Left Bundle Branch Block

This study investigates a new way to diagnose severe heart attacks in patients who have a specific electrical heart pattern called a Left Bundle Branch Block (LBBB). When patients present to the emergency department with chest pain, doctors routinely perform an electrocardiogram (ECG) to check for a heart attack. However, the presence of an LBBB can alter the heart's electrical signals on the ECG, effectively masking or hiding the typical signs of an ongoing acute coronary occlusion (a completely blocked artery). This making it highly challenging for emergency physicians to make an accurate and rapid diagnosis. The primary purpose of this prospective and observational research is to develop and evaluate an artificial intelligence/machine learning (ML) model that can analyze digital 12-lead ECG signals to accurately predict a true blocked coronary artery in patients with LBBB. The machine learning model will analyze raw digital ECG waveforms to detect subtle, microscopic patterns that might be missed by the human eye. To confirm the accuracy of the model, its predictions will be compared directly with invasive coronary angiography results, which is the gold standard reference method used to visualize blocked vessels. Additionally, the study aims to evaluate if the model can differentiate between a true heart attack caused by a blocked artery (Type 1 MI) and other non-occlusive conditions that cause elevated heart enzymes (Type 2 MI). Ultimately, the investigators intend to determine whether integrating this machine learning tool into emergency care can safely reduce the rate of unnecessary emergency invasive procedures for patients who do not have a true coronary blockage.

This study will utilize 3D mapping as a tool to explore electro-anatomical and electrocardiographic characteristics of the Left Bundle Branch Area. We plan on prospectively reviewing the data found from 3D mapping the left bundle branch implantation cases and using the data to improve understanding of electro-anatomical characteristics of this area for a better definition of the implantation target and depth.

Heart failure (HF) is the most common nosology encountered in clinical practice. Its incidence and prevalence increase exponentially with increasing age and it is associated with increased mortality, more frequent hospitalization and decreased quality of life. An initial approach to the treatment of HF patients with reduced left ventricular (LV) systolic function and left bundle branch block (LBBB) was implantation of cardioresynchronization device using biventricular pacing. This has resulted in long-term clinical benefits such as improved quality of life, increased functional capacity, reduced HF hospitalizations and overall mortality. However, conventional cardiac resynchronization therapy (CRT) is effective in only 70% of patients. And the remaining 30% of patients are non-responders to conventional CRT. Subsequently, His bundle pacing (HBP) has been developed to achieve the same results. According to other studies HBP has showed greater improvement in hemodynamic parameters than with conventional biventricular CRT. But, nevertheless, there are significant clinical troubles with HBP. In this regard, in 2017, the left bundle branch pacing (LBBP) was developed, which demonstrated clinical advantages compared to biventricular CRT. This method has become an alternative to HBP due to the stimulation of LBB outside the blocking site, a stable pacing threshold and a narrow QRS duration. A series of case reports and observational studies have demonstrated the efficacy and safety of LBBP in patients with CRT indications. However, it is not enough data about CRT with LBBP effectiveness in LV remodeling, reducing mortality and complications. According to our hypothesis, CRT with LBBP compared with conventional biventricular CRT will significantly improve the clinical outcomes and reverse LV remodeling in patients with chronic HF with reduced LV ejection fraction and reduce the number of non-responders to conventional CRT.

The main objective of the project is to demonstrate that in patients with heart failure and QRS complex of nonRBBB morphology lasting over 130 ms, UHF-ECG can differentiate patients with trueLBBB from IVCD better than existing approaches based on the assessment of QRS complex morphology and duration from 12-lead ECG. Another goal of the proposed study is to demonstrate that trueLBBB patients will benefit more from CRT using left bundle branch pacing than from CRT using biventricular pacing. The final aim of the project is to demonstrate that the echocardiographic and clinical response in patients with intraventricular conduction disturbance will be dependent on the degree of reduction in ventricular dyssynchrony after CRT.

The purpose of this study is to show that Electrocardiogram Ambulatory Monitoring-guided strategy is superior to ElectroPhysiological Study on the rate of alive patients with an appropriate Pacemaker implantation/non-implantation, at 12 months after randomization, in patients with New Onset Persistent Left Bundle Branch Block after Transcatheter Aortic Valve Implantation.

Cardiac resynchronization therapy (CRT) is an effective therapeutic strategy in patients with symptomatic heart failure (HF) patients with LVEF of ≤35% and left bundle branch block (LBBB). However, approximately one-third of CRT-recipients do not improve after therapy (non-responders), despite meeting the required criteria. Previous studies have documented that the positive respons to CRT is related to the delayed electrical activation of the left ventricle in patients with LBBB. It has also been illustrated that non-ischemic CRT-candidates with LBBB demonstrate lower regional myocardial blood flow and metabolism in the septum. Additionally, it has been suggested that LBBB can lead to impaired coronary blood flow in the left anterior descending artery (LAD). This observation is based on an echocardiography-based study, that showed that the percentage of diastolic flow duration (%DD) in LAD was shorter in patients with LBBB compared to the control-group and patients with right-ventricular pacing. It has been demonstrated that CRT has positive effects on septal myocardial perfusion in patients with HF and LBBB. The dominant hypothesis explaining this phenomenon is built on improved septal myocardial work after CRT-implantation, which leads to increased myocardial energy and therefore increased myocardial perfusion. In contrast, it has been suggested that due to re-established synchronous left ventricular electrical activation, CRT reduces the septal intramyocardial pressure in early diastole, leading to a relatively longer antegrade flow duration in LAD. Therefore, the aim of the study is to evaluate the effect of CRT on coronary blood flow in LAD in patients with non-ischemic HF and LBBB. The investigators hypothesize that increased LV-function after CRT not only is due to resynchronized LV ejection and filling, but also improved coronary flow. The study aims to enroll 60 patients with heart failure due to non-ischemic dilated cardiomyopathy, LBBB, with or without CRT. All patients meeting the criteria will be recruited from the outpatient clinic at the Department of Cardiology, Aalborg University Hospital. Invasive flow measurements in the LAD, including fractional flow reserve (FFR), absolute coronary flow and -reserve will be conducted with the CRT on and off, respectively.

The primary hypothesis of the proposed study is that an electrophysiology-based algorithmic approach is superior to standard clinical follow-up with 30-day monitoring in reducing the combined endpoint of syncope, hospitalization, and death in patients in patients with new of left bundle branch block following transcatheter aortic valve implantation (TAVI).

Transcatheter aortic valve replacement (TAVR) has become an established alternative for the treatment of severe symptomatic aortic stenosis irrespective of surgical risk. The development of new-onset left bundle branch block (LBBB) is the most common complication, which impairs outcomes after TAVR. Glucocorticoid has been proven safe and effective in arrythmia after cardiac surgery. The anti-inflammatory effect of glucocorticoid may alleviate the occurrence of LBBB and thus the prognosis. EAGLE-TAVR is a multi-center, randomized, double blind, placebo-controlled trial. A total of 200 patients selected to undergo TAVR will be randomized in a 1:1 ratio to the treatment with intravenous Methylprednisolone 1mg/kg/day or placebo for 3 days started from the day of the procedure. According to the definition of the Valve Academic Research Consortium 3, persistent LBBB is defined as present LBBB at discharge or \>7 days post-TAVR. The primary endpoint is the occurrence of new-onset LBBB at 30 days post TAVR.

Heart failure (HF) is the most common nosology encountered in clinical practice. Its incidence and prevalence increase exponentially with increasing age and it is associated with the increased mortality, more frequent hospitalization and decreased quality of life. An initial approach to the treatment of HF patients with reduced left ventricular (LV) systolic function and left bundle branch block (LBBB) was implantation of device for cardiac resynchronization therapy using biventricular pacing. This has resulted in long-term clinical benefits such as improved quality of life, increased functional capacity, reduced HF hospitalizations and overall mortality. However, conventional cardiac resynchronization therapy (CRT) is effective in only 70% of patients. And the remaining 30% of patients are non-responders to conventional CRT. Cardiac conduction system pacing is currently a promising technique for these patients. Particularly, His bundle pacing (HBP) has been developed to achieve the same results. According to other studies HBP has shown greater improvement in hemodynamic parameters comparing with conventional biventricular CRT. But, nevertheless, there are significant clinical troubles with HBP, especially high pacing threshold. In this regard, in 2017, the left bundle branch pacing (LBBP) was developed, which demonstrated clinical advantages compared to conventional biventricular CRT. Also, since 2019, left bundle branch pacing-optimized CRT (LBBPO CRT) has been used in clinical practice. These methods have become an alternative to HBP due to the stimulation of LBB outside the blocking site, a stable pacing threshold and a narrow QRS complex duration on electrocardiogram. A series of case reports and observational studies have demonstrated the efficacy and safety of LBBP and LBBPO CRT in patients with CRT indications. However, it is not enough data about impact of CRT with LBBP and combined CRT with LBBP and LV pacing on myocardial remodeling, reducing mortality and complications. According to our hypothesis, CRT with LBBP and combined CRT with LBBP and LV pacing compared with conventional biventricular pacing will significantly improve the clinical outcomes and reverse myocardial remodeling in patients who are non-responders to biventricular CRT with HF, reduced LV ejection fraction and with indications to CRT devices with defibrillator function (CRT-D) or one of the CRT-D leads replacement.

The objective of this prospective, multicenter controlled study is to assess the feasibility of a patient-tailored implantation by creating a cloud-based pre-procedural multimodality CRT-roadmap by integration of 3D images from 3D activation sequence from ECG, and coronary venous anatomy from cardiac computed tomography. This CRT-roadmap will be used to guide LV lead placement to a coronary vein in an electrically late-activated region. Study Hypothesis: At least 75% of patients undergoing a CRT implantation guided by non-invasive electrical and venous anatomy assessment (XSPLINE technology) will show a reduction of left ventricular end-systolic volume of 15% or more at 6-month evaluation.

Right ventricular pacing causes ventricular dyssynchrony and may be associated with impaired outcome. In the last decade, several approaches for more physiological pacing became available and were implemented in the latest guidelines. However, compared to conventional device implantation, cardiac resynchronization, His bundle pacing and left bundle area pacing remain demanding procedures in the individual case. Goal of the single center observational "Pace conduct" study is to evaluate implantation success, safety and outcome of pacing methods that maintain physiologic ventricular activation.

The goal of this observational study is to evaluate the clinical characteristics of patients undergoing permanent cardiac pacing and to compare procedural efficacy and safety of different implantation approaches in the clinical practice of the participating centres. The contribution of non-fluoroscopic anatomical and electrophysiological reconstruction systems to device implantation procedures will also be evaluated. Participants \[patients over 18 years old with an indication to receive a definitive pacemaker/intracardiac defibrillator implant\] will receive a permanent cardiac pacing implant as requested according to European Society of Cardiology (ESC) guidelines; the investigators will evaluate procedural efficacy and safety of different implantation approaches.

Patients with left bundle branch block have an increased risk for the development of heart-failure and death. However, risk factors for unfavorable outcomes are still poorly defined. This study aims to identify echocardiographic parameters and ECG characteristics by machine learning in order to develop individual risk assessment