Clinical implications of left anterior fascicular block for cardiac remodeling in hypertensive patients

Background Left anterior fascicular block (LAFB) has traditionally been regarded as a benign electrocardiographic finding; however, growing evidence suggests that it may reflect underlying myocardial remodeling. Hypertension is a major driver of structural and functional cardiac changes, particularly left ventricular hypertrophy (LVH) and left atrial enlargement. This study aimed to investigate the association between LAFB and detailed echocardiographic markers of cardiac remodeling, including chamber volumes and diastolic function, in patients with essential hypertension. Methods We prospectively enrolled 225 consecutive patients with essential hypertension (mean age 61.9 ± 7.8 years; 42.7% male). All patients underwent transthoracic echocardiography and 12-lead electrocardiography. LAFB was diagnosed using standard electrocardiographic criteria. Conventional echocardiographic measurements, left atrial and left ventricular volumes, tissue Doppler parameters, and indices of diastolic function were compared between patients with and without LAFB. Multivariate logistic regression analysis was performed to identify independent predictors of LAFB. Results LAFB was present in 50 patients (22.2%). Compared with patients without LAFB, those with LAFB exhibited significantly larger left atrial diameter, left atrial volume and higher left atrial volume index (38.9 ± 8.1 vs. 30.6 ± 7.6 mL/m², p < 0.001), increased interventricular septal and posterior wall thickness, and greater left ventricular mass and mass index (all p < 0.01). Left ventricular systolic function and ventricular volumes were similar between groups. Patients with LAFB showed more pronounced diastolic dysfunction, characterized by lower e′ velocities, higher E/e′ ratio, and a higher prevalence of grade II diastolic dysfunction. In multivariate analysis, left atrial diameter, left atrial volume index, left ventricular mass index, and the presence of LVH emerged as independent predictors of LAFB. Conclusion In patients with essential hypertension, LAFB is independently associated with left atrial enlargement, increased LV mass, and impaired diastolic function, supporting its association with advanced hypertensive cardiac remodeling.