Left Bundle Branch Block Research Articles

Influence of Right and Left Bundle Branch Block in Patients With Cardiogenic Shock and Cardiac Arrest.

The study investigates the prognostic impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) in patients with cardiogenic shock (CS) compared with no bundle branch block (BBB). In patients with heart failure, existence of RBBB and LBBB has influence on prognosis. Prospective registry-study. ICU of a tertiary academic hospital in Germany. Adult patients with CS. None. Consecutive patients with CS were included. The prognostic impact of RBBB and LBBB on 30-day all-cause mortality was tested within the entire cohort and in the subgroup of CS patients with cardiac arrest at admission. The final study cohort comprised 248 patients. Patients with RBBB showed the highest 30-day all-cause mortality followed by LBBB and no BBB (72.5% vs. 52.9% vs. 50.0%; log-rank p = 0.015). These findings were consistent even after solely including CS patients with cardiac arrest (90.0% vs. 73.3% vs. 62.2%; log-rank p = 0.008). After adjustment for lactate, norepinephrine, troponin I, Acute Physiology Score, Society of Cardiovascular Angiography & Interventions shock stage, and heart rate in a multivariable Cox regression analysis, RBBB still revealed a negative impact on 30-day all-cause mortality (hazard ratio [HR], 1.807; 95% CI, 1.107-2.947; p = 0.018), whereas LBBB was not associated with 30-day all-cause mortality. In this multivariable Cox regression model lactate (HR, 1.065; 95% CI, 1.018-1.115; p = 0.006), troponin I (HR, 1.003; 95% CI, 1.001-1.005; p = 0.001), and Acute Physiology Score (HR, 1.033; 95% CI, 1.001-1.066; p = 0.041) were as well associated with 30-day all-cause mortality. Finally, no association of RBBB was found with the incidence of liver or severe renal failure. Besides the Acute Physiology Score, lactate, and troponin levels, RBBB was associated with an increased 30-day all-cause mortality in consecutive CS patients with and without cardiac arrest, whereas LBBB showed no prognostic impact.

CMR characterisation of patients with heart failure and left bundle branch block

Abstract Introduction Cardiac magnetic resonance (CMR) is recommended internationally for tissue characterisation, volumetric assessment and assessment of prior myocardial infarction (1). Patients with left bundle branch block (LBBB) form a significant sub-group of individuals, however, there is limited data available to accurate determine whether LBBB is associated with any CMR-definable phenotypes. Aim We aimed to identify the distinctive cardiac magnetic resonance (CMR) features of patients with left bundle branch block (LBBB) and heart failure with reduced ejection fraction (HFrEF) of presumed non-ischaemic aetiology. Methods Participants from the MATCH (MyocArdial Tissue CHaracteristics in patients with heart failure according to glycaemic status) registry were prospectively enrolled. Exclusion criteria included: LVEF >40% at initial evaluation, established diagnosis of coronary artery disease, known presence of structural heart disease, suspected myocarditis, congenital heart disease and significantly impaired renal function. Following identification of HF, guideline-directed medical therapy was initiated based on the decision of the treating physician. LV recovery was defined as achieving ≥10% absolute improvement to a level of 40% or greater of LVEF from baseline evaluation upon the date of CMR quantification. Electrocardiograms were analysed to establish the presence or absence of LBBB. Results A total of 391 patients were recruited including 115 (29.4%) presenting with LBBB. Compared to controls, LBBB patients exhibited larger left ventricles and smaller right ventricles, but no differences were observed with respect to LVEF (35.8±12 vs. 38± 12 %, p=0.105) or right ventricular ejection fraction (RVEF). The prevalence of ischaemic scar (18.3% vs 21%, p=0.54), non-ischaemic fibrosis (25.2% vs 32.6%, p=0.15) and inducible ischaemia (6.1% vs. 7.6%, p=0.6) was comparable in patients with LBBB and those without. The overall rate of LV recovery was not significantly different between LBBB and non-LBBB patients (27.8% vs. 33%, p=0.32) from their baseline evaluation to the time of CMR assessment (70 [42 - 128] days). In the multivariate logistic regression, reduced LVEF remained an independent predictor of LV non-recovery in patients with LBBB, even after adjusting for gender and QRS duration (OR 0.93, 95%CI 0.87 – 0.99, p=0.03). In contrast, this association was not observed among patients without LBBB, whereas ischaemic scar was the primary predictor of LV non-recovery (OR 4.31, 95%CI 1.85 – 10.04, p=0.0007). Conclusion In this study patients presenting with a combination of HFrEF and LBBB had a larger LV cavity and smaller RV cavity than those without LBBB. However, there were no differences in the prevalence of ischaemic scar, non-ischaemic scar of inducible ischaemia according to the presence of absence of LBBB. Rates of LV recovery were similar between LBBB and non-LBBB patients.Clinical CMR ParametersSegmental Distributions

Effect of physical activity level on the association of LBBB, heart failure, and mortality

Abstract Background The beneficial effect of physical activity (PA) on adverse cardiovascular outcomes in patients with heart failure (HF) and left bundle branch block (LBBB) is well established. Yet, the impact of PA on individuals with LBBB without evident HF remains unexplored. Our objective is to investigate how PA modifies the outcomes of new-onset LBBB patients concerning HF-related hospitalizations and mortality. Methods Among the UK Biobank participants without a diagnosis of HF, we identified individuals with new-onset LBBB and available PA quantification. Patients were dichotomized into normal QRS and LBBB groups, following by stratification according to summed minutes of PA per week. The primary outcome was all-cause mortality, and HF-related hospitalizations. Cox proportional hazard model and Kaplan-Meier survival analysis were applied. Results The final cohort comprised 367,934 individuals, with a mean age of 56.6±8.2 years and 47% male. Among them, 3,427 (0.9%) developed new-onset LBBB, characterized by advanced age, male predominance, and higher rates of comorbidities. Median summed PA minutes per week were 100 (IQR: 125-180), with no significant difference between normal QRS and LBBB patients. Over a median follow-up of 13.8 years (IQR: 13-14.5), 26,304 patients (7.15%) died. Kaplan-Meier analysis revealed higher mortality risk with reduced PA level and/or LBBB (log-rank p<0.001 for both). Multivariate Cox analysis adjusted for age, sex, and comorbidities showed LBBB patients had over 3.5-fold increased risk of death (HR 3.67, 95% CI 3.39-3.97, p<0.001) compared to normal QRS. The association of LBBB with mortality was modified by weekly PA minutes; those with <150 minutes had nearly 40% higher risk compared to those with ≥150 minutes (HR 3.78, 95% CI 3.43–4.15, p<0.001; HR 3.4, 95% CI 2.93–3.95, p<0.001; p for interaction=0.035). The protective effect of PA was 6% among normal QRS patients, compared to 22% among individuals with LBBB (HR 0.94, 95% CI 0.91 – 0.96, p<0.001 vs. HR 0.78, 95% CI 0.66 – 0.93, p=0.004). Similar findings were observed for HF hospitalizations. Conclusions Although the correlation between LBBB and adverse cardiovascular outcomes remained consistent across both levels of physical activity (PA), it was more pronounced among patients with low PA levels. When assessing the risk in patients with newly diagnosed LBBB, particular attention should be directed towards their PA status.

Assessment of mechanical dyssynchrony can improve the new ESC-2021 guidelines for cardiac resynchronization therapy

Abstract Background In 2021, new guidelines for cardiac resynchronization therapy (CRT) were published by the European society of cardiology (ESC-2021), where the different classes of recommendations were based on a new ECG-based definition of left bundle branch block (LBBB). However, its association with reverse LV remodeling and additive prognostic value remain unknown. Aim To investigate (1) the association between the ESC-2021 CRT guidelines and reverse LV remodeling at follow up, and (2) the additive prognostic value of baseline assessment of mechanical dyssynchrony to the ESC-2021 guidelines. Methods We investigated 244 heart failure patients in sinus rhythm treated with CRT in two European centers. 70% of the population were males. Mean age was 69 ± 10 years, QRS duration: 154 ± 24 msec. Mechanical dyssynchrony at baseline was defined as the presence of apical rocking or septal flash (ApRock/SF) in 2D transthoracic echocardiography. LV volumes were measured at baseline and at 12 ± 6 months after CRT, where the amount of CRT induced reverse LV remodeling was calculated as the percent change of LVESV at follow-up compared to baseline. Results Applying the ESC-2021 LBBB definition, only 18% (n=45) of patients had LBBB. Applying the guidelines, only 14% (n=35) had class I recommendation (LBBB + QRS ≥ 150 msec), 44% (n=107) had class IIa (LBBB + QRS 130-149 msec or non-LBBB + QRS ≥ 150 msec), 29% (n=70) had class IIb (Non-LBBB + QRS 130-149 msec), and 13% (n = 33) were not recommended according to the ESC-2021 because of having baseline QRS duration between 120 and 129 msec. On the other hand, ApRock/SF was evident in 57% (n=140) of the patients. There was non-significant difference in the relative decrease in LVESV at follow up between patients with LBBB and non-LBBB applying the new LBBB definition (44% [IQR: 32-63], vs. 39%, IQR [20-57], P = 0.08, panel A). Similarly, there was no significant difference in the relative decrease in LVESV at CRT follow up among the four guideline recommendation classes, panel B. We combined presence of mechanical asynchrony at baseline with each of the guideline recommendation classes. The combination of ApRock/SF with classes IIa and IIb improved the prediction of reverse LV remodeling significantly (P<0.001 and <0.01 respectively), while adding mechanical asynchrony did not significantly improve prediction in the class I and the not-recommended subgroups. However, results of these last 2 may have been impacted by a small number of patients, panel C. Conclusion The new ESC-2021 definition of LBBB is associated with few patients with LBBB and consequently small number of patients with class I recommendation according to the new guidelines. There was weak association between the new ESC-2021 guideline classes of recommendation and reverse LV remodeling after CRT. However, baseline assessment of ApRock and SF can significantly improve the guidelines in predicting CRT outcome.

Differences in left ventricular contraction in left bundle branch block with preserved and reduced ejection fraction: an evaluation using 2-dimensional speckle tracking echocardiography

Abstract Background Left ventricular (LV) contraction in left bundle branch block (LBBB) is characterized by early septal contraction and delayed contraction of the lateral wall, but the process may differ depending on myocardial contractility in addition to the degree of conduction block. Purpose This study aimed to evaluate LV contraction in patients with LBBB by analysis of longitudinal strain (LS) and to compare it between patients with preserved LV ejection fraction (pEF: EF>50%) and reduced LV EF (rEF: EF<40%). Methods We studied 87 patients with LBBB. Fifty had pEF (EF 59±7%) with a mean QRS duration of 144±12ms, and 38 had rEF (EF: 29±4%) with a mean QRS duration of 147±12ms (p=0.32 vs. pEF). We also studied 43 patients without conduction block (Narrow-QRS; pEF, n=23; rEF, n=20). Patients with a heart rate less than 60 or greater than 80 beats/min during echocardiography or with a history of myocardial infarction were excluded. Three standard apical images were recorded, and the LS of one heartbeat starting at the beginning of the QRS was evaluated in 18 LV segments. When the strain waveform showed a negative peak during the pre-ejection period, it was identified as early systolic contraction (ESC), and the first negative peak that appeared after aortic valve opening (AVO) was identified as late systolic contraction (LSC). The time from the beginning of QRS to the peak of the LSC (Q-Peak) and the strain value at the end of the QRS were measured in each segment. Results In patients with LBBB, the septum contracted early, and ESC was seen mainly in the early contracted area. The lateral wall contraction was delayed, and the difference between the maximum and minimum Q-Peak was greater than the Narrow-QRS in the same EF category. Patients with rEF and LBBB had a larger number of segments with ESC and a smaller minimum Q-Peak than those with pEF. The difference between the maximum and minimum Q-Peak was greater for patients with rEF than for patients with pEF. Conclusions Although patients with LBBB had significant dyssynchrony due to conduction block even those with pEF, LV contractile properties were altered in patients with rEF and associated with further increased dyssynchrony.

Presence of Atrial Fibrillation (AF) is a poor prognostic marker in patients with Heart Failure with reduced Ejection Fraction (HFrEF) and Left Bundle Branch Block (LBBB)

Abstract Background Observational data indicate that between 20-30% of patients with HFrEF have LBBB. While numerous independent variables are implicated in the overall prognosis of these patients, this group of patients respond poorly to medical therapy. Presence of AF further impairs the functioning of the left ventricle by several mechanisms e.g., left atrial dilatation, decreased left ventricular filling, irregular cycle length, functional mitral regurgitation etc. Literature is sparse on the cumulative effect of AF in this group of patients. Purpose To assess the effect of AF on left ventricular ejection fraction (LVEF) and mortality in patients presenting with HFrEF and LBBB Methods Single centre, retrospective, observational study over 33 months (Jan 2021 – Sept 2023). Patients with HFrEF and LBBB (as defined by the European Society of Cardiology, 2021) identified from the heart failure database. Results (Table) N=80 Whole cohort: age 74.8 +/- 13.6 years (median:79, range 39-96); 57/80 (67.5%) males. Hypertension [41/80 (51.3%)] was most common comorbidity. Majority were on 3 drugs (23/80, 28.8%) of guideline directed medical therapy (GDMT) with ~1 in 4 patients [19/80 (23.8%)] on all 4 drugs. 32/80 (40.0%) were in AF, remainder in sinus rhythm (SR). Mean baseline LVEF: 21.8 +/- 8.4. Mean LVEF continued to be ≤35% (paired echocardiograms available in 50.0% patients) inspite of GDMT. The QRS duration continued to prolong on follow-up. Patients in AF were statistically significantly older, were less often on all 4 GDMT drugs (particularly sodium glucose transporter 2 inhibitors - SGLT2i’s), and were less likely to survive than those in SR. No difference in comorbid conditions or QRS prolongation on follow-up were seen between patients with AF versus SR. There was trend towards a larger increase in mean LVEF in patients with SR than AF. Conclusions In our experience, patients with HFrEF and LBBB continue to have a high mortality (45.0% at ~ 3 years) inspite of GDMT. AF is seen in a high percentage of patients (40.0%) in this cohort, worsening the prognosis further, with mortality nearly 3 times higher than those in SR. Aggressive management of patients with HFrEF and LBBB with, where indicated, early cardiac resynchronisation therapy (CRT) and more so, of those with AF (with +/- atrioventricular node ablation or left atrial ablation) should be considered at an early stage after diagnosis.Table

ECG as a screening tool for detection of significant functional mitral regurgitation in patients with left bundle branch block

Abstract Background Functional mitral regurgitation (FMR) may occur in the left bundle branch block (LBBB) due to mechanical left ventricular (LV) dyssynchrony, by the imbalance between the tethering and the closing forces exerted on the mitral apparatus1-3. Progressive FMR and LV remodeling result in a reciprocal worsening downward spiral and worse clinical outcomes1-3. Therefore, timely screening and follow-up of these patients to prevent the irreversible progression of FMR is required. To date, only LBBB morphology and QRS duration have been proven predictors of FMR4. Purpose This study aimed to assess the relationship between ECG parameters of LV dyssynchrony and the severity of FMR in patients with LBBB. Methods We retrospectively included 154 consecutive patients with LBBB, in sinus rhythm, who had an echocardiogram, with no more than mild organic valvular heart disease. We measured the following intraventricular dyssynchrony markers: LV activation times (LVAT), intrinsicoid deflection (ID) in lateral and aVF leads and a newly defined marker – the difference (Diff) between aVL and aVF ID’s (Diff_IDaVL_aVF). These two leads record the electrical activation of the two opposing myocardial segments adjacent to the posteromedial and anterolateral papillary muscles, respectively5 (Figure 1). Based on the severity of FMR, the patients were divided into two groups: no/mild FMR (grade II or less) (61%), and significant FMR (grade III and IV) (39%). Results In patients with significant FMR, the LVAT measured in lateral leads, the IDaVL and Diff_IDaVL_aVF were significantly longer, but IDaVF was significantly shorter compared to patients with no/mild FMR (p<0.001). Of all studied ECG parameters, the Diff_IDaVL_ aVF was the parameter that had the strongest correlation with significant FMR (r correlation coefficient 0.82, p < 0.001). In multivariable analysis the Diff_IDaVL_aVF (p = 0.010) was the only parameter independently correlated with significant FMR. On ROC analysis the best cut-off for significant FMR prediction was 55 ms (AUC of 0.99, sensitivity 90% and specificity 97%) (Figure 2). Conclusions In LBBB, a simple intraventricular dyssynchrony ECG parameter can provide insights into FMR severity. A 55 msec Diff_IDaVL_aVF identifies significant FMR that may benefit from early medical or CRT treatment to avoid progression and worse prognosis.

Long-term prognostic value of heart rate recovery in patients with left bundle branch block without inducible ischemia and without known coronary artery disease

Abstract Background Heart rate recovery (HRR) has been shown to predict cardiovascular and all-­cause morbidity and mortality. Left bundle branch block (LBBB) is often associated with significant heart disease and is often the result of underlying coronary artery disease (CAD), myocardial injury, strain or hypertrophy. However, there are insufficient data on the prognostic value of HRR in patients with LBBB without inducible ischemia and without known CAD. Aim The aim of this study was to determine the long-term prognostic value of HRR in patients with LBBB without inducible ischemia and without known CAD. Methods This retrospective study included 182 patients (64, 35.2% male gender, average age 63 ± 10 years) with LBBB and without known CAD who were referred to the SECHO test for chest pain. All the patients had negative SECHO test according the Bruce protocol. Risk factors for CAD (diabetes, smoking, hypertension, high cholesterol and positive family history of CAD), functional capacity (Metabolic Equivalents - METs) and heart rate recovery (HRR) were recorded in all patients. HRR was calculated as the difference between heart rate at the peak stress and heart rate in the first minute of rest. Slow HRR was defined as ≤18 beats/min. Median follow up of the patients was 102.5 months (IQR 68-146 months) for the occurrence of MACE (all-cause mortality, non-fatal myocardial infarction (MI), coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI)). Results Overall, 16pts (8.8%) had slow HRR. During the follow-up period 34 out of 182 patients (18.7%) had an adverse event (16 deaths, 10 non-fatal MI, 1 CABG and 7 PCI). Using the Cox regression analysis, univariate predictors of MACE were age (B=0.050, HR 1.051 [95% CI 1.011-1.093], p=0.012), hypertension (B=-1.219, HR 3.385 [95% CI 1.071-10.699], p=0.038), MET (B=-0.183, HR 0.833 [95% CI 0.706-0.982], p=0.030), diabetes (B=0.981, HR 2.667 [95% CI 1.267-5.612], p=0.010) and slow HRR (B=1.171, HR 3.225 [95% CI 1.307-7.959], p=0.011). However, in the multivariate analysis only slow HRR remained the independent predictor of MACE (B=0.974, HR 2.648 [95% CI 0.980-7.151], p=0.048). Using the Kaplan-Meier survival curve we see that the patients with slow HRR had much shorter event-free time compared to the patients with normal HRR (106.9 ± 14.9 months vs 157.9 ± 24 months, Log Rank 7.227, p=0.007) (Figure 1.). Conclusion Slow HRR is an independent long-term predictor of adverse events in patients with left bundle branch block without inducible ischemia and without known coronary artery disease.Kaplan-Meier survival curve for the MACE

Utilizing unsupervised machine learning to uncover novel phenogroups within the broad QRS complex

Abstract Background Conduction disease can manifest as a broad QRS complex on the ECG. Broad QRS is conventionally categorised as left bundle branch block (LBBB) and right bundle branch block (RBBB) or non-specific intraventricular conduction delay (IVCD), based on QRS morphology. These subgroups were coined over a century ago and have been relevant for heart failure with reduced ejection fraction and cardiac resynchronization therapy (CRT). However, there may be more precise phenogroups underlying broad QRS complexes. Purpose Using unsupervised machine learning to define novel broad QRS phenogroups and characterise them using clinical variables and disease outcomes. Methods We extracted 51 relevant features using a Variational Autoencoder from 47,456 median-beat ECGs with broad QRS intervals (QRS ≥ 130ms) from a secondary care cohort. These were input into Discriminative Dimensionality Reduction via Learning a Tree (DDRTree), a clustering method that models the continuum of heterogeneity by projecting the underlying distribution as a tree structure in a low-dimensional space, while assigning distinct branch/cluster labels. Results Six distinct phenogroups were identified within broad QRS morphologies (Figure-1). Two branches were RBBB dominant (Branch 1: more males, high-comorbidity; Branch 6: low-comorbidity/healthy-RBBB). Two branches were LBBB dominant (Branch 4: mixed IVCD with CHB burden; Branch 5: more females, CRT responders). Two branches were IVCD/mixed-phenotype (Branch 2: IVCD-dominant, high risk of future cardiovascular events; Branch 3: average/core branch). Within LBBB, Branch 4 and 5 showed similar trends with improving echocardiography profiles and CRT response when adjusted for covariates, each compared against the core branch. Branch 5 was distinct due its high risk of future HF (HR 1.19 [1.07-1.33] p < 0.01), cardiovascular death (HR 1.35 [1.20-1.50] p < 0.0001), all-cause mortality (HR 1.08 [1.01-1.16] p < 0.05) and CHB (HR 1.35 [1.16-1.56] p < 0.0001) (Figure-2). Conversely within RBBB, Branch 1 and 6 showed stark differences across various traits. Branch 1 captured a high-risk profile associated to higher risk of cardiovascular death (HR 1.37 [1.24-1.52] p < 0.0001), all-cause mortality (HR 1.20 [1.12-1.29] p < 0.0001) and CHB (HR 1.15 [1.01-1.32] p < 0.05) (Figure-2), while Branch 6 retained a low-risk phenotype. The tree dimensions also revealed relevant trends in cardiac anatomy and valvular dysfunction; the top-left region in Figure-1 associated with higher left ventricular ejection fraction and lower left ventricular end-diastolic dimension, lower left ventricular end-systolic dimension and a greater CRT response. Conclusion Through unsupervised methods we have identified conduction disease phenogroups with additive value for disease prognosis and CRT response prediction beyond traditional LBBB and RBBB labels. These novel phenogroups may help guide precision care for patients with a broad QRS complex.Figure-1Figure-2

Optimizing patient selection for cardiac resynchronization therapy in a multicenter study of Japanese patients: assessment of the MADIT-ICD benefit group

Abstract Background The MADIT-ICD benefit group, derived from ventricular tachycardia (VT)/ventricular fibrillation (VF) scores and non-arrhythmic mortality scores (Table 1), facilitates the appropriate selection of candidates for implantable cardioverter-defibrillator (ICD) therapy. While the 2021 European Society of Cardiology Guidelines have discussed the advantages and considerations of adding a defibrillator in patients undergoing cardiac resynchronization therapy (CRT), the optimal selection of CRT with or without a defibrillator remains unclear, particularly in Asian populations. This is especially relevant for primary prevention using ICD, which is characterized by fewer cases of ischemic etiology compared to Western countries. Purpose This study aimed to evaluate the utility of the MADIT-ICD benefit group in Japanese CRT patients and identify key indicators for determining the necessity of CRT with or without a defibrillator. Methods We conducted a retrospective, multicenter evaluation of 505 consecutive Japanese CRT patients enrolled between 2012 and 2020. Among these patients, 76% were male, with a mean age of 65 years and a mean body mass index of 22.5 kg/m2. Ischemic etiology was present in 25% of patients, with 20% undergoing secondary prevention. The study assessed the cumulative incidences of VT/VF and non-arrhythmic mortality based on the MADIT-ICD benefit group (lowest, intermediate, and highest). Predictors for each outcome were explored, and the MADIT-ICD benefit group was validated in the Japanese cohort. Results Of the 400 included patients, 60 (15%) were categorized into the lowest MADIT-ICD benefit group, 279 (70%) into the intermediate group, and 61 (15%) into the highest group. Over a median follow-up period of 34 months, VT/VF occurred in 4 (13%), 68 (24%), and 14 (23%) patients in the lowest, intermediate, and highest benefit groups, respectively (Gray’s test, P = 0.027, Figure 1A). Non-arrhythmic death occurred in 15 (25%), 91 (33%), and 9 (15%) patients in the lowest, intermediate, and highest benefit groups, respectively (Log-rank test, P = 0.025, Figure 1B). Multivariable analysis identified MADIT-ICD VT/VF score (hazard ratio [HR] 1.23; 95% confidence interval [CI] 1.12-1.35; P < 0.001) and left bundle branch block (LBBB) (HR 0.48; 95% CI 0.27-0.86; P = 0.014) as significant predictors for VT/VF, while MADIT-ICD non-arrhythmic mortality score (HR 1.16; 95% CI 1.07-1.27; P < 0.001), serum creatinine (Cr) (HR 1.28; 95% CI 1.13-1.45; P < 0.001), and mineral corticoid receptor antagonist (MRA) use (HR 1.84; 95% CI 1.21-2.79; P = 0.004) were significant predictors for non-arrhythmic death (Table 2). Conclusion The MADIT-ICD benefit group, in conjunction with left bundle branch block and renal function, may serve as valuable predictors for determining the necessity of cardioverter-defibrillator therapy in Japanese CRT patients.Table 1 and Figure 1

Safety of electrophysiological study in atrioventricular block risk stratification in new-onset persistent left bundle brunch block following transcathether aortic valve implantation

Abstract Background A significant percentage of patients develops a persistent complete left bundle branch block (LBBB) following TAVI. Electrophysiological (EP) study could be useful to stratify the risk of atrioventricular block (AVB) in these patients, guiding the need of follow-up and the indication of definite pacemaker. Purpose The primary objective of the study was describing the incidence of bradyarrhythmic events in the 30-day follow-up of patients with new-onset LBBB: AV block with ECG long-term monitoring system (Nuubo) in patients with negative EP study, and ≥ 5 % of ventricular stimulation in patients with positive EP study and pacemaker implantation. Methodology Observational prospective study of consecutive patients without previous permanent pacemaker implantation where transfemoral TAVI was implanted between 2021 and 2023. In case new-onset complete LBBB was present after TAVI, an EP study was performed. EP study was considered positive when His-Ventricule interval was more than 70ms, or after procainamide infusion at 10mg/kg, more than 100ms or more than double the basal HV interval. In case EP was positive, a permanent pacemaker was implanted. In case EP was negative, a 30-day follow-up with ECG long-term monitoring system (Nuubo) was performed. Results In this cohort, 266 patients without pacemaker following TAVI were included. Persistent new-onset left bundle branch block was present in 10,15% of patients (n=27). EP study was positive in 29.62% of patients (n=8), following a definite pacemaker implantation. During follow-up, only one patient (12.5%) was dependent of ventricular stimulation. The group with negative EP study (n=19) were monitored with a 30-day ECG long-term monitoring system (Nuubo). No bradyarrhythmic events were registered in this group. Conclusions Approximately one tenth of patients develop persistent new-onset LBBB after TAVI. Events were seldom in both study groups. Positive EP study patients were dependent of ventricular stimulation in 12.5% of cases, and there was no bradyarrhythmic event registered in EP negative group. EP study could be a safe tool to stratify AVB risk in new-onset LBBB following TAVI.

Interplay between strain pattern-based classification of dyssynchrony and myocardial scar in CRT patients

Abstract Introduction Echocardiography-derived septal strain patterns are valuable for predicting volumetric reverse remodelling and survival in patients undergoing cardiac resynchronization therapy (CRT). Nevertheless, presence of myocardial scarring in the left ventricle (LV) is known to attenuate CRT treatment response. Purpose This study aims to investigate the interplay between septal strain patterns and myocardial scarring in CRT candidates, and how they link to outcome after CRT. Methods In this prospective multicentre study, CRT candidates from five European institutions underwent pre-implantation assessments using speckle-tracking strain analysis on echocardiography and cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE). Dyssynchrony was graded through analysis of septal strain curves, categorizing patients into five distinct patterns, denoted as strain Stage-0 through strain Stage-4 (Fig. A). LGE of the LV wall was quantitatively assessed using CMR (as a percentage). The study endpoints were volumetric reverse remodelling (volume responder = more than 15% decrease LV end-systolic volume) after one year, and all-time all-cause mortality. Results A total of 267 patients, with a mean age of 66±11 years (69% males, 90% left bundle branch block [LBBB]) presented with an average LV ejection fraction (EF) of 30±7%. With each stepwise increase in strain stage, global LV scarring decreased (p<0.01; Fig. B) and the proportion of volume responders increased (all p<0.0001; Fig. C). ROC curves demonstrated that the predictive power of strain stages for CRT volumetric response was not significantly improved when scarring percentage was added (AUC 0.78 [95% CI: 0.69-0.83] vs. 0.81 [95% CI: 0.71-0.90]; p>0.05; Fig. D). In a multivariate cox regression model – including clinical characteristics that were significantly related to survival in univariate analysis – a patients’ strain stage was the only significant predictor of survival, also outperforming scar burden as determinant of outcome (HR 0.68; p=0.041; Fig. E). Conclusions Septal strain patterns show a strong association with the extent of reverse remodelling and outcome in CRT-treated patients. An inverse relationship is observed between pre-implant strain stages and the extent of myocardial scarring. However, scar burden did not provide incremental predictive value over the strain stages. Strain-pattern-based dyssynchrony assessment is a meaningful predictive marker which integrates information on myocardial dysfunction due to dyssynchrony as well as scar burden.

Differences in clinical features of patients with heart failure and reduced, mildly reduced, and preserved ejection fraction in a contemporary cohort: is the clinical profile changing?

Abstract Introduction Heart failure is a serious health problem and continues to have a high mortality and incidence of decompensations, despite advances in its management. The type of HF, defined by the LVEF value, has a great influence on treatment, since not all drugs and procedures have been shown to improve prognosis in the different subtypes of HF (reduced-HFrEF, mildly reduced-HFmrEF, and preserved-HFpEF). In addition, there are differences in clinical characteristics and comorbidities that may also influence these aspects, although the demographic and social changes that have occurred in recent years may have changed this perspective. Purpose To analyze in a contemporary registry of HF patients followed in specialized HF units in Spain the differences in clinical and demographic characteristics and comorbidities among the three subtypes of HF. Methods We analyzed data from the registry of the SEC-Excelente-IC quality accreditation program of the Spanish Society of Cardiology, with 1716 patients with HF included between 2019 and 2021 by 45 specialized HF units accredited by the SEC. Patients were included consecutively in two 1-month cutoffs (March and October) in that period. The clinical and demographic characteristics and comorbidities of the patients were compared according to the type of HF. Results Of the 1716 patients, 55.5% were HFrEF, 11.9% HFmrEF and 32.6% HFpEF. Figure 1 shows the main demographic and cardiovascular characteristics of the three subgroups. The median LVEFs were 30% (23-35), 45% (42-48) and 58% (53-65), respectively. Figure 2 shows the prevalence of major comorbidities. Patients with HFpEF were older and female in higher proportion, and presented a significantly higher prevalence of atrial fibrillation, valvular heart disease, obesity, hypertension, and anemia. Patients with HFrEF had a higher prevalence of coronary artery disease, smoking, admissions for HF in the previous year, and left bundle branch block. There were no differences between the three groups in the remaining comorbidities, including chronic kidney disease and chronic respiratory diseases. The characteristics of HFmrEF were intermediate between HFrEF and HFpEF (figures 1 and 2). Conclusions In our contemporary cohort of real-life HF patients, slight differences were observed between the 3 types of HF, particularly in relation to age, proportion of women, and prevalence of cardiac diseases. However, the prevalence of most of the major comorbidities did not show significant differences between the 3 groups, suggesting that a shift toward greater similarity in clinical characteristics between the 3 types of HF may be occurring.

Clinical and angiographic features of patients experiencing exercise-induced out-of-hospital cardiac arrest

Abstract Background Out-of-hospital cardiac arrest (OHCA) is a devastating condition that exhibits significant clinical heterogeneity. Previous studies have reported coronary artery disease (CAD) as the most common cause of OHCA. Possible causes of exercise-induced OHCA in patients with CAD include ST-elevation myocardial infarctions (STEMI), exercise-induced myocardial ischaemia and other triggers. We investigated whether there are differences in the clinical and angiographic features between 'exercise-induced (EX)' and 'non-exercise-induced (non-EX)' OHCA secondary to CAD. Methods In total, resuscitated 2300 patients (from 72 institutions) with OHCA due to CAD were registered within our regional CCU network database between 2010 and 2021. The population of the coverage area is 16.8 million during the day and 14.1 million at night. Patients with a trigger were grouped based on their triggering event: at rest, sleeping, eating, drinking, watching television, bathing, excretion, mild physical activity, driving, exercise and other activity. We classified the patients into 2 groups based on their triggering event as exercise: exercise (EX) group(n=169) and Non-Ex group(n=2131). The primary clinical outcome of interest was favorable 30-day neuroprognosis. Results Baseline characteristics was shown in the Table (below). Acute coronary syndrome (ACS) was the most common type of clinical presentation in each group. In ACS, the EX group had less ST elevation and/or left bundle branch block in electrocardiogram (57% vs. 68%; P=0.01), and initial good flow (TIMI grade 3) of culprit lesion in coronary artery was more frequently seen in the EX group than in the Non-EX group (23% vs. 12%; P< 0.01). A Kaplan-Meier survival curve analysis showed that EX group had favorable clinical outcome compared with Non-EX group (71% vs 58%, p<0.001:log-rank test). Multivariate analysis demonstrated that exercise-related trigger for OHCA was an independent predictor of favorable outcome (OR:0.59, 95%CI:0.38-0.90; P=0.015). Conclusion EX-OHCA had favorable clinical outcome compared with non-EX-OHCA. Reason may be that these patient present with culprit lesion that has good blood flow, possibly leading to fewer STEMI events.Baseline charactaristicComparison in Patients with ACS

Left atrial function and long-term survival after cardiac resynchronization therapy

Abstract Background Left atrial (LA) reservoir strain after CRT has been linked to long-term outcome, but the role of LA function in response to cardiac resynchronization therapy (CRT) is incompletely understood. LA dyssynchrony during left bundle branch block has negative effects on LA function beyond LA reservoir strain. We hypothesized that correction of LA dyssynchrony after CRT has added value to LA reservoir strain as a marker of long-term outcome. Purpose To explore the role of LA function in long-term survival after CRT. Methods In a recent prospective multicenter study of 168 patients, LA segmental and global strains were measured by speckle-tracking echocardiography before and 7 ± 1 months after CRT. LA reservoir strain was measured as the difference between peak and minimum global strain during the atrial cycle and LA dyssynchrony as the time delay between onset systolic stretch of the interatrial septum and LA lateral wall. Since LA reservoir strain < 18% is associated with elevated LV filling pressure, we used 18% as cutoff and for LA dyssynchrony 43 ms (mean after CRT in the present study). All-cause mortality was used as clinical endpoint during follow-up. Results After 6 years ± 21 months (mean ± SD) follow-up, 35 (21%) patients died. LA reservoir strain was significantly lower (15 ± 9% vs 20 ± 10%, p = 0.003) and LA dyssynchrony numerically higher (61 ± 68 ms vs 39 ± 69 ms, p = 0.099) in patients who died compared to survivors. LA reservoir strain ≥ 18% after CRT was associated with favorable long-term survival (HR: 0.51, 95% CI: 0.26 - 0.98) (upper panel in the Figure). LA dyssynchrony was not independently associated with mortality. However, when used in concert with LA reservoir strain ≥ 18% after CRT, it identified patients with perticularly excellent long-term survival (HR: 0.17, 95% CI: 0.05 - 0.58 vs patients with reservoir strain ≥ 18% and persistent LA dyssynchrony) (lower panel in the Figure). Patients with preserved LA reservoir strain but persistent LA dyssynchrony had similar outcome as patients with reduced LA reservoir strain (HR: 0.98, 95% CI: 0.45 - 2.12). Conclusion LA reservoir strain ≥ 18% and absence of LA dyssynchrony is associated with excellent long-term survival after CRT.LA strain after CRT and survival

Thrombolysis versus primary percutaneous coronary intervention in patients with suspected ST-elevation myocardial infarction - a SWEDEHEART observational study

Abstract Background Primary percutaneous coronary intervention (PCI) is the recommended reperfusion strategy in ST-elevation myocardial infarction (STEMI) patients provided time to reperfusion is ≤120 minutes. In patients presenting early with an estimated time to reperfusion >120 minutes, thrombolytic therapy should be considered according to European Society of Cardiology guidelines. However, there is a lack of contemporary data on patients treated with thrombolysis. Aims Our aim was to determine how often thrombolysis was administered in STEMI patients having an estimated time to reperfusion of >120 minutes and to study outcome differences between patients treated with thrombolysis compared to those treated with primary PCI. Methods We calculated transport times to nearest primary PCI centre using three-digit zip codes for each patient enrolled in the SWEDEHEART registry from 2008–2021 in the five geographic areas in Sweden routinely using thrombolysis and included those with >120 min estimated transportation time to reperfusion time. Patients without ST-elevations on prehospital ECG and ongoing chest pain as well as patients with left bundle branch block, pacemaker rhythm and patients with contraindications to thrombolysis were excluded. Patients were grouped by received reperfusion therapy with prehospital thrombolysis or no prehospital thrombolysis and studied with regard to 1- and 3-year mortality using Kaplan-Meier failure estimates and Cox regression adjusted for difference in baseline characteristics. Results A total of 1,840 patients were included of whom 1,381 (75.1%) received thrombolysis. A final diagnosis of STEMI was observed in 92.6% of patients receiving thrombolysis and 80.2% of patients treated with primary PCI. The median transport time estimate to a PCI centre was 153 minutes in both groups. Median time from onset of symptoms to reperfusion therapy was 131 minutes for the thrombolysis group and 255 minutes for the PCI group. Patients who received thrombolysis were on average 2 years younger and had fewer comorbidities such as diabetes, cancer and heart failure. Among patients treated with thrombolysis, a total of 42.7% of patients underwent rescue PCI. There was no significant difference in 365-day mortality (6.7% vs 11.8%, adjusted HR 0.84, 95% CI: 0.59-1.19, p=0.33) or 3-year mortality rates (10.3% vs 16.6%, adjusted HR 0.89, 95% CI: 0.66-1.19, p=0.44) between patients treated with thrombolysis and primary PCI groups. Conclusions In this population-based study of patients where primary PCI cannot be expeditiously used, we observed a commendable adherence rate of 75% to the ESC guidelines for thrombolysis treatment. Moreover, our findings revealed that the administration of thrombolysis was not associated with any discernible benefits or harm.Unadjusted and adjusted Cox-modelKaplan-Meier survival analysis

Functional correlates of ischemic electrocardiographic changes during stress echocardiography. data form stress echo 2030 survey

Abstract Background/Introduction Cardiac stress tests are carried out in populations with a low probability of ischemic heart disease (IHD) much more frequently than in the past. Stress ECG remains a frequently used modality for the diagnosis of IHD in vast areas of the world with limited facilities. Purpose To assess the diagnostic value of stress ECG for diagnosing IHD using inducible regional wall motion abnormalities (RWMA) on stress echocardiography (SE) as the gold standard method of diagnosis. Methods The 12-lead ECG response was retrospectively analyzed in 4317 patients (age 64±13 years, 59.6% males) undergoing SE for chronic coronary syndromes who were prospectively recruited from 39 cardiac centers between March 2021 and February 2024. Exclusion criteria were left bundle branch block or pacemaker rhythm. ECG response was considered ischemic according to standard criteria (if ST-segment deviated >1.0 mm from baseline in ≥2 contiguous leads at 80 ms from J point) during an exercise (n=2980, 69.8%), dobutamine (n = 766, 18.0%), or vasodilator (n=519, 12.2%) SE. All patients underwent a comprehensive SE protocol with an assessment of wall motion score index (WMSI), B-lines (4-site simplified score), left ventricular contractile reserve (LVCR) based on force, coronary flow velocity reserve (CFVR) in the mid-distal left anterior descending artery (LAD), and heart rate reserve (HRR). Results ECG changes occurred in 641 patients (14.8%, Group 1) for the overall studied population. Compared to patients without ECG changes (Group 2, n=3676, 85.2%), patients with ECG changes showed higher values of peak WMSI and lower values of CFVR and LVCR (see table).Amongst patients without inducible RWMA (n=3553), there were 392 (11%) patients with an ischemic ECG at stress (89% specificity). Of 764 patients with inducible RWMA during SE, 249 had an ischemic ECG trace (sensitivity 33%). In patients without inducible RWMA, those with ischemic ECG changes showed similar abnormal stress B-lines (23% vs. 21%, p=0.719), LVCR (61% vs. 63%, p=0.602), CFVR (31% vs 33%, p=0.607) and HRR (37% vs 41%, p=0.097) compared to those without ECG changes. Amongst patients with inducible RWMA and ECG changes, CFVR was significantly lower in patients with ECG changes (39.2% and 60.8%, respectively, p<0.001). Conclusions Simple standard stress ECG diagnostic value in the current era in populations with a low probability of IHD seems to be low. However, during SE, stress-induced ischemic ECG changes are associated with more extensive RWMA and blunted global LVCR, with reduced CFVR in the LAD. Therefore, analysis of ST segment changes during stress imaging studies can offer additional, significant information.

Safety profile, electrical performances and clinical outcomes of a novel leadless pacemaker; first results from real-world clinical practice in Saudi Arabia

Abstract Introduction Leadless pacemakers (LP) are emerging as an effective and safe alternative to transvenous pacemakers to reduce lead-related and pocket-related complications and to improve patient experience. A new LP system, the Aveir VR, has been approved in 2022 for US and other countries, and in 2023 for Europe, and features innovative characteristics such as the active fixation helix mechanism and the possibility to measure sensing/pacing parameters before LP deployment. Purpose Evaluate safety, electrical performances and clinical outcomes associated with the first Aveir VR LP implants in 2 Hospitals in Saudi Arabia. Methods We performed a prospective evaluation of all-comer patients who received Aveir VR LP. Decision for LP implant was based on conditions such as cardiac pacing indication, lack of upper extremity venous access, risk of device infection, and life expectancy, and using shared decision-making. Clinical and electrical data were collected at implant and at 1st and 6th month visits. Results A total of 54 patients (25 female, mean age 69 years) were included between December 2022 and October 2023. Pacemaker implant indication was AV block in 25 (46%) patients, sinus node disease in 19 (35%) patients, atrial fibrillation and slow ventricular response in 9 (17%) patients and left bundle branch block in 1 (2%) patient. Implant was successful in all attempted cases. Final device position was lower septum in 51/54 (94.4%) patients and mid-septum in 3/54 (5.6%) patients. Mean procedure time was 48±22 minutes and showed a decreasing trend as a function of operator experience with a mean of 55, 50 and 36 minutes in the first, second and third group of consecutive implants, respectively. Mean fluoroscopic time was 11±8 minutes and showed a decreasing trend as a function of operator experience with a mean of 13, 13 and 6 minutes in the first, second and third group of consecutive implants, respectively. Final device position was achieved at first attempt in 42/54 (77.8%) cases and at first or second attempt in 51/54 (94.4%) cases. At implant mean R wave sensing was 7.6±3.7 mV, mean impedance was 724±335 Ohm, mean threshold was 1.0±0.6 V at 0.4 ms. During implant there was one patient with pericardial effusion treated with pericardiocentesis. In a mean follow-up of 73 days there were no procedure-related or device-related complications, electrical parameters showed acceptable values, and all implanted devices performed as expected. Median longevity, estimated at last follow-up visit, was 19 years (interquartile range: 12-20 years). Conclusion First real-world cases of use of a novel leadless pacemaker in Saudi Arabia show optimal feasibility and good safety profile and electrical performances. Procedure and fluoroscopic times were acceptable and decreased as a function of operator experience. Longevity estimations predict very long service life-times.

Predictors for mitral regurgitation improvement in patients with pure severe aortic regurgitation undergoing transcatheter aortic valve replacement: when can kill two birds with one stone?

Abstract Objective Transcatheter aortic valve replacement (TAVR) has been recognized as a significant treatment for pure severe aortic regurgitation (PSAR). Part of patients with PSAR concurrently suffer from functional mitral regurgitation (FMR). Whether TAVR could improve FMR in patients with PSAR and the predictors have not yet been clarified. This study aims to explore predictors of FMR improvement in patients with PSAR undergoing TAVR and subsequently provide evidence for further clinical therapy. Method Patients with PSAR and FMR who underwent TAVR at Zhongshan Hospital Affiliated with Fudan University were enrolled from June 2021 to August 2023. Depending on whether FMR improved one month post-TAVR, they were divided into groups with or without FMR improvement. The baseline data, imaging results, and follow-up data of the patients were collected. Result This study included 75 patients, among whom 38 patients had improved FMR and 37 patients did not. Compared to patients without FMR improvement, more patients in the FMR-improved group were diagnosed with renal insufficiency (10.8% vs. 0%, p=0.018), left bundle branch block (8.1% vs. 0%, p= 0.037), and less right bundle branch block (0% vs. 10.5%, p=0.017). The transthoracic ultrasound examination showed that patients with FMR improvement were prone to have lower left ventricular ejection fraction (LVEF) and larger left ventricle end dimension diastole (LVEDd). A higher proportion of patients in the FMR-improved group were found to have had more moderate to severe FMR (28.9% vs. 2.7%, P=0.029). In both groups, the degree of aortic regurgitation was significantly improved during the 1-day and 1-month follow-ups post-TAVR (p<0.001). No significant differences were found in the incidence of postoperative adverse events between the two groups during the short-term follow-up. Conclusion FMR improvement is observed in approximately half of PSAR patients undergoing TAVR. A higher FMR degree, lower LVEF, and hypertension before TAVR are independent predictors of FMR improvement.Figure 1 AR and MR post TAVRTable 1 Logistic regression

Mitral regurgitation improvement following left bundle branch pacing versus right ventricular septum pacing: a dedication to postoperative amelioration of mitral regurgitation

Abstract Background Mitral regurgitation (MR) is correlated with left ventricular (LV) remodeling and LV function in patients. Left bundle branch pacing (LBBP) exhibits a significant decline in MR in left bundle branch block (LBBB) and cardiomyopathy patients. This research aims to evaluate the influence of LBBP on MR in comparison to right ventricular septal pacing (RVSP) in patients with atrioventricular block (AVB) or sick sinus syndrome (SSS). Methods Sixty consecutive patients with SSS or AVB were enrolled if they underwent pacemaker implantation via LBBP or RVSP. Patients with a history of mitral valve surgery were excluded. Echocardiogram parameters were assessed to measure MR and LV remodeling as well as LV function at baseline and follow-up. Results Thirty-six patients (60 %; mean age: 70.39 ± 14.80 years; 61.1 % male) underwent successful LBBP, and 24 patients (40 %; mean age: 71.58 ± 10.91 years; 66.7 % male) underwent RVSP. The average follow-up duration was relatively comparable between the two groups. In comparison to RVSP, LBBP demonstrated significant changes in MR area, and severity at baseline and follow-up (P<0.05). LBBP independently predicted MR amelioration in patients who underwent pacemaker implantation (HR=0.289, CI=0.087–0.9961; P=0.043). At follow-up, the LBBP subgroup with moderate/severe MR exhibited significantly shorter lead-TVA-dist, higher left atrium (LA) diameters, and mitral E/A ratio (P<0.05) compared to the none/mild MR subgroup. In LBBP with MR amelioration, LV remodeling (ΔLVEDD) was significantly enhanced compared to baseline (P=0.016). Additionally, a non-significant trend toward better improvement in LV function (ΔLVEF and ΔE/A) was observed in patients with MR amelioration. Conclusion LBBP, considered an optimal pacing technique for SSS or AVB patients, may substantially reduce MR and subsequently enhance LV remodeling and function compared to RVSP. This open, observational pilot study warrants confirmation through further investigations.Comparison between LBBP and RVSPKaplan-Meier curves for MR amelioration