceptible to traumatic block caused by "bumping" during right-heart catheterization. In the era of cardiac electrophysiology, catheter-induced RBB block (CI-RBBB) has become a common phenomenon observed during electrophysiological studies and catheter ablation procedures. While typically transient, it may persist for the entire procedure time. Compared to pre-existing RBBB, the transient nature of CI-RBBB allows for comparative analysis relative to the baseline rhythm. Furthermore, unlike functional RBBB, it occurs at similar heart rates, making the comparison of conduction intervals more reliable. While CI-RBBB can provide valuable diagnostic information in various conditions, it is often overlooked by cardiac electrophysiologists. Though it is usually a benign and self-limiting conduction defect, it may occasionally lead to diagnostic difficulties, pitfalls, or undesired consequences. Avoidance of CI-RBBB is advised in the presence of baseline complete left bundle branch block and when approaching arrhythmic substrates linked to the right His-Purkinje-System, such as fasciculo-ventricular pathways, bundle branch reentry, and right-Purkinje focal ventricular arrhythmias. This article aims to provide a comprehensive practical review of the electrophysiological phenomena related to CI-RBBB and its impact on the intrinsic conduction system and various arrhythmic substrates., (© 2023 Wiley Periodicals LLC.)

Background: The association between bundle branch block (BBB) and recurrence of atrial fibrillation (AF) after catheter ablation is unclear. The aim of this study was to determine whether AF combined with BBB is associated with AF recurrence after catheter ablation., Methods: A total of 477 consecutive AF patients who underwent catheter ablation were included. The AF patients were divided into three groups according to BBB: AF without BBB (n = 427), AF with right bundle branch block (AF with RBBB) (n = 16), and AF with intraventricular conduction delay (AF with IVCD) (n = 34)., Results: Of the 477 AF patients (mean age 57 years, 81% men, median CHA 2 DS 2 -VASc score of 1), 16 (3.4%) patients had RBBB, and 34 (7.1%) patients had IVCD. During a mean follow-up of 15.2 ± 6.7 months, 119 patients (24.9%) had recurrence of AF. Of these, 111 (26%) patients were in the AF without BBB group, with 2 (12.5%) and 6 (17.6%) patients in the RBBB and IVCD groups, respectively. The Kaplan-Meier estimate of the rate of recurrent AF was not significantly different among the three groups (p = .39). Multivariable analysis showed that persistent AF (HR 1.7, 95% CI 1.15-2.50, p = .007), chronic kidney disease (HR 2.94, 95% CI 1.20-7.17, p = .01), and left atrial diameter (HR 1.04, 95% CI 1.009-1.082, p = .01) were significantly associated with AF recurrence., Conclusion: AF with BBB was not significantly associated with the recurrence of AF after catheter ablation in middle-aged patients with low-risk cardiovascular profile., (© 2023 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

Background/aim: Despite advancements in valve technology and increased clinical experience, complications related to conduction defects after transcatheter aortic valve implantation (TAVR) have not improved as rapidly as expected. In this study, we aimed to predict the development of complete atrioventricular (AV) block and bundle branch block during and after the TAVR procedure and to investigate any changes in the cardiac conduction system before and after the procedure using electrophysiological study., Materials and Methods: A total of 30 patients who were scheduled for TAVR at our cardiovascular council were planned to be included in the study. TAVR was performed on patients at Erciyes University Medical Faculty Hospital as a single center between May 2019 and August 2020 Diagnostic electrophysiological study was performed before the TAVR procedure and after its completion. Changes in the cardiac conduction system during the preprocedure, intra-procedure, and postprocedure periods were recorded., Results: Significant increases in baseline cycle length, atrial-His (AH) interval, his-ventricular (HV) interval and atrioventricular (AV) distance were observed before and after the TAVR procedure (p = 0.039, p < 0.001, p = 0.018, p < 0.001, respectively). During the TAVR procedure, the preprocedural HV interval was longer in patients who developed AV block and bundle branch block compared to those who did not and this difference was statistically significant (p = 0.024). ROC curve analysis revealed that a TAVR preprocedure HV value >59.5 ms had 86% specificity and 75% sensitivity in detecting AV block and bundle branch block (AUC = 0.83, 95% CI: 0.664-0.996, p = 0.013). The preprocedure HV distance was 98 ± 10.55ms in the group with permanent pacemaker implantation and the mean value in the group without permanent pacemaker implantation was 66.27 ± 15.55 ms, showing a borderline significant difference (p = 0.049)., Conclusion: The prolongation of HV interval in patients with AV block and bundle branch block suggests that the block predominantly occurs at the infra-hisian level. Patients with longer preprocedural HV intervals should be closely monitored for the need for permanent pacemaker implantation after the TAVR procedure., (© TÜBİTAK.)

Objective: Based on the logistic regression model, analyze the risk factors for high degree atrioventricular block after transcatheter aortic valve replacement (TAVI) surgery and further analyze its predictive value., Methods: 402 patients who underwent TAVI surgery at Henan Thoracic Hospital for "aortic stenosis" between January 2020 and January 2023 were selected as the study subjects. The study subjects were divided into A group (N = 89) and B group (N = 313) based on whether high degree atrioventricular block occurred after surgery. The age, biochemistry and other general data of patients were systematically collected through inpatient cases, and the preoperative Right bundle branch block, I degree atrioventricular block, QRS duration, and indoor block were collected through our hospital's electrocardiogram (ECG) system, Calcification integral of Aortic valve was calculated by computed tomography (CT) results. Logistic regression analysis was performed on the clinical data, and the predictive value of related factors was further analyzed through the Receiver operating characteristic., Results: The preoperative QRS wave duration in the A group (165.06 ± 61.25) was significantly higher than that in the B group (108.30 ± 16.30), and the difference was statistically significant (p < 0.05). Compared with the B group, the incidence of Right bundle branch block in the A group was significantly higher before operation. The calcification score of Aortic valve in the A group (97.58 ± 61.25) was significantly higher than that in the B group (43.59 ± 7.56), with a statistically significant difference (p < 0.05). Further multivariate logistic regression analysis showed that the duration of QRS wave before operation and Aortic valve calcification score were independent risk factors for high atrioventricular block after TAVI (p < 0.05). Through Receiver operating characteristic analysis, it was found that preoperative QRS wave duration and Aortic valve calcification score had a high predictive value for the occurrence of high atrioventricular block after TAVI. The optimal cutoff value of QRS wave duration for predicting high atrioventricular block was 152, area under curve (AUC): 0.780 (95% CI: 0.718-0.841, p < 0.001). The optimal cutoff value for predicting high degree atrioventricular block with aortic calcification score is 61.5, AUC: 0.997 (95% CI: 0.992-1.000, p < 0.001)., Conclusions: Preoperative QRS wave duration and Aortic valve calcification score are independent risk factors for high degree atrioventricular block after TAVI, and they have high predictive value. In clinical work, risk factors should be found early and responded in time.

Introduction: The management of patients with conduction disease and supraventricular arrhythmias presents a multitude of clinical challenges.Intra-Hisian block, a condition characterized by delayed or blocked electrical conduction within the His bundle, can result in debilitating symptoms, such as syncope or presyncope. This case report aims to elucidate the diagnostic and therapeutic considerations that were taken in a patient who presented with recurrent syncopal episodes that corresponded to atrial flutter (AFL) and subsequently underwent cavotricuspid isthmus ablation., Case Presentation: A 65-year-old male with paroxysmal AFL and a pre-existing right bundle branch block and left anterior fascicular block (RBBB+LAFB) experienced recurrent syncopal episodes that were found to be correlated with AFL episodes. Following CTI ablation, an electrophysiology study (EPS) revealed a prolonged HV interval of 101ms, which indicated potential conduction abnormalities. With coronary sinus pacing, an intra-Hisian delay of 211ms was observed. During instances of atrioventricular block, intra-Hisian delay was evident on conducted beats, followed by intra-Hisian block on non-conducted beats. Ultimately, the patient's syncopal episodes prompted the placement of a dual-chamber pacemaker, which resulted in the resolution of symptoms., Conclusion: Intra-Hisian block is a condition that is often associated with delayed or blocked electrical conduction within the His bundle. When symptomatic, patients often present with syncope or presyncope. Etiologies of this condition include degenerative changes, myocardial infarction, autoimmune disorders, infections, medications, and more. This case emphasizes the importance of electrophysiology studies (EPS) in the diagnosis and management of patients with intra-Hisian block. Prompt intervention, such as the placement of a dual-chamber pacemaker, can alleviate symptoms and improve patient outcomes. Thus, clinical awareness and utilization of EPS can aid in accurate diagnosis and appropriate treatment selection for patients with conduction abnormalities and supraventricular arrhythmias.cuspid isthmus (CTI) ablation., (© 2023 Wiley Periodicals LLC.)

Background: Left bundle branch pacing (LBBP) achieves resynchrony and improves cardiac function in heart failure (HF) patients with reduced ejection fraction (EF) by correcting left bundle branch block (LBBB). Few data on the efficacy of early LBBP in HF with mildly reduced EF (HFmrEF) and LBBB have been reported., Objective: The purpose of this study was to explore the efficacy of early LBBP in patients with HFmrEF and LBBB., Methods: Consecutive patients with HFmrEF (left ventricular EF [LVEF] 35%-50%) and LBBB were prospectively enrolled to receive LBBP (Early-LBBP group) plus guideline-directed medical therapy (GDMT) or GDMT alone (GDMT group). Study outcomes included changes in LVEF, LV end-diastolic diameter (LVEDD), New York Heart Association (NYHA) functional classification, and N-terminal pro-brain natriuretic peptide (NT-proBNP), and clinical events (HF rehospitalization or syncope). Subgroup analysis compared efficacy of LBBP between patients with LBBB only without comorbidities or late gadolinium enhancement (LGE) (LBBB-Only group) and patients with either comorbidities or LGE (LBBB-Combined group)., Results: Fifty-four patients were enrolled and analyzed (37 Early-LBBP group; 15 GDMT group). LBBP achieved greater improvement in LVEF (+14.75% ± 7.37% vs -2.42% ± 2.84%; P <.001), reduction of LVEDD (-7.51 ± 5.40 mm vs -0.87 ± 4.36 mm; P <.001) and NYHA classification (-0.84 ± 0.76 vs -0.13 ± 0.74; P = .004), and similar reduction of NT-proBNP (-408.83 ± 920.29 pg/mL vs -229.05 ± 1579.17 pg/mL; P = .610) at 6 months. Early LBBP showed significantly reduced clinical events (0.0% vs 40.0%; P <.001) after 20.68 ± 13.55 months of follow-up. Subgroup analysis showed patients in the LBBB-Only group benefited more from LBBP with regard to LVEF improvement and LVEDD reduction than the LBBB-Combined group., Conclusion: Early LBBP with GDMT demonstrated greater improvement of cardiac function and reduced clinical events than GDMT alone in patients with HFmrEF and LBBB., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: Increased rates of postoperative left bundle branch block (LBBB) and permanent pacemaker implantation (PPI) frequently occur after implantation of rapid deployment valves. The impact of LBBB on follow-up outcomes remains controversial. So far, no data regarding long-term outcomes exist., Aim: The aim of this study was to analyze the impact of LBBB on postoperative outcomes after rapid deployment aortic valve replacement (RDAVR)., Methods: A total of 620 consecutive patients without preexisting LBBB or PPI who underwent rapid deployment AVR between March 2012 and September 2019 were included. New-onset LBBB was defined as any new LBBB that persisted at hospital discharge. The median follow-up time for clinical data was 1.7 years post-RDAVR., Results: At discharge, new-onset LBBB was seen in 109 patients (17.5%). There were no differences between the LBBB groups and no-LBBB groups regarding baseline characteristics. At a median follow-up of 1.7 years, no difference was found between LBBB groups and no-LBBB groups concerning all-cause mortality (12.8 vs. 11.7%; hazard ratio [HR]: 1.08; 95% confidence interval [CI]: 0.74-1.53; p  = 0.54). Nevertheless, new-onset LBBB was associated with significant higher pacemaker implantation rates at follow-up (10.1 vs. 6.3%; HR: 3.58; 95% CI: 1.89-6.81 p  < 0.001)., Conclusion: After a median follow-up of 1.7 years, new-onset LBBB was not associated with increased mortality. Nevertheless, higher pacemaker implantation rates were observed in patients with new-onset LBBB after RDAVR., Competing Interests: M.S., M.B., and J.S. received lecture fees from Edwards Lifesciences, Irvine, California, United States. All other authors state that there is no potential conflict of interest to report., (Thieme. All rights reserved.)

Background: Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block., Methods: This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual., Findings: Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group., Interpretation: Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials., Funding: Medtronic., Competing Interests: Declaration of interests BLW reports participating in physician advisory committees of Medtronic, Abbott, Boston Scientific, Biotronik, and Philips, and receiving honoraria from Medtronic, Abbott, Boston Scientific, Biotronik, Philips, and Cook. GF reports receiving lecture fees, participating in committees of trials sponsored by Bayer, Boehringer Ingelheim, Novartis, Servier, Vifor, Impulse Dynamics, and Medtronic, and receiving research grants from the European Union. CL reports participating in a Medtronic advisory board and receiving honoraria from Medtronic, Biotronik, LivaNova, Boston Scientific, and Abbott. MRG reports being a consultant for Medtronic and Boston Scientific and receiving honoraria from Medtronic, Boston Scientific, and EBR Systems. KK reports receiving speaker's honoraria and research grants from Medtronic Japan and Biotronik Japan. GMF reports receiving research grants from the National Heart, Lung, and Blood Institute, American Heart Association, Amgen, Bayer, Bristol Myers Squibb, Merck, Cytokinetics, and CSL-Behring, acting as a consultant for Novartis, Amgen, Bristol Myers Squibb, Cytokinetics, Cardionomic, Boehringer-Ingelheim, American Regent, Abbott, AstraZeneca, Regeneron, Reprieve, Myovant, Sequana, Windtree Therapuetics, Rocket Pharma, and Whiteswell, and serving on clinical endpoint committees or data safety monitoring boards for Amgen, Merck, Medtronic, EBR Systems, V-Wave, and LivaNova. MFE-C reports consultancy work for Medtronic and Boston Scientific. VE reports receiving support from a Clinical Research Scholar Award from the Fonds de recherche du Québec-Santé (FRQS) and honoraria from Abbott, Boston Scientific, and Medtronic. BP reports consultancy work for Abbott, Biotronik, Boston Scientific, and Microport, and receiving honoraria from Medtronic. FP reports receiving research grants from Medtronic, Boston Scientific, and Abbott. ESC reports consultancy work for Medtronic, Abbott, Intershunt, and Cardionomic, and serving on data safety monitoring boards and clinical events committees for LivaNova, EBR, and Abbott. BB reports consultancy work for Medtronic, Boston Scientific, and Pfizer. HHE reports receiving research grants from Medtronic. NV reports consultancy work for Medtronic, Abbott, Biotronik, Boston Scientific, EP Solutions, Implicity, and Pacemate. JvW, BG, DES, and DHF report being employees of Medtronic. DB reports being a mid-career investigator (supported by the Heart and Stroke Foundation of Ontario and the University of Ottawa Chair in Electrophysiology Research) and receiving research funding from Medtronic, Boston Scientific, Boehringer Ingelheim, Bayer, Biotronik, Pfizer, and Bristol Myers Squibb. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The coronavirus disease 2019 (COVID-19) may lead to a wide spectrum of clinical manifestations ranging from asymptomatic to symptomatic by having targets on various tissues such as lung parenchyma and myocardium (Shahrbaf et al., Cardiovasc Hematol Disord Drug Targets. 21(2):88-90, 2021). As an RNA-dependent RNApolymerase inhibitor, favipiravir has been proposed as a treatment in clinical studies done during the pandemic period (Furuta et al., Antiviral Res. 100(2):446-454, 2013). Although favipiravir is generally a safe medication, it may rarely cause cardiac adverse effects (Shahrbaf et al., Cardiovasc Hematol Disord Drug Targets. 21(2):88-90, 2021). To the best of our knowledge, favipiravir has not been reported to cause left bundle branch block (LBBB)., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: New and persistent left bundle branch block (NP-LBBB) following Transcatheter Aortic Valve Replacement (TAVR) is an ongoing concern with incidence ranging from as low as 4% to up to 65% (varying for different types of valves). Such patients are at risk of developing high-grade atrioventricular block (HAVB) warranting permanent pacemaker (PPM) implantation. However, currently, there are no consensus guidelines or large prospective studies to risk stratify these patients for safer discharge after TAVR., Objectives: To provide insight from a single center study on using modified electrophysiology (EP) study to risk stratify post-TAVR patients to outpatient monitoring for low-risk versus pacemaker implantation for high-risk patients., Methods and Results: Between June 2020 and March 2023, all patients who underwent a TAVR procedure (324 patients) at our institution were screened for development of NP-LBBB post-operatively. Out of 26 patients who developed NP-LBBB, after a pre-specified period of observation, 18 patients were deemed eligible for a modified EP study to assess His-Ventricular (HV) interval. 11 out of 18 patients (61.1%) had normal HV interval (HV < 55 ms). Three out of 18 patients (16.7%) had HV prolongation (55 ms < HV < 70 ms) without significant HV prolongation (defined as an increase in HV interval > 30%) with intra-procedural procainamide challenge. Four out of 18 patients (22.2%) had significant HV prolongation (HV > 70 ms) warranting PPM implantation based on a multidisciplinary approach and shared decision-making with the patients. Total of 50% of patients discharged with PPM (two out of four patients) were noted to be pacemaker dependent based on serial device interrogations. All patients who did not receive PPM were discharged with ambulatory monitoring with 30-day event monitor and did not develop HAVB on serial follow-up., Conclusion: Normal HV interval up to 55 ms on modified EP study after TAVR and development of NP-LBBB can be utilized as a threshold for risk stratification to facilitate safe discharge. The optimal upper limit of HV interval threshold remains unclear in determining appropriate candidacy for PPM., (© 2023 Wiley Periodicals LLC.)

Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare.

Background: Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT) has shown encouraging results for QRS duration reduction and heart function improvement. However, the feasibility and efficacy of LOT-CRT have not been well established in intraventricular conduction delay patients. This study aims to assess and compare the efficacy and clinical outcome of CRT based on left bundle branch pacing, combined with coronary sinus left ventricular pacing (LOT-CRT) with CRT via biventricular pacing (BiV-CRT) in intraventricular conduction delay patients indicated for CRT., Methods: Consecutive patients with intraventricular conduction delay and CRT indications were assigned nonrandomized to LOT-CRT (n=30) or BiV-CRT (n=55). Addition of the left bundle branch pacing (or coronary venous) lead was at the discretion of the implanting physician guided by suboptimal paced QRS complex and on clinical grounds. Echocardiographic parameters and clinical characteristics were accessed at baseline and during 2-years' follow-up., Results: Success rate for LOT-CRT and BiV-CRT was 96.8% and 96.4%. LOT-CRT had greater reduction of QRS duration compared with BiV-CRT (42.7±17.4 ms versus 21.9±21.5 ms; P <0.001). Higher left ventricular ejection fraction was also achieved in LOT-CRT than BiV-CRT at 6-month (36.7±9.8% versus 30.5±6.4%; P <0.05), 12-month (34.8±7.6% versus 30.3±6.2%; P <0.05), 18-month (36.3±7.9% versus 28.1±6.6%; P <0.005), and 24-month follow-up (37±9.5% versus 30.5±7%; P <0.05). Adverse clinical outcomes including heart failure rehospitalization and mortality were lower in LOT-CRT group for 24 months follow-up (hazard ratio, 0.33; P =0.035)., Conclusions: LOT-CRT improves ventricular electrical synchrony and may provide greater clinical outcomes as compared with BiV-CRT in intraventricular conduction delay patients. These findings need further evaluation in future randomized controlled trials., Competing Interests: Disclosures None.

Aims: The aim of this study was to conduct a meta-analysis of prospective studies assessing the relationship between bundle branch block (BBB) or wide QRS and risk of all-cause mortality in patients with acute heart failure (AHF)., Methods and Results: We searched the PubMed, Scopus and Web of Science database from inception to February 2022 to identify single centre or multicentre studies including a minimum of 400 patients and assessing the association between BBB or wide QRS and mortality in patients with AHF. Study-specific hazard ratio (HR) estimates were combined using a random-effects meta-analysis. Two meta-analyses were performed: (1) grouping by conduction disturbance and follow-up length and, (2) using the results from the longest follow-up for each study and grouping by the type of BBB. The meta-analysis included 21 publications with a total of 116,928 patients. Wide QRS (considering right (RBBB) and left (LBBB) altogether) was associated with a significant increment in the risk of all-cause mortality (pooled adjusted HR 1.112, 95% CI 1.065-1.160). The increased risk of death was also present when LBBB (HR 1.121, 95% CI 1.042-1.207) and RBBB (HR 1.187, 95% CI 1.045-1.348) were considered individually. There was no difference in risk between LBBB and RBBB (P for interaction = 0.533). Other outcomes including sudden death, rehospitalization and a combination of cardiovascular death or rehospitalization were also increased in patients with BBB or wide QRS., Conclusions: This meta-analysis suggests a modest increase in the risk of all-cause mortality among patients with AHF and BBB or wide QRS, irrespective of the type of BBB., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Aims: Initial proof suggests that a non-specific intraventricular conduction delay (NIVCD) is a risk factor for mortality. We explored the prognosis of intraventricular conduction delays (IVCD)-right bundle branch block (RBBB), left bundle branch block (LBBB), and the lesser-known NIVCD-in patients with acute coronary syndrome (ACS)., Methods and Results: This is a retrospective registry analysis of 9749 consecutive ACS patients undergoing coronary angiography and with an electrocardiographic (ECG) recording available for analysis (2007-18). The primary outcome was cardiac mortality. Mortality and cause of death data (in ICD-10 format) were received from the Finnish national register with no losses to follow-up (until 31 December 2020). The risk associated with IVCDs was analysed by calculating subdistribution hazard estimates (SDH; deaths due to other causes being considered competing events). The mean age of the population was 68.3 years [standard deviation (Sd) 11.8]. The median follow-up time was 6.1 years [interquartile range (IQR) 3.3-9.4], during which 3156 patients died. Cardiac mortality was overrepresented among IVCD patients: 76.9% for NIVCD (n = 113/147), 67.6% for LBBB (n = 96/142), 55.7% for RBBB (n = 146/262), and 50.1% for patients with no IVCD (n = 1275/2545). In an analysis adjusted for age and cardiac comorbidities, the risk of cardiac mortality was significantly higher in all IVCD groups than among patients with no IVCD: SDH 1.37 (1.15-1.64, P < 0.0001) for RBBB, SDH 1.63 (1.31-2.03 P < 0.0001) for LBBB, and SDH 2.68 (2.19-3.27) for NIVCD. After adjusting the analysis with left ventricular ejection fraction, RBBB and NIVCD remained significant risk factors for cardiac mortality., Conclusion: RBBB, LBBB, and NIVCD were associated with higher cardiac mortality in ACS patients., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The use of left bundle branch pacing (LBBP) has dramatically increased since it was first described in 2016, but to date there are no published data on the safety of performing magnetic resonance imaging (MRI) in these patients., Methods: Patients with LBBP who underwent MRI between January 2016 and October 2022 were retrospectively studied in our clinical center, which has a special program for imaging patients with cardiac devices. All patients underwent close cardiac monitoring throughout the MRI scans. Occurrence of arrhythmias or other adverse effects during MRI were assessed. LBBP lead parameters immediately pre- and post-MRI and at an outpatient follow-up were compared., Results: Fifteen patients with LBBP underwent a total of 19 MRI sessions during the study period. Lead parameters did not significantly change after the MRI or on follow-up, which took place at a median of 91 days after the MRI. No patient developed arrhythmias during the MRI sessions, and no adverse effects such as lead dislodgement were reported., Conclusion: Although larger studies are necessary to verify our findings, MRI in patients with LBBP appears safe based on this initial case series., (© 2023 Wiley Periodicals LLC.)

Background: Transcatheter aortic valve implantation (TAVI) can either be conducted as an elective (scheduled in advance) or a non-elective procedure performed during an unplanned hospital admission. The objective of this study was to compare the outcomes of elective and non-elective TAVI patients., Methods: This single-centre study included 512 patients undergoing transfemoral TAVI between October 2018 and December 2020; 378 (73.8%) were admitted for elective TAVI, 134 (26.2%) underwent a non-elective procedure. Our TAVI programme entails an optimized fast-track concept aimed at minimizing the total length of stay to ≤ 5 days for elective patients which in the German healthcare system is currently defined as the minimal time period to safely perform TAVI. Clinical characteristics and survival rates at 30 days and 1 year were analysed., Results: Patients who underwent non-elective TAVI had a significantly higher comorbidity burden. Median duration from admission to discharge was 6 days (elective group 6 days versus non-elective group 15 days; p < 0.001), including a median postprocedural stay of 5 days (elective 4 days versus non-elective 7 days; p < 0.001). All-cause mortality at 30 days was 1.1% for the elective group and 3.7% for non-elective patients (p = 0.030). At 1 year, all-cause mortality among elective TAVI patients was disproportionately lower than in non-elective patients (5.0% versus 18.7%, p < 0.001). In the elective group, 54.5% of patients could not be discharged early due to comorbidities or procedural complications. Factors associated with a failure of achieving a total length of stay of ≤ 5 days comprised frailty syndrome, renal impairment as well as new permanent pacemaker implantation, new bundle branch block or atrial fibrillation, life-threatening bleeding, and the use of self-expanding valves. After multivariate adjustment, new permanent pacemaker implantation (odds ratio 6.44; 95% CI 2.59-16.00), life-threatening bleeding (odds ratio 4.19; 95% confidence interval 1.82-9.66) and frailty syndrome (odds ratio 5.15; 95% confidence interval 2.40-11.09; all p < 0.001, respectively) were confirmed as significant factors., Conclusions: While non-elective patients had acceptable periprocedural outcomes, mortality rates at 1 year were significantly higher compared to elective patients. Approximately only half of elective patients could be discharged early. Improvements in periprocedural care, follow-up strategies and optimized treatment of both elective and non-elective TAVI patients are needed., (© 2023. The Author(s).)

Background: We evaluated the incidence, prognosis, and predictive factors of new onset of persistent left bundle branch block (NOP-LBBB) after rapid-deployment aortic valve replacement (RD-AVR)., Methods: This was an observational, retrospective, single-center study of 274 consecutive patients with no baseline ventricular conduction disorder and no previous permanent pacemaker implantation (PPI) who underwent RD-AVR with an INTUITY valve (n = 55) or INTUITY Elite Valve (n = 219) (Edwards Lifesciences). Transthoracic echocardiography and 12-lead electrocardiography was performed preoperatively, at discharge, and at 1-month and 1-year intervals. The incidence, prognosis, and predictive factors of NOP-LBBB were evaluated., Results: NOP-LBBB occurred in 58 patients (21.2%) after discharge. In multivariate analysis, age (P < .01), INTUITY valve diameter ≥23 mm (P = .02), and INTUITY Elite implantation (P = .01) were independent predictors of NOP-LBBB. By 1:1 propensity matching analysis between the NOP-LBBB group and the control group, there were no significant differences in 1-year overall mortality (P = .23), hospitalization for congestive heart failure (P = .99), or PPI (P = .99). NOP-LBBB exposed patients to a high rate of dysrhythmic events (12.1% vs 1.4%, P < .01) and was associated with a significant decrease in left ventricular ejection fraction (0.62 ± 0.095 vs 0.652 ± 0.0783, P = .02) without an impact on New York Heart Association functional status (1.25 ± 0.32 and 1.52 ± 0.70, P = .32). PPI was performed in 17 patients (6.2%) before discharge, including 14 NOP-LBBB patients., Conclusions: NOP-LBBB after RD-AVR is prevalent in patients with no prior conduction disorders. INTUITY Elite is associated with a significantly higher rate of NOP-LBBB. The persistence of NOP-LBBB predisposed patients to the occurrence of high-grade conduction disorders and might have led to PPI but did not increase death or hospitalization for congestive heart failure., (Copyright © 2023 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Introduction: Electrophysiological testing has been proposed in the latest European Society of Cardiology (ESC) guidelines for cardiac pacing to identify left bundle branch block (LBBB) patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His-ventricular (HV) interval of >55 ms, a cut-off of ≥70 ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow-up in such patients is largely unknown. As such, we aimed to assess the VP burden during follow-up of patients receiving PM therapy for LBBB after TAVR based on an HV interval > 55 ms and ≥70 ms., Methods: All patients with new-onset or pre-existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (>55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI-DDD)., Results: 701 patients underwent TAVR at the University Hospital of Basel. One hundred seventy-seven patients presented with new-onset or pre-existing LBBB the day following TAVR and underwent EP testing. An HV interval > 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber PC in 12 (23%) patients, respectively. Median follow-up was 21 months. The median VP burden overall was 3%. The median VP burden was not significantly different between patients with an HV ≥ 70 ms (6.5 [0.8-52]) and those with an HV between 55 and 69 ms (2 [0-17], p = .23). 31% of patients demonstrated a VP burden < 1%, 27% 1%-5% and 41% > 5%. The median HV intervals in patients with VP burdens < 1%, 1%-5% and >5% were 66 (IQR 62-70) ms, 66 (IQR 63-74) ms and 68 (IQR 60-72) ms, respectively, p = .52. When only assessing patients with an HV interval 55-69 ms, 36% demonstrated a VP burden of <1%, 29% of 1%-5% and 35% of >5%. In patients with an HV Interval ≥ 70 ms, 25% demonstrated a VP burden < 1%, 25% of 1%-5% and 50% of >5% %, p = .64 (Figure)., Conclusion: In patients with LBBB after TAVR and IHCD defined by an HV interval > 55 ms, VP burden is relevant in a non-negligible amount of patients during follow-up. Further studies are warranted to define the optimal cut-off value for the HV interval or to develop risk models incorporating HV measurements and other risk factors to trigger PM implantation in patients with LBBB after TAVR., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Left bundle branch block-induced cardiomyopathy is an increasingly recognized type of dilated cardiomyopathy identified in a minority but not negligible proportion of patients with newly diagnosed heart failure. However, it has not yet been included among the possible etiologies of dilated cardiomyopathies or among the unclassified cardiomyopathies. Although a few sets of diagnostic criteria have been proposed, currently there is a lack of universal consensus regarding diagnostic criteria. Some specific clinical features and electrocardiography, echocardiography, and cardiac magnetic resonance imaging findings are recommended to help physicians in the diagnosis of left bundle branch block-induced cardiomyopathy. In this review, prevalence, pathophysiological mechanisms, diagnostic criteria, diagnostic modalities, and specific features of left bundle branch block-induced cardiomyopathy have been addressed with attention to the differential diagnosis of other dilated cardiomyopathies.

Aims: Several procedural and electrocardiogram (ECG) parameters have been associated with the occurrence of high-degree atrioventricular block (AVB) requiring permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR). We hereunder sought to assess if the baseline R-wave amplitude in V1 ECG lead of patients with normal QRS duration undergoing TAVR is associated with a higher patient's risk for developing high-degree AVB following left bundle branch block (LBBB)., Methods and Results: In this retrospective single-centre study in 720 consecutive patients who underwent TAVR, 141 (19.6%) patients with normal QRS duration developed a new LBBB after TAVR. The 24 (17%) patients who underwent PPI for reasons other than high-degree AVB were excluded from further analysis. In the remaining 117 study patients, 14 (12%) developed high-degree AVB requiring PPI (Group 1) while the remaining 103 (88%) patients did not (Group 2). There were no significant differences in baseline demographic or procedural characteristics nor in PR interval, QRS duration, and QRS axis between these two groups. The incidence of left anterior hemiblock was higher in Group 1 (3 of 14, 21.4%) than that in Group 2 (9 of 103, 8.7%), but the difference was not statistically significant (P = 0.156). The R-wave amplitude in V1 was smaller in Group 1 than that in Group 2 (0.029 ± 0.04 mV vs. 0.11 ± 0.14 mV, P = 0.0316). In the receiver-operating characteristics analysis, the cutoff for R-wave amplitude pre-TAVR was 0.03 mV, area under the curve = 0.7219 (P = 0.0002)., Conclusion: The R-wave amplitude in lead V1 during baseline ECG in patients with normal QRS duration may predict the occurrence of high-degree AVB following new LBBB after TAVR., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: New-onset left bundle branch block (LBBB) is one of the most frequent complications after transcatheter aortic valve implantation (TAVI) and is associated with delayed high degree atrioventricular (AV) block., Objectives: The objectives of this study were to determine the incidence of AV block in such a population and to assess the performance and safety of a risk stratification algorithm on the basis of electrophysiology study (EPS) followed by implantation of a pacemaker or implantable loop recorder (ILR)., Methods: This was a prospective open-label study with 12-month follow-up. From June 8, 2015, to November 8, 2018, 183 TAVI recipients (mean age 82.3 ± 5.9 years) were included at 10 centers. New-onset LBBB after TAVI persisting for >24 hours was assessed by electrophysiology study during initial hospitalization. High-risk patients (His-ventricle interval ≥70 ms) were implanted with a dual-chamber pacemaker recording AV conduction disturbance episodes. Patients at lower risk were implanted with an ILR with automatic remote monitoring., Results: A high-grade AV conduction disorder was identified in 56 patients (30.6%) at 12 months. Four subjects were symptomatic, all in the ILR group. No complications were associated with the stratification procedure. Patients with His-ventricle interval ≥70 ms displayed more high-grade AV conduction disorders (53.2% [25 of 47] vs 22.8% [31 of 136]; P < .001). In a multivariate analysis, His-ventricle interval ≥70 ms was independently associated with the occurrence of a high-grade conduction disorder (subdistribution hazard ratio 2.4; 95% confidence interval 1.2-4.8; P = .010)., Conclusion: New-onset LBBB after TAVI was associated with high rates of high-grade AV conduction disturbances. The stratification algorithm provided safe and valuable aid to management decisions and reliable guidance on pacemaker implantation., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)