Prognostic significance of isolated left bundle branch block in patients presenting with chest pain without prior cardiometabolic disease

BACKGROUND: Left bundle branch block (LBBB) is a cardiac abnormality frequently associated with structural heart disease and adverse cardiovascular outcomes. However, its prognostic significance in patients without prior cardiometabolic disease remains unclear. OBJECTIVE: To evaluate cardiovascular outcomes in patients presenting with chest pain with versus without LBBB in the absence of prior cardiometabolic or structural heart disease. METHODS: We conducted a retrospective cohort study using TriNetX. Adults presenting with chest pain were divided into two cohorts: patients with LBBB and patients without LBBB. Patients with prior cardiometabolic or structural heart disease were excluded. Propensity score matching was performed, yielding 12,035 patients in each cohort. Outcomes included myocardial infarction, heart failure, and incident heart disease. RESULTS: After matching, patients with LBBB had higher rates of myocardial infarction compared with patients without LBBB (3.8%vs 1.4%, p<0.001). Heart failure was also more common in the LBBB cohort (13.2%vs 4.5%, p<0.001). Incident heart disease occurred in 3.4% of patients with LBBB compared with 0.9% of patients without LBBB (p<0.001). Kaplan-Meier analysis demonstrated significantly worse event-free survival for myocardial infarction, heart failure, and heart disease among patients with LBBB. CONCLUSION: Among patients presenting with chest pain without prior cardiometabolic or structural heart disease, LBBB was associated with increased risks of MI, HF, and heart disease. These findings suggest an association between LBBB and adverse cardiovascular outcomes in this population.