Background: Pro-fibrotic changes create a substrate for initiation and perpetuation of arrhythmias. PR interval prolongation ( pPR ) reflects the electrophysiological conduction disturbances in atria, while bundle branch block ( BBB ) mirrors impaired conduction in ventricles. Both pPR and BBB might be caused by fibrosis leading to remodeling processes, which can be recognized using ECG. Coronary artery disease ( CAD ) may impair blood circulation and facilitate cardiomyocytes’ death with their consequent replacement by fibrotic cells. Aims: To analyze the association between BBB and coronary artery status in the LIFE-Heart Study. We hypothesized that fibrotic patterns in ECG measured as BBB and pPR are associated with CAD. Methods: We analyzed patients with available demographic, echocardiographic, ECG and coronary catheterization data recruited at the Heart Center Leipzig between 2006 and 2014. CAD was defined as stenosis ≥50%, coronary artery sclerosis (CAS) - as plaque obstruction <50%, pPR interval as PR≥200 ms, BBB as QRS ≥120 ms. Results: In total, 1.750 patients (median age 65 (IQR 55-71) years, females 36%) were included. There were 376 (22%) patients with CAS and 669 (38%) with CAD, pPR and BBB were documented in 181 (10.3%) and 176 (10.1%) patients, respectively. There was a significant association between pPR and BBB (OR 2.70, 95%CI 1.78-4.03, p<0.001). CAD extent and origin were not associated with pPR and BBB. However, after adjustment for age and gender, CAS (OR 1.51, p=0.021) was associated with BBB. On multivariable analysis, beside age (OR 1.05, 95%CI 1.03-1.08, p<0.001), males (OR 1.72, 95%CI 1.12-2.64, p=0.013), and EF (OR 0.95, 95%CI 0.93-0.96, p<0.001), both CAS (OR 1.61, 95%CI 1.08-2.39, p=0.019), and pPR (OR 2.07, 95%CI 1.30-3.32, p=0.002) remained robustly associated with BBB. Conclusion: The prevalence of BBB and pPR was similar in LIFE-Heart Study. Patients with CAS have more often BBB than patients with CAD or normal coronary vessels. Neither CAD extent, nor origin were associated with BBB.