Microbial response to Nature-Based Solutions in urban soils: A comprehensive analysis using Biolog® EcoPlates™.

The study presents a comprehensive examination of changes in soil microbial functional diversity (hereafter called microbial activity) following the implementation of Nature-Based Solutions (NBS) in urban areas. Utilizing the Biolog® EcoPlates™ technique, the study explored variations in microbial diversity in urban soil under NBSs implementation across timespan of two years. Significant differences in microbial activity were observed between control location and those with NBS implementations, with seasonal variations playing a crucial role. NBS positively impacted soil microbial activity especially at two locations: infiltration basin and wild flower meadow showing the most substantial increase after NBS implementation. The study links rainfall levels to microbial functional diversity, highlighting the influence of climatic conditions on soil microbiome. The research investigates also the utilization of different carbon sources by soil microorganisms, shedding light on the specificity of substrate utilization across seasons and locations. The results demonstrate that NBSs implementations lead to changes in substrate utilization patterns, emphasizing the positive influence of NBS on soil microbial communities. Likewise, biodiversity indices, such as Shannon-Weaver diversity (H'), Shannon Evenness Index (E), and substrate richness index (S), exhibit significant variations in response to NBS. Notably, NBS implementation positively impacted H' and E indexes, especially in infiltration basin and wild flower meadow, underlining the benefits of NBS for enhancing microbial diversity. The obtained results demonstrated valuable insight into the dynamic interactions between NBS implementation and soil microbial activity. The findings underscore the potential of NBS to positively influence soil microbial diversity in urban environments, contributing to urban sustainability and soil health. The study emphasizes the importance of monitoring soil microbial activity to assess the effectiveness of NBS interventions and guides sustainable urban development practices.

The occurrence of heavy metals and antimicrobials in sewage sludge and their predicted risk to soil - Is there anything to fear?

The study assessed the occurrence of legally-monitored heavy metals and unmonitored antimicrobials in sludge from small, medium, large and very large municipal wastewater treatment plants (WWTPs), and the predicted environmental risk and risk of resistance selection associated with sludge administration to soil. The temporal variations of the studied compounds in sludge and associated risks to soil were determined by sampling over a year. Although the highest concentrations of heavy metals were noted in sludge from the largest WWTP, i.e. from 1.50 mg/kg (mean 1.61 mg/kg) for Cd to 2188 mg/kg (mean 1332 mg/kg) for Zn, the obtained values only reached a few percent of the legal limits. The same WWTP also demonstrated lower concentrations of antimicrobials compared to the smaller ones. The highest concentrations of antimicrobials, ranging from 24.04 µg/kg for trimethoprim to 900.24 µg/kg for tetracycline, were found in the small and medium WWTPs. However, due to lack of regulations at the national and EU levels, the results cannot be compared with legal limits. Principal Component Analysis (PCA), cluster and heatmap analysis separated samples according to WWTP size. Small WWTP demonstrated correlation with antimicrobials (tetracycline, trimethoprim, clindamycin, ciprofloxacin and ofloxacin), while the large and very large WWTP revealed correlations with heavy metals (Cu and Cr). The obtained environmental risk quotients confirmed that the heavy metals did not present a threat, measured either as individual risk quotients (RQenv), cumulative risk (RQcumulative) or risk of mixture of heavy metals (RQmix-metals). In the case of antimicrobials, only tetracycline demonstrated moderate RQenv, RQcumulative and RQmix-antimicrobials in the small WWTP sludge, with values of 0.1 to 1. Our findings highlight the importance of monitoring sewage sludge before soil application, especially from small WWTPs, to reduce the potential environmental impact of antimicrobials. They also confirm our previous data regarding the environmental risk associated with various toxic compounds, including emerging contaminants, in the sludge from small WWTPs.

Serial echocardiographic evaluation of COVID-19 patients without prior history of structural heart disease: a 1-year follow-up CRACoV-HHS study.

Background: It is a well-known fact that COVID-19 affects the cardiovascular system by exacerbating heart failure in patients with preexisting conditions. However, there is a poor insight into the cardiovascular involvement and sequelae in patients without preexisting conditions. The aim of the study is to analyse the influence of COVID-19 on cardiac performance in patients without prior history of structural heart disease. The study is part of the CRACoV project, which includes a prospective design and a 12-month follow-up period. Material and methods: The study included 229 patients hospitalised with a diagnosis of COVID-19 (median age of 59 years, 81 were women). A standard clinical assessment and laboratory tests were performed in all participants. An extended echocardiographic image acquisition was performed at baseline and at a 3-, 6-, and 12-month follow-up. All analyses were performed off-line. A series of echocardiographic parameters was compared using repeated measures or Friedman analysis of variance. Results: In all subjects, the left ventricular (LV) ejection fraction at baseline was preserved [63.0%; Q1:Q3 (60.0-66.0)]. Elevated levels of high-sensitivity cardiac troponin T were detected in 21.3% of the patients, and elevated NT-proBNP levels were detected in 55.8%. At the 1-year follow-up, no significant changes were observed in the LV diameter and volume (LV 48.0 ± 5.2 vs. 47.8 ± 4.8 mm, p = 0.08), while a significant improvement of the parameters in the biventricular strain was observed (LV -19.1 ± 3.3% vs. -19.7 ± 2.5%, p = 0.01, and right ventricular -19.9 ± 4.5% vs. -23.2 ± 4.9%, p = 0.002). In addition, a decrease in the LV wall thickness was also observed (interventricular septum 10.4 ± 1.6 vs. 9.7 ± 2.0 mm, p < 0.001; LV posterior wall 9.8 ± 1.4 vs. 9.1 ± 1.5 mm, p < 0.001). Conclusions: In an acute phase of COVID-19, the elevation of cardiac biomarkers in patients with normal left ventricular ejection fraction is a frequent occurrence; however, it does not translate into clinically significant cardiac dysfunction after 1 year. The serial echocardiographic evaluations conducted in patients without preexisting structural heart disease demonstrate an overall trend towards an improved cardiac function and a reduced myocardial thickening at 1-year follow-up. This suggests that the acute cardiac consequences of COVID-19 are associated with systemic inflammation and haemodynamic stress in patients without preexisting conditions.

Between flood and drought: How cities are facing water surplus and scarcity.

Droughts and floods are weather-related hazards affecting cities in all climate zones and causing human deaths and material losses on all inhabited continents. The aim of this article is to review, analyse and discuss in detail the problems faced by urban ecosystems due to water surplus and scarcity, as well as the need of adaptation to climate change taking into account the legislation, current challenges and knowledge gaps. The literature review indicated that urban floods are much more recognised than urban droughts. Amongst floods, flash floods are currently the most challenging, which by their nature are difficult to monitor. Research and adaptation measures related to water-released hazards use cutting-edge technologies for risk assessment, decision support systems, or early warning systems, among others, but in all areas knowledge gaps for urban droughts are evident. Increasing urban retention and introducing Low Impact Development and Nature-based Solutions is a remedy for both droughts and floods in cities. There is the need to integrate flood and drought disaster risk reduction strategies and creating a holistic approach.

Left bundle branch area pacing prevents pacing induced cardiomyopathy in long-term observation.

BACKGROUND: Left bundle branch area pacing (LBBAP) is one of the methods to deliver conduction system pacing which potentially avoids the negative impact of conventional right ventricular pacing. OBJECTIVE: To assess echocardiographic outcomes in a long-term observation in patients with LBBAP implemented for bradyarrhythmia indications. METHODS AND RESULTS: A total of 151 patients with symptomatic bradycardia and LBBAP pacemaker implanted, were prospectively included in the study. Subjects with left bundle branch block and CRT indications (n = 29), ventricular pacing burden <40% (n = 11), and loss of LBBAP (n = 10) were excluded from further analysis. At baseline and the last follow-up visit, echocardiography with global longitudinal strain (GLS) assessment, 12-lead ECG, pacemaker interrogation, and blood level of NT-proBNP were performed. The median follow-up period was 23 months (15.5-28). None of the analyzed patients fulfilled the criteria for pacing induced cardiomyopathy (PICM). Improvement in left ventricular ejection fraction (LVEF) and GLS was observed in patients with LVEF <50% at baseline (n = 39): 41.4 ± 9.2% versus 45.6 ± 9.9%, and 12.9 ± 3.6% versus 15.5 ± 3.7%, respectively. In the subgroup with preserved EF (n = 62), LVEF and GLS remained stable at follow-up: 59.3 ± 5.5% versus 60 ± 5.5%, and 19 ± 3.9% versus 19.4 ± 3.8%, respectively. CONCLUSION: LBBAP prevents PICM in patients with preserved LVEF and improves left ventricle function in subjects with depressed LVEF. LBBAP might be the preferred pacing modality for bradyarrhythmia indications.

Efficient traceless modification of the P1 bacteriophage genome through homologous recombination with enrichment in double recombinants: A new perspective on the functional annotation of uncharacterized phage genes.

The advent of high-throughput omic technologies has caused unprecedented progress in research on bacteriophages, the most abundant and still the least explored entities on earth. Despite the growing number of phage genomes sequenced and the rejuvenation of interest in phage therapy, the progress in the functional analysis of phage genes is slow. Simple and efficient techniques of phage genome targeted mutagenesis that would allow one to knock out particular genes precisely without polar effects in order to study the effect of these knock-outs on phage functions are lacking. Even in the case of model phages, the functions of approximately half of their genes are unknown. P1 is an enterobacterial temperate myophage of clinical significance, which lysogenizes cells as a plasmid. It has a long history of studies, serves as a model in basic research, is a gene transfer vector, and is a source of genetic tools. Its gene products have structural homologs in several other phages. In this perspective article, we describe a simple and efficient procedure of traceless P1 genome modification that could also serve to acquire targeted mutations in the genomes of certain other temperate phages and speed up functional annotations of phage genes.

Right bundle branch pacing: Criteria, characteristics, and outcomes.

BACKGROUND: Targets for right-sided conduction system pacing (CSP) include His bundle and right bundle branch. Electrocardiographic patterns, diagnostic criteria, and outcomes of right bundle branch pacing (RBBP) are not known. OBJECTIVE: Our aims were to delineate electrocardiographic and electrophysiological characteristics of RBBP and to compare outcomes between RBBP and His bundle pacing (HBP). METHODS: Patients with confirmed right CSP were divided according to the conduction system potential to QRS complex interval at the pacing lead implantation site. Six hypothesized RBBP criteria as well as pacing parameters, echocardiographic outcomes, and all-cause mortality were analyzed. RESULTS: All analyzed criteria discriminated between HBP and RBBP: double QRS complex transition during the threshold test, selective paced QRS complex different from conducted QRS complex, stimulus to selective-QRS complex > potential-QRS complex, small increase in V6 R-wave peak time (V6RWPT) during QRS complex transition, equal capture thresholds of CSP and myocardium, and stimulus-V6RWPT > potential-V6RWPT (adopted as the diagnostic standard). According to the last criterion, RBBP was observed in 19.2% of patients (64 of 326) who had been targeted for HBP, present mainly among patients with potential to QRS complex interval <35 ms (90.6% [48 of 53]) and occasionally among the remaining patients (5.6% [16 of 273]). RBBP was characterized by longer QRS complex (by 10.5 ms), longer V6RWPT (by 11.6 ms), and better sensing (by 2.6 mV) compared with HBP. During a median follow-up duration of 29 months, no differences in capture threshold, echocardiographic outcomes, or mortality were found. CONCLUSION: RBBP has distinct features that separate it from HBP and is observed in approximately a fifth of patients in whom HBP is intended.

Left bundle branch area pacing in patients with heart failure and right bundle branch block: Results from International LBBAP Collaborative-Study Group.

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) is a novel physiologic pacing option. Objective: The aim of the study was to assess the feasibility and outcomes of LBBAP in HF patients with RBBB and reduced left ventricular systolic function, and indication for CRT or ventricular pacing. Methods: LBBAP was attempted in patients with left ventricular ejection fraction (LVEF) <50%, RBBB, HF, and indications for CRT or ventricular pacing. Procedural, pacing, and electrocardiographic parameters; clinical response (no HF hospitalization and improvement in NYHA class); and echocardiographic response (≥5% increase in ejection fraction) to LBBAP were assessed. Results: LBBAP was attempted in 121 patients and successful in 107 (88%). Patient characteristics included age 74 ± 12 years, female 25%, ischemic cardiomyopathy 49%, and ejection fraction 35% ± 9%. QRS axis at baseline was normal in 24%, left axis 63%, right axis 13%. LBBAP threshold and R-wave amplitudes were 0.8 ± 0.3 V @ 0.5 ms and 10 ± 9 mV at implant and remained stable during mean follow-up of 13 ± 8 months. LBBAP resulted in narrowing of QRS duration (156 ± 20 ms to 150 ± 24 ms (P = .01) with R-wave peak times in V6 of 85 ± 16 ms. LVEF improved from 35% ± 9% to 43% ± 12% (P < .01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female sex and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response. Conclusion: LBBAP is a feasible alternative to deliver CRT or physiologic ventricular pacing in patients with RBBB, HF, and LV dysfunction.

Functional Dissection of P1 Bacteriophage Holin-like Proteins Reveals the Biological Sense of P1 Lytic System Complexity.

P1 is a model temperate myovirus. It infects different Enterobacteriaceae and can develop lytically or form lysogens. Only some P1 adaptation strategies to propagate in different hosts are known. An atypical feature of P1 is the number and organization of cell lysis-associated genes. In addition to SAR-endolysin Lyz, holin LydA, and antiholin LydB, P1 encodes other predicted holins, LydC and LydD. LydD is encoded by the same operon as Lyz, LydA and LydB are encoded by an unlinked operon, and LydC is encoded by an operon preceding the lydA gene. By analyzing the phenotypes of P1 mutants in known or predicted holin genes, we show that all the products of these genes cooperate with the P1 SAR-endolysin in cell lysis and that LydD is a pinholin. The contributions of holins/pinholins to cell lysis by P1 appear to vary depending on the host of P1 and the bacterial growth conditions. The pattern of morphological transitions characteristic of SAR-endolysin-pinholin action dominates during lysis by wild-type P1, but in the case of lydC lydD mutant it changes to that characteristic of classical endolysin-pinholin action. We postulate that the complex lytic system facilitates P1 adaptation to various hosts and their growth conditions.

The V6-V1 interpeak interval: a novel criterion for the diagnosis of left bundle branch capture.

AIMS: We hypothesized that during left bundle branch (LBB) area pacing, the various possible combinations of direct capture/non-capture of the septal myocardium and the LBB result in distinct patterns of right and left ventricular activation. This could translate into different combinations of R-wave peak time (RWPT) in V1 and V6. Consequently, the V6-V1 interpeak interval could differentiate the three types of LBB area capture: non-selective (ns-)LBB, selective (s-)LBB, and left ventricular septal (LVS). METHODS AND RESULTS: Patients with unquestionable evidence of LBB capture were included. The V6-V1 interpeak interval, V6RWPT, and V1RWPT were compared between different types of LBB area capture. A total of 468 patients from two centres were screened, with 124 patients (239 electrocardiograms) included in the analysis. Loss of LVS capture resulted in an increase in V1RWPT by ≥15 ms but did not impact V6RWPT. Loss of LBB capture resulted in an increase in V6RWPT by ≥15 ms but only minimally influenced V1RWPT. Consequently, the V6-V1 interval was longest during s-LBB capture (62.3 ± 21.4 ms), intermediate during ns-LBB capture (41.3 ± 14.0 ms), and shortest during LVS capture (26.5 ± 8.6 ms). The optimal value of the V6-V1 interval value for the differentiation between ns-LBB and LVS capture was 33 ms (area under the receiver operating characteristic curve of 84.7%). A specificity of 100% for the diagnosis of LBB capture was obtained with a cut-off value of >44 ms. CONCLUSION: The V6-V1 interpeak interval is a promising novel criterion for the diagnosis of LBB area capture.

Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group.

BACKGROUND: Cardiac resynchronization therapy (CRT) based on the conventional biventricular pacing (BiV-CRT) technique sometimes results in broad QRS complex and suboptimal response. OBJECTIVE: We aimed to assess the feasibility and outcomes of CRT based on left bundle branch area pacing (LBBAP, in lieu of the right ventricular lead) combined with coronary venous left ventricular pacing in an international multicenter study. METHODS: LBBAP-optimized CRT (LOT-CRT) was attempted in nonconsecutive patients with CRT indications. Addition of the LBBA (or coronary venous) lead was at the discretion of the implanting physician, who was guided by suboptimal paced QRS complex, and/or on clinical grounds. RESULTS: LOT-CRT was successful in 91 of 112 patients (81%). The baseline characteristics were as follows: mean age 70 ± 11 years, female 22 (20%), left ventricular ejection fraction 28.7% ± 9.8%, left ventricular end-diastolic diameter 62 ± 9 mm, N-terminal pro-B-type natriuretic peptide level 5821 ± 8193 pg/mL, left bundle branch block 47 (42%), nonspecific intraventricular conduction delay 25 (22%), right ventricular pacing 26 (23%), and right bundle branch block 14 (12%). The procedure characteristics were as follows: mean fluoroscopy time 27.3 ± 22 minutes, LBBAP capture threshold 0.8 ± 0.5 V @ 0.5 ms, and R-wave amplitude 10 mV. LOT-CRT resulted in significantly greater narrowing of QRS complex from 182 ± 25 ms at baseline to 144 ± 22 ms (P < .0001) than did BiV-CRT (170 ± 30 ms; P < .0001) and LBBAP (162 ± 23 ms; P < .0001). At follow-up of ≥3 months, the ejection fraction improved to 37% ± 12%, left ventricular end-diastolic diameter decreased to 59 ± 9 mm, N-terminal pro-B-type natriuretic peptide level decreased to 2514 ± 3537 pg/mL, pacing parameters were stable, and clinical improvement was noted in 76% of patients (New York Heart Association class 2.9 vs 1.9). CONCLUSION: LOT-CRT is feasible and safe and provides greater electrical resynchronization as compared with BiV-CRT and could be an alternative, especially when only suboptimal electrical resynchronization is obtained with BiV-CRT. Randomized controlled trials comparing LOT-CRT and BiV-CRT are needed.

Novel approach to diagnosis of His bundle capture using individualized left ventricular lateral wall activation time as reference.

BACKGROUND: During nonselective His bundle (HB) pacing, it is clinically important to confirm His bundle capture versus right ventricular septal (RVS) capture. The present study aimed to validate the hypothesis that during HB capture, left ventricular lateral wall activation time, approximated by the V6 R-wave peak time (V6 RWPT), will not be longer than the corresponding activation time during native conduction. METHODS: Consecutive patients with permanent HB pacing were recruited; cases with abnormal His-ventricle interval or left bundle branch block were excluded. Two corresponding intervals were compared: stimulus-V6 RWPT and native HB potential-V6 RWPT. The difference between these two intervals (delta V6 RWPT), which was diagnostic of lack of HB capture, was identified using receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 723 electrocardiograms (ECGs) (219 with native rhythm, 172 with selective HB, 215 with nonselective HB, and 117 with RVS capture) were obtained from 219 patients. The native HB-V6 RWPT, nonselective-, and selective-HB paced V6 RWPT were nearly equal, while RVS V6 RWPT was 32.0 (±9.5) ms longer. The ROC curve analysis indicated delta V6 RWPT > 12 ms as diagnostic of lack of HB capture (specificity of 99.1% and sensitivity of 100%). A blinded observer correctly diagnosed 96.7% (321/332) of ECGs using this criterion. CONCLUSIONS: We validated a novel criterion for HB capture that is based on the physiological left ventricular activation time as an individualized reference. HB capture can be diagnosed when paced V6 RWPT does not exceed the value obtained during native conduction by more than 12 ms, while longer paced V6 RWPT indicates RVS capture.

Comparison of six risk scores for the prediction of atrial fibrillation recurrence after cryoballoon-based ablation and development of a simplified method, the 0-1-2 PL score.

INTRODUCTION: There are several prognostic scores for the assessment of risk of atrial fibrillation (AF) recurrence post ablation procedure. However, the use of these complex scores is difficult and the validation on different populations brought divergent results. Our goal was to compare the performance of these risk scores as the basis for the development of a new, simplified score based only on few universally predictive variables. METHODS: All cryoballoon-based AF ablations performed in a single-center over a 10-year period were prospectively analyzed with regard to AF recurrence. This served to analyze the performance of APPLE, CAAP-AF, SCALE-CryoAF, MB-LATER, CHADS2, and CHA2DS2-VASc risk scores. RESULTS: A total of 597 patients, mostly (78.1%) with paroxysmal AF were studied. Analyzed risk scores performed poorer than in the original publications because some risk factors were not predictive of AF recurrence. A simplified score named 0-1-2 PL, composed of just two universally predictive variables, AF type (1 point for Persistent AF) and LA dimension (1 point for LA size >45 mm) was developed. The 0-1-2 PL score stratified patients into low risk (0 points), intermediate risk (1 point), and high risk categories (2 points) which were related to a 2-year risk of AF recurrence of 21%, 37%, and 55%, respectively. This score had C-statistics (0.620) higher/comparable to other investigated much more complex scores. CONCLUSION: The assessment of risk of AF recurrence at the pre-ablation stage can be simplified without compromising accuracy. This could help to popularize risk assessment and standardization of AF management.

Patent foramen ovale and left atrial appendage flow velocity predict atrial fibrillation recurrence post cryoballoon ablation.

BACKGROUND: Transesophageal echocardiography (TEE) allows detailed characterization of atrial fibrillation (AF) substrate and could be valuable for predicting pulmonary vein isolation (PVI) procedure outcomes. AIMS: We aimed at assessing the value of TEE-derived left atrial (LA) and LA appendage (LAA) features as prognostic markers for AF recurrence after cryoballoon-based ablation. METHODS: Patients were enrolled using a prospective database of consecutive PVI procedures performed over a 7-year period. The following TEE-derived parameters were investigated: LAA emptying flow velocity (LAA-FV), the presence of patent foramen ovale (PFO), LA spontaneous echo contrast, and mitral regurgitation. Diagnosis of AF recurrence was based on scheduled and symptoms triggered ECG monitoring. The Cox's regression model and Kaplan-Meier survival curves were applied for statistical analysis. RESULTS: A total of 417 consecutive patients who underwent their first PVI using cryoballoon were analyzed (mean age: 59 years). AF recurrence was noted in 25.7% of patients (median follow-up of 24 months). Four TEE-derived variables had predictive values for AF recurrence: LAA-FV <45 cm/s, presence of PFO at resting state, LA spontaneous echo contrast, and mitral regurgitation. In the multivariable model, apart from the transthoracic echocardiography-derived LA size, two TEE-derived features (LAA-FV <45 cm/s and the presence of PFO) remained as independent predictors. CONCLUSIONS: This study proposed a novel TEE-derived AF recurrence risk factor - the presence of PFO - and confirmed the prognostic value of LAA flow velocity in patients undergoing cryoballoon-based AF ablation. These risk factors could be useful in the global assessment of AF recurrence risk and potentially helpful in planning the ablation strategy.

Physiology-based electrocardiographic criteria for left bundle branch capture.

BACKGROUND: During left bundle branch (LBB) area pacing, it is important to confirm that capture of the LBB, and not just capture of only adjacent left ventricular (LV) myocardium, has been achieved. OBJECTIVE: The purpose of this study was to establish electrocardiographic (ECG) criteria for LBB capture. We hypothesized that because LBB pacing results in physiological depolarization of the LV, then the native QRS can serve as a reference for diagnosis of LBB capture in the same patient. METHODS: Only patients with evidence of LBB capture (QRS morphology transition) were included. Several QRS characteristics were compared between the native rhythm and different types of LBB area capture. RESULTS: A total of 357 ECGs (124 patients) were analyzed: 118 with native rhythm, 124 with nonselective LBB capture, 69 with selective LBB capture, and 46 with LV septal capture. Our hypotheses that during LBB capture the paced V6 R-wave peak time (RWPT; measured from QRS onset) equals the native V6 RWPT and that the paced V6 RWPT (measured from the stimulus) equals the LBB potential to V6 R-wave peak interval were positively validated. Criteria based on these rules had sensitivity and specificity of 88.2%-98.0% and 85.7%-95.4%, respectively. Moreover, 100% specific V6 RWPT cutoff for LBB capture diagnosis in patients with narrow QRS/right bundle branch block was determined to be 74 ms. CONCLUSION: We showed equivalency of LV activation times on ECG during native and paced LBB conduction. Therefore, if V6 RWPT is longer during pacing, this finding is indicative of lack of LBB capture.

Left Bundle Branch Area Pacing for Cardiac Resynchronization Therapy: Results From the International LBBAP Collaborative Study Group.

OBJECTIVES: The aim of this study was to assess the feasibility and outcomes of left bundle branch area pacing (LBBAP) in patients eligible for cardiac resynchronization therapy (CRT) in an international, multicenter, collaborative study. BACKGROUND: CRT using biventricular pacing is effective in patients with heart failure and left bundle branch block (LBBB). LBBAP has been reported as an alternative option for CRT. METHODS: LBBAP was attempted in patients with left ventricular ejection fraction (LVEF) <50% and indications for CRT or pacing. Procedural outcomes, left bundle branch capture, New York Heart Association functional class, heart failure hospitalization, echocardiographic data, and lead complications were recorded. Clinical (no heart failure hospitalization and improvement in New York Heart Association functional class) and echocardiographic responses (≥5% improvement in LVEF) were assessed. RESULTS: LBBAP was attempted in 325 patients, and CRT was successfully achieved in 277 (85%) (mean age 71 ± 12 years, 35% women, ischemic cardiomyopathy in 44%). QRS configuration at baseline was LBBB in 39% and non-LBBB in 46%. Procedure and fluoroscopy duration were 105 ± 54 and 19 ± 15 min, respectively. LBBAP threshold and R-wave amplitudes were 0.6 ± 0.3 V at 0.5 ms and 10.6 ± 6 mV at implantation and remained stable during mean follow-up of 6 ± 5 months. LBBAP resulted in significant QRS narrowing from 152 ± 32 to 137 ± 22 ms (p < 0.01). LVEF improved from 33 ± 10% to 44 ± 11% (p < 0.01). Clinical and echocardiographic responses were observed in 72% and 73% of patients, respectively. Baseline LBBB (odds ratio: 3.96; 95% confidence interval: 1.64 to 9.26; p < 0.01) and left ventricular end-diastolic diameter (odds ratio: 0.62; 95% confidence interval: 0.49 to 0.79; p < 0.01) were independent predictors of echocardiographic response. CONCLUSIONS: LBBAP is feasible and safe and provides an alternative option for CRT. LBBAP provides remarkably low and stable pacing thresholds and was associated with improved clinical and echocardiographic outcomes.

Nonselective versus selective His bundle pacing: An acute intrapatient speckle-tracking strain echocardiographic study.

INTRODUCTION: We aimed to compare the acute differences in left ventricular (LV) function and mechanical synchrony during nonselective His bundle pacing (ns-HBP) versus selective His bundle pacing (s-HBP) using strain echocardiography. METHODS AND RESULTS: Consecutive patients with permanent His bundle pacing, in whom it was possible to obtain both s-HBP and ns-HBP, were studied in two centers. In each patient, echocardiography was performed sequentially during s-HBP and ns-HBP. Speckle-tracking echocardiography parameters were analyzed: Global longitudinal strain (GLS), the time delay between peak systolic strain in the basal septal and basal lateral segments (BS-BL delay), peak strain dispersion (PSD) and strain delay index. Right ventricle function was assessed using tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler velocity of the lateral tricuspid annulus (S'). A total of 69 patients (age: 75.6 ± 10.5 years; males: 75%) were enrolled. There were no differences in LV ejection fraction and GLS between s-HBP and ns-HBP modes: 59% versus 60%, and -15.6% versus -15.7%, respectively; as well as no difference in BS-BL delay and strain delay index. The PSD value was higher in the ns-HBP group than in the s-HBP group with the most pronounced difference in the basal LV segments. No differences in right ventricular function parameters (TAPSE and S') were found. CONCLUSION: The ns-HBP and s-HBP modes seem comparable regarding ventricular function. The dyssynchrony parameters were significantly higher during ns-HBP, however, the difference seems modest and clarification of its impact on LV function requires a larger long-term study.

Fixation beats: A novel marker for reaching the left bundle branch area during deep septal lead implantation.

BACKGROUND: One of the challenges of left bundle branch (LBB) pacing is placing the pacing lead deep enough in the septum to reach the LBB area, yet not too deep to avoid perforation. OBJECTIVE: The purpose of this study was to investigate whether the occurrence of the ectopic beats with qR/rsR' morphology in lead V1 (fixation beats) during lead fixation would predict whether the desired intraseptal lead depth had been reached, whereas the lack of fixation beats would indicate a too-shallow position and the need for more lead rotations. METHODS: Consecutive patients during LBB pacing device implantation were analyzed retrospectively and then prospectively with respect to the occurrence of fixation beats during each episode of lead rotation. We compared the presence of fixation beats during the lead rotation event directly before the LBB area depth was reached vs during the events before intermediate/unsuccessful positions. RESULTS: A total of 339 patients and 1278 lead rotation events were analyzed. In the retrospective phase, fixation beats were observed in 327 of 339 final lead positions and in 9 of 939 intermediate lead positions (P <.001). Sensitivity, specificity, and positive and negative predictive values of the fixation beats as a marker for reaching the LBB area were 96.4%, 97.3%, 97.3%, and 96.5%, respectively. In the prospective, fixation beats-guided implantation phase, fixation beats were observed in all patients and only at the LBB capture depth. CONCLUSION: Monitoring fixation beats during deep septal lead deployment can facilitate the procedure and possibly increase the safety of lead implantation.

Programmed deep septal stimulation: A novel maneuver for the diagnosis of left bundle branch capture during permanent pacing.

INTRODUCTION: Permanent deep septal stimulation with capture of the left bundle branch (LBB) enables maintenance/restoration of the physiological activation of the left ventricle. However, it is almost always accompanied by the simultaneous engagement of the local septal myocardium, resulting in a fused (nonselective) QRS complex, therefore, confirmation of LBB capture remains difficult. METHODS: We hypothesized that programmed extrastimulus technique can differentiate nonselective LBB capture from myocardial-only capture as the effective refractory period (ERP) of the myocardium is different from the ERP of the LBB. Consecutive patients undergoing pacemaker implantation underwent programmed stimulation delivered from the lead implanted in a deep septal position. Responses to programmed stimulation were categorized on the basis of sudden change in the QRS morphology of the extrastimuli, observed when ERP of LBB or myocardium was encroached upon, as: "myocardial," "selective LBB," or nondiagnostic (unequivocal change of QRS morphology). RESULTS: Programmed deep septal stimulation was performed 269 times in 143 patients; in every patient with the use of a basic drive train of 600 milliseconds and in 126 patients also during intrinsic rhythm. The average septal-myocardial refractory period was shorter than the LBB refractory period: 263.0 ± 34.4 vs 318.0 ± 37.4 milliseconds. Responses diagnostic for LBB capture ("myocardial" or "selective LBB") were observed in 114 (79.7%) of patients. CONCLUSIONS: A novel maneuver for the confirmation of LBB capture during deep septal stimulation was developed and found to enable definitive diagnosis by visualization of both components of the paced QRS complex: selective paced LBB QRS and myocardial-only paced QRS.