Left Anterior Fascicular Block as a Predictor of Outcomes and Reduced Cardiac Functional Improvement in Heart Failure

Although preliminary studies have elucidated the clinical relevance of left anterior fascicular block (LAFB) in the general population, its specific impact on disease progression, cardiac functional deterioration, and adverse outcomes in heart failure patients remains underexplored. This study evaluated the short-term prognostic value of LAFB in hospitalized heart failure patients and its influence on cardiac functional improvement.

This prospective cohort study enrolled 291 hospitalized heart failure patients from Beijing Anzhen Hospital. Patients were categorized into LAFB (n = 78) and no-LAFB (n = 213) groups based on electrocardiographic findings using the Minnesota Code classification. The primary composite endpoint was all-cause mortality and heart failure readmission at 6 months. Secondary endpoints included changes in left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. Kaplan-Meier survival analysis and multivariate Cox regression were performed to assess prognostic associations.

Patients with LAFB were older (70.46 ± 12.88 vs. 64.98 ± 13.42 years, p = 0.002) and had worse baseline cardiac function, with lower LVEF (30.86 ± 11.10% vs. 33.80 ± 8.49%, p = 0.036) and higher NT-proBNP levels (2397.31 ± 634.24 vs. 2161.23 ± 612.14 pg/mL, p = 0.004). Kaplan-Meier analysis showed worse event-free survival in the LAFB group (log-rank p = 0.012). Multivariate Cox regression indicated that the absence of LAFB was associated with a reduced risk of the primary composite endpoint (hazard ratio [HR] 0.48, 95% confidence interval [95% CI]: 0.23-0.99, p = 0.048). At 6 months, the no-LAFB group exhibited greater LVEF improvement (between-group difference 2.94%, 95% CI: 0.55-5.33) and more pronounced reverse remodeling.

LAFB is an independent predictor of adverse outcomes in hospitalized heart failure patients and is associated with reduced cardiac functional recovery, highlighting its potential for risk stratification and individualized therapeutic strategies.