Relation of intraventricular conduction delay to risk of new-onset heart failure and structural heart disease in the general population

Background: Intraventricular conduction delays (IVCDs) are hallmarks of heart failure (HF) and structural heart disease (SHD) but their prognostic value for HF and SHD is unclear. Methods: Relation of eight IVCDs and the incidence of first-time HF or SHD was studied in a nationally representative random sample of 6080 Finnish subjects aged ≥ 30 years (mean age 52.1, SD 14.5 years) who participated in the health examination including 12-lead ECG. Results: During 16.5 years’ follow up, half of the subjects with left bundle branch block (LBBB) and one third of the subjects with non-specific IVCD developed HF. After controlling for known clinical risk factors the hazard ratio (HR) for new-onset HF for LBBB was 3.29 (95% confidence interval 1.93–5.63, P < 0.001) and 3.53 for non-specific IVCD (1.65–7.55, P = 0.001). In corresponding analysis, LBBB predicted SHD with HR 2.60 (1.21–5.62, P = 0.015). Excluding subjects with history of heart disease, including coronary heart disease, did not have impact on results. Right bundle branch block and other IVCDs displayed no relation to endpoints. Conclusion: LBBB and non-specific IVCD were associated with more than three-fold risk of new-onset HF. Furthermore, LBBB was associated with novel SHD. Their presence should alert clinician even in subjects free from any known heart disease.