Left Bundle Branch Block ECG Characteristics in the Evaluation of Acute Coronary Syndrome

Purpose of the study: The goal of this study is to evaluate the relationship of electrocardiogram (ECG) findings with clinical outcomes in a cohort of patients with left bundle branch block (LBBB) who are being evaluated for acute coronary syndrome (ACS) in the Emergency Department (ED). Background and significance: The significance of specific ECG findings in patients with LBBB being evaluated for ACS has been inadequately studied, and this gap in knowledge is a barrier to optimal management of this population. Due to the speed, availability, low cost, and non-invasive nature of the ECG, it would be ideal to identify ECG characteristics that help to risk stratify these patients in order to inform clinical decision-making, reduce unnecessary invasive testing, and conserve resources. Methods: In this prospective observational study the investigators will identify a consecutive series of adult patients with LBBB presenting to the ED with suspicion of ACS. The investigators will collect data including demographics, cardiac risk factors, initial ECG measurements, lab and radiographic results, procedure results, and clinical outcomes such as 30-day death or myocardial infarction (MI). The investigators will analyze the data using a cohort study design to calculate odds ratios between ECG characteristics and the outcomes of interest.