Association between T-wave Discordance and the Development of Heart Failure in Left Bundle Branch Block Patients: Results from the Copenhagen ECG study

Abstract Background In left bundle branch block (LBBB), discrepancies between depolarization and repolarization of the heart can be assessed by similar direction (concordant) or opposite direction (discordant) of the lateral T-waves compared to the direction of the QRS complex and by the QRS-T angle. We examined the association between discordant T-waves and high QRS-T angles for heart failure development in primary care LBBB patients. Methods Between 2001 and 2011, we identified 2540 patients from primary care with LBBB without overt heart failure. We examined the development of heart failure in relation to two ECG measures: (1) LBBB as either discordant (two or three monophasic T-waves in the opposite direction of the QRS complex in leads I, V5 or V6) or concordant, and (2) the frontal plane QRS-T angle in quartile groups. Results In total, 244 of 913 patients (26.7%) with discordant LBBB developed heart failure compared to 302 of 1627 patients (16.7%) with concordant LBBB. Multivariable Cox regression comparing discordant with concordant LBBB showed a hazard ratio (HR) of 2.58 (95% Confidence interval [CI] 1.71–3.89) for heart failure development within 30 days of follow-up and a HR of 1.45 (95%CI 1.19–1.77) after 30 days. For QRS-T angle, comparing the highest quartile (160°-180°) with the lowest quartile (0°-110°) we found a HR of 2.25 (95%CI 1.26–4.02) within 30 days and a HR of 1.67 (95%CI 1.25–2.23) after 30 days. Conclusion T-wave discordance in lateral ECG leads and a high QRS-T angle are associated with heart failure development in primary care LBBB patients.