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Conduction disturbances (CDs) are common after transcatheter aortic valve replacement. Continuous improvements in preprocedural planification, implant techniques, and device design have markedly reduced periprocedural complications. However, CDs rate remains in the double-digit range. Because CDs after TAVR are associated with poorer outcomes, seeking a reduction in their occurrence is paramount. Several nonmodifiable and modifiable factors are associated with an increased risk of CDs. Previous right bundle branch block has been shown to have a strong association with pacemaker implant after TAVR. Among the modifiable factors, a lower implantation depth seems to be associated with a higher risk of CDs, and several implant strategies aiming to obtain a higher implant depth have shown promising results. This literature review provides a detailed description of updated evidence about the epidemiology, impact, and preventive and management strategies of CDs after TAVR. Also, based on these updated data, a fast-track protocol CDs management is proposed. [Display omitted] • Conduction disturbances are a frequent adverse event after TAVR, with only a few studies showing permanent pacemaker rates in the 1-digit frame. • Permanent pacemaker implantation and new-onset persistent left bundle branch block are associated with impaired outcomes, including a higher risk of long-term mortality and heart failure hospitalization. • The identification of modifiable factors associated with a higher risk of conduction disturbance appearance has led to the development of refined implantation techniques (high implant depth), leading to a significant reduction of permanent pacemaker implantation. • Future studies are warranted to reduce the incidence of conduction disturbances and also to reduce the burden associated with permanent pacemaker implantation such as the use of conduction system pacing. [ABSTRACT FROM AUTHOR]

The impact of new-onset left bundle branch block (N-LBBB) developing after Transcatheter Aortic Valve Replacement (TAVR) on cardiac function and mechanical dyssynchrony is not well defined. We retrospectively screened all patients who underwent TAVR in our centre between Oct 2018 and Sept 2021 (n = 409). We identified 38 patients with N-LBBB post-operatively (of which 28 were persistent and 10 were transient), and 17 patients with chronic pre-existent LBBB (C-LBBB). We excluded patients requiring pacing post TAVR. For all groups, we retrospectively analysed stored echocardiograms at 3 time points: before TAVR (T0), early after TAVR (T1, 1.2 ± 1.1 days), and late follow-up (T2, 1.5 ± 0.8 years), comparing LV mass and volumes, indices of LV function (LV ejection fraction, LVEF; global longitudinal strain, GLS), and mechanical dyssynchrony indices (systolic stretch index, severity of septal flash). At baseline (T0), C-LBBB had worse cardiac function, and larger LV volumes and LV mass, compared with patients with N-LBBB. At T1, N-LBBB resulted in mild dyssynchrony and decreased LVEF and GLS. Dyssynchrony progressed at T2 in persistent N-LBBB but not C-LBBB. In both groups however, LVEF remained stable at T2, although individual response was variable. Patients with better LVEF at baseline demonstrated a higher proportion of developing LBBB-induced LV dysfunction at T2. Lack of improvement of LVEF immediately after TAVR predicted deteriorating LVEF at T2. In transient LBBB, cardiac function and most dyssynchrony indices returned to baseline. N-LBBB after TAVR results in an immediate reduction of cardiac function, in spite of only mild dyssynchrony. When LBBB persists, patients with better cardiac function before TAVR are more likely to have LBBB-induced LV dysfunction after TAVR. • New onset LBBB after TAVR results in an immediate reduction of cardiac function, in spite of only mild dyssynchrony. • Patients with better cardiac function at baseline have higher proportion of LBBB-induced cardiac dysfunction after TAVR. • In patients with severe cardiac dysfunction at baseline, the afterload relief of TAVR seems to overcome the impact of LBBB. • A clinical trial addressing the benefit of resynchronization therapy in this population is needed. [ABSTRACT FROM AUTHOR]

Background: For the initial treatment strategy for patients with cardiac resynchronization therapy (CRT) indications, whether to choose left bundle branch area pacing (LBBaP) or biventricular pacing (BVP) remains controversial. We aimed to investigate the cost‐effectiveness ratio (CER) of LBBaP and BVP in heart failure (HF) patients with left bundle branch block (LBBB). Methods: This observational study included HF patients with LBBB who underwent successful LBBaP or BVP. The primary outcomes were echocardiographic response (left ventricular ejection fraction [LVEF] increase ≥5%), LVEF improvement, hospitalization costs, and CER (CER = cost/echocardiographic response rate). Secondary outcomes included other echocardiographic parameters, New York Heart Association (NYHA), N‐terminal pro–B‐type natriuretic peptide (NT‐proBNP), pacemaker parameters, complications, ventricular arrhythmia (VA) events, HF hospitalization (HFH), and all‐cause mortality. Results: A total of 130 patients (85 LBBaP and 45 BVP) were included (65.6 ± 10.0 years, 70.77% men). The median follow‐up period was 16(12,30), months. Compared with BVP, the LBBaP group showed a greater increase in LVEF (20.2% ± 11.8% vs. 10.5% ± 13.9%; p < 0.001), higher echocardiographic response rate (86.1% vs. 57.8%; p < 0.001), and lower hospitalization costs [$9707.7 (7751.2, 18,088.5) vs. $20,046.1 (18,840.1, 22,447.3); p < 0.0001]. The CER was 112.7 and 346.8 in LBBaP and BVP, respectively. The incremental cost‐effectiveness ratio (ICER = △cost/△echocardiographic response rate) was $−365.3/per 1% increase in effectiveness. LBBaP improved cardiac function more significantly than BVP. There were no significant differences in clinical outcomes. Conclusions: LBBaP‐CRT is more cost‐effective than BVP, offering greater LVEF improvement, higher echocardiographic response rates, lower hospitalization costs, and more significantly improved cardiac function. These findings need large randomized clinical trials for further confirmation. [ABSTRACT FROM AUTHOR]

This article reviews and discusses non-myocardial disorders that represent diagnostic challenges when evaluating patients for suspected heart failure with preserved left ventricular ejection fraction. This includes pre-capillary pulmonary hypertension, which is important to differentiate from post-capillary hypertension caused by left-sided heart disease. The impact of electrical disorders on LV diastolic function is also reviewed, and includes a discussion of left bundle branch, which has both a direct effect on LV diastolic function, as well as a long-term effect due to remodelling. Furthermore, evaluation of diastolic function in patients with atrial fibrillation is discussed. Pericardial diseases are reviewed as well as effects of a normal pericardium on diastolic function in failing hearts. Finally, the article reviews how valvular diseases impact LV diastolic function. [ABSTRACT FROM AUTHOR]

Background: Functional mitral regurgitation (FMR) and its severity are associated with adverse outcomes in heart failure patients. This study aims to analyze the predictors of FMR improvement after successful left bundle branch area pacing (LBBAP) in patients with LVEF < 50% and complete left bundle branch block (CLBBB). Methods: Consecutive patients with LVEF < 50% and CLBBB who underwent successful LBBAP from July 2018 to July 2023 were retrospectively identified. Significant MR was defined as regurgitation of moderate severity or greater. Patients with significant FMR were included in the analysis. FMR improvement (FMRI) was defined as a reduction of at least one grade in regurgitation severity compared to baseline at 3 months or longer follow‐up. Results: Among the 81 identified patients, 42 patients with significant FMR preoperatively were included. After LBBAP, QRS duration significantly shortened from 170.6 ± 18.8 ms to 114.5 ± 20.2 ms (p <.001). Significant FMR improves in approximately 76.2%, and the patients were divided into an FMRI group (n = 32) and a non‐FMRI group (n = 10). Univariate analysis showed that absence of persistent atrial fibrillation, typical CLBBB, and left atrium diameter at baseline were associated with improvement of FMR after LBBAP. Of these variables, only absence of persistent atrial fibrillation remains an independent predictor in the multivariate model (OR 12.436, p =.009). Conclusion: LBBAP is able to improve FMR in heart failure patients who had CLBBB with LVEF < 50%. Meanwhile, the absence of persistent atrial fibrillation is an independent predictor of FMR improvement. [ABSTRACT FROM AUTHOR]

Abstract Aims Cardiac resynchronization therapy (CRT) is an established treatment for drug‐refractory heart failure (HF) in patients with left bundle branch block (LBBB). Acute haemodynamic improvement after CRT implantation may enable the intensification of HF medication soon thereafter. Immediate pharmacotherapy intensification (IPI) after CRT implantation achieves a synergetic effect, possibly leading to a better prognosis. This study aimed to explore the incidence, characteristics, and impact of IPI on real‐world outcomes among CRT recipients with a history of hospitalization for acute HF. Methods and results This multicentre retrospective study enrolled CRT recipients with LBBB morphology, a QRS width ≥120 ms, a left ventricular ejection fraction ≤35%, and New York Heart Association II–IV HF symptoms. All patients had previous HF hospitalizations within the previous year and received guideline‐directed medical therapy before CRT implantation. Patient baseline characteristics, including HF medication, were collected. IPI was defined as the intensification of beta‐blockers, angiotensin‐converting enzyme inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor antagonists within 30 days of CRT implantation. The primary endpoint was all‐cause death or first hospitalization for HF; the secondary endpoint was all‐cause death. We enrolled 194 patients (75% male; mean age, 65 ± 13 years; 78% with non‐ischaemic cardiomyopathy). One hundred five (54%) patients received IPI. Patients who received IPI exhibited a significantly shorter QRS duration (159 ± 26 vs. 171 ± 32 ms; P = 0.004), higher estimated glomerular filtration rate (55.2 ± 20.0 vs. 47.8 ± 24.7 mL/min/1.73 m2; P = 0.022), and more dilated cardiomyopathy. During a median follow‐up period of 29 months, 70 (36%) patients reached the primary endpoint and 42 (22%) patients died. Patients with IPI showed significantly better outcomes for the primary and secondary endpoints than patients without IPI. The volumetric responder ratio at 6 months after implantation was not significantly different between patients with and without IPI; however, patients who received IPI had reduced mortality even at 6 months after implantation. In the multivariate analysis, IPI was an independent predictor of the primary endpoint (hazard ratio, 0.51; 95% confidence interval, 0.27–0.97; P = 0.043). Conclusions Immediate intensification of HF medication was achieved in 54% of CRT recipients and was significantly higher in patients without excessive QRS prolongation, preserved renal function, and dilated cardiomyopathy than others. In patients with LBBB morphology and QRS ≥ 120 ms, IPI was associated with a significantly better prognosis and fewer HF hospitalizations after CRT implantation than others.

Abstract Aims Left bundle branch block (LBBB) is associated with an increased risk of adverse outcomes for patients with heart failure. The prognosis of LBBB in patients with a preserved ejection fraction (EF) remains controversial. This study investigated the predictive value of T‐wave discordance for the prognosis of patients with LBBB and preserved or mildly reduced EF. Methods and results We enrolled 707 patients with complete LBBB and left ventricular (LV) EF ≥ 40% observed using electrocardiograms (ECGs) and echocardiograms between January 2010 and December 2018. Their serial ECGs were reviewed during the follow‐up period. The T‐wave pattern was classified as discordant LBBB (dLBBB) or concordant LBBB (cLBBB) according to the 12‐lead ECG T‐wave morphology. The primary outcome was the composite of cardiovascular death or hospitalization for heart failure during a median follow‐up period of 3.1 years. A multivariable Cox regression analysis was used to evaluate the independent predictors of the primary outcome. Patients with dLBBB had more comorbidities, a higher heart rate, a longer QRS and QTc duration, a larger LV end‐systolic volume and left atrial dimension, a lower LVEF, and a higher mitral E/A ratio and E/e′, compared with those with cLBBB. Older age [hazard ratio (HR) = 1.023, 95% confidence interval (CI) = 1.001–1.046, P = 0.023], history of heart failure (HR = 2.440, 95% CI = 1.524–3.905, P = 0.001), chronic kidney disease (HR = 1.917, 95% CI = 1.182–3.110, P = 0.008), larger LV end‐systolic volume (HR = 1.046, 95% CI = 1.017–1.075, P = 0.002), lower LVEF (HR = 0.916, 95% CI = 0.885–0.948, P = 0.001), and presence of dLBBB (HR = 1.63, 95% CI = 1.011–2.628, P = 0.032) were independent predictors of the primary outcome in patients with LBBB and LVEF ≥ 40%. The discordant or concordant T‐wave morphology of LBBB could transform from one subtype to the other in up to 23% of the study population during the follow‐up period, and individuals with persistent or transformed dLBBB faced an increased risk of cardiovascular death or non‐fatal heart failure hospitalization. Conclusions In patients with LBBB and EF ≥ 40%, dLBBB serves as an independent predictor of a higher risk of cardiovascular death or non‐fatal heart failure hospitalization.

Takotsubo cardiomyopathy is a rare cardiac presentation. It can be associated with severe complications such as hemodynamically significant ventricular septal defect and cardiac free wall rupture. In cases of mechanical complications, surgical repair is often indicated. Despite best medical and surgical efforts, patients with Takotsubo cardiomyopathy and mechanical complications carry significant mortality risk. Herein, we present an unusual presentation of Takotsubo cardiomyopathy that was associated with a mechanical complication. Although the patient underwent a successful surgical repair, she passed away from multiorgan failure during the postoperative period. Article highlights Takotsubo's cardiomyopathy is a rare cardiac pathology. It is usually managed conservatively. Diagnosis of Takotsubo's cardiomyopathy should be made once other etiologies and causes have been ruled out. Takotsubo's cardiomyopathy is very rarely associated with mechanical complications, including ventricular septal defect and cardiac rupture. While prognosis is guarded and outcomes are dire, early recognition of mechanical complications secondary to Takotsubo's cardiomyopathy may facilitate quicker interventions, which may slightly improve clinical outcomes. [ABSTRACT FROM AUTHOR]

Introduction: The association between paced LVAT and cardiac structure and function at baseline, as well as whether longer LVAT is associated with worse cardiac reverse remodeling in patients with heart failure (HF) and left bundle branch block (LBBB) has not been well investigated. The purpose of this study is to investigate the association between paced LVAT and baseline echocardiographic parameters and cardiac reverse remodeling at follow‐up. Methods: Patients with HF and LBBB receiving successful left bundle branch pacing (LBBP) from June 2018 to April 2023 were enrolled and grouped based on paced LVAT. NT‐proBNP and echocardiographic parameters were recorded during routine follow‐up. The relationships between paced LVAT and echocardiographic parameters at baseline and follow‐up were analyzed. Results: Eighty‐three patients were enrolled (48 males, aged 65 ± 9.8, mean LVEF 32.1 ± 7.5%, mean LVEDD 63.0 ± 8.5 mm, median NT‐proBNP 1057[513–3158] pg/mL). The paced QRSd was significantly decreased (177 ± 17.9 vs. 134 ± 18.5, p <.001) and median paced LVAT was 80[72–88] ms. After a median follow‐up of 12[9–29] months, LVEF increased to 52.1 ± 11.2%, LVEDD decreased to 52.6 ± 8.8 mm, and NT‐proBNP decreased to 215[73–532]pg/mL. Patients were grouped based on paced LVAT: LVAT < 80 ms (n = 39); 80 ≤ LVAT < 90 ms (n = 24); LVAT ≥ 90 ms (n = 20). Patients with longer LVAT had larger LVEDD and lower LVEF (LVEDDbaseline: p <.001; LVEFbaseline: p =.001). The difference in LVEF6M was statistically significant among groups (p <.001) and patients with longer LVAT had lower LVEF6M, while the difference in LVEF1Y was not seen (p =.090). There was no significant correlation between ΔLVEF6M‐baseline, ΔLVEF1Y‐6M and LVAT respectively (ΔLVEF6M‐baseline: p =.261, r = −.126; ΔLVEF1Y‐6M: p =.085, r =.218). Conclusion: Long paced LVAT was associated with worse echocardiographic parameters at baseline, but did not affect the cardiac reverse remodeling in patients with HF and LBBB. Those with longer LVAT required longer time to recover. [ABSTRACT FROM AUTHOR]

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. This study sought to investigate the chronologic dynamics of LBBB to left ventricular dysfunction and the pathologic mechanism of LBBB-CM. 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. 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. 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. [Display omitted] [ABSTRACT FROM AUTHOR]

Aims: Left bundle branch block (LBBB) is associated with an increased risk of adverse outcomes for patients with heart failure. The prognosis of LBBB in patients with a preserved ejection fraction (EF) remains controversial. This study investigated the predictive value of T‐wave discordance for the prognosis of patients with LBBB and preserved or mildly reduced EF. Methods and results: We enrolled 707 patients with complete LBBB and left ventricular (LV) EF ≥ 40% observed using electrocardiograms (ECGs) and echocardiograms between January 2010 and December 2018. Their serial ECGs were reviewed during the follow‐up period. The T‐wave pattern was classified as discordant LBBB (dLBBB) or concordant LBBB (cLBBB) according to the 12‐lead ECG T‐wave morphology. The primary outcome was the composite of cardiovascular death or hospitalization for heart failure during a median follow‐up period of 3.1 years. A multivariable Cox regression analysis was used to evaluate the independent predictors of the primary outcome. Patients with dLBBB had more comorbidities, a higher heart rate, a longer QRS and QTc duration, a larger LV end‐systolic volume and left atrial dimension, a lower LVEF, and a higher mitral E/A ratio and E/e′, compared with those with cLBBB. Older age [hazard ratio (HR) = 1.023, 95% confidence interval (CI) = 1.001–1.046, P = 0.023], history of heart failure (HR = 2.440, 95% CI = 1.524–3.905, P = 0.001), chronic kidney disease (HR = 1.917, 95% CI = 1.182–3.110, P = 0.008), larger LV end‐systolic volume (HR = 1.046, 95% CI = 1.017–1.075, P = 0.002), lower LVEF (HR = 0.916, 95% CI = 0.885–0.948, P = 0.001), and presence of dLBBB (HR = 1.63, 95% CI = 1.011–2.628, P = 0.032) were independent predictors of the primary outcome in patients with LBBB and LVEF ≥ 40%. The discordant or concordant T‐wave morphology of LBBB could transform from one subtype to the other in up to 23% of the study population during the follow‐up period, and individuals with persistent or transformed dLBBB faced an increased risk of cardiovascular death or non‐fatal heart failure hospitalization. Conclusions: In patients with LBBB and EF ≥ 40%, dLBBB serves as an independent predictor of a higher risk of cardiovascular death or non‐fatal heart failure hospitalization. [ABSTRACT FROM AUTHOR]

Aims: Cardiac resynchronization therapy (CRT) is an established treatment for drug‐refractory heart failure (HF) in patients with left bundle branch block (LBBB). Acute haemodynamic improvement after CRT implantation may enable the intensification of HF medication soon thereafter. Immediate pharmacotherapy intensification (IPI) after CRT implantation achieves a synergetic effect, possibly leading to a better prognosis. This study aimed to explore the incidence, characteristics, and impact of IPI on real‐world outcomes among CRT recipients with a history of hospitalization for acute HF. Methods and results: This multicentre retrospective study enrolled CRT recipients with LBBB morphology, a QRS width ≥120 ms, a left ventricular ejection fraction ≤35%, and New York Heart Association II–IV HF symptoms. All patients had previous HF hospitalizations within the previous year and received guideline‐directed medical therapy before CRT implantation. Patient baseline characteristics, including HF medication, were collected. IPI was defined as the intensification of beta‐blockers, angiotensin‐converting enzyme inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor antagonists within 30 days of CRT implantation. The primary endpoint was all‐cause death or first hospitalization for HF; the secondary endpoint was all‐cause death. We enrolled 194 patients (75% male; mean age, 65 ± 13 years; 78% with non‐ischaemic cardiomyopathy). One hundred five (54%) patients received IPI. Patients who received IPI exhibited a significantly shorter QRS duration (159 ± 26 vs. 171 ± 32 ms; P = 0.004), higher estimated glomerular filtration rate (55.2 ± 20.0 vs. 47.8 ± 24.7 mL/min/1.73 m2; P = 0.022), and more dilated cardiomyopathy. During a median follow‐up period of 29 months, 70 (36%) patients reached the primary endpoint and 42 (22%) patients died. Patients with IPI showed significantly better outcomes for the primary and secondary endpoints than patients without IPI. The volumetric responder ratio at 6 months after implantation was not significantly different between patients with and without IPI; however, patients who received IPI had reduced mortality even at 6 months after implantation. In the multivariate analysis, IPI was an independent predictor of the primary endpoint (hazard ratio, 0.51; 95% confidence interval, 0.27–0.97; P = 0.043). Conclusions: Immediate intensification of HF medication was achieved in 54% of CRT recipients and was significantly higher in patients without excessive QRS prolongation, preserved renal function, and dilated cardiomyopathy than others. In patients with LBBB morphology and QRS ≥ 120 ms, IPI was associated with a significantly better prognosis and fewer HF hospitalizations after CRT implantation than others. [ABSTRACT FROM AUTHOR]

Background/Objectives: Coronary artery disease, a leading global cause of death, highlights the essential need for early detection and management of modifiable cardiovascular risk factors to prevent further coronary events. Methods: This study, conducted at a major tertiary academic PCI-capable hospital in Romania from 1 January 2011 to 31 December 2013, prospectively analyzed 387 myocardial infarction with ST-segment elevation (STEMI) patients to assess the long-term management of modifiable risk factors. This study particularly focused on patients with new-onset left bundle branch block (LBBB) and compared them with a matched control group without LBBB. Results: During median follow-up periods of 9.6 years for LBBB patients and 9.2 years for those without LBBB, it was found that smoking, obesity, and dyslipidemia were prevalent in 73.80%, 71.42%, and 71.42% of the LBBB group, respectively, at baseline. Significant reductions in smoking were observed in both groups, with the LBBB group's smoking rates decreasing significantly to 61.90% (p = 0.034). Patients with LBBB more frequently achieved low-density lipoprotein cholesterol (LDLc) target levels during the follow-up period (from 71.42% to 59.52%; p = 0.026) compared to the control group (from 66.67% to 71.42%; p = 0.046). Prescription rates for dual antiplatelet therapy (DAPT), angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARBs), beta-blockers, and statins were initially high but then decreased by the follow-up. Statin use was reduced from 97.62% to 69.04% (p = 0.036) in the LBBB group and from 100% to 61.90% (p = 0.028) in the non-LBBB group. This study also highlighted moderate correlations between obesity (r = 0.627, p = 0.040) and subsequent coronary reperfusion in the LBBB group, while dyslipidemia and smoking showed very strong positive correlations across both groups (dyslipidemia: r = 0.903, p = 0.019 for LBBB; r = 0.503, p = 0.048 for non-LBBB; smoking: r = 0.888, p = 0.035 for LBBB; r = 0.517, p = 0.010 for non-LBBB). Conclusions: These findings underscore the crucial need for targeted management of modifiable risk factors, particularly focusing on dyslipidemia and smoking cessation, to improve subsequent coronary reperfusion outcomes post-STEMI, especially in patients with complicating factors like LBBB. [ABSTRACT FROM AUTHOR]

Left bundle branch block (LBBB) is an important cause of heart failure. When LBBB occurs, the excitation sequence of the left ventricle changes, leading to the change of cardiac systolic pattern, resulting in cardiac electromechanical asynchronism, and eventually heart failure. At present, there is no unified standard for the diagnosis of true LBBB, and the epidemiological characteristics are unclear. This paper will focus on a comprehensive discussion of LBBB's anatomic features, electrocardiographic manifestations, epidemiology, etiology, clinical significance and treatment.

Abstract Background Integration of a patient’s non-invasive imaging data in a digital twin (DT) of the heart can provide valuable insight into the myocardial disease substrates underlying left ventricular (LV) mechanical discoordination. However, when generating a DT, model parameters should be identifiable to obtain robust parameter estimations. In this study, we used the CircAdapt model of the human heart and circulation to find a subset of parameters which were identifiable from LV cavity volume and regional strain measurements of patients with different substrates of left bundle branch block (LBBB) and myocardial infarction (MI). To this end, we included seven patients with heart failure with reduced ejection fraction (HFrEF) and LBBB (study ID: 2018-0863, registration date: 2019–10–07), of which four were non-ischemic (LBBB-only) and three had previous MI (LBBB-MI), and six narrow QRS patients with MI (MI-only) (study ID: NL45241.041.13, registration date: 2013–11–12). Morris screening method (MSM) was applied first to find parameters which were important for LV volume, regional strain, and strain rate indices. Second, this parameter subset was iteratively reduced based on parameter identifiability and reproducibility. Parameter identifiability was based on the diaphony calculated from quasi-Monte Carlo simulations and reproducibility was based on the intraclass correlation coefficient ( $${ICC}$$ ICC ) obtained from repeated parameter estimation using dynamic multi-swarm particle swarm optimization. Goodness-of-fit was defined as the mean squared error ( $${{{\chi}}}^{{2}}$$ χ 2 ) of LV myocardial strain, strain rate, and cavity volume. Results A subset of 270 parameters remained after MSM which produced high-quality DTs of all patients ( $${{{\chi}}}^{{2}}$$ χ 2

Supraventricular tachycardia (SVT) with ventriculoatrial (VA) block can represent a diagnostic challenge. We present a case of SVT where His-His interval shortening was repeatedly observed during episodes of VA block. This novel observation is more diagnostically suggestive of atrioventricular nodal re-entrant tachycardia, as opposed to orthodromic re-entry using a nodofascicular or nodoventricular pathway where a constant His-His is recorded during episodes of VA block. (Level of Difficulty: Intermediate.).

This systematic review investigates the diagnostic and prognostic utility of coronary flow reserve (CFR) assessment through echocardiography in patients with left bundle branch block (LBBB), a condition known to complicate the clinical evaluation of coronary artery disease (CAD). The literature search was performed on PubMed, EMBASE, Web of Science, Scopus, and Google Scholar, was guided by PRISMA standards up to March 2024, and yielded six observational studies that met inclusion criteria. These studies involved a diverse population of patients with LBBB, employing echocardiographic protocols to clarify the impact of LBBB on coronary flow dynamics. The findings emphasize the importance of CFR in stratifying cardiovascular risk and guiding clinical decision‐making in patients with LBBB. Pooled results reveal that patients with LBBB and significant left anterior descending (LAD) artery stenosis exhibited a marked decrease in stress‐peak diastolic velocity (MD = ‐19.03 [‐23.58; ‐14.48] cm/s; p <.0001) and CFR (MD = ‐.60 [‐.71; ‐.50]; p <.0001), compared to those without significant LAD lesions, suggesting the efficacy of stress echocardiography CFR assessment in the identification of clinically significant CAD among the LBBB population. This review highlights the clinical relevance of echocardiography CFR assessment as a noninvasive tool for evaluating CAD and stratifying risk in the presence of LBBB and underscores the need for standardized protocols in CFR measurement. [ABSTRACT FROM AUTHOR]

The results of clinical trials show that up to one-third of patients who are eligible for cardiac resynchronization therapy (CRT) do not benefit from biventricular pacing. The reasons vary, including technical problems related to left ventricle pacing lead placement in the appropriate branch of the coronary sinus. Herein, we present a case report of a patient with heart failure with reduced ejection fraction and left bundle branch block, in whom a poor coronary sinus bed made implantation of classic biventricular CRT impossible, but in whom, alternatively, rescue-performed left bundle branch area pacing allowed effective electrical and mechanical cardiac resynchronization. The report confirms that left bundle branch area pacing may be a rational alternative in such cases. [ABSTRACT FROM AUTHOR]

Aims: TOMM40 single nucleotide polymorphism (SNP) rs2075650 consists of allelic variation c.275-31A > G and it has been linked to Alzheimer disease, apolipoprotein and cholesterol levels and other risk factors. However, data on its role in cardiovascular disorders are lacking. The first aim of the study is to evaluate mortality according to TOMM40 genotype in a cohort of selected patients affected by advanced atherosclerosis. Second aim was to investigate the relationship between Xg and AA alleles and the presence of conduction disorders and implantation of defibrillator (ICD) or pacemaker (PM) in our cohort. Materials and Methods: We enrolled 276 patients (mean age 70.16 ± 7.96 years) affected by hemodynamic significant carotid stenosis and/or ischemia of the lower limbs of II or III stadium Fontaine. We divided the population into two groups according to the genotype (Xg and AA carriers). We evaluated several electrocardiographic and echocardiographic parameters, including heart rate, rhythm, presence of right and left bundle branch block (LBBB and RBBB), PR interval, QRS duration and morphology, QTc interval, and left ventricular ejection fraction (LVEF). We clinically followed these patients for 82.53 ± 30.02 months and we evaluated the incidence of cardiovascular events, number of deaths and PM/ICD implantations. Results: We did not find a difference in total mortality between Xg and AA carriers (16.3 % vs. 19.4%; p = 0.62). However, we found a higher mortality for fatal cardiovascular events in Xg carriers (8.2% vs. 4.4%; HR = 4.53, 95% CI 1.179–17.367; p = 0.04) with respect to AA carriers. We noted a higher percentage of LBBB in Xg carriers (10.2% vs. 3.1%, p = 0.027), which was statistically significant. Presence of right bundle branch block (RBBB) was also higher in Xg (10.2% vs. 4.4%, p = 0.10), but without reaching statistically significant difference compared to AA patients. We did not observe significant differences in heart rate, presence of sinus rhythm, number of device implantations, PR and QTc intervals, QRS duration and LVEF between the two groups. At the time of enrolment, we observed a tendency for device implant in Xg carriers at a younger age compared to AA carriers (58.50 ± 0.71 y vs. 72.14 ± 11.11 y, p = 0.10). During the follow-up, we noted no statistical difference for new device implantations in Xg respect to AA carriers (8.2% vs. 3.5%; HR = 2.384, 95% CI 0.718–7.922; p = 0.156). The tendency to implant Xg at a younger age compared to AA patients was confirmed during follow-up, but without reaching a significant difference(69.50 ± 2.89 y vs. 75.63 ± 8.35 y, p = 0.074). Finally, we pointed out that Xg carriers underwent device implantation 7.27 ± 4.43 years before AA (65.83 ± 6.11 years vs. 73.10 ± 10.39 years) and that difference reached a statistically significant difference (p = 0.049) when we considered all patients, from enrollment to follow-up. Conclusions: In our study we observed that TOMM40 Xg patients affected by advanced atherosclerosis have a higher incidence of developing fatal cardiovascular events, higher incidence of LBBB and an earlier age of PM or ICD implantations, as compared to AA carriers. Further studies will be needed to evaluate the genomic contribution of TOMM40 SNPs to cardiovascular deaths and cardiac conduction diseases. [ABSTRACT FROM AUTHOR]

Background: Left bundle branch block (LBBB) induced cardiomyopathy is an increasingly recognized disease entity. However, no clinical testing has been shown to be able to predict such an occurrence. Case report: A 70‐year‐old male with a prior history of LBBB with preserved ejection fraction (EF) and no other known cardiovascular conditions presented with presyncope, high‐grade AV block, and heart failure with reduced EF (36%). His coronary angiogram was negative for any obstructive disease. No other known etiologies for cardiomyopathy were identified. Artificial intelligence‐enabled ECGs performed 6 years prior to clinical presentation consistently predicted a high probability (up to 91%) of low EF. The patient successfully underwent left bundle branch area (LBBA) pacing with correction of the underlying LBBB. Subsequent AI ECGs showed a large drop in the probability of low EF immediately after LBBA pacing to 47% and then to 3% 2 months post procedure. His heart failure symptoms markedly improved and EF normalized to 54% at the same time. Conclusions: Artificial intelligence‐enabled ECGS may help identify patients who are at risk of developing LBBB‐induced cardiomyopathy and predict the response to LBBA pacing. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) is typically attempted with biventricular (BiV) pacing. One-third of patients are nonresponders. Left bundle branch area pacing (LBBAP) has been evaluated as an alternative means. The purpose of this study was to assess the feasibility and clinical response of permanent LBBAP as an alternative to BiV pacing. Of 479 consecutive patients referred with heart failure, 50 with BiV-CRT and 51 with LBBAP-CRT were included in this analysis after study exclusions. Quality-of-Life (QoL) assessments, echocardiographic measurements, and New York Heart Association (NYHA) class were obtained at baseline and at 6-monthly intervals. There were no differences in baseline characteristics between groups (all P >.05). Clinical outcomes such as left ventricular ejection fraction, left ventricular end-systolic volume, QoL, and NYHA class were significantly improved for both pacing groups compared to baseline. The LBBAP-CRT group showed greater improvement in left ventricular ejection fraction at 6 months (P =.001) and 12 months (P =.021), accompanied by greater reduction in left ventricular end-systolic volume (P =.007). QRS duration < 120 ms (baseline 160.82 ± 21.35 ms vs 161.08 ± 24.48 ms) was achieved in 30% in the BiV-CRT group vs 71% in the LBBAP-CRT group (P ≤.001). Improvement in NYHA class (P =.031) and QoL index was greater (P =.014). Reduced heart failure admissions (P =.003) and health care utilization (P <.05) and improved lead performance (P <.001) were observed in the LBBAP-CRT group. LBBAP-CRT is feasible and effective CRT. It results into a meaningful improvement in QoL and reduction in health care utilization. This can be offered as an alternative to BiV-CRT or potentially as first-line therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Integration of a patient's non-invasive imaging data in a digital twin (DT) of the heart can provide valuable insight into the myocardial disease substrates underlying left ventricular (LV) mechanical discoordination. However, when generating a DT, model parameters should be identifiable to obtain robust parameter estimations. In this study, we used the CircAdapt model of the human heart and circulation to find a subset of parameters which were identifiable from LV cavity volume and regional strain measurements of patients with different substrates of left bundle branch block (LBBB) and myocardial infarction (MI). To this end, we included seven patients with heart failure with reduced ejection fraction (HFrEF) and LBBB (study ID: 2018-0863, registration date: 2019–10–07), of which four were non-ischemic (LBBB-only) and three had previous MI (LBBB-MI), and six narrow QRS patients with MI (MI-only) (study ID: NL45241.041.13, registration date: 2013–11–12). Morris screening method (MSM) was applied first to find parameters which were important for LV volume, regional strain, and strain rate indices. Second, this parameter subset was iteratively reduced based on parameter identifiability and reproducibility. Parameter identifiability was based on the diaphony calculated from quasi-Monte Carlo simulations and reproducibility was based on the intraclass correlation coefficient ( ICC ) obtained from repeated parameter estimation using dynamic multi-swarm particle swarm optimization. Goodness-of-fit was defined as the mean squared error ( χ 2 ) of LV myocardial strain, strain rate, and cavity volume. Results: A subset of 270 parameters remained after MSM which produced high-quality DTs of all patients ( χ 2 < 1.6), but minimum parameter reproducibility was poor ( ICC min = 0.01). Iterative reduction yielded a reproducible ( ICC min = 0.83) subset of 75 parameters, including cardiac output, global LV activation duration, regional mechanical activation delay, and regional LV myocardial constitutive properties. This reduced subset produced patient-resembling DTs ( χ 2 < 2.2), while septal-to-lateral wall workload imbalance was higher for the LBBB-only DTs than for the MI-only DTs (p < 0.05). Conclusions: By applying sensitivity and identifiability analysis, we successfully determined a parameter subset of the CircAdapt model which can be used to generate imaging-based DTs of patients with LV mechanical discoordination. Parameters were reproducibly estimated using particle swarm optimization, and derived LV myocardial work distribution was representative for the patient's underlying disease substrate. This DT technology enables patient-specific substrate characterization and can potentially be used to support clinical decision making. [ABSTRACT FROM AUTHOR]

The electrocardiographic diagnosis of acute myocardial infarction (AMI) in patients with pacemakers has always been a problem in clinical practice, causing delays in management and worse clinical outcomes. Although complete left bundle branch block (LBBB) and right ventricular pacing can produce electrocardiogram (ECG) abnormalities, specific morphological changes often allow the diagnosis of AMI or an old infarction. Case report: A 76-year-old patient with history of permanent pacemaker implantation due to a 3rd-degree atrioventricular block was admitted for chest pain. Upon admission, he was hemodynamically stable but with ECG showing pacemaker rhythm with LBBB fulfilling 2 points of Sgarbossa criteria (discordant elevation of the ST segment > 5 mm in leads V1 to V3) and ST/S ratio < -0.25 in leads V3-V4. Laboratories showed elevated troponins, integrating diagnosis of AMI, and moving on to urgent coronary angiography. A lesion on the anterior descending coronary artery was documented, and a drug-eluting stent was successfully implanted. The patient was discharged stable, asymptomatic, and with pharmacological management for secondary prevention. Conclusion: ECG identification of an AMI in patients with pacemakers is essential to initiate reperfusion therapy. Guideline recommendations are constantly changing, but an algorithm that uses hemodynamic instability and the modified Sgarbossa criteria (MSC) to decide these patients' management could be a high-sensitivity tool and allow physicians to make the best decisions without waiting for laboratory results. MSC, which are more sensitive than the original criteria, continue to be helpful in the diagnosis of AMI. Clinicians should carefully choose the appropriate MSC cut-off (ST/T Ratio -0.20 and -0.25) on a case-by-case basis. [ABSTRACT FROM AUTHOR]

Cardiac conduction involves electrical activity from one myocyte to another, creating coordinated contractions in each. Disruptions in the conducting system, such as left bundle branch block (LBBB), can result in premature activation of specific regions of the heart, leading to heart failure and increased morbidity and mortality. Structural alterations in T-tubules and the sarcoplasmic reticulum can lead to dyssynchrony, a condition that can be treated by cardiac resynchronization therapy (CRT), which stands as a cornerstone in this pathology. The heterogeneity in patient responses underscored the necessity of improving the diagnostic approach. Vectocardiography, ultra-high-frequency ECG, 3D echocardiography, and electrocardiographic imaging seem to offer advanced precision in identifying optimal candidates for CRT in addition to the classic diagnostic methods. The advent of His bundle pacing and left bundle branch pacing further refined the approach in the treatment of dyssynchrony, offering more physiological pacing modalities that promise enhanced outcomes by maintaining or restoring the natural sequence of ventricular activation. HOT-CRT emerges as a pivotal innovation combining the benefits of CRT with the precision of His bundle or left bundle branch area pacing to optimize cardiac function in a subset of patients where traditional CRT might fall short. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) mapping of the ventricular conduction system is challenging. The purpose of this study was to use ripple mapping to distinguish conduction system activation to that of adjacent myocardium in order to characterize the conduction system in the postinfarct left ventricle (LV). High-density mapping (PentaRay, CARTO) was performed during normal rhythm in patients undergoing ventricular tachycardia ablation. Ripple maps were viewed from the end of the P wave to QRS onset in 1-ms increments. Clusters of >3 ripple bars were interrogated for the presence of Purkinje potentials, which were tagged on the 3D geometry. Repeating this process allowed conduction system delineation. Maps were reviewed in 24 patients (mean 3112 ± 613 points). There were 150.9 ± 24.5 Purkinje potentials per map, at the left posterior fascicle (LPF) in 22 patients (92%) and at the left anterior fascicle (LAF) in 15 patients (63%). The LAF was shorter (41.4 vs 68.8 mm; P =.0005) and activated for a shorter duration (40.6 vs 64.9 ms; P =.002) than the LPF. Fourteen of 24 patients had left bundle branch block (LBBB), with 11 of 14 (78%) having Purkinje potential–associated breakout. There were fewer breakouts from the conduction system during LBBB (1.8 vs 3.4; 1.6 ± 0.6; P =.039) and an inverse correlation between breakout sites and QRS duration (P =.0035). We applied ripple mapping to present a detailed electroanatomic characterization of the conduction system in the postinfarct LV. Patients with broader QRS had fewer LV breakout sites from the conduction system. However, there was 3D mapping evidence of LV breakout from an intact conduction system in the majority of patients with LBBB. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Electrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%-30% of patients suffering from heart failure with reduced ejection fraction. However, predicting which LBBB patients will benefit from cardiac resynchronization therapy (CRT) or conduction system pacing remains challenging. This study aimed to establish a translational model of LBBB to enhance our understanding of its pathophysiology and improve therapeutic approaches. Methods: Fourteen male pigs underwent radiofrequency catheter ablation of the proximal LBB under fluoroscopy and ECG guidance. Comprehensive clinical assessments (12-lead ECG, bloodsampling, echocardiography, electroanatomical mapping) were conducted before LBBB induction, after 7, and 21 days. Three pigs received CRT pacemakers 7 days after LBB ablation to assess resynchronization feasibility. Results: Following proximal LBB ablation, ECGs displayed characteristic LBBB features, including QRS widening, slurring in left lateral leads, and QRS axis changes. QRS duration increased from 64.2 ± 4.2 ms to 86.6 ± 12.1 ms, and R wave peak time in V6 extended from 21.3 ± 3.6 ms to 45.7 ± 12.6 ms. Echocardiography confirmed cardiac electromechanical dyssynchrony, with septal flash appearance, prolonged septal-to-posterior-wall motion delay, and extended ventricular electromechanical delays. Electroanatomical mapping revealed a left ventricular breakthrough site shift and significantly prolonged left ventricular activation times. RF-induced LBBB persisted for 3 weeks. CRT reduced QRS duration to 75.9 ± 8.6 ms, demonstrating successful resynchronization. Conclusion: This porcine model accurately replicates the electrical and electromechanical characteristics of LBBB observed in patients. It provides a practical, cost-effective, and reproducible platform to investigate molecular and translational aspects of cardiac electromechanical dyssynchrony in a controlled and clinically relevant setting. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Typical left bundle branch block (LBBB) shows 2 peaks of the R wave, which reflect activation reaching the interventricular septum (R) and posterolateral wall (Rʹ) sequentially. The purpose of this study was to investigate the relationship among R-Rʹ interval (RRʹ), mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes in cardiac resynchronization therapy (CRT) candidates. The study enrolled 49 patients (34 men; mean age: 69 ± 11 years) with LBBB who received CRT. The LBBB definition used requires the presence of mid-QRS notching in leads V 1 , V 2 , V 5 , V 6 , I, and aVL. Baseline evaluations were QRS duration (QRSd) and RRʹ measured from the 12-lead electrocardiogram; eyeball dyssynchrony (apical rocking and septal flash) and opposing-wall delay by speckle tracking from echocardiography, and extent of viable myocardium assessed by thallium-201 single-photon emission computed tomography. Primary outcomes included the combination of all-cause death and heart failure–related hospitalization. RRʹ predicted volumetric response better than QRSd (area under the curve 0.73 vs 0.67, respectively). The long RRʹ group (≥48 ms) revealed more frequent eyeball dyssynchrony and significantly greater radial (SL) and circumferential dyssynchrony (AP and SL) and %viable segment than the short RRʹ group. In multivariate regression analysis, only RRʹ ≥48 ms was independently associated with higher event-free survival rates following CRT (hazard ratio 0.21; P =.014). These findings suggest that RRʹ in complete LBBB was associated with mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes following CRT. [ABSTRACT FROM AUTHOR]

Background: In patients with left bundle branch block (LBBB), the diagnosis of ischemia by noninvasive modalities is cumbersome. Most of them such as stress tests, nuclear imaging, and magnetic resonance imaging have limitations in the detection of ischemia in this subset. The postsystolic motion (PSM) during the isovolumetric relaxation period on tissue Doppler imaging (TDI) is a sensitive and specific marker of ischemia. We aimed to see whether the TDI parameters can detect coronary artery disease (CAD) in patients with LBBB. Materials and Methods: Patients with LBBB (n = 64) who underwent coronary angiography were divided into two groups. Group A (n = 30) included patients with left anterior descending (LAD) artery stenosis of ≥70%, and group B (n = 34) included patients without LAD stenosis. All patients underwent TDI and various myocardial tissue velocity parameters were analyzed to detect the presence of CAD. P < 0.05 was considered significant. Results: The TDI of the mid-interventricular septum showed a higher delayed amplitude of PSM (>100 ms after aortic valve closure), lower myocardial systolic (Sm), and early diastolic (Em) velocities, and a higher late diastolic (Am) velocity in group A when compared to group B (all were significant, P < 0.0001). Both the ratios Sm/PSM and Em/Am were significantly lower in group A compared to group B (P < 0.0001). On receiver operating characteristic curve analysis to predict the presence of significant LAD stenosis, the value of Sm/PSM ratio

Aim. To assess myocardial changes during left bundle branch block (LBBB) in patients with dilated cardiomyopathy (DCM) and in structurally normal hearts. Materials and methods. Seventy three patients with clinic-instrumental signs of DCM, were divided into 2 groups with LBBB (group 1; n=41) and without LBBB (group 2; n=32). Moreover, 15 patients with LBBB with no signs of structural heart diseases (group 3) and 10 healthy subjects were included in the study. Fibrosis assessment and the inflammation detection was performed by cardiovascular magnetic resonance (CMR). The inflammation in 15 patients from group 1 and 16 patients from group 2 was confirmed by endomyocardial biopsy (EMB). Moreover, the level of transforming growing factor β1was assessed in serum of all patients and healthy subjects (TGF-β1). Results. The diffuse inflammatory process was defined in 46.7% cases of group 1 according to EMB data. The frequency of inflammation detection in groups 1 and 2 was comparable in EMB analyses (p=0,64) and CMR analyses (12,2% positive cases in group 1 vs 50% in group 2; p=0,18). The frequency of focal left ventricular fibrosis and intramural scar in the interventricular septum (“stria”) was also comparable in groups 1 and 2: 16 (39%) positive cases with focal fibrosis in group 1 versus 17 (53%) cases in group 2; p=0,35 and 6 (14,6%) cases with intramural scar in group 1 versus 7 (22%) in group 2; p=0,12. Patients from group 3 demonstrated no late gadolinium enhancement on CMR images but increased TGF-β1 level in the serum. Conclusion. Focal myocardial fibrosis is not related to the LBBB. Patients with idiopathic LBBB are characterized by increased TGF-β1 level with no myocardial fibrosis. Diffuse inflammation in LBBB-DCM patients may contribute to the progression of systolic dysfunction but is not the reason for LBBB formation.

3DQRSarea is a strong marker for cardiac resynchronization therapy and can be obtained by taking the (i) summation or the (ii) difference of the areas subtended by positive and negative deflections in X, Y, Z vectorcardiographic electrocardiogram (ECG) leads. We correlated both methods with the instantaneous‐absolute‐3D‐voltage‐time‐integral (VTIQRS‐3D). 3DQRSarea consistently underestimated the VTIQRS‐3D, but the summation method was a closer and more reliable approximation. The dissimilarity was less apparent in left bundle branch block (r2 summation.996 vs. difference.972) and biventricular paced ECGs (r2.996 vs..957) but was more apparent in normal ECGs (r2.988 vs..653). [ABSTRACT FROM AUTHOR]

The left bundle branch block (LBBB) is associated with ventricular septal mid-wall fibrosis (SMF) in patients with dilated cardiomyopathy (DCM). However, whether LBBB is also associated with SMF in patients with preserved left ventricular ejection fraction (LVEF) remains unclear. We performed a retrospective study of 210 patients with preserved LVEF (male, n = 116; female, n = 94; mean age, 44 ± 17 years). LBBB was defined as QRS duration ≥140 ms for men or ≥ 130 ms for women, QS or rS in V 1 -V 2 , mid-QRS notching or slurring in at least two leads (V 1 , V 2 , V 5 , V 6 , I, and aVL). SMF determined by late gadolinium-enhancement cardiovascular magnetic resonance was defined as stripe-like or patchy mid-myocardial hyper-enhancement in the interventricular septal segments. SMF was detected in 24.8% (52/210) of these patients. The proportion of patients with SMF with LBBB was higher than the proportion of patients with SMF without LBBB (58.3% vs. 20.4%; P < 0.001). In the forward multivariate logistic analysis, LBBB (OR , 4.399; 95% CI , 1.774–10.904; P = 0.001) and age (OR , 1.028; 95% CI , 1.006–1.051; P = 0.011) were independently associated with SMF. The presence of LBBB showed a sensitivity of 27%%, specificity of 94%, positive predictive value of 58%%, and negative predictive value of 80% for the detection of SMF. LBBB was significantly associated with SMF in hospitalized patients with preserved LVEF. Screening with a resting 12‑lead ECG may help to identify patients who are at a high risk of the presence of SMF. [ABSTRACT FROM AUTHOR]

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Background: The cardiac resynchronization therapy (CRT) non‐response rate can reach 30% in heart failure (HF) patients with left bundle branch block (LBBB). This study aimed to evaluate the value of baseline q waves in leads I, V5, or V6 in predicting response to CRT in patients with HF and LBBB. Methods: Patients with HF (left ventricular ejection fraction ≤35%) and LBBB receiving CRT implantation were retrospectively enrolled. Baseline characteristics and electrocardiogram parameters, including lateral and left precordial q waves were evaluated. Non‐response to CRT was defined as the improvement of left ventricular ejection fraction (LVEF) < 5% at a 6‐month follow‐up. Results: A total of 132 patients (mean age 63.0 ± 10.4 years, 94 [71.2%] male) were included. Among them, 32 patients with q waves in leads I, V5, or V6 were classified into the qLBBB (+) group, and the rest without q waves in these leads were defined as the qLBBB (‐) group. The CRT non‐response rate in the qLBBB (+) group was markedly higher than that in the qLBBB (‐) group (68.8% vs. 33.3%, p <.001). Multivariable logistic regression analysis revealed that the presence of baseline q waves in leads I, V5, or V6 remained significantly associated with a higher rate of CRT non‐response in patients with HF and LBBB (odds ratio: 4.8, 95% confidence interval: 1.5–15.0, p =.007). Conclusion: Any q wave in leads I, V5, or V6 was an independent predictive factor for CRT non‐response in patients with HF and LBBB. [ABSTRACT FROM AUTHOR]

Aims Identifying heart failure (HF) patients who will benefit from cardiac resynchronization therapy (CRT) remains challenging. We evaluated whether virtual pacing in a digital twin (DT) of the patient's heart could be used to predict the degree of left ventricular (LV) reverse remodelling post-CRT. Methods and results Forty-five HF patients with wide QRS complex (≥130 ms) and reduced LV ejection fraction (≤35%) receiving CRT were retrospectively enrolled. Echocardiography was performed before (baseline) and 6 months after CRT implantation to obtain LV volumes and 18-segment longitudinal strain. A previously developed algorithm was used to generate 45 DTs by personalizing the CircAdapt model to each patient's baseline measurements. From each DT, baseline septal-to-lateral myocardial work difference (MWLW-S,DT) and maximum rate of LV systolic pressure rise (dP/dtmax,DT) were derived. Biventricular pacing was then simulated using patient-specific atrioventricular delay and lead location. Virtual pacing–induced changes ΔMWLW-S,DT and ΔdP/dtmax,DT were correlated with real-world LV end-systolic volume change at 6-month follow-up (ΔLVESV). The DT's baseline MWLW-S,DT and virtual pacing–induced ΔMWLW-S,DT were both significantly associated with the real patient's reverse remodelling ΔLVESV (r = −0.60, P < 0.001 and r = 0.62, P < 0.001, respectively), while correlation between ΔdP/dtmax,DT and ΔLVESV was considerably weaker (r = −0.34, P = 0.02). Conclusion Our results suggest that the reduction of septal-to-lateral work imbalance by virtual pacing in the DT can predict real-world post-CRT LV reverse remodelling. This DT approach could prove to be an additional tool in selecting HF patients for CRT and has the potential to provide valuable insights in optimization of CRT delivery. [ABSTRACT FROM AUTHOR]

Aims His-bundle pacing has emerged as a novel method to deliver cardiac resynchronization therapy (CRT). However, there are no data comparing conventional biventricular (BiV)-CRT with His-CRT with regard to effects on mechanical dyssynchrony and longitudinal contractile function. Methods and results Patients with symptomatic heart failure, left ventricular ejection fraction ≤ 35%, and left bundle branch block (LBBB) by strict ECG criteria were randomized 1:1 to His-CRT or BiV-CRT. Two-dimensional strain echocardiography was performed prior to CRT implantation and at 6 months after implantation. Differences in changes in mechanical dyssynchrony (standard deviation of time-to-peak in 12 midventricular and basal segments) and regional longitudinal strain in the six left ventricular walls were compared between the BiV-CRT and His-CRT groups. In the on-treatment analysis, 31 received BiV-CRT and 19 His-CRT. In both groups, mechanical dyssynchrony was significantly reduced after 6 months [BiV group from 120 ms (±45) to 63 ms (±22), P < 0.001, and His group from 116 ms (±54) to 49 ms (±11), P < 0.001] but no significant differences in changes could be demonstrated between groups [−9.0 ms (−36; 18), P = 0.50]. Global longitudinal strain (GLS) improved in both groups [BiV group from −9.1% (±2.7) to −10.7% (±2.6), P = 0.02, and His group from −8.6% (±2.1) to −11.1% (±2.0), P < 0.001], but no significant differences in changes could be demonstrated from baseline to follow-up [−0.9% (−2.4; −0.6), P = 0.25] between groups. There were no regional differences between groups. Conclusion In heart failure, patients with LBBB, BiV-CRT, and His-CRT have comparable effects with regard to improvements in mechanical dyssynchrony and longitudinal contractile function. [ABSTRACT FROM AUTHOR]

The state of the heart after a coronavirus disease 2019 (COVID-19, coronavirus disease 2019) is very diverse and in some cases requires a complex differential diagnosis. We described a 35-year-old smoking male patient who, by the end of the first month after COVID-19, developed left ventricular dysfunction with decrease in ejection fraction to 25-30% and persistent left bundle branch block (LBBB). Echocardiography also detected local contractility disorders. A significant increase in blood anticardiac antibody titers was noted. Myocardial biopsy revealed active lymphocytic myocarditis, coronavirus ribonucleic acid, while coronary angiography revealed extensive stenosis of the anterior interventricular artery. On the first day after balloon angioplasty and stenting, the disappearance of LBBB block was noted with the appearance of deep negative T waves in the precordial leads, which did not allow ruling out a previous myocardial infarction. As a result of treatment of heart failure and steroid therapy, the structural and functional cardiac parameters and the electrocardiography were completely normalized by the end of the second year of treatment. Only a transient LBBB remained at high loads. Cardiac computed tomography after 2 years showed no delayed contrast agent accumulation in the myocardium, and coronary stenosis up to 30%.The mechanisms of complex myocardial and coronary damage (including the role of coronaritis in the atherosclerosis progression) after COVID-19 are discussed.

Abstract Background Patients with heart failure and left bundle branch block (LBBB) may receive cardiac resynchronization therapy (CRT), but current selection criteria are imprecise, and many patients have limited treatment response. Hemodynamic forces (HDF) have been suggested as a marker for CRT response. The aim of this study was therefore to investigate left ventricular (LV) HDF as a predictive marker for LV remodeling after CRT. Methods Patients with heart failure, EF 0.87. Intragroup comparison found higher HDF ratio in systole compared to diastole for responders (p = 0.003), but not for non-responders (p = 0.8). Conclusion Hemodynamic force ratio is a potential marker for identifying patients with heart failure and LBBB who are unlikely to benefit from CRT. Larger-scale studies are required before implementation of HDF analysis into clinical practice. Graphical Abstract

IntroductionMultiple abnormal electrocardiographic findings have been documented in patients experiencing acute pulmonary embolism. Although sinus tachycardia is the most commonly encountered rhythmic disturbance, subsequent reports have highlighted other findings. These include right bundle branch block, right axis deviation, nonspecific ST segment/T wave changes, and T wave inversion in the right precordial leads. To date, only a limited number of cases involving a complete atrioventricular block have been reported in acute pulmonary embolism.Case presentationHere, we present the case of a 91-year-old woman with acute pulmonary embolism, whose initial electrocardiogram showed a complete atrioventricular block. She presented with presyncope and an initial blood pressure of 77/63 mmHg. Echocardiography confirmed signs of right ventricular dysfunction. Catheter-directed thrombolysis and a temporary pacemaker insertion were carried out sequentially. The following day, electrocardiography showed sinus rhythm with a left bundle branch block.DiscussionThe presence of a complete atrioventricular block in patients with acute pulmonary embolism serves as a clinical marker of high-risk status.

Introduction: Left bundle branch pacing has gained significant momentum in the last few years. The procedure involves deploying the lead deep inside the interventricular septum through left subclavian vein. We aimed at analyzing the feasibility, efficacy and long‐term outcome of left bundle branch pacing (LBBP) using lumen‐less lead through the right subclavian vein. Methods: This was a retrospective‐institutional, single center observational study done in consecutive patients who underwent LBBP using 3830 selectsecuretm lead. Left subclavian venous access was the primary strategy for lead implantation. Patients requiring right sided approach due to venous obstruction or persistent left superior‐vena‐cava (PLSVC) for LBBP were included in the study. Results: Right sided approach was successful in 16 out of 19 (84%) attempted patients. C315‐His catheter was used in all patients without modifying its curvature. PLSVC (n = 7), left venous obstruction (n = 7), right sided device upgradation (n = 1) and left pocket infection (n = 1) were the reasons for right sided approach. Mean follow‐up duration was 17 ± 12 months. LBBP resulted in reduction in QRS duration from 137.3 ± 37.8 ms to 122.3 ± 9.5 ms (p −.13) and increase in LV ejection fraction from 46.2 ± 16.3% to 54.4 ± 11.6% (p −.11). The mean fluoroscopy duration and radiation dose were significantly high in right sided approach (n = 16) as compared to left sided approach (n = 293). In patients requiring cardiac‐resynchronization therapy (CRT), right sided LBBP resulted in reduction in QRS duration from 171.8 ± 18.5 to 125.5 ± 11.9 ms (p −.0001) and increase in LVEF from 29.1 ± 3.8 to 45.1 ± 11.9% (p −.005). Conclusion: Right sided LBBP is feasible, safe and effective in patients requiring pacing for symptomatic bradyarrhythmia and CRT. Further development in dedicated tools for right‐sided approach would help in reducing the fluoroscopy‐duration and radiation‐dose. [ABSTRACT FROM AUTHOR]

Left bundle branch block (LBBB) pattern on the electrocardiogram includes patients with both complete conduction block in the His-Purkinje system as well as nonspecific left ventricular conduction delay without discrete block. The purpose of this study was to characterize electrocardiographic morphological features of LBBB patterns in patients with (1) LBBB after transcatheter aortic valve replacement (TAVR) and (2) LBBB correctable by conduction system pacing (CSP). Consecutive patients with post-TAVR (n = 123) or CSP-correctable LBBB (n = 58) from 2 centers were included in this retrospective evaluation. QRS durations as well as detailed morphological features, including notching and slurring, of QRS complexes in leads I, aVL, V 1 , V 2 , V 5 , and V 6 and in all 3 inferior leads were recorded. The mean age of the entire cohort was 78.3 ± 10.1 years, with 48% of the cohort being male (87/181). In the CSP-correctable group (n = 58), 14 (24.1%) underwent His-bundle pacing and 44 (75.9%) left bundle branch area pacing. A total of 17 of 181 (9.4%) of the combined cohort failed to completely meet the Strauss criteria. QRS morphology in lead 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%). Strauss criteria and QRS notching are highly prevalent in LBBB after TAVR and in LBBB correctable by CSP. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) through permanent His bundle pacing (p-HBP) normalizes interventricular conduction disorders and QRS. Similarly, there are immediate and long-term changes in repolarization, which could be prognostic of a lower risk of sudden death (SD) at follow-up. We aimed to compare the changes in different electrocardiographic (ECG) repolarization parameters related to the risk of SD before and after CRT through p-HBP. Methods: In this prospective, descriptive single-center study (May 2019 to December 2021), we compared the ECG parameters of repolarization related to SD in patients with non-ischemic dilated cardiomyopathy, left bundle branch block (LBBB), and CRT indications, at baseline and after CRT through p-HBP. Results: Forty-three patients were included. Compared to baseline, after CRT through p-HBP, there were immediate significant changes in the QT interval (ms): 445 [407.5–480] vs 410 [385–440] (p = 0.006), QT dispersion (ms): 80 [60–100] vs 40 [40–65] (p < 0.001), Tp-Te (ms): 90 [80–110] vs 80 [60–95] (p < 0.001), Tp-Te/QT ratio: 0.22 [0.19–0.23] vs 0.19 [0.16–0.21] (p < 0.001), T wave amplitude (mm): 6.25 [4.88–10] vs − 2.5 [− 7–2.25] (p < 0.001), and T wave duration (ms): 190 [157.5–200] vs 140 [120–160] (p = 0.001). In the cases of the corrected QT (Bazzett and Friederichia) and the Tp-Te dispersion, changes only became significant at 1 month post-implant (468.5 [428.8–501.5] vs 440 [410–475.25] (p = 0.015); 462.5 [420.8–488.8] vs 440 [400–452.5] (p = 0.004), and 40 [30–52.5] vs 30 [20–40] (p < 0.001), respectively) (Table 1). Finally, two parameters did not improve until 6 months post-implant: the rdT/JT index, 0.25 [0.21–0.28] baseline vs 0.20 [0.19–0.23] 6 months post-implant (p = 0.011), and the JT interval, 300 [240–340] baseline vs 280 [257–302] 6 months post-implant (p = 0.027). Additionally, most of the parameters continued improving as compared with immediate post-implantation. Conclusions: After CRT through His bundle pacing and LBBB correction, there was an improvement in all parameters of repolarization related to increased SD reported in the literature. [ABSTRACT FROM AUTHOR]

Background and Aims: Left bundle branch block (LBBB) is common after transcatheter aortic valve replacement (TAVR) and associated with a left or normal QRS axis. We aim to assess the QRS frontal plane axis shift changes during LBBB after TAVR and determine if the risk of procedure‐related high degree atrioventricular block (AVB) is affected by QRS axis shift changes. Methods and Results: In a retrospective single‐center study of 720 consecutive patients who underwent TAVR, 141 (19.6%) with normal baseline QRS duration developed a new LBBB after TAVR and constituted the study group. Most patients (59.6%) were females and the mean age of the cohort was 81.2 ± 6 years. Results: As compared with the baseline QRS axis before TAVR, the occurrence of LBBB was associated with a leftward QRS axis shift (by 40 ± 28.3°) in 73% of the study patients and a rightward (by 18.6 ± 19.4°) or no change in QRS axis in 25.6% and 1.4% of the study patients, respectively. A left QRS axis (−30°) was observed in 14.9% and 38.3% of the study patients before and after TAVR, respectively. The group of patients exhibiting a rightward or no QRS axis shift had a greater incidence of high degree AVB than the group of patients exhibiting a leftward QRS axis shift (18.4% vs. 6.8%, p =.056). Conclusion: Although post TAVR‐LBBB is associated with a leftward QRS axis shift in most patients, a non‐negligible proportion of patients (27%) exhibited a rightward or no QRS axis shift. The latter group tend to have a higher risk of developing high degree AVB. [ABSTRACT FROM AUTHOR]

We present the case of a 42 year old patient with a history of childhood lymphoma treated with chemotherapy and radiation who underwent combined aortic and mitral valve replacements and who postoperatively developed an interesting ECG which showed complete heart block and an alternating left bundle branch and narrow complex QRS pattern at a heart rate of 69 beats per minute (bpm). We discuss potential mechanisms for this interesting pattern. [ABSTRACT FROM AUTHOR]

Introduction: In left bundle branch area pacing (LBBAP), several methods allow determination of lead depth during active fixation inside the septum: among these, visualization of a Purkinje potential indicates that the subendocardial area has been reached. In LBB block (LBBB) patients, fascicular potentials are visible as presystolic only in rare conditions. Methods and Results: Since October 2022 until August 2023, LBBAP was attempted in 21 patients with LBBB at our Center: among the 18 consecutive patients (86%) in which it was successful, focusing on the terminal part of the unipolar ventricular electrogram (VEGM) recorded in the LBBA (where fixation beats occurred and conduction system (CS) capture was confirmed), we always observed discrete high‐frequency, low‐amplitude signals during spontaneous rhythm with LBBB morphology, showing a consistent coupling with the QRS onset, falling in a portion of QRS interval ranging from 58% to 80% of its overall duration, and disappearing during pacing. As found in a recently published case report, these sharp signals could represent the activation of left ventricular CS fibers, occurring passively from the septal working myocardium, and thus appearing lately in the VEGM. Conclusion: The possibility of recognizing discrete high‐frequency, low‐amplitude signals within the terminal portion of the unipolar VEGM, possibly representing left CS potentials, even in patients with LBBB, may constitute a useful additional means to notice operators about having reached the LBBA, thus helping to avoid perforation in the left ventricle. [ABSTRACT FROM AUTHOR]